JP2004504448A - Molten Al2O3-rare earth oxide-ZrO2 eutectic material, abrasive particles, abrasive article, and methods of making and using them - Google Patents

Abstract

Al ₂ O ₃ - melt crystalline eutectic material comprising a rare earth oxide -ZrO ₂ eutectic. Examples of useful articles that include a molten eutectic material include fibers and abrasive particles. It is possible to incorporate molten abrasive particles into abrasive products such as coated abrasives, bonded abrasives, nonwoven abrasives and abrasive brushes.

Description

【０１５０】
比較例Ｈ
（ａ）１４４．５ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１４７．４ｇの酸化セリウム（ＩＶ）（ＣｅＯ_２）粉末（Ａｌｄｒｉｃｈ　Ｃｈｅｍｉｃａｌ　Ｃｏｍｐａｎｙ，Ｉｎｃ．から得たもの）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１３７．５ｇの蒸留水をポリエチレン瓶に投入したことと、（ｂ）粉末が、７５モル％のＡｌ_２Ｏ_３および２５モル％のＣｅ_２Ｏ_３を生じさせる量で存在したことを除き、比較例Ａに記載された通り比較例Ｈ溶融材料および研磨剤粒子を調製した。溶融材料の色は濃い黄色−緑色であった。
【０１５１】
図１２は、比較例Ｈ溶融材料の磨き断面（比較例Ａに記載された通り調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。コロニーのサイズは約５〜３０マイクロメートルであった。比較例Ｈ材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＣｅＡｌＯ_３および結晶質ＣｅＯ_２であり、暗い部分が結晶質ＣｅＡｌ_１１Ｏ_１８であったことが考えられる。磨き断面で観察されたこれらの相の幅は約０．５マイクロメートル以下であった。さらに、樹枝状突起の形で存在する大きな一次結晶（ＣｅＡｌＯ_３および／またはＣｅＯ_２であると考えられる）は磨き断面の一部の領域において観察され、ＣｅＡｌＯ_３および／またはＣｅＯ_２に富む組成に向けた厳密な共晶組成からの組成の起きうる偏りを示唆した。
【０１５２】
比較例Ｉ
（ａ）１４６．５ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１４７．４ｇの酸化ジスプロシウム粉末（Ａｌｄｒｉｃｈ　Ｃｈｅｍｉｃａｌ　Ｃｏｍｐａｎｙ，Ｉｎｃ．から得たもの）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１３６．３ｇの蒸留水をポリエチレン瓶に投入したことと、（ｂ）粉末が、７８モル％のＡｌ_２Ｏ_３および２２モル％のＤｙ_２Ｏ_３を生じさせる量で存在したことを除き、比較例Ａに記載された通り比較例Ｉ溶融材料および研磨剤粒子を調製した。溶融材料の色は白色であった。
【０１５３】
図１３は、比較例Ｉ溶融材料の磨き断面（比較例Ａに記載された通り調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。コロニーのサイズは約５〜２０マイクロメートルであった。比較例Ｉ材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質Ｄｙ_３Ａｌ_５Ｏ_１２であり、暗い部分がα−Ａｌ_２Ｏ_３であったことが考えられる。磨き断面で観察されたこれらの相の幅は約１マイクロメートル以下であった。一次結晶は観察されなかった。
【０１５４】
比較例Ｊ
（ａ）１４６．３ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１４８．４ｇの酸化イッテルビウム粉末（Ａｌｄｒｉｃｈ　Ｃｈｅｍｉｃａｌ　Ｃｏｍｐａｎｙ，Ｉｎｃ．から得たもの）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１３９．６ｇの蒸留水をポリエチレン瓶に投入したことと、（ｂ）粉末が、７８．６モル％のＡｌ_２Ｏ_３および２１．４モル％のＹｂ_２Ｏ_３を生じさせる量で存在したことを除き、比較例Ａに記載された通り比較例Ｊ溶融材料および研磨剤粒子を調製した。溶融材料の色は灰色であった。
【０１５５】
図１４は、比較例Ｊ溶融材料の磨き断面（比較例Ａに記載された通り調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。コロニーのサイズは約５〜２５マイクロメートルであった。比較例Ｊ材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質Ｙｂ_３Ａｌ_５Ｏ_１２であり、暗い部分がα−Ａｌ_２Ｏ_３であったことが考えられる。磨き断面で観察されたこれらの相の幅は約１マイクロメートル以下であった。さらに、樹枝状突起の形で存在する大きな一次結晶（α−Ａｌ_２Ｏ_３であると考えられる）は磨き断面の一部の領域において観察され、Ａｌ_２Ｏ_３に富む組成に向けた厳密な共晶組成からの組成の起きうる偏りを示唆した。
【０１５６】
比較例Ｋ
（ａ）１４９．５ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１４９．４ｇのイットリア−安定化酸化ジルコニア粉末（９４重量％のＺｒＯ_２（＋ＨｆＯ_２）および５．４重量％のＹ_２Ｏ_３の公称組成のもの、ジョージア州マリエッタのＺｉｒｃｏｎｉａ　Ｓａｌｅｓ，Ｉｎｃ．から商品名「ＨＳＹ３．０」で得たもの）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１３６．５ｇの蒸留水をポリエチレン瓶に投入したことと、（ｂ）粉末が、５４．８モル％のＡｌ_２Ｏ_３および４５．２モル％のＺｒＯ_２を生じさせる量で存在したことを除き、比較例Ａに記載された通り比較例Ｋ溶融材料および研磨剤粒子を調製した。溶融材料の色は白色であった。
【０１５７】
図１５は、比較例Ｋ溶融材料の磨き断面（比較例Ａに記載された通り調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。コロニーのサイズは約５〜４０マイクロメートルであった。比較例Ｋ材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＺｒＯ_２であり、暗い部分がα−Ａｌ_２Ｏ_３であったことが考えられる。磨き断面で観察されたこれらの相の幅は約０．５マイクロメートル以下であった。
【０１５８】
比較例Ｋの平均微小硬度は、１５．３ＧＰａであると比較例Ｂで上述したように決定した。
【０１５９】
幾つかの比較例Ｋ粒子を白金るつぼに入れて加熱し、５０℃／時間で１０００℃に加熱し、（空気中で）１０００℃で４時間にわたり保持し、その後、約１００℃／時間で室温に冷却した。加熱後の研磨剤粒子の色は白であった。加熱後の研磨剤粒子の平均微小硬度は１５．０ＧＰａであった。二次電子モードのＳＥＭを用いて、微小硬度測定のために調製された磨き断面を検査した。加熱前の比較例Ｋ材料のＳＥＭ顕微鏡写真を図２０に示している。加熱後に観察された微小構造は、加熱前に観察された微小構造と実質的に同じであった。
【０１６０】
約２θ＝３０度で立方晶および／または正方晶反射の１１１のピーク強度を約２θ＝２８度で単斜晶反射の１１１のピーク強度と比較することにより、上述した熱処理前および熱処理後の比較例Ｋ材料中に存在する相を定性的に測定するために、比較例Ｆに関して上で記載されたような別の粉末Ｘ線回折を用いた。熱処理しなかった比較例Ｋ材料は、熱処理前および熱処理後に立方晶および／または正方晶ジルコニアを主として含んでいた（すなわち、Ｘ線回折結果で顕著な相違は認められなかった）。
【０１６１】
幾つかの比較例Ｋ粒子をまた白金るつぼに入れて加熱し、５０℃／時間で１０００℃に加熱し、（空気中で）１０００℃で８時間にわたり保持し、その後、約１００℃／時間で室温に冷却した。加熱後の研磨剤粒子の色は白色であった。加熱後の研磨剤粒子の平均微小硬度は１５．０ＧＰａであった。二次電子モードのＳＥＭを用いて、微小硬度測定のために調製された磨き断面を検査した。加熱後に観察された微小構造は、加熱前に観察された微小構造とはわずかだけ異なっていた。加熱後の比較例ＫのＳＥＭ顕微鏡写真を図２１に示している。一般にＺｒＯ_２の一次結晶付近で幾つかの割れが熱処理材料中に観察された。
【０１６２】
比較例Ｂ、Ｃ、ＦおよびＫ研磨剤粒子／材料の示差走査熱分析（ＤＴＡ）および熱重量分析（ＴＧＡ）
示差走査熱分析（ＤＴＡ）および熱重量分析（ＴＧＡ）を比較例Ｂ、Ｃ、ＦおよびＫ研磨剤粒子／材料の各々について行った。各材料を乳鉢と乳棒で粉砕し、４００〜５００マイクロメートルサイズ範囲内にある粒子を保持するように篩った。
【０１６３】
篩ったサンプルの各々についてＤＴＡ／ＴＧＡ試験を行った（ドイツ国セルブのＮｅｔｚｓｃｈ　Ｉｎｓｔｒｕｍｅｎｔｓから商品名「ＮＥＴＺＳＣＨ　ＳＴＡ４０９ＤＴＡ／ＴＧＡ」で得た計器を用いて）。１００マイクロリットルＡｌ_２Ｏ_３サンプルホールダーに入れた篩った各サンプルの量は、それぞれ１２７．９マイクログラム（比較例Ｂ）、１２５．８マイクログラム（比較例Ｋ）、１２７．３マイクログラム（比較例Ｂ）であった。室温（約２５℃）から１３００℃まで１０℃／分の速度において静止空気中で各サンプルを加熱した。
【０１６４】
図４を参照すると、線１６７は、比較例Ｂ材料についてプロットされたＤＴＡデータである。線１６９はプロットされたＴＧＡデータである。図５を参照すると、線１９７は、比較例Ｃ材料についてプロットされたＤＴＡデータである。線１９９はプロットされたＴＧＡデータである。図６を参照すると、線１７７は比較例Ｋ材料についてプロットされたＤＴＡデータである。線１７９はプロットされたＴＧＡデータである。図７を参照すると、線１８７は比較例Ｆ材料についてプロットされたＤＴＡデータである。線１８９はプロットされたＴＧＡデータである。ＴＧＡ試験を通したサンプルの重量変化は、比較例Ｂについては０．２２％、比較例Ｃについては０．２２％、比較例Ｋについては０．７３％および比較例Ｆについては１．１６％であった。
【０１６５】
実施例１
１２２．４ｇのアルミナ粉末（「ＡＰＡ−０．５」）、酸化ガドリニウム粉末の代わりに１３２．６ｇの酸化イッテルビウム粉末（Ａｌｄｒｉｃｈ　Ｃｈｅｍｉｃａｌ　Ｃｏｍｐａｎｙ，Ｉｎｃ．から得たもの）、４５ｇの酸化ジルコニウム粉末（１００重量％のＺｒＯ_２（＋ＨｆＯ_２）の公称組成のもの、ジョージア州マリエッタのＺｉｒｃｏｎｉａ　Ｓａｌｅｓ，Ｉｎｃ．から商品名「ＤＫ−２」で得たもの）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１４０．２ｇの蒸留水をポリエチレン瓶に投入したこと除き、比較例Ａに記載された通り実施例１溶融材料および研磨剤粒子を調製した。溶融材料の色は白色−灰色であった。
【０１６６】
図２２は、実施例１材料の磨き断面（比較例Ａに記載された通り調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。コロニーのサイズは約５〜２５マイクロメートルであった。実施例１材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質Ｙｂ_３Ａｌ_５Ｏ_１２であり、暗い部分が結晶質α−Ａｌ_２Ｏ_３であったことが考えられる。ＺｒＯ_２微結晶の形状は顕微鏡写真上では容易に判別されなかった。磨き断面で観察されたこれらの相の幅は約１マイクロメートル以下であった。
【０１６７】
実施例２
１２７．２５ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１２７．７５ｇの酸化ガドリニウム粉末（Ｍｏｌｙｃｏｒｐ，Ｉｎｃ．から得たもの）、４５ｇの酸化ジルコニウム粉末（「ＤＫ−２」）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１５０ｇの蒸留水をポリエチレン瓶に投入したこと除き、比較例Ａに記載された通り実施例２溶融材料、研磨剤粒子およびディスクを調製した。
【０１６８】
図２３は、実施例２溶融材料の磨き断面（比較例Ａに記載された通り調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は共晶誘導微小構造を示している。実施例２材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＧｄＡｌＯ_３であり、暗い部分がα−Ａｌ_２Ｏ_３であったことが考えられる。ＺｒＯ_２微結晶の形状は顕微鏡写真上では容易に判別されなかった。磨き断面で観察された相の結晶の幅は約１マイクロメートル以下であった。
【０１６９】
実施例３
１２４．５ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１２５．３ｇの酸化ジスプロシウム粉末（Ａｌｄｒｉｃｈ　Ｃｈｅｍｉｃａｌ　Ｃｏｍｐａｎｙ，Ｉｎｃ．から得たもの）、４５ｇの酸化ジルコニウム粉末（「ＤＫ−２」）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１４０ｇの蒸留水をポリエチレン瓶に投入したこと除き、比較例Ａに記載された通り実施例３溶融材料および研磨剤粒子を調製した。
【０１７０】
図２４は、実施例３溶融材料の磨き断面（比較例Ａに記載されたように調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。コロニーのサイズは約５〜１５マイクロメートルであった。実施例３材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質Ｇｙ_３Ａｌ_５Ｏ_１２であり、暗い部分がα−Ａｌ_２Ｏ_３であったことが考えられる。ＺｒＯ_２微結晶の形状は顕微鏡写真上では容易に判別されなかった。磨き断面で観察された相の結晶の幅は約１マイクロメートル以下であった。
【０１７１】
幾つかの実施例３研磨剤粒子を白金るつぼに入れ、５０℃／時間で１０００℃に加熱し、（空気中で）１０００℃で８時間にわたり保持し、その後、約１００℃／時間で室温に冷却した。加熱後の実施例３研磨剤粒子の平均微小硬度は１５．６ＧＰａであった。二次電子モードのＳＥＭを用いて、微小硬度測定のために調製された磨き断面を検査した。加熱後の実施例３研磨剤粒子について観察された微小構造は、加熱前に観察された微小構造と実質的に同じであった。
【０１７２】
実施例４
１４７．９ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１３７．１ｇの酸化ランタン粉末（Ｍｏｌｙｃｏｒｐ，Ｉｎｃ．から得たもの）、１５ｇの酸化ジルコニウム粉末（「ＤＫ−２」）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１４５ｇの蒸留水をポリエチレン瓶に投入したこと除き、比較例Ａに記載された通り実施例４溶融材料および研磨剤粒子を調製した。
【０１７３】
図２５は、実施例４溶融材料の磨き断面（比較例Ａに記載されたように調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。コロニーのサイズは約５〜２０マイクロメートルであった。実施例４材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＬａＡｌＯ_３であり、暗い部分が結晶質ＬａＡｌ_１１Ｏ_１８であり、灰色部分が結晶質単斜晶ＺｒＯ_２であったことが考えられる。磨き断面で観察されたこれらの相の幅は約１．５マイクロメートル以下であった。
【０１７４】
実施例５
１０９ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１０１ｇの酸化ランタン粉末（Ｍｏｌｙｃｏｒｐ，Ｉｎｃ．から得たもの）、９０ｇの酸化ジルコニウム粉末（「ＤＫ−２」）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１４５ｇの蒸留水をポリエチレン瓶に投入したこと除き、比較例Ａに記載された通り実施例５溶融材料、研磨剤粒子およびディスクを調製した。
【０１７５】
図２６は、実施例５溶融材料の磨き断面（比較例Ａに記載されたように調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。実施例５材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＬａＡｌＯ_３であり、暗い部分が結晶質ＬａＡｌ_１１Ｏ_１８であり、灰色部分がＬａ_２Ｚｒ_２Ｏ_７であったことが考えられる。さらに、粉末Ｘ線回折に基づいて、材料は単斜晶ＺｒＯ_２と立方晶ＺｒＯ_２の二種の変種も含んでいた。ＺｒＯ_２微結晶の形状および位置は顕微鏡写真上では容易に判別されなかった。
【０１７６】
実施例５研磨剤粒子の平均微小硬度は、１２．０ＧＰａであると比較例Ｂで上述したように決定した。
【０１７７】
幾つかの実施例５研磨剤粒子をまた白金るつぼに入れ、５０℃／時間で１０００℃に加熱し、（空気中で）１０００℃で８時間にわたり保持し、その後、約１００℃／時間で室温に冷却した。加熱後の実施例５研磨剤粒子の平均微小硬度は１１．８ＧＰａであった。二次電子モードのＳＥＭを用いて、微小硬度測定のために調製された磨き断面を検査した。加熱後の実施例５研磨剤粒子について観察された微小構造は、加熱前に観察された微小構造と実質的に同じであった。
【０１７８】
実施例２、５および比較例Ｅ−Ｇ被覆研磨剤ディスクの研削性能を比較例Ａ−Ｇに関して上述したように評価した。結果を以下の表２に報告している。
【０１７９】
【表２】
表２

【０１８０】
実施例６
１０９ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１０１ｇの酸化ランタン粉末（Ｍｏｌｙｃｏｒｐ，Ｉｎｃ．から得たもの）、９ｇの酸化イットリウム粉末（マサツセッチュ州ニュートンのＨ．Ｃ．Ｓｔａｒｃｋから得たもの）、８１ｇの酸化ジルコニウム粉末（「ＤＫ−２」）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１４５ｇの蒸留水をポリエチレン瓶に投入したこと除き、実施例１に記載された通り実施例６溶融材料および研磨剤粒子を調製した。
【０１８１】
図２７は、溶融実施例６材料の磨き断面（実施例１に記載されたように調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。実施例６材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＬａＡｌＯ_３であり、暗い部分が結晶質ＬａＡｌ_１１Ｏ_１８であり、灰色部分が立方晶ＺｒＯ_２であったことが考えられる。ＺｒＯ_２微結晶の形状および位置は顕微鏡写真上では容易に判別されなかった。
【０１８２】
実施例７
１１１ｇのアルミナ粉末（「ＡＰＡ−０．５」）、９３ｇの酸化ネオジム粉末（Ｍｏｌｙｃｏｒｐ，Ｉｎｃ．から得たもの）、９０ｇの酸化ジルコニウム粉末（「ＤＫ−２」）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１３８ｇの蒸留水をポリエチレン瓶に投入したこと除き、比較例Ａに記載された通り実施例７溶融材料および研磨剤粒子を調製した。
【０１８３】
図２８は、実施例７溶融材料の磨き断面（比較例Ａに記載されたように調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。実施例７材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＮｄＡｌＯ_３であり、暗い部分が結晶質ＮｄＡｌ_１１Ｏ_１８であったことが考えられる。磨き断面で観察されたこれらの相の幅は約０．３マイクロメートル以下であった。さらに、粉末Ｘ線回折に基づいて、材料は立方晶ＺｒＯ_２の二種の変種も含んでいた。ＺｒＯ_２微結晶の形状および位置は顕微鏡写真上では容易に判別されなかった。
【０１８４】
実施例８
１０６．１ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１０３．９ｇの酸化セリウム（ＩＶ）（ＣｅＯ_２）粉末（ウィスコンシン州ミルウォーキーのＡｌｄｒｉｃｈ　Ｃｈｅｍｉｃａｌ　Ｃｏｍｐａｎｙ，Ｉｎｃ．から得たもの）、９０ｇの酸化ジルコニウム粉末（「ＤＫ−２」）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１３９．５ｇの蒸留水をポリエチレン瓶に投入したこと除き、比較例Ａに記載された通り実施例８溶融材料および研磨剤粒子を調製した。
【０１８５】
図２９は、実施例８溶融材料の磨き断面（比較例Ａに記載されたように調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は共晶誘導微小構造を示している。実施例８の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＣｅＡｌＯ_３であり、暗い部分が結晶質ＣｅＡｌ_１１Ｏ_１８であり、灰色部部がＣｅ_２Ｚｒ_２Ｏ_７であったことが考えられる。磨き断面で観察されたこれらの相の幅は約５マイクロメートル以下であった。さらに、粉末Ｘ線回折に基づいて、材料は単斜晶ＺｒＯ_２と立方晶ＺｒＯ_２の二種の変種も含んでいた。ＺｒＯ_２微結晶の形状および位置は顕微鏡写真上では容易に判別されなかった。さらに、大きな一次結晶（ＣｅＡｌＯ_３および／またはＣｅＯ_２であると考えられる）は磨き断面の一部の領域において観察され、ＣｅＡｌＯ_３および／またはＣｅＯ_２に富む組成に向けた厳密な共晶組成からの組成の起きうる偏りを示唆した。
【０１８６】
比較例Ｌ
（ａ）１５５．６ｇのアルミナ粉末（「ＡＰＡ−０．５」）、１４４．３ｇの酸化ランタンン粉末（カリフォルニア州ブレアのＭｏｌｙｃｏｒｐ，Ｉｎｃ．から得たもの）、０．６ｇの分散剤（「ＤＵＲＡＭＡＸ　Ｄ−３０００５」）および１３０ｇの蒸留水をポリエチレン瓶に投入したことと、（ｂ）粉末が、７７．５モル％のＡｌ_２Ｏ_３および２２．５モル％のＬａ_２Ｏ_３を生じさせる量で存在したことを除き、比較例Ａに記載された通り比較例Ｌ溶融材料、研磨剤粒子およびディスクを調製した。溶融材料の色は白色−赤色であった。但し、研磨剤粒子の幾つかは他のものより赤かった。
【０１８７】
図３０は、比較例Ｌ溶融材料の磨き断面（比較例Ａに記載されたように調製されたもの）の走査電子顕微鏡（ＳＥＭ）の顕微鏡写真である。顕微鏡写真は、複数のコロニーを含む共晶誘導微小構造を示している。コロニーのサイズは約５〜３０マイクロメートルであった。比較例Ｂ材料の一部の粉末Ｘ線回折および後方散乱モードでＳＥＭを用いる磨きサンプルの検査に基づいて、顕微鏡写真の白い部分が結晶質ＬａＡｌＯ_３であり、暗い部分が結晶質ＬａＡｌ_１１Ｏ_１８であったことが考えられる。磨き断面で観察されたこれらの相の幅は約０．５マイクロメートル以下であった。さらに、樹枝状突起の形で存在する大きな一次結晶（ＬａＡｌＯ_３であると考えられる）は磨き断面の一部の領域において観察され、Ｌａ_２Ｏ_３に富む組成に向けた厳密な共晶組成からの組成の起きうる偏りを示唆した。
【０１８８】
比較例Ｅ−ＧおよびＬ被覆研磨剤ディスクの研削性能を比較例Ａ−Ｇに関して上述したように評価した。結果を以下の表３に報告している。
【０１８９】
【表３】
表３

【０１９０】
本発明の種々の修正および変更は本発明の範囲および精神を逸脱せずに当業者に対して明らかになるであろう。本発明が本明細書に記載された例証的実施形態に不当に限定されないことが理解されるべきである。
【図面の簡単な説明】
【図１】本発明による溶融研磨剤粒子を含む被覆研磨剤物品の部分断面概略図である。
【図２】本発明による溶融研磨剤粒子を含む結合研磨剤物品の透視図である。
【図３】本発明による溶融研磨剤粒子を含む不織研磨剤物品の拡大概略図である。
【図４】比較例Ｂ溶融材料の示差走査熱分析（ＤＴＡ）プロットおよび熱重量分析（ＴＧＡ）プロットである。
【図５】比較例Ｃ溶融材料のＤＴＡプロットおよびＴＧＡプロットである。
【図６】比較例Ｋ溶融材料のＤＴＡプロットおよびＴＧＡプロットである。
【図７】比較例Ｆ研磨剤粒子のＤＴＡプロットおよびＴＧＡプロットである。
【図８】比較例Ａ溶融材料の磨き断面の走査電子顕微鏡写真である。
【図９】比較例Ｂ溶融材料の磨き断面の走査電子顕微鏡写真である。
【図１０】比較例Ｃ溶融材料の磨き断面の走査電子顕微鏡写真である。
【図１１】比較例Ｄ溶融材料の磨き断面の走査電子顕微鏡写真である。
【図１２】比較例Ｈ溶融材料の磨き断面の走査電子顕微鏡写真である。
【図１３】比較例Ｉ溶融材料の磨き断面の走査電子顕微鏡写真である。
【図１４】比較例Ｊ溶融材料の磨き断面の走査電子顕微鏡写真である。
【図１５】比較例Ｋ溶融材料の磨き断面の走査電子顕微鏡写真である。
【図１６】比較例Ｆ研磨剤粒子の磨き断面の走査電子顕微鏡写真である。
【図１７】種々の加熱条件にさらされた後の比較例Ｆ研磨剤粒子の磨き断面の走査電子顕微鏡写真である。
【図１８】種々の加熱条件にさらされた後の比較例Ｆ研磨剤粒子の磨き断面の走査電子顕微鏡写真である。
【図１９】ガラス化結合材料にさらされた後の比較例Ｆ研磨剤粒子の磨き断面の走査電子顕微鏡写真である。
【図２０】種々の加熱条件にさらされた後の比較例Ｋ材料の磨き断面の走査電子顕微鏡写真である。
【図２１】種々の加熱条件にさらされた後の比較例Ｋ材料の磨き断面の走査電子顕微鏡写真である。
【図２２】実施例１溶融材料の磨き断面の走査電子顕微鏡写真である。
【図２３】実施例２溶融材料の磨き断面の走査電子顕微鏡写真である。
【図２４】実施例３溶融材料の磨き断面の走査電子顕微鏡写真である。
【図２５】実施例４溶融材料の磨き断面の走査電子顕微鏡写真である。
【図２６】実施例５溶融材料の磨き断面の走査電子顕微鏡写真である。
【図２７】実施例６溶融材料の磨き断面の走査電子顕微鏡写真である。
【図２８】実施例７溶融材料の磨き断面の走査電子顕微鏡写真である。
【図２９】実施例８溶融材料の磨き断面の走査電子顕微鏡写真である。
【図３０】比較例Ｌ溶融材料の磨き断面の走査電子顕微鏡写真である。[0001]
Field of the invention
The present invention relates to Al₂O₃-Rare earth oxide-ZrO₂It relates to a molten material containing a eutectic. Molten Al₂O₃・ Rare earth oxide-ZrO₂Examples of useful articles that include a eutectic material include fibers and abrasive particles. It is possible to incorporate molten abrasive particles into various abrasive articles, including bonded abrasives, coated abrasives, nonwoven abrasives, and abrasive brushes.
[0002]
Description of related technology
Various molten eutectic metal oxide materials are known in the art, including two-dimensional and three-dimensional eutectic materials. Molten eutectic metal oxide materials typically charge various metal oxide sources and other desired additives to the furnace, heat the material above the melting point of the material, and cool the melt. (See, e.g., U.S. Patent Nos. 1,161,620 (Coulter), 1,192,709 (Tone), 1,247, No. 337 (Saunders et al.), No. 1,268,533 (Allen), No. 2,424,645 (Baumann et al.), No. 3,891,408 (Rose) No. 3,781,172 (Pett et al.), No. 3,893,826 (Quinan et al.), No. 4,126,429 (Watson) 4,457,767 (Poon et al.), 5,143,522 (Gibson et al.), 5,023,212 (Dubotts et al.) And 5,336. , 280 (see Dubots et al.).
[0003]
However, there is a need for new materials that can provide different performance characteristics (including combinations of properties) than conventional materials, are easier to manufacture, and / or are less expensive to manufacture. Have been.
[0004]
In another embodiment, various abrasive particles known in the art (eg, diamond particles, cubic boron nitride particles, fused abrasive particles, and sintered ceramic abrasive particles (including sol-gel derived abrasive particles)). Exists. In some polishing applications, the abrasive particles are used in powder form, while in other applications, the particles are used in abrasive products (eg, coated abrasive products, bonded abrasive products, nonwoven abrasive products and abrasive products). Brush). Criteria used in selecting the abrasive particles used for a particular polishing application include polishing life, cutting speed, substrate surface finish, grinding efficiency and product cost.
[0005]
From about the 1900's to about the mid-1980's, the finest abrasive particles for polishing applications, such as those utilizing coated and bonded abrasive products, were typically fused abrasive particles. There are two general types of fused abrasive particles. (1) Fused alpha alumina abrasive particles (e.g., U.S. Pat. Nos. 1,161,620 (Coulter), 1,192,709 (Tone), and 1,247,337 ( See, Saunders et al., Nos. 1,268,533 (Allen), 2,424,645 (Baumann et al.) And (2) melting (sometimes referred to as "co-melting"). ) Alumina-zirconia abrasive particles (e.g., U.S. Patent Nos. 3,891,408 (Rowse et al.); 3,781,172 (Pett et al.); 3,893. No. 826 (Quinan et al.), No. 4,126,429 (Watson), No. 4,457,767 (Poon (P. on) et al.) and No. 5,143,522 (referring to Gibson (Gibson) et al)). See also, for example, U.S. Pat. Nos. 5,023,212 (Dubots et al.) And 5,336,280 (Dubots et al.) Which report some fused oxynitride abrasive particles. To do. Fused alumina abrasive particles typically charge an alumina source such as aluminum ore or bauxite and other desired additives into a furnace, heating the material above the melting point of the material and cooling the melt. It is produced by forming a coagulum, breaking the coagulum into particles, and then sieving and screening the particles to provide the desired abrasive particle size distribution. Fused alumina-zirconia abrasive particles are typical, except that both the alumina source and the zirconia source are charged to the furnace and the melt is cooled faster than the melt used to produce the fused alumina abrasive particles. It is manufactured in a similar manner. For fused alumina-zirconia abrasive particles, the amount of alumina source is typically about 50-80% by weight, and the amount of zirconia is 50-20% by weight zirconia. The process of producing fused alumina and fused alumina abrasive particles may include removing impurities from the melt prior to the cooling step.
[0006]
Although fused alpha-alumina abrasive particles and fused alumina-zirconia abrasive particles are still widely used in abrasive applications (including abrasive applications utilizing coated abrasive products and bonded abrasive products), since the 1980's many have been The finest abrasive particles for abrasive applications are sol-gel derived alpha alumina particles (eg, U.S. Patent Nos. 4,314,827 (Leitheiser et al.) And 4,518,397 (Lyseizer ( Leitheiser et al.), No. 4,623,364 (Cottringer et al.), No. 4,744,802 (Schwabel), No. 4,770,671 (Monroe et al.), No. 4,881,951 (Wood et al.), No. 4, Nos. 60,441 (Pellow et al.), 5,139,978 (Wood), 5,201,916 (Berg et al.), 5,366,523 (loan No. 5,429,647 (Larmie), No. 5,547,479 (Conwell et al.), No. 5,498,269 (Larmie), Nos. 5,551,963 (Larmie) and 5,725,162 (Garg et al.).
[0007]
The sol-gel derived alpha alumina abrasive particles may have a microstructure composed of very fine alpha alumina crystallites with or without the presence of added secondary phases. For example, the grinding performance of sol-gel derived abrasive particles on metal, as measured by the life of the abrasive product made with the abrasive particles, is dramatically greater than such products made from conventional fused alumina abrasive particles. long.
[0008]
Typically, the process of producing sol-gel derived abrasive particles is more complicated and expensive than the process of producing conventional molten abrasive particles. In general, sol-gel derived abrasive particles typically prepare a dispersion or sol comprising water, alumina monohydrate (boehmite) and optionally a peptizer (eg, an acid such as nitric acid), and gel the dispersion to a gel. And dried gelled dispersion, crushed dried dispersion into particles, sieved particles to produce particles of desired size, calcined particles to remove volatiles, calcined Manufactured by sintering particles at a temperature below the melting point of alumina and sieving the particles to provide the desired abrasive particle size distribution. Metal oxide modifiers are often incorporated into sintered abrasive particles to change or otherwise modify the physical properties and / or microstructure of the sintered abrasive particles.
[0009]
There are a variety of abrasive products known in the art (also referred to as "abrasive articles"). Typically, the abrasive product comprises a binder and abrasive particles fixed within the abrasive product by the binder. Examples of abrasive products include coated abrasives, bonded abrasives, nonwoven abrasives, and abrasive brushes.
[0010]
Examples of bonded abrasive products include grinding wheels, cut-off wheels, and honing wheels. The main types of adhesive systems used to make bonded abrasive products are resinous, glassy and metallic. Resinous bonded abrasives use an organic binder system (eg, a phenolic binder system) to combine and bond the abrasive particles and form a shaped mass (eg, US Pat. No. 4,741,743 (Narayanan) No. 4,800,685 (Haynes et al.), No. 5,038,453 (Narayanan et al.) And No. 5,110,332 (Narayanan). See)). Another major type is a vitreous wheel that uses a glass binder system to hold the abrasive particle mass together (eg, US Pat. No. 4,543,107 (Rue), No. 4). No. 4,898,587 (Hay et al.), No. 4,997,461 (Markhoff @ Matheny et al.) And No. 5,863,308 (Qi et al.). ). These glass bonds are usually aged at temperatures between 900C and 1300C. Currently, glassy wheels use both fused alumina abrasive particles and sol-gel derived abrasive particles. However, fused alumina-zirconia is generally not incorporated into glassy wheels due in part to the thermal stability of alumina-zirconia. At the high temperatures that age the glass tie layer, the physical properties of the alumina-zirconia degrade, leading to a significant decrease in polishing performance. Metal bonded abrasive products typically use a sintered or plated metal to bond the abrasive particles.
[0011]
The abrasive industry has developed abrasive particles and abrasives that are easier to manufacture, less expensive to manufacture, and / or provide performance advantages compared to conventional abrasive particles and abrasive products. Abrasive products continue to be needed.
[0012]
Summary of the Invention
The present invention provides at least (a) crystalline ZrO₂And (b) (i) crystalline Al₂O₃(Ii) the first crystalline complex Al₂O₃A rare earth oxide or (iii) a second different (ie first crystalline complex Al₂O₃・ Different from rare earth oxides) crystalline complex Al₂O₃-To provide a molten crystalline eutectic material comprising a eutectic with at least two rare earth oxide materials.
[0013]
One preferred eutectic material according to the invention comprises at least (a) crystalline ZrO₂, (B) crystalline Al₂O₃And (c) crystalline complex Al₂O₃-Including eutectic of rare earth oxides. Another preferred eutectic material according to the invention comprises at least (a) crystalline ZrO₂, (B) the first crystalline complex Al₂O₃A rare earth oxide and (c) a second different crystalline complex Al₂O₃-Including eutectic of rare earth oxides.
[0014]
In another embodiment, the present invention provides at least (a) a crystalline complex Al₂O₃・ Rare earth oxide and (b) crystalline ZrO₂And a molten crystalline eutectic material comprising a eutectic.
[0015]
In another embodiment, the molten crystalline material according to the invention preferably has at least 30% by weight (or at least 40, 50, 60, 70 or even 80% by weight, based on the total metal oxide content of the material). ) AlO₃On a theoretical oxide basis.
[0016]
The molten crystalline material according to the present invention can be produced, formed, or converted to fibers or abrasive particles.
[0017]
In another embodiment, the present invention relates to the method of (preferably at least 20, 30, 40, 50, 60, 70, 75, 80, 85, 90, 95, 98, 99, based on the total metal oxide volume of the particles. Or 100% by volume of a eutectic material, wherein the eutectic material comprises at least (a) crystalline ZrO₂And (b) (i) crystalline Al₂O₃(Ii) the first crystalline complex Al₂O₃A rare earth oxide or (iii) a second different (ie first crystalline complex Al₂O₃・ Different from rare earth oxides) crystalline complex Al₂O₃Providing molten crystalline abrasive particles comprising a eutectic with at least two rare earth oxide materials; One preferred eutectic material comprises at least (a) crystalline ZrO₂, (B) crystalline Al₂O₃And crystalline complex Al₂O₃-Including eutectic of rare earth oxides. Another preferred eutectic material comprises at least (a) crystalline ZrO₂, (B) the first crystalline complex Al₂O₃A rare earth oxide and (c) a second different crystalline complex Al₂O₃-Including eutectic of rare earth oxides.
[0018]
In another embodiment, the present invention relates to the method of (preferably at least 20, 30, 40, 50, 60, 70, 75, 80, 85, 90, 95, 98, 99, based on the total metal oxide volume of the particles. Or 100% by volume of a eutectic material, wherein the eutectic material comprises at least (a) a crystalline complex Al₂O₃・ Rare earth oxide and (b) crystalline ZrO₂The present invention provides molten crystalline abrasive particles comprising a eutectic of:
[0019]
Preferably, the molten crystalline abrasive particles according to the present invention have at least 30% (or even at least 40, 50, 60, 70 or even 80% by weight) Al based on the total metal oxide content of the particles.₂O₃On a theoretical oxide basis.
[0020]
In another embodiment, the present invention provides a number of particles, wherein at least a portion of the number of particles having a particle size distribution ranging from fine particles to coarse particles are molten crystalline abrasive particles according to the present invention.
[0021]
In this application,
“Simple metal oxide” refers to a metal oxide containing one or more of the same metal element and oxygen (eg, AlO₃, CeO₂, MgO, SiO₂And Y₂O₃).
“Complex metal oxide” refers to a metal oxide containing two or more different metal elements and oxygen (eg, CeAl₁₁O₁₈, Dy₃Al₁₁O₁₂, MgAl₂O₄And Y₃Al₅O₁₂).
"Complex AlO₃"Metal oxide" is Al₂O₃And complex metal oxides containing one or more metal elements other than Al on a theoretical oxide basis (for example, CeAl₁₁O₁₈, Dy₃Al₅O₁₂, MgAl₂O₄And Y₃Al₅O₁₂).
"Complex Al₂O₃・ Y₂O₃"Means Al₂O₃And Y₂O₃Metal oxides (e.g., Y₃Al₅O₁₂).
"Complex Al₂O₃・ Rare earth oxide ”or“ Complex Al₂O₃・ REO ”means Al₂O₃And complex metal oxides containing rare earth oxides on a theoretical oxide basis (for example, CeAl₁₁O₁₈And Dy₃Al₅O₁₂).
“Rare earth oxide” refers to CeO₂, Dy₂O₃, Er₂O₃, Eu₂O₃, Gd₂O₃, Ho₂O₃, La₂O₃, Lu₂O₃, Nd₂O₃, Pr₆O₁₁, Sm₂O₃, Th₄O₇, Tm₂O₃And Yb₂O₃Means on a theoretical oxide basis.
"REO" means rare earth oxide.
"Size" is the longest dimension of a particle.
[0022]
In another aspect, the present invention relates to a method for producing a molten crystalline material according to the invention, comprising at least one type of Al to provide a melt.₂O₃Source, at least one rare earth oxide source and at least one ZrO₂Providing a method comprising: melting a source; and converting the melt to the molten crystalline material.
[0023]
In another embodiment, the present invention relates to a method for producing the molten crystalline abrasive particles according to the present invention, comprising at least one Al-containing material for providing a melt.₂O₃Source, at least one rare earth oxide source and at least one ZrO₂Melting the source; and converting the melt to the molten crystalline abrasive particles.
[0024]
The molten abrasive particles according to the present invention can be incorporated into various abrasive products such as coated abrasives, bonded abrasives, nonwoven abrasives and abrasive brushes.
[0025]
The present invention relates to the steps of contacting at least one molten abrasive particle according to the present invention (preferably a plurality of molten abrasive particles according to the present invention) with a surface of a workpiece; Displacing at least one of the molten abrasive particles or the surface with respect to the other according to the present invention for polishing with the molten abrasive particles.
[0026]
Preferred fused abrasive particles according to the present invention provide superior grinding performance as compared to conventional fused abrasive particles. The preferred fused abrasive particles according to the present invention can be used to convert the preferred fused abrasive particles according to the present invention into a vitrified bonding system without significantly reducing the polishing performance of the conventional fused alumina-zirconia abrasive particles used by the vitrified bonding system. It is sufficiently microstructurally and chemically stable to allow its use.
[0027]
Detailed description
The molten crystalline material according to the invention can be manufactured or formed as fibers, reinforcing particles, abrasive particles or paints (eg protective coatings) or fibers, reinforcing particles, abrasive particles or paints (eg protective coatings). ). Abrasive particles that can be used are incorporated into the abrasive article or are in powder form. The fibers are useful, for example, as insulation and reinforcement members in composites (eg, ceramic matrix composites, metal matrix composites, or polymer matrix composites).
[0028]
Generally, the molten material according to the present invention is obtained by heating a suitable metal oxide source to form a melt, preferably a homogeneous melt, and then rapidly cooling the melt to produce a solidified mass. It is possible to manufacture. To produce abrasive particles, the solidified mass is typically crushed to produce a desired size distribution of the abrasive particles.
[0029]
The molten abrasive particles according to the present invention can be obtained by heating a suitable metal oxide source to form a melt, preferably a homogeneous melt, and then rapidly cooling the melt to form a solidified mass. It is possible to manufacture. The coagulum is typically crushed to produce the desired size distribution of the abrasive particles.
[0030]
More specifically, the molten material (including fused abrasive particles) according to the present invention comprises (on a theoretical oxide basis) Al₂O₃, Rare earth oxide, ZrO₂And any other additives (eg, other metal oxides and processing aids) to the furnace. The metal oxide source can be, for example, added to the furnace and melted together, or can be sequentially added to the furnace and melted.
[0031]
With respect to the solidified molten material containing the complex metal oxide, at least a portion of the metal oxide present in the molten metal oxide source (ie, the melt) reacts during the process of forming the solidified material to form the complex metal oxide. Let it form. For example, Al₂O₃Source and Yb₂O₃The source reacts and Yb₃Al₅O₁₂(Ie, 5Al₂O₃+ 3Yb₂O₃→ 2Yb₃Al₅O₁₂). Similarly, for example, Al₂O₃Source and Er₂O₃The source reacts and Er₃AlO₁₂Can be formed. Further, for example, Al₂O₃Source and Gd₂O₃The source reacts and GdAlO₃(Ie, Al₂O₃+ Gd₂O₃→ 2GdAlO₃). Similarly, for example, Al₂O₃Source and CeO₂Source, Dy₂O₃Source, Eu₂O₃Source, La₂O₃Source, Nd₂O₃Source, Pr₂O₃Source or Sm₂O₃The sources react, each with CeAlO₃, Dy₃Al₅O₁₂, EuAlO₃, LaAlO₃, NdAlO₃, PrAlO₃And SmAlO₃Can be formed. Further, for example, Al₂O₃Source and La₂O₃The source reacts, LaAlO₃(That is, Al₂O₃+ La₂O₃→ 2LaAlO₃) And LaAl₁₁O₁₈(That is, 11Al₂O₃+ La₂O₃→ 2LaAl₁₁O₁₈) Can be formed. Similarly, for example, Al₂O₃Source and CeO₂Source, Eu₂O₃Source, Nd₂O₃Source, Pr₂O₃Source or Sm₂O₃The sources react and each CeAl₁₁O₁₈, EuAl₁₁O₁₈, NdAl₁₁O₁₈, PrAl₁₁O₁₈And SmAl₁₁O₁₈Can be formed.
[0032]
Al₂O₃, Rare earth oxides and / or ZrO₂Depending on the relative proportion of the resulting solidified and final molten material,
(A) crystalline Al₂O₃-Complex Al₂O₃・ Metal oxide (complex Al₂O₃The metal oxide is, for example, Dy₃Al₅O₁₂, Er₃Al₅O₁₂, GdAlO₃Or Yb₃Al₅O₁₂-ZrO₂Eutectic and crystalline Al₂O₃
(B) crystalline Al₂O₃-Complex Al₂O₃A metal oxide (again, complex Al₂O₃The metal oxide is, for example, Dy₃Al₅O₁₂, Er₃Al₅O₁₂, GdAlO₃Or Yb₃Al₅O₁₂-ZrO₂Eutectic
(C) crystalline Al₂O₃-Complex Al₂O₃A metal oxide (again, complex Al₂O₃The metal oxide is, for example, Dy₃Al₅O₁₂, Er₃Al₅O₁₂, GdAlO₃Or Yb₃Al₅O₁₂-ZrO₂Eutectic and crystalline Al₂O₃A metal oxide (again, complex Al₂O₃The metal oxide is, for example, Dy₃Al₅O₁₂, Er₃Al₅O₁₂, GdAlO₃Or Yb₃Al₅O₁₂), And / or
(D) crystalline complex Al₂O₃A metal oxide (again, complex Al₂O₃The metal oxide is, for example, Dy₃Al₅O₁₂, Er₃Al₅O₁₂, GdAlO₃Or Yb₃Al₅O₁₂-ZrO₂Eutectic and crystalline ZrO₂Can be included.
[0033]
Al₂O₃Reacts with the rare earth oxide to form two complex metal oxides, the resulting solidified material and final molten material are Al₂O₃And the relative proportion of the rare earth metal oxide,
(A) First crystalline complex Al₂O₃A metal oxide (for example, CeAlO)₃, EuAlO₃, LaAlO₃, NdAlO₃, PrAlO₃Or SmAlO₃)-A second different (i.e. a first crystalline complex Al)₂O₃-Different from metal oxide) crystalline complex Al₂O₃A metal oxide (for example, Ce, respectively)₃Al₁₁O₁₈, EuAl₁₁O₁₈, LaAl₁₁O₁₈, NdAl₁₁O₁₈, PrAl₁₁O₁₈Or SmAl₁₁O₁₈) -ZrO₂Eutectic and first crystalline complex Al₂O₃Metal oxides (again, for example, CeAlO₃, EuAlO₃, LaAlO₃, NdAlO₃, PrAlO₃Or SmAlO₃)
(B) First crystalline complex Al₂O₃Metal oxides (again, for example, CeAlO₃, EuAlO₃, LaAlO₃, NdAlO₃, PrAlO₃Or SmAlO₃)-A second different crystalline complex Al₂O₃Metal oxides (again, for example, respectively Ce₃Al₁₁O₁₈, EuAl₁₁O₁₈, LaAl₁₁O₁₈, NdAl₁₁O₁₈, PrAl₁₁O₁₈Or SmAl₁₁O₁₈) -ZrO₂Eutectic
(C) First crystalline complex Al₂O₃Metal oxides (again, for example, CeAlO₃, EuAlO₃, LaAlO₃, NdAlO₃, PrAlO₃Or SmAlO₃)-A second different crystalline complex Al₂O₃Metal oxides (again, for example, respectively Ce₃Al₁₁O₁₈, EuAl₁₁O₁₈, LaAl₁₁O₁₈, NdAl₁₁O₁₈, PrAl₁₁O₁₈Or SmAl₁₁O₁₈) -ZrO₂Eutectic and second different crystalline complex Al₂O₃Metal oxides (again, for example, CeAl₁₁O₁₈, EuAl₁₁O₁₈, LaAl₁₁O₁₈, NdAl₁₁O₁₈, PrAl₁₁O₁₈Or SmAl₁₁O₁₈), And / or
(D) First crystalline complex Al₂O₃Metal oxides (again, for example, CeAlO₃, EuAlO₃, LaAlO₃, NdAlO₃, PrAlO₃Or SmAlO₃)-A second different crystalline complex Al₂O₃Metal oxides (again, for example, respectively CeAl₁₁O₁₈, EuAl₁₁O₁₈, LaAl₁₁O₁₈, NdAl₁₁O₁₈, PrAl₁₁O₁₈Or SmAl₁₁O₁₈) -ZrO₂Eutectic and crystalline ZrO₂
Can be included.
[0034]
However, it will be appreciated that the particular phase formed depends on several factors, including the melt composition and the solidification conditions. Typically, the composition and solidification conditions of the melt are such that the resulting solidified material is occupied by a eutectic (i.e., the composition of the solidified material depends on the various metal oxides present in the material) (Corresponding to close to the eutectic proportion of the phase) Although not wishing to be bound by theory, some unstable conditions during the formation of the solidified material can lead to the formation of alternating eutectics. For example, under standard stable conditions, the resulting eutectic is Al₂O₃/ Dy₃Al₅O₁₂/ ZrO₂Where, under some unstable conditions, Al₂O₃/ DyAlO₃/ ZrO₂Eutectic is Al₂O₃/ Dy₃Al₅O₁₂/ ZrO₂Instead of or Al₂O₃/ Dy₃Al₅O₁₂/ ZrO₂Can occur in addition to
[0035]
Complex Al₂O₃-REO (for example, Dy₃Al₅O₁₂, Er₃Al₅O₁₂, GdAlO₃, Yb₃Al₅O₁₂Or La₃Al₁₁O₁₈It is also within the scope of the present invention to replace some of the rare earth cations and / or aluminum cations in) with other cations. For example, the complex Al₂O₃-A part of Al cation in REO may be replaced by at least one cation of an element selected from the group consisting of Cr, Ti, Sc, Fe, Mg, Ca, Si, Co and a combination thereof. For example, the complex Al₂O₃A part of the rare earth cations in the REO is at least one element selected from the group consisting of Y, Fe, Ti, Mn, V, Cr, Co, Ni, Cu, Mg, Ca, Sr and combinations thereof; It may be replaced by a cation. Similarly, substituting some of the aluminum cations in alumina is within the scope of the invention. For example, Cr, Ti, Sc, Fe, Mg, Ca, Si, Co can replace aluminum in the alumina structure. The cation substitution as described above can affect the properties (eg, hardness, toughness, strength, thermal conductivity, etc.) of the molten material.
[0036]
Moreover, other eutectics will be apparent to those of skill in the art after reviewing the present disclosure. For example, phase diagrams depicting various eutectics are known in the art.
[0037]
The molten material according to the invention containing a eutectic material contains eutectic colonies. Individual colonies generally include homogeneous microstructural features (eg, similar size and orientation of the component phase crystals within the colony). Typically, if impurities are present in the molten crystalline material according to the present invention, the impurities will tend to separate towards colony boundaries and, as a crystalline and / or amorphous (glass) phase, Alone and / or as a reaction product (for example, complex Al₂O₃Metal oxides and / or complex REOs (as metal oxides).
[0038]
In general, the phases constituting the eutectic colony are (a) single crystals of three different metal oxides (for example, Al₂O₃, Yb₃Al₅O₁₂And ZrO₂(B) two kinds of metal oxide single crystals (for example, single crystal Al₂O₃And single crystal ZrO₂) And a plurality of crystals of different metal oxides (eg, polycrystalline Yb₃Al₅O₁₂), (C) a kind of single crystal of metal oxide (for example, single crystal Al₂O₃Or ZrO₂) And a plurality of crystals of different metal oxides (eg, polycrystalline Yb₃Al₅O₁₂And polycrystalline ZrO₂) Or (d) three different polycrystalline metal oxides (eg, polycrystalline Al₂O₃, Polycrystalline Yb₃Al₅O₁₂And polycrystalline ZrO₂)including.
[0039]
Colonies can be of any of a variety of shapes, typically ranging from essentially spheres to cylinders. The composition, phase, and / or microstructure (eg, crystalline (ie, single or polycrystalline) and crystal size) of each colony can be the same or different. The orientation of crystals within a colony may vary from one colony to another. The phases that make up some eutectic colonies may exist in various shapes, such as, for example, from sticks or platelets to “Kanji characters”. Such differences between colonies may even exist between adjacent colonies.
[0040]
The microstructure may be a mixture of two component phases in a "Kanji character" arrangement, the third phase being present as bars or plates. Alternatively, for example, the two component phases may be present as an interpenetrating network, for example, with a third phase present as a plate or rod.
[0041]
Colony number, colony size and composition are affected, for example, by melt composition and coagulation conditions. While not wishing to be bound by theory, it is believed that the closer the melt composition is to the exact eutectic composition, the fewer colonies formed. However, in another embodiment, slow unidirectional solidification of the melt also tends to minimize the number of colonies that form, while multidirectional solidification at a relatively higher cooling rate causes the colonies that form to form. It is conceivable that the number tends to increase. The rate of solidification of the melt (ie, the rate of cooling) and / or the multi-directional solidification of the melt tends to affect the type and / or number of microstructural defects (eg, holes) present in the resulting molten material. is there. For example, while not wishing to be bound by theory, relatively rapid solidification (ie, solidification at relatively high cooling rates) and / or multidirectional solidification may result from microstructural defects present in the resulting molten material. This tends to increase the type and / or number of (eg, holes). However, relatively slow solidification tends to increase the size and / or crystals of the colonies present in the solidified material. However, for example, eliminating colony formation may be possible through slow controlled cooling. Thus, in selecting the cooling rate and / or the degree of multidirectional solidification, the cooling rate must be increased or decreased to achieve an optimal balance between the desired microstructure properties and the undesirable microstructure properties associated with the various cooling rates. There can be.
[0042]
Furthermore, for a given composition, the size of the colonies and the phases present within the colonies tend to decrease as the cooling rate of the melt is increased. Typically, the eutectic colonies in the molten material according to the present invention average less than 100 micrometers, preferably less than 50 micrometers, where such sizes for a given colony are determined by scanning electron microscopy (SEM). As observed, the average of the two largest dimensions measured from the polished section of the colony. Typically, the smallest dimension of the crystalline phase constituting the eutectic in the colony as measured from the polished cross section of the colony observed by SEM is less than 10 micrometers, preferably less than 5 micrometers, more preferably Less than 1 micrometer, or even less than 0.5 micrometer.
[0043]
Certain molten materials according to the present invention also include at least one primary crystal of a metal oxide phase that makes up the eutectic component of the molten material. For example, if the eutectic part is Al₂O₃Phase, complex Al₂O₃・ REO (for example, Yb₃Al₅O₁₂) Phase and ZrO₂When composed of phases, the microstructure is such that the composition of the melt forming the molten material is Al₂O₃, Yb₂O₃Or ZrO₂That can be present when rich in Al₂O₃, Yb₃Al₅O₁₂Or ZrO₂Primary crystals.
[0044]
It is conceivable that the formation of primary crystals results from a deviation from a particular eutectic fraction. The greater the bias, the greater the overall proportion of primary crystals. Primary crystals may be found in a variety of shapes, typically ranging from rod-like structures to dendritic structures. While not wishing to be bound by theory, it is believed that the presence and / or formation of primary crystals adjacent to the colony can affect the resulting microstructure of the colony. In some cases, the primary crystals present in the molten material (eg, primary Al₂O₃It can be advantageous to have crystals) (eg for improved polishing performance). However, it is also conceivable that the polishing performance of the abrasive particles tends to decrease as the size of the primary crystal increases.
[0045]
Further, while not wishing to be bound by theory, small additions of metal oxides other than those constituting the eutectic (eg, less than 5% by weight) can affect colony boundaries, It is then believed that the properties (eg, hardness and toughness) of the molten material can be affected.
[0046]
Al for producing molten material according to the invention₂O₃Sources (on a theoretical oxide basis) include those known in the art for producing conventional fused alumina abrasive particles and alumina-zirconia abrasive particles. Commercially available Al₂O₃Sources include bauxite (including both natural and synthetically produced bauxite), calcined bauxite, aluminum oxide trihydrate (eg, boehmite and gibbsite), Bayer process alumina, aluminum ore, gamma alumina, alpha alumina, aluminum salts , Aluminum nitrate and combinations thereof. Al₂O₃Source is Al₂O₃Or Al₂O₃May simply occur. Alternatively, Al₂O₃Source is Al₂O₃And Al₂O₃One or more metal oxides (complex Al₂O₃A metal oxide (for example, Dy₃Al₅O₁₂, Y₃Al₅O₁₂, CeAl₁₁O₁₈Etc.) may be included or produced.
[0047]
Commercial sources of rare earth oxides for producing molten materials according to the present invention include rare earth oxide powders, rare earth metals, rare earth containing ores (bustnessite and monazite), rare earth salts, rare earth nitrates and rare earth carbonates. . The rare earth oxide source may contain a rare earth oxide or may only produce a rare earth oxide. Alternatively, the rare earth oxide source is a rare earth oxide and one or more metal oxides other than the rare earth oxide (a complex rare earth oxide / other metal oxide (for example, Dy₃Al₅O₁₂, CeAl₁₁O₁₈Etc.) may be included or produced.
[0048]
ZrO for producing molten material according to the invention₂Commercial sources (on a theoretical oxide basis) include zirconium oxide powder, zircon sand, zirconium, zirconium-containing ores and zirconium salts (e.g., zirconium carbonate, acetate, nitrate, chloride, hydroxide and their salts). Combinations). Additionally or alternatively, ZrO₂Source is ZrO₂And other metal oxides such as hafnia.
[0049]
Optionally, the molten material according to the present invention may contain other metal oxides (ie, Al₂O₃, Rare earth oxides and ZrO₂Other metal oxides). The addition of certain metal oxides can change the crystal structure or microstructure of the resulting molten material. For example, while not wishing to be bound by theory, it is desired that certain metal oxides or metal oxide-containing compounds (relatively small amounts, for example, from 0.01 to 5 based on the total metal oxide content of the molten material). It is theorized that (even when even weight percent is used) may be present at the boundaries between eutectic colonies. Reaction products of each other or Al₂O₃, Rare earth oxides and / or ZrO₂The presence of these metal oxides, which may take the form of a reaction product with, can affect the fracture properties and / or microstructure of the molten material and / or affect the grinding properties of abrasive particles containing the molten material. Can be effected. Any metal oxide can also serve as a processing aid by reducing the size and / or number of holes in the molten material, for example, to increase the density of the molten material. The optional metal oxide can also function as a processing aid to, for example, increase or decrease the effective melting temperature of the melt. Thus, certain metal oxides may be added for processing reasons.
[0050]
ZrO₂Metal oxides known to stabilize the tetragonal / cubic morphology of₂O₃, TiO₂, CaO and MgO) may be desirable. In some embodiments of the molten material according to the present invention, the crystalline ZrO₂Is the crystalline complex Al₂O₃Stabilized by oxides other than the rare earth oxides present in the rare earth oxides. For example, LaAlO₃-LaAl₁₁O₁₈-ZrO₂For eutectics, for example, Y₂O₃By ZrO₂May be stabilized.
[0051]
The molten material according to the present invention typically has less than 50 wt% (more typically less than 20 wt%, in some cases less than 0 wt%, based on the total metal oxide content of the molten material (or individual abrasive particles). 0.01 to 5% by weight (otherwise in the range of 0.1 to 1% by weight) of metal oxides (on a theoretical oxide basis) other than alumina, rare earth oxides and zirconia. Sources of other metal oxides are already commercially available.
[0052]
Examples of any metal oxide include, on a theoretical oxide basis, BaO, CaO, Cr₂O₃, CoO, Fe₂O₃, HfO₂, Li₂O, MgO, MnO, NiO, SiO₂, TiO₂, Na₂O, Sc₂O₃, SrO, V₂O₃, ZnO, Y₂O₃And combinations thereof. Furthermore, Y₂O₃With respect to Y for producing the molten material according to the invention₂O₃Commercial sources (on a theoretical oxide basis) include yttrium oxide powder, yttrium, yttrium-containing ores and yttrium salts (eg, yttrium carbonate, nitrate, chloride, hydroxide and combinations thereof). . Y₂O₃Source is Y₂O₃Or Y₂O₃May simply occur. Or Y₂O₃Source is Y₂O₃And Y₂O₃One or more metal oxides (complex Y₂O₃A metal oxide (for example, Y₃Al₅O₁₂) May be included or produced.
[0053]
The metal oxide source for producing the molten material according to the present invention may include molten abrasive particles (eg, fused alumina abrasive particles) or the same composition that together with the remaining metal oxide source provides the desired composition of molten particles Other molten materials having different compositions (eg, fused alumina materials) are also included.
[0054]
A reducing agent such as a carbon source may be added to reduce impurities during the melting process. Examples of carbon sources include coal, graphite or petroleum coke. The amount of carbon contained in the charge to the furnace is typically no more than 5%, more typically no more than 3%, more typically no more than 2% by weight of the charge. Iron may also be added to the furnace charge to help remove impurities. For example, iron can be combined with impurities to produce a material that can be magnetically removed from the melt or crushed solidified material.
[0055]
It is also within the scope of the present invention to include metal borides, carbides, nitrides and combinations thereof in the molten crystalline material according to the present invention. Such materials may even be present within the eutectic material (eg, as inclusions). Examples of metal borides, carbides and nitrides may include titanium diboride, aluminum carbide, aluminum nitride, titanium carbide, titanium nitride, silicon carbide, boron carbide and boron nitride. Such materials are known in the art and are commercially available.
[0056]
The particular choice of metal oxide source and other additives for producing the molten material according to the invention will typically depend, for example, on the desired composition and microstructure of the resulting molten material, the resulting abrasive particles. The desired physical properties (eg, hardness and toughness), avoidance or minimization of undesirable impurities, and / or the specific processes used to prepare the molten material (prior to melting and / or solidification and / or (Including the equipment and any refining of the raw materials during melting and / or solidification), and with respect to the abrasive particles, the desired grinding characteristics of the resulting abrasive particles.
[0057]
The metal oxide source and other additives can take any form suitable for the process and equipment used to produce the molten material. The raw materials are the techniques and equipment known in the art for producing conventional fused alumina materials and fused alumina zirconia materials (such as the techniques and equipment for producing conventional fused alumina zirconia abrasive particles (eg, US Pat. 3,781,172 (Pet et al.), 3,891,408 (Rose, et al.), 4,035,162 (Brothers et al.), 4,070,796 No. (Scott), No. 4,073,096 (Ueltz et al.), No. 4,126,429 (Watson), No. 4,457,767 (Poon et al.) No. 5,143,522 (Gibson et al.) And U.S. Pat. No. 31,128 (Waker). It is possible to melt with includes) to see ker) et al)).
[0058]
Examples of furnaces for melting metal oxide sources and other additives include arc furnaces, pit furnaces, arc tap furnaces, electric furnaces, electric arc furnaces and gas fired furnaces. Suitable electric furnaces include furnaces in which the electrodes are arranged to create a "kissing arc", furnaces in which the lower tip of the electrodes are not in contact with the molten mass, and resistive heating via current passing through the melt. Furnaces include submerging the electrodes in a molten mass to provide.
[0059]
The furnace may have a lining (sometimes called a "shell" or "skeleton") that lines the inside of the furnace wall. The lining may be manufactured from a material that does not resemble the composition of the molten material. However, it is typically preferable to manufacture the furnace lining from a composition or material that is similar, sometimes nearly the same, or similar to the composition of the molten material. Thus, during processing, even if the outer (exposed) surface of the lining melts, potential contamination of the melt is reduced or minimized.
[0060]
For some metal oxide sources and other additives, the raw materials may also be preheated before the raw materials are introduced into the furnace or before the raw materials are separately combined with other metal oxide sources and other additives. It may be desirable. For example, if carbonates, nitrates or other salts are used as the metal oxide source, calcine such materials (e.g., at about 400-1000 <0> C) before adding them with other metal oxide source materials. (By heating them in air).
[0061]
Generally, if a metal oxide source and other additives are present, they are heated to the molten state and mixed until the melt is homogeneous. Typically, the melt is heated to and maintained at a temperature at least 50 ° C. (preferably at least 100 ° C.) above the melting point of the melt. If the temperature of the melt is too low, the viscosity of the melt may be undesirably high, thus homogenizing the various metal oxide sources and other additives that make up the melt, or reducing the melt. It makes it more difficult to pour from the furnace or transfer the melt from the furnace to another wind. If the temperature of the melt is too high and / or the melt is heated for too long, energy is wasted and undesirable volatilization of the components of the melt may occur.
[0062]
Optionally, if there is a metal oxide source and other additives (e.g., volatile components (e.g., water or organic solvents) that help to form a homogeneous mixture or blend), a melt may be formed. In some cases, it may be desirable to mix them or blend them differently. For example, a particulate metal oxide source can be milled (ball milling) to mix the materials together and to reduce the size of the particulate material. Other techniques for mixing or blending the metal oxide source and other additives, if present, prior to forming the melt include high shear mixers, paddle mixers, V-blenders. And a tumbler. Milling times can range from minutes to hours, or even days. Optionally, transient materials such as water and organic solvents may be removed from the mixture or blend of metal oxide source and other additives, for example, by heating before forming a melt. For ease of handling, the metal oxide source and other additives may be agglomerated before they enter the furnace.
[0063]
The atmosphere above the melt may be at atmospheric, superatmospheric, or subatmospheric pressure. However, a pressure below atmospheric pressure may be preferred to reduce the number of holes in the resulting solidified material. The atmosphere over the melt may be controlled to provide an oxidizing, reducing, or inert atmosphere that can affect the chemistry of the melt.
[0064]
The reducing conditions during the melting can help to refine the melt. In addition to, or as an alternative to, adding a reducing agent to the melt, suitable reducing conditions may be obtained using a carbon electrode in an electric arc melting furnace. Under suitable reducing conditions, some impurities (eg, silica, iron oxide and titania) convert to their individual molten metal forms, thus leading to higher specific gravity for the melt. These free metal impurities will then tend to sink to the bottom of the furnace.
[0065]
In another embodiment, it may be desirable to oxidize free metals present in the melt before cooling the melt (eg, before transferring the melt from the furnace). For example, an oxygen lance may be inserted into the melt just prior to transferring the melt from the furnace (see, for example, U.S. Patent No. 960,712).
[0066]
The melt can be cooled using any of a variety of techniques known in the art. It is typically possible to tilt the furnace containing the melt to pour the melt onto or into the heat sink. Examples of heat sinks include metal balls (eg, cast iron balls or carbon steel balls), metal bars, metal plates, metal rolls, and the like. In some cases, these heat sink materials may be internally cooled (e.g., water cooled or a suitable refrigerant) to achieve fast cooling rates. The heat sink material may be part of a previously melted material (same or different from the composition to be solidified) or other refractory material.
[0067]
Further, with respect to the heat sink, it is possible to cool the melt by pouring the melt onto or between the metal balls. Balls typically range in diameter from about 1 to 50 cm, more typically from 5 to 25 cm. The melt may be cooled using a book mold. Suitable book molds consist of a plurality of sheets (eg, metal or graphite) that are relatively close to one another. The plates are usually less than 10 cm apart, typically less than 5 cm, preferably less than 1 cm. The melt may be poured into a graphite or cast iron mold to form a slab. It is generally preferred that such "slabs" be relatively thin to achieve faster cooling rates.
[0068]
It is believed that the cooling rate affects the microstructure and physical properties of the solidified material, and thus the molten material. Preferably, the melt is cooled quickly because the size of the crystalline phase of the solidified material generally decreases as the cooling rate increases. Preferred cooling rates are at least 500 ° C / min, more preferably at least 1000 ° C / min, and even more preferably at least 1500 ° C / min. The rate of cooling may depend on several factors, including the melt chemistry, the melting point of the melt, the heat sink type and the heat sink material.
[0069]
Rapid cooling is performed under controlled atmospheres such as reducing, neutral or oxidizing environments to maintain and / or affect the desired crystalline phase, oxidation state, etc. during cooling. May go.
[0070]
Additional details regarding the cooling of the melt can be found, for example, in US Pat. No. Re. 31,128 (Walker et al.), US Pat. No. 3,781,172 (Pett et al.), 4,070. 4,796,887 (Ueltz et al.), 4,415,510 (Richmond), 4,439,845 (Richmond). )) And 5,143,522 (Gibson et al.).
[0071]
The resulting (coagulated) molten material is typically larger in size than desired for the abrasive particles. The molten material is converted into smaller pieces using art-known crushing and / or milling techniques, including roll crushing, canary milling, jaw crushing, hammer milling, ball milling, jet milling and impact crushing, and the like. It is possible or typically converted. In some cases, it is desirable to have two or multiple crushing steps. For example, after the molten material has solidified, the molten material may take the form of a relatively large bulk structure (eg, a diameter greater than 5 cm). The first crushing step may include crushing these larger chunks or "chunks" to form smaller pieces. This crushing of these chunks may be performed using a hammer mill, impact crusher or jaw crusher. Thereafter, these smaller pieces are subsequently crushed to produce the desired particle size distribution. In order to produce the desired particle size distribution (sometimes called grit size or grit grade), it may be necessary to perform a multiple crushing step. Generally, the crushing conditions are optimized to achieve the desired particle shape and size distribution.
[0072]
The shape of the molten abrasive particles according to the present invention depends, for example, on the composition and / or microstructure of the abrasive particles, the shape of the cooled particles, and the hammer that breaks the solidified material (ie, the crushing technique used). Generally, where a "chunky" shape is preferred, more energy may be used to achieve this shape. Conversely, if a "sharp" shape is preferred, less energy may be used to achieve this shape. The crushing technique may be varied to achieve different desired shapes. Alternatively, the abrasive particles may be formed directly into the desired shape by pouring the melt into a mold or allowing the melt to form in the mold.
[0073]
The shape of the abrasive particles may be measured by various techniques known in the art, including apparent density and aspect ratio. The larger the abrasive particle size, the higher the apparent density due to the large chunks associated with the larger particle size. Thus, when comparing apparent densities, the comparison should be made with abrasive particles having essentially the same particle size. In general, the higher the apparent density value, the more the abrasive particles are considered to have a "chunkier" shape. Conversely, the lower the apparent density value, the more abrasive particles are considered to be "sharper". Another way to measure sharpness is by aspect ratio. For example, the aspect ratio of grade 36 can range from about 1: 1 to about 3: 1, typically about 1.2: 1 to 2: 1.
[0074]
The apparent density of the abrasive particles can be measured according to ANSI standard B74.4-1992 (1992). Generally, the apparent density is measured by pouring the abrasive particle sample through the funnel so that the abrasive particles fall through the funnel in a free flowing manner. A collector (typically a graduated cylinder) is directly below the funnel. A predetermined volume of abrasive particles is collected and then weighed. Apparent density is calculated in terms of weight / volume.
[0075]
Abrasive particles according to the present invention can be made using techniques known in the art including the use of industry certification ratings such as ANSI (American Standards Association), FEPA (European Federation of Abrasives) and JIS (Japanese Industrial Standards). It can be used to screen and sort. Abrasive particles according to the present invention typically have from about 0.1 to about 5000 micrometers, more typically from about 1 to about 2000 micrometers, preferably from about 5 to about 1500 micrometers, more preferably from about 100 to about 1500 micrometers. It may be used in sizes from up to about 1500 micrometers and in a wide range of particle sizes.
[0076]
In a given particle size distribution, there is a range of particle sizes from coarse particles to fine particles. In the abrasive art, this range is sometimes referred to as the "fraction", "control" and "fine" portions. Abrasive particles rated according to industry-recognized rating standards define a particle size distribution for each nominal grade within numerical limits. Such industry certification ratings include those known as the American National Standards Institute (ANSI) standards, the European Federation of Abrasive Industries (FEPA) standards, and the Japanese Industrial Standards (JIS) standards. ANSI grade designations (ie, defined nominal grades) include ANSI4, ANSI6, ANSI8, ANSI16, ANSI24, ANSI36, ANSI40, ANSI50, ANSI60, ANSI80, ANSI100, ANSI120, ANSI150, ANSI180, ANSI220, ANSI240, ANSI280, ANSI320. , ANSI 360, ANSI 400 and ANSI 600. Preferred ANSI grades containing abrasive particles according to the present invention are ANSI 8-220. FEPA grade designations include P8, P12, P16, P24, P36, P40, P50, P60, P80, P100, P120, P150, P180, P220, P320, P400, P500, P600, P800, P1000 and P1200. . Preferred FEPA grades containing abrasive particles according to the present invention are P12-P220. The JIS grade names include JIS8, JIS12, JIS16, JIS24, JIS36, JIS46, JIS54, JIS60, JIS80, JIS100, JIS150, JIS180, JIS220, JIS240, JIS280, JIS320, JIS360, JIS400, JIS400, JIS600, JIS800. JIS 1500, JIS 2500, JIS 4000, JIS 6000, JIS 8000 and JIS 10,000 are listed. Preferred JIS grades containing the abrasive particles according to the present invention are JIS 8-220.
[0077]
After crushing and sieving, there are typically a plurality of different abrasive particle size distributions or grades. These multiple grades may not match the needs of the manufacturer or supplier at that particular point in time. To minimize inventory, it is possible to recycle unrequired grades back into molten mass. This recirculation may be performed after a crushing step in which the particles are large chunks or smaller pieces (sometimes called "fine") that have not been sieved to a particular distribution. The charge to the furnace for producing the fused abrasive particles according to the invention consists of 0-100% by weight, typically between 0 and 50% by weight, of recycled molten abrasive particles somewhere. You may.
[0078]
Typically, the true density, sometimes referred to as specific gravity, of a molten material (including molten abrasive particles) according to the present invention is typically at least 80% of the theoretical density. However, lower true density abrasive particles are also useful in abrasive applications. The true density of the molten material according to the invention is preferably at least 85% of theoretical density, more preferably at least 90% of theoretical density, even more preferably at least 95% of theoretical density.
[0079]
Typically, the molten material according to the invention has an average hardness of at least 11 GPa, preferably at least 12, 13 or 14 GPa, more preferably at least 15 GPa, even more preferably at least 16 GPa (ie deformation resistance, "microhardness"). Also called)). In another embodiment, the molten material according to the present invention typically has at least 2.0 MPa^1/2, Preferably at least 2.5MPam^1/2, More preferably at least 3.0 MPam^1/2Average toughness (ie, rupture resistance).
[0080]
For example, it is within the scope of the present invention to provide a surface coating on the molten abrasive particles. Such surface coatings are known, for example, to improve the adhesion between the abrasive particles and the binder material in the abrasive particles. Surface coatings are described, for example, in U.S. Pat. Nos. 1,910,444 (Nicholson), 3,041,156 (Rowse et al.), And 4,997,461 (Mark Hofmatney ( No. 5,009,675 (Kunz et al.), No. 5,042,991 (Kunz et al.) And No. 5,085,671 (Martin et al.). It is described in. Further, in some cases, the addition of a coating improves the abrasive properties of the abrasive particles. In another embodiment, a surface coating may improve the adhesion between the abrasive particles of the present invention and a binder.
[0081]
In another embodiment, after producing a molten material according to the present invention, the molten material may be further heat treated to improve physical properties and / or grinding performance. This heat treatment process may be performed in an oxidizing atmosphere. This heat treatment process is typically performed at a temperature between about 1100C and 1600C, usually between about 1200C and 1400C. The time may range from about 1 minute to several days, usually between about 5 minutes and 1 hour.
[0082]
Other preparative techniques suitable for producing molten materials according to the present invention are disclosed herein and, for example, U.S. Patent Application Nos. 09 / 459,978, 09 / 496,422, filed February 2, 2000, respectively. Nos. 09 / 496,638 and 09 / 496,713 and 09 / 618,876, 09 / 618,879, 09 / 619,106, 09 / 619,191 filed on July 19, 2000, respectively. No. 09 / 619,215, 09 / 619,289, 09 / 619,563, 09 / 619,729 and 09 / 620,262. .
[0083]
For certain molten materials according to the present invention, the eutectic phase constituting the colonies (eg, Al₂O₃-Yb₃Al₅O₁₂-ZrO₂) Has a lamellar arrangement in which one crystal phase (for example, alumina crystal) shows a trigonal shape. Further, the orientation of at least some of the adjacent lamellae (ie, the orientation of eutectic crystallization) follows the orientation of the trigonal (shape) profile at an angle of about 120 degrees. While not wishing to be bound by theory, during crystallization of a melt of composition at or near the three-dimensional eutectic, the primary crystals of one phase (eg, alumina) assume a trigonal shape. It is conceivable that the seeds taken could be crystallized first. The resulting coupled growth of the eutectic in the form of a lamella follows at least initially the seed orientation. The eutectic colony then contains a seed (eg, alumina seed) (or single seed) of the same orientation with the eutectic lamella growth. In addition, the colony boundaries are phase coarsened as observed in two-dimensional eutectics, such as the phase coarseness observed for Comparative Example A (indicated by significant coarsening of the crystals of the eutectic phase immediately adjacent to the colony boundary). May not be shown.
[0084]
Preferred molten materials according to the present invention are thermally stable at elevated temperatures at elevated temperatures as compared to conventional fused alumina zirconia materials (including alumina-zirconia abrasive particles available under the trade designation "NORZON" from Norton Company of Worcester, Mass.). is there. When heating alumina-zirconia eutectic abrasive particles available from Norton Company of Worcester, Mass. Under the trade name "NORZON", e.g., in air to at least about 350 [deg.] C., typically at least a portion of the zirconia is typically tetragonal. And / or undergo a phase transition from cubic to monoclinic. This phase transition is usually detrimental to the structural integrity of the alumina-zirconia material because it involves a volume change to the zirconia crystalline phase. In addition, it has been observed that such phase transitions occur preferentially at the boundaries of eutectic colonies, so that the phase transitions tend to weaken the boundaries, and in turn the mechanical properties (ie, hardness, Strength, etc.). In addition, various impurities, which are typically separated at the eutectic colony boundaries during solidification of the melt, may also undergo volumetric structural changes (eg, due to oxidation) and the mechanical properties (ie, hardness, strength) of the material Etc.).
[0085]
In contrast, preferred molten materials according to the present invention typically do not show a phase transition of the eutectic phase when heated to 1000 ° C. in air (sometimes even up to 1400 ° C.) Therefore, it is thermally stable. While not wishing to be bound by theory, it is believed that this thermal stability allows such molten materials to be incorporated into vitrified bonded articles (eg, vitrified bonded abrasives).
[0086]
The thermal stability of certain preferred molten materials according to the present invention includes differential scanning calorimetry (DTA), thermogravimetric analysis (TGA), X-ray diffraction, hardness measurement, microstructure analysis, color change and interaction with the glass bonding layer. May be measured or exemplified using a variety of different techniques, including: The thermal stability of the molten material can depend, for example, on the composition, chemistry of the molten material and processing conditions.
[0087]
In one test for measuring the thermal stability of certain preferred molten materials according to the present invention, the average hardness of the molten material is measured before and after heating at 1000 ° C. for 4 hours in air. (See Comparative Example B (below) for a more complete description of the test). Although there may be some degradation of the average microhardness after heating in air at 1000 ° C. for 4 hours, the average hardness of the preferred molten material according to the invention after heating in air at 1000 ° C. for 4 hours is: It is at least 85% (preferably at least 90%, more preferably at least 95%, even more preferably at least 100% or more) of the average microhardness of the molten material prior to such heating.
[0088]
Certain preferred molten materials according to the present invention have a thermal stability that determines the average microstructure (eg, porosity, crystal structure, colony size and crystal size (eutectic and primary crystals, if present) and integrity) of the molten material. Observation may be made using a scanning electron microscope (SEM) inspecting before and after heating at 1000 ° C. for 4 hours in air. Certain preferred microstructures of the molten material according to the invention are essentially the same before and after heating at 1000 ° C. for 4 hours in air.
[0089]
Further, the thermal stability of certain preferred molten materials according to the present invention may be illustrated by comparing the color of the molten material before and after heating at 1000 ° C. for 4 hours in air. Certain preferred microstructures of the molten material according to the invention are essentially the same before and after heating at 1000 ° C. for 4 hours in air.
[0090]
The thermal stability of certain preferred molten materials according to the present invention may be illustrated by comparing the powder XRD results of the molten material before and after heating at 1000 ° C. for 4 hours in air. As discussed above, when heating an alumina-zirconia eutectic material in air, typically at least a portion of the zirconia undergoes a phase transition from tetragonal and / or cubic to monoclinic. The effect of this phase transition is typically significant enough to be observed via powder XRD. In contrast, the eutectic phase of certain preferred molten materials according to the present invention does not show such a phase transition when heated to 1000 ° C. in air, and thus no such transition of the eutectic phase is observed in the XRD results. .
[0091]
The fused abrasive particles according to the present invention include coated abrasive products, bonded abrasive products (including vitrified bonded wheel wheels, resinous bonded wheel wheels and metal bonded wheel wheels, cut-off wheels and honing wheels), nonwoven abrasives. It can be used in conventional abrasive products such as products and abrasive brushes. Typically, the abrasive product (ie, the abrasive article) comprises a binder and abrasive particles, at least a portion of which are fused abrasive particles according to the present invention secured within the abrasive product by the binder. Methods of making and using such abrasive products are well known to those skilled in the art. Further, the molten abrasive particles according to the present invention can be used in abrasive applications utilizing powdered abrasive particles such as slurries such as abrasive compounds (eg, polishing compounds), milling media, shot blast media, and vibration mill media. It is possible.
[0092]
Coated abrasive products generally include a backing, abrasive particles, and at least one binder for retaining the abrasive particles on the backing. The backing can be of any suitable material, including fabrics, polymer films, fibers, nonwoven webs, papers, combinations thereof, and processed variants thereof. The binder can be any suitable binder, including an inorganic binder or an organic binder (including thermosetting resins and reactive curable resins). The abrasive particles can be present in one or two layers of the coated abrasive product.
[0093]
An example of a coated abrasive product is depicted in FIG. Referring to this figure, a coated abrasive product 1 has a backing (substrate) 2 and an abrasive layer 3. Abrasive layer 3 includes fused abrasive particles 4 according to the present invention secured to the major surface of backing 2 by make coat 5 and size coat 6. In some cases, a supersize coat (not shown) is used.
[0094]
A bonded abrasive product typically comprises a shaped mass of abrasive particles bound by an organic, metallic or glassy binder. Such shaped mass can take the form of a wheel, for example, a grinding wheel or a cut-off wheel. The diameter of the wheel is typically from about 1 cm to more than 1 meter. The diameter of the cut-off wheel is about 1 cm to greater than 80 cm (more typically 3 cm to 50 cm). The thickness of the cutoff wheel is typically from about 0.5 mm to about 5 cm, more typically from about 0.5 mm to about 2 cm. The shaped mass can also take the form of, for example, a honing wheel, segment, fixed point, disk (eg, dual disk grinder) or other conventional bonded abrasive shape. The bonded abrasive product is typically about 3-50% by volume of binder material, about 30-90% by volume of abrasive particles (or abrasive particle blend), based on the total volume of the bonded abrasive product. , Up to 50% by volume of additives (including grinding aids) and up to 70% by volume of holes.
[0095]
The preferred form is a grinding wheel. Referring to FIG. 2, there is depicted a grinding wheel 10 including molten abrasive particles 11 according to the present invention formed on the wheel and mounted on a hub 12.
[0096]
Nonwoven abrasive products typically include an open porous lofty polymer filament structure having molten abrasive particles according to the present invention distributed throughout the structure and adhesively bonded to the structure by an organic binder. Examples of filaments include polyester fibers, polyamide fibers and polyaramid fibers. In FIG. 3, a schematic representation of a typical nonwoven abrasive product at about 100 times magnification is shown. Such a nonwoven abrasive product includes a fibrous mat 50 as a substrate on which the fused abrasive particles 52 according to the present invention are adhered by a binder 54.
[0097]
Useful abrasive brushes include brushes having a plurality of bristles integral with the backing (eg, US Pat. Nos. 5,427,595 (Pihl et al.) And 5,443,906 (Phil). (Pihl et al.), 5,679,067 (Johnson et al.) And 5,903,951 (Ionta et al.). Preferably, such brushes are made by injection molding a mixture of polymer and abrasive particles.
[0098]
Organic binders suitable for making abrasive products include thermosetting organic polymers. Examples of suitable thermosetting organic polymers include phenolic resins, ureaformaldehyde resins, melamine formaldehyde resins, urethane resins, acrylate resins, polyester resins, aminoplast resins having α, β-unsaturated carbonyl groups in the side chain, and epoxy resins. Acrylated urethanes, acrylated epoxies and combinations thereof. Binder and / or abrasive products include fibers, lubricants, wetting agents, thixotropic materials, surfactants, pigments, dyes, antistatic agents (eg, carbon black, vanadium oxide, graphite, etc.), coupling agents (eg, Additives such as silane coupling agents, titanate coupling agents, zircoaluminate coupling agents), plasticizers and suspending agents may also be included. The amounts of these optional additives are selected to provide the desired properties. The coupling agent can improve the adhesion to the abrasive particles and / or the filler. The binder chemistry may be heat cured, radiation cured, or a combination thereof. Additional details regarding binder chemistry can be found in U.S. Pat. Nos. 4,588,419 (Coul et al.), 4,751,137 (Tumey et al.) And 5,436,063 (Follett, US Pat. Follett) et al.).
[0099]
More particularly with respect to vitrified bonded abrasives, typically vitrified bonded materials that exhibit an amorphous structure are well known in the art. In some cases, the vitrified bonding material includes a crystalline phase. The glassy abrasive product according to the present invention may take the form of wheels (including cut-off wheels), honing wheels, fixed points or other conventional bonded abrasive shapes. A preferred vitrified bonded abrasive product according to the present invention is a grinding wheel.
[0100]
Examples of metal oxides used to form the vitrified bonding material include silica, silicate, alumina, soda, calcia, potasia, titania, iron oxide, zinc oxide, lithium oxide, magnesia, boria, aluminum silicate, boron silicate Examples include silicate glass, lithium aluminum silicate and combinations thereof. Typically, the vitrified bonding material can be formed from a composition that includes 10-100% glass frit. However, more typically, the composition comprises from 20% to 80% glass frit, or from 30% to 70% glass frit. The remaining portion of the vitrified bonding material can be a non-frit material. Alternatively, the vitrified tie layer may be derived from a non-frit containing composition. The vitrified bonding material is typically in the range of about 700C to about 1500C, usually in the range of about 800C to about 1300C, and sometimes in the range of about 900C to about 1200C, about 950C. Aging is at a temperature even within the range of about 1100C to about 1100C. The actual temperature at which the tie layer is aged will depend, for example, on the chemistry of the particular tie layer.
[0101]
Preferred vitrified bonding materials include those comprising silica, alumina (preferably at least 10% by weight alumina) and boria (preferably at least 10% by weight boria). In most cases, the vitrified binding material is an alkali metal oxide (eg, Na₂O and K₂O) (optionally at least 10% by weight of an alkali metal oxide).
[0102]
The binding material may also contain a filler material or grinding aid, typically in the form of a particulate material. Typically, the particulate material is an inorganic material. Examples of fillers useful for the present invention include metal carbonates (eg, calcium carbonate (eg, chalk, calcite, marl, travertine, marble and limestone), calcium magnesium carbonate, sodium carbonate, magnesium carbonate). , Silica (eg, quartz, glass beads, glass bubbles and glass fibers), silicates (eg, talc, clay, (montmorillonite) feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate), metal sulfate (Eg, calcium sulfate, barium sulfate, sodium sulfate, sodium aluminum sulfate, aluminum sulfate), gypsum, vermiculite, wood flour, aluminum trihydrate, carbon black, metal oxide (eg, calcium oxide (lime), oxide Aluminum, titanium dioxide ) And metal sulfites (e.g., calcium sulfite) and the like.
[0103]
Generally, the addition of grinding aids increases the useful life of the abrasive product. Grinding aids are materials that have a significant effect on the chemical and physical processes of polishing, leading to improved performance. Although not wishing to be bound by theory, the grinding aid does not (a) reduce the friction between the abrasive particles and the workpiece being polished, or (b) the abrasive particles do not "cap". (I.e., to prevent the metal particles from fusing onto the abrasive particles), or at least reduce the tendency of the abrasive particles to cap, And / or (d) lowering the grinding force.
[0104]
Grinding aids encompass a wide range of different materials and can be inorganic or organic. Examples of chemical groups of grinding aids include waxes, halogenated organic compounds, halide salts, metals and alloys of metals. Halogenated organic compounds typically decompose during polishing to release halogen acids or gaseous halogenated compounds. Examples of such materials include chlorinated waxes such as tetrachloronaphthalene, pentachloronaphthalene and polyvinyl chloride. Examples of halide salts include sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluoride, potassium chloride and magnesium chloride. Examples of metals include tin, lead, bismuth, cobalt, antimony, cadmium and iron titanium. Other miscellaneous grinding aids include sulfur, organic sulfur compounds, graphite and metal sulfides. It is also within the scope of the present invention to use a combination of different grinding aids, which in some cases may have a synergistic effect. The preferred grinding aid is cryolite, and the most preferred grinding aid is potassium tetrafluoroborate.
[0105]
Grinding aids can be particularly useful in coated and bonded abrasive products. In coated abrasive products, grinding aids are typically used in a supersize coat that is applied over the surface of the abrasive particles. However, sometimes grinding aids are added to the size coat. The amount of grinding aid incorporated into the coated abrasive product is typically about 50-300 g / m²(Preferably about 80 to 160 g / m²). In vitrified bonded abrasive products, grinding aids are typically impregnated into the holes of the product.
[0106]
The abrasive product can contain 100% of the molten abrasive particles according to the present invention or a blend of such abrasive particles with other abrasive and / or diluent particles. However, at least about 2%, preferably at least about 5%, more preferably at least about 30-100% by weight of the abrasive particles in the abrasive product should be abrasive particles according to the present invention. Optionally, the abrasive particles according to the present invention have a ratio of between 5:75 wt%, about 25:75 wt%, about 40:60 wt% or about 50:50 wt% (ie, equivalent by weight). It may be blended with other abrasive particles and / or diluent particles. Examples of suitable conventional abrasive particles include fused aluminum oxide (including white fused alumina, heat treated aluminum oxide and brown aluminum oxide), silicon carbide, boron carbide, titanium carbide, diamond, cubic boron nitride, garnet, fused alumina Zirconia and sol-gel derived abrasive particles and the like. The sol-gel derived abrasive particles may be seeded or non-seed. Similarly, the sol-gel derived abrasive particles may be randomly shaped or may have a shape associated with the particles such as rods or triangles. Examples of sol-gel derived abrasive particles include U.S. Patent Nos. 4,314,827 (Leitheiser et al.), 4,518,397 (Leitheiser et al.), 4,623,364. Nos. (Cottringer et al.), No. 4,744,802 (Schwabel), No. 4,770,671 (Monroe et al.), No. 4,881,951 (Wood) No. 5,011,508 (Wald et al.), No. 5,090,968 (Pellow), No. 5,139,978 (Wood), No. 5, No. 201,916 (Berg et al.), No. 5,227,104 (Bauer), No. 5,366,523 ( -Enhorst et al., 5,429,647 (Larmie), 5,498,269 (Larmie) and 5,551,963 (Larmie). Particles. Additional details regarding sintered alumina abrasive particles produced by using alumina powder as a raw material source are described in U.S. Patent Nos. 5,259,147 (Falz), 5,593,467 (Monroe Monroe) and 5,665,127 (Molgen). In some cases, the blend of abrasive particles may result in an abrasive article that exhibits improved grinding performance as compared to an abrasive particle that includes 100% of either type of abrasive particle.
[0107]
When a blend of abrasive particles is present, the type of abrasive particles forming the blend may be of the same size. Alternatively, the type of abrasive particles may be of a different size. For example, a larger size abrasive particle may be an abrasive particle according to the present invention in combination with another abrasive particle type that is a smaller size particle. Conversely, for example, the smaller sized abrasive particles may be abrasive particles according to the present invention in combination with another abrasive particle type that is a larger sized particle.
[0108]
Examples of suitable diluent particles include marble, gypsum, flint, silica, iron oxide, aluminum silicate, glass (including glass bubbles and glass beads), alumina bubbles, alumina beads and diluent aggregates. The molten abrasive particles according to the invention can also be mixed into or combined with the abrasive agglomerates. The abrasive aggregate particles typically comprise a plurality of abrasive particles, a binder and optional additives. The binder may be organic and / or inorganic. The abrasive agglomerates may be randomly shaped or may have a predetermined shape associated with the particles. The shape may be a block, cylinder, pyramid, coin, square or the like. The abrasive aggregate particles typically have a particle size in the range of about 100 to about 500 micrometers, typically about 250 to about 2500 micrometers. Additional details regarding abrasive agglomerate particles can be found, for example, in U.S. Patent Nos. 4,311,489 (Kressner), 4,652,275 (Blocher et al.), 4,799, No. 939 (Blocher et al.), 5,549,962 (Holmes et al.) And 5,975,988 (Christianson).
[0109]
The abrasive particles may be uniformly distributed throughout the abrasive article, or may be concentrated at selected areas or portions of the abrasive article. For example, in a coated abrasive, there may be two layers of abrasive particles. The first layer comprises abrasive particles other than the abrasive particles according to the invention, and the second (outermost) layer comprises the abrasive particles according to the invention. Similarly, in the bonded abrasive, there may be two separate parts of the wheel. The outermost part may contain the abrasive particles according to the invention, while the innermost part does not contain the abrasive particles according to the invention. Alternatively, the abrasive particles according to the present invention may be evenly distributed throughout the combined abrasive particles.
[0110]
Additional details regarding coated abrasive products can be found, for example, in U.S. Pat. Nos. 4,734,104 (Broberg), 4,737,163 (Larkey), 5,203,884 ( No. 5,152,917 (Pieper et al.), No. 5,378,251 (Culler et al.), No. 5,417,726 (Stout et al.) 5,436,063 (Follett et al.), 5,496,386 (Broberg et al.), 5,609,706 (Benedict et al.), 5, 520,711 (HELMIN), 5,954,844 (Law et al.), 5,961, No. 74 (Gaguriaji (Gagliardi) et al.) And No. 5,975,988 can be seen in (Kurisuchinason (Christinason)). Additional details regarding bonded abrasive products can be found, for example, in U.S. Patent Nos. 4,543,107 (Rue), 4,741,743 (Narayanan et al.), 4,800,685. (Haynes et al.), 4,898,597 (Hay et al.), 4,997,461 (Markhoff-Matheny et al.), 5,038,453 (Narayanan). No. 5,110,332 (Narayanan et al.) And 5,863,308 (Qi et al.). Further details on vitrified bonded abrasives can be found, for example, in U.S. Pat. Nos. 4,543,107 (Rue), 4,898,587 (Hay), and 4,997,461. (Markhoff-Matheny et al.), 5,094,672 (Giles et al.), 5,118,326 (Sheldon et al.), 5,131,926. No. 5,203,886 (Sheldon et al.), No. 5,282,875 (Wood et al.), No. 5,738,696 (Wu) Et al.) And 5,863,308 (Qi et al.). Additional details regarding nonwoven abrasive products can be found, for example, in US Pat. No. 2,958,593 (Hoover et al.).
[0111]
Methods of polishing with abrasive particles according to the present invention range from snagging (ie, high pressure, high material removal) to polishing (eg, polishing medical implants with a coated abrasive belt), the latter typically involving polishing. This is done with a finer clade of agent particles (eg, smaller ANSI 220 and finer). The abrasive particles may be used in precision polishing applications such as grinding a camshaft with a vitrified bonding wheel. The size of the abrasive product used for a particular polishing application will be apparent to those skilled in the art.
[0112]
The polishing with the abrasive particles according to the present invention may be performed in a dry or wet manner. For wet polishing, the liquid may be introduced and supplied in the form of a light mist to complete the flood. Examples of commonly used liquids include water, water-soluble oils, organic lubricants and emulsions. The liquid can function to reduce the heat associated with polishing and / or function as a lubricant. Liquids may contain minor amounts of additives such as germicides and antifoams.
[0113]
Abrasive particles according to the present invention can be used to form workpieces such as aluminum metal, carbon steel, mild steel, tool steel, stainless steel, hardened steel, titanium, glass, ceramic, wood, wood-like materials, paints, painted surfaces and organic coated surfaces. It may be used for polishing. The force applied during polishing typically ranges from about 1 to about 100 kg.
[0114]
Example
The following examples further illustrate the invention, but the specific materials and amounts of materials and other conditions and details listed in these examples should not be construed as unduly limiting the invention. Various modifications and alterations of this invention will become apparent to those skilled in the art. All parts and percentages are by weight unless otherwise indicated.
[0115]
Comparative Example A
242.5 g of alumina powder (obtained under the trade designation "APA-0.5" from Condea Vista, Tucson, Ariz.), 257.5 g of gadolinium oxide powder (obtained from Polycorp, Inc., Blair, CA) , 0.6 g of a dispersant (obtained under the trade name "DURAMAX D-30005" from Rohm and Haas Company of Deer Park, Texas) and 150.6 g of distilled water were charged into a polyethylene bottle. The powder contains 77 mol% of Al₂O₃And 23 mol% Gd₂O₃Was present in an amount that resulted in About 450 g of alumina milling media (10 mm diameter, 99.9% alumina, obtained from Union Process, Akron, OH) was added to the bottle and the mixture was milled for 4 hours to thoroughly mix the ingredients. After milling, the milling media was removed and the slurry was poured onto a glass ("PYREX") dish, where the slurry was dried using a heat gun held about 46 cm (18 inches) above the dish. The dish was shaken while drying to prevent settling of the powder before complete drying. After drying using a heat gun, the dishes were placed in a drying oven at 90 ° C. for another 30 minutes to dry the material more completely. The dry powder layer (bed) was then scored with a spatula and scraped from the dish to form small material flakes. Each flake weighed about 0.5-3 g. The flakes were fired in air by heating the flakes to 600 ° C. at a rate of about 1 ° C./min, and then holding the flakes at 600 ° C. for 1 hour. Thereafter, the power for the furnace power was turned off, and the furnace was left to cool and return to room temperature.
[0116]
Some of the fired flakes were melted in an arc discharge furnace (Model No. 1-VAMF-20-22-45 from Advanced Vacuum Systems, Air, Mass.). About 15 g of fired flakes were placed on a cooled copper plate located inside the furnace chamber. The furnace chamber was evacuated and then filled with argon gas at a pressure of 200 Torr. The arc sparked between the electrode and the plate. The temperature generated by the arc discharge was high enough to rapidly melt the fired flakes. After melting was over, the material was maintained in the molten state for 30 seconds to homogenize the melt. The resulting melt was quickly cooled by turning off the arc and allowing it to cool on its own. Rapid cooling was ensured by the small mass of sample and the large endothermic capacity of the water-cooled copper plate. After turning off the power to the furnace, the molten material was removed from the furnace within one minute. Without wishing to be bound by theory, it is estimated that the cooling rate of the melt on the surface of the water-cooled copper plate was 1500 ° C./min. The color of the molten material was white-yellow.
[0117]
FIG. 8 is a scanning electron microscope (SEM) micrograph of a polished cross section of the molten material of Comparative Example A. Polished sections were prepared by conventional mounting and polishing techniques. Polishing was performed using a polisher (obtained from Buehler, Lakeburg, Ill. Under the trade name “ECOMMET3TYPE @ POLISHER-GRINDER”). The sample was polished with a diamond wheel for about 3 minutes, followed by 3 minutes with each of the 45, 30, 15, 9 and 3 micrometer diamond slurries. The polished sample was coated with a thin layer of gold-palladium and viewed using a JEOL @ SEM (Model @ JSM-840A). Referring again to FIG. 8, the photomicrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5-20 micrometers. Based on inspection of polished samples using SEM in powder X-ray diffraction and backscatter mode for a portion of Comparative Example A material, the white portion of the micrograph shows crystalline GdAlO₃And the dark part is α-Al₂O₃It is thought that was. The width of these phases observed in the polished section was less than about 0.7 micrometers. It is also noted that many holes were observed in the molten material.
[0118]
Comparative Example A Molten material was crushed into (abrasive) particles by using a "Chipmunk" jaw crusher (Type @ VD manufactured by BICO Inc., Burbank, Calif.) And -25 + 30 and -30 + 35 mesh portions (USA standard test sieve). These two mesh portions were combined to form a 50/50 blend. 30 g of a 50/50 blend of −25 + 30 portions and −30 + 35 mesh portions was incorporated into the coated abrasive disc. Coated abrasive discs were manufactured according to conventional procedures. Conventional calcium carbonate filled phenolic make resin (48% resole phenolic resin diluted to 81% solids with water and glycol ether, 52% calcium carbonate) and conventional cryolite filled phenolic size resin (78% in water and glycol ether) Vulcanized fiber lining 12.8 cm in diameter and 0.8 mm thick (center 2.2 cm in diameter) using 32% resole phenolic resin diluted to 2% solids, 2% iron oxide, 66% cryolite) (With holes) were bonded with the molten abrasive particles. Wet makeup resin weight is about 185g / m²Met. Immediately after applying the make coat, the molten abrasive particles were electrostatically applied. The make resin was pre-cured at 88 ° C. for 120 minutes. Thereafter, a cryolite-filled phenolic size coat was coated over the make coat and abrasive particles. Wet size weight is about 850g / m²Met. The size resin was cured at 99 ° C. for 12 hours. The coated abrasive disc was bent before the test.
[0119]
Comparative Example B
(A) 145.6 g of alumina powder ("APA-0.5"), 151.2 g of lanthanum oxide powder (obtained from Molycorp, Inc., Blair, CA), 0.6 g of dispersant ("DURAMAX" D-30005 ") and 129.5 g of distilled water were charged into a polyethylene bottle, and (b) the powder contained 75 mol% of Al.₂O₃And 25 mol% La₂O₃Comparative Example B molten material, abrasive particles and disk were prepared as described in Comparative Example A, except that they were present in an amount that resulted in The color of the molten material was white-red. However, some of the abrasive particles were redder than others.
[0120]
FIG. 9 is a scanning electron microscope (SEM) photomicrograph of a polished cross section of a melted material of Comparative Example B (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5-30 micrometers. Based on inspection of polished samples using SEM in powder X-ray diffraction and backscattering mode for a portion of Comparative Example B material, the white part of the micrograph shows crystalline LaAlO₃And the dark part is crystalline LaAl₁₁O₁₈It is thought that was. The width of these phases observed in the polished section was less than about 0.5 micrometers. Furthermore, large primary crystals (LaAlO) that exist in the form of dendrites₃Is observed in some areas of the polished section and La₂O₃A possible deviation of the composition from a strict eutectic composition towards a rich composition was suggested.
[0121]
Comparative Example B Powdered abrasive particles (combined with the abrasive particles of Comparative Examples C and D) (about 10 mesh in size) were obtained from a mounting resin (Buehler, Ltd., Lakeburg, Ill.) Under the trade name "ECOMMET". ), The average microhardness of the abrasive particles of Comparative Example B was measured. The resulting cylinder of resin was about 2.5 cm (1 inch) in diameter and about 1.9 cm (0.75 inch) in height. A conventional grinder / polisher (obtained from Buehler Ltd. under the trade name "ECOMMET"), together with a final polishing step using a 1 micrometer diamond slurry (obtained under the trade name "METADI" from Buehler Ltd.). The attached sample was polished using conventional diamond slurry and a polished cross section of the sample was obtained.
[0122]
Microstructure measurements were performed using a conventional microstructure tester equipped with a Vickers indenter using a 500 g indentation load (obtained under the trade name "MITUTYOYO MVK-VL" from Mitutoyo Corporation, Tokyo, Japan). The microstructure was measured in accordance with the guidelines described in ASTM Test Method E384 “Measurement Method for Microhardness of Material (1991)”. The microhardness value was the average of 20 measurements. The average microhardness was 15.0 GPa.
[0123]
Some Comparative Example B abrasive particles (together with the Comparative Example C and D abrasive particles) were heated in a platinum crucible, heated to 1000 ° C. at 50 ° C./hour, and 1000 ° C. (in air). For 4 hours, and then cooled to room temperature at about 100 ° C./hour. The color of Comparative Example B abrasive particles after heating was the same as before heating (ie, white-red). The average microhardness of the abrasive particles of Comparative Example B after heating was 14.1 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed for Comparative Example B abrasive particles after heating was substantially the same as the microstructure observed before heating.
[0124]
Some Comparative Example B abrasive particles (together with those of Comparative Examples C and D) were also placed in a platinum crucible and heated, heated to 1000 ° C. at 50 ° C./hour, and 1000 ° C. (in air). C. for 8 hours, then cooled to room temperature at about 100.degree. C./hour. The color of Comparative Example B abrasive particles after heating was the same as before heating (ie, white-red). The average microhardness of the abrasive particles of Comparative Example B after heating was 14.3 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed for Comparative Example B abrasive particles after heating was substantially the same as the microstructure observed before heating.
[0125]
Comparative Example B The effect of the two vitrified binders on the abrasive particles was evaluated as follows. 70 parts of glass frit (39.9% SiO₂, 28.5% B₂O₃, 15.6% Al₂O₃, 13.9% Na₂O and 4.1% K₂O, obtained from Ferro Corporation of Cleveland, Ohio under the trade name "FERRO FRIT 3227", 27 parts of Kentucky Ball Clay (No. 6DC, obtained from Old @ Hickory @ Clay @ Company of Hickory, Kentucky), 3.5 parts of Li.₂CO₃(From Alfa Aesar Chemical Company of Ward Hill, Mass.) And 625 g of 0.5 cm (1.3 cm) plastic coated steel media in a plastic jar (4.3 / 8 inch (11.1 cm) high. A first vitrified bonding material was prepared by dosing to a diameter of 4.3 / 8 inch (11.1 cm) and then dry grinding the contents at 90 rpm for 7 hours. About 45% SiO₂, About 19% Al₂O₃, About 20% B₂O₃, About 10% Na₂O, about 3% K₂O, about 1.5% Li₂The composition was formulated to provide a vitrified binder comprising O and about 1.5% CaO. The dry ground material and Example 2 abrasive particles (as well as Example 3 and 4 abrasive particles) were pressed into 3.2 cm x 0.6 cm (1.25 in x 0.25 in) pellets. The pellets were heated at 50 ° C./hour to 1000 ° C., held at 1000 ° C. (in air) for 8 hours, and then cooled to room temperature at about 100 ° C./hour. 26 parts of Comparative Example B, C and D abrasive particles (ie, Comparative Example B, C and D abrasive particles are mixed together but differentiated visually based on color and under SEM based on composition) Was possible) (-20 + 30 mesh), 0.24 parts hydrolyzed starch (obtained under the trade designation "DEXTRIN" from Aldrich Chemical Company, Milwaukee, Wis.), 0.02 parts glycerin (from Aldrich Chemical Company). Pellets were prepared by mixing, in that order, 0.72 parts of water, 3.14 parts of the dry ground material, and 0.4 parts of hydrolyzed starch ("DEXTRIN"). The pellet was pressed under a load of 2273 kg (5000 lb.). The polished sections prepared as described above were examined for microhardness measurements using SEM in secondary electron mode. The microstructure observed after heating was substantially the same as the microstructure observed before heating. The color of Comparative Example B abrasive particles after heating with the vitrified binder was the same as before heating (ie, white-red).
[0126]
45 parts of Kentucky Ball Clay (No6DC, obtained from Old Hickory Clay Company), 28 parts of anhydrous sodium tetraboride (obtained from Alfa Aesar Chemical Company), 25 parts of feldspar (Feldor, Atlanta, Georgia) (Obtained under the trade name "G-200 Feldspar") 3.5 parts of Li₂CO₃(Obtained from Alfa Aesar Chemical Company), 2.5 parts of CaSiO3 (obtained from Alfa Aesar Chemical Company), and 625 g of 0.5 inch diameter plastic-coated steel media in a plastic jar (diameter). The second glass was poured into a 4.3 / 8 inch (11.1 cm), 4.3 / 8 inch (11.1 cm) high diameter, and then the contents were dried and ground at 90 rpm for 7 hours. A chemically bonded material was prepared. About 45% SiO₂, About 19% Al₂O₃, About 20% B₂O₃, About 10% Na₂O, about 3% K₂O, about 1.5% Li₂The composition was formulated to provide a vitrified binder comprising O and about 1.5% CaO. The dried and ground material and Comparative Example B abrasive particles were pressed into 3.2 cm x 0.6 cm (1.25 in x 0.25 in) pellets. The pellets were heated at 50 ° C./hour to 1000 ° C., held at 1000 ° C. (in air) for 8 hours, and then cooled to room temperature at about 100 ° C./hour. 26 parts of Comparative Example B, C and D abrasive particles (i.e., the Comparative Example B, C and D abrasive particles were mixed together) (-20 + 30 mesh), 0.24 part of hydrolyzed starch ("DEXTRIN") ), 0.02 parts of glycerin (obtained from Aldrich Chemical Company), 0.72 parts of water, 3.14 parts of dry ground material and 0.4 parts of hydrolyzed starch ("DEXTRIN"). A pellet was prepared by mixing in order. The pellet was pressed under a load of 2273 kg (5000 lb.). The polished sections prepared as described above were examined for microhardness measurements using SEM in secondary electron mode. The microstructure observed after heating was substantially the same as the microstructure observed before heating. The color of Comparative Example B abrasive particles after heating with the vitrified binder was the same as before heating (ie, white-red).
[0127]
Comparative Example C
(A) 143.6 g of alumina powder ("APA-0.5"), 147.6 g of neodymium oxide powder (obtained from Molycorp, Inc., Blair, CA), 0.6 g of dispersant ("DURAMAX" D-30005 ") and 138.5 g of distilled water were charged into a polyethylene bottle, and (b) the powder contained 75 mol% of Al.₂O₃And 25 mol% Nd₂O₃Comparative Example C The molten material, abrasive particles and disk were prepared as described in Comparative Example A, except that they were present in an amount that resulted in The color of the molten material was white-blue. However, some of the abrasive particles were bluer than others.
[0128]
FIG. 10 is a scanning electron microscope (SEM) micrograph of a polished cross section of the molten material of Comparative Example F (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 10 to 40 micrometers. Based on inspection of polished samples using SEM in powder X-ray diffraction and backscatter mode for a portion of Comparative Example C material, the white portion of the micrograph shows crystalline NdAlO₃And the dark part is crystalline NdAl₁₁O₁₈It is thought that was. The width of these phases observed in the polished section was less than about 0.5 micrometers. Furthermore, large primary crystals (NdAlO) that exist in the form of dendrites₃Is observed in some areas of the polished section and Nd₂O₃A possible deviation of the composition from a strict eutectic composition towards a rich composition was suggested.
[0129]
Comparative Example C The average microhardness of the abrasive particles was determined to be 14.5 GPa as described above in Comparative Example B.
[0130]
Some Comparative Example C abrasive particles (together with Comparative Example B and D abrasive particles) were heated in a platinum crucible, heated to 1000 ° C. at 50 ° C./hour, and 1000 ° C. (in air) For 4 hours, and then cooled to room temperature at about 100 ° C./hour. The color of Comparative Example C abrasive particles after heating was the same as before heating (ie, white-blue). The average microhardness of Comparative Example C abrasive particles after heating was 14.1 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed for Comparative Example C abrasive particles after heating was substantially the same as the microstructure observed before heating.
[0131]
Some Comparative Example C abrasive particles (together with those of Comparative Examples B and D) were also heated in a platinum crucible, heated to 1000 ° C. at 50 ° C./hour, and 1000 ° C. (in air). C. for 8 hours, then cooled to room temperature at about 100.degree. C./hour. The color of Comparative Example C abrasive particles after heating was the same as before heating (ie, white-blue). The average microhardness of the abrasive particles of Comparative Example C after heating was 14.5 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed for Comparative Example C abrasive particles after heating was substantially the same as the microstructure observed before heating.
[0132]
Comparative Example C The effect of the two vitrified binders on the abrasive particles was evaluated as described in Comparative Example B. The polished sections were examined using a secondary electron mode SEM. The microstructure observed after heating was substantially the same as the microstructure observed before heating. The color of Comparative Example C abrasive particles after heating with the vitrified binder was the same as before heating (ie, white-blue).
[0133]
Comparative Example D
Lanthanum carbonate powder (obtained from Aptec Service, LLC, Houston, Texas, Lot No. SH99-5-7) was heated to 900 ° C. to convert it to lanthanum oxide and some cerium (IV) oxide ( The manufacturer's conversion specification is 95% LA₂O₃And 4.19% CeO₂And the yield of carbonate to oxide was 49.85% by weight metal oxide). (A) 148.6 g of lanthanum oxide / cerium oxide powder, 146.4 g of alumina powder ("APA-0.5"), 0.6 g of dispersant ("DURAMAX @ D-30005") and 141.3 g of distillation Water was charged into a polyethylene bottle, and (b) the powder contained 75 mol% of Al.₂O₃And 25 mol% La₂O₃/ Ce₂O₃Comparative Example D The molten material, abrasive particles and disk were prepared as described in Comparative Example A, except that they were present in an amount that resulted in It was observed that the slurry was significantly more viscous than the slurry of Comparative Example B. The color of the molten material was light orange.
[0134]
FIG. 11 is a scanning electron microscope (SEM) micrograph of a polished cross section of a melted material of Comparative Example D (prepared as described in Comparative Example B). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5 to 25 micrometers. Based on inspection of polished samples using SEM in powder X-ray diffraction and backscatter mode for a portion of Comparative Example D material, the white part of the micrograph shows crystalline LaAlO₃And the dark part is crystalline LaAl₁₁O₁₈It is thought that was. The width of these phases observed in the polished section was less than about 0.5 micrometers. Furthermore, large primary crystals (LaAlO) that exist in the form of dendrites₃Is observed in some areas of the polished section and La₂O₃A possible deviation of the composition from a strict eutectic composition towards a rich composition was suggested.
[0135]
Comparative Example D The average microhardness of the abrasive particles was determined to be 14.8 GPa as described above in Comparative Example B.
[0136]
Some Comparative Example D abrasive particles (along with those of Comparative Examples B and C) were heated in a platinum crucible, heated at 50 ° C / hr to 1000 ° C, and 1000 ° C (in air). For 4 hours, and then cooled to room temperature at about 100 ° C./hour. The color of Comparative Example D abrasive particles after heating was the same as before heating (ie, bright orange). The average microhardness of the abrasive particles of Comparative Example D after heating was 14.7 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed for Comparative Example D abrasive particles after heating was substantially the same as the microstructure observed before heating.
[0137]
Some Comparative Example D abrasive particles (together with the Comparative Example B and C abrasive particles) were also heated in a platinum crucible, heated to 1000 ° C. at 50 ° C./hour, and 1000 ° C. (in air). C. for 8 hours, then cooled to room temperature at about 100.degree. C./hour. The color of Comparative Example D abrasive particles after heating was the same as before heating (ie, bright orange). The average microhardness of the abrasive particles of Comparative Example D after heating was 14.1 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed for Comparative Example D abrasive particles after heating was substantially the same as the microstructure observed before heating.
[0138]
Comparative Example D The effect of the two vitrified binders on the abrasive particles was evaluated as described in Comparative Example B. The polished sections were examined using a secondary electron mode SEM. The microstructure observed after heating was substantially the same as the microstructure observed before heating. The average microhardness of Comparative Example D abrasive particles after heating in the two vitrified binders was 14.2 GPa and 14.3 GPa, respectively. The color of the Comparative Example D abrasive particles after heating with each of the two vitrified binder materials was the same as before heating (ie, light orange).
[0139]
Comparative Example E
Comparative Example A Heat treated fused alumina abrasive particles (obtained under the trade name "ALODUR @ BFRPL" from Triebacher, Villach, Austria) were used in Comparative Example A except that the fused abrasive particles were used. A Comparative Example E coated abrasive disc was prepared as described above.
[0140]
Comparative Example F
Alumina-zirconia abrasive particles (53% AL₂O₃And 47% Zr₂Comparative Example A having the eutectic composition of O (obtained under the trade name "NORZON" from Norton Company of Worcester, Mass.) Was used in Comparative Example A except that the fused abrasive particles were used. A Comparative Example F coated abrasive disc was prepared as described above.
[0141]
Comparative Example F The average microhardness of the abrasive particles was determined to be 16.0 GPa, as described above in Comparative Example B. Comparative Example F The color of the abrasive particles was gray-dark blue.
[0142]
Some Comparative Example F abrasive particles were heated in a platinum crucible, heated at 50 ° C./hour to 1000 ° C., held at 1000 ° C. (in air) for 4 hours, and then at about 100 ° C./hour And cooled to room temperature. The color of the abrasive particles after heating was beige. The average microhardness of the abrasive particles after heating was 12.9 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. FIG. 16 shows a SEM electron micrograph of the abrasive particles of Comparative Example F before heating. FIG. 17 shows an SEM electron micrograph of the abrasive particles of Comparative Example F after heating. The microstructure observed after heating was different from the microstructure observed before heating. Differences were most notably observed at the colony boundaries.
[0143]
By comparing the peak intensity of 111 of cubic and / or tetragonal reflection at about 2θ = 30 degrees with the peak intensity of 111 of monoclinic reflection at about 2θ = 28 degrees, the above-mentioned comparison before and after the heat treatment is performed. Example F Another powder X-ray diffraction (using a Phillips @ XRG3100 X-ray diffractometer equipped with 1.54050 Angstroms copper Kα1 radiation) was used to qualitatively determine the phases present in the abrasive particles. For reference, see "Phase Analysis in Zirconia Systems", Garvie, R .; C. and @Nicholson, P.M. S. , Journal of the American American Ceramic Society, Vol. 55 (6), pp. 303-305, 1972. The sample was ground and -120 mesh powder was used for analysis. Comparative Example F abrasive particles that were not heat treated contained both monoclinic and cubic and / or tetragonal zirconia phases. For the heat treated sample, a decrease in cubic and / or tetragonal content was observed with a corresponding increase in monoclinic phase content.
[0144]
Some Comparative Example F abrasive particles were heated in a platinum crucible, heated at 50 ° C./hour to 1000 ° C., held at 1000 ° C. (in air) for 8 hours, and then at about 100 ° C./hour And cooled to room temperature. The color of the abrasive particles after heating was beige. The average microhardness of the abrasive particles after heating was 12.8 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. FIG. 18 shows an SEM electron micrograph of the abrasive particles of Comparative Example F after heating. The microstructure observed after heating was different from the microstructure observed before heating. Differences larger than those observed for the heat treatment at 1000 ° C. for 4 hours were again most prominently observed at the colony boundary.
[0145]
The effect of the two vitrified binders on the Comparative Example F abrasive particles as described in Comparative Example B except that there were 20 parts of Comparative Example F abrasive particles (-20 + 30 mesh) instead of 26 parts. The effect was evaluated. The average microhardness of the abrasive particles after heating in the vitrified binding material was 13.6 GPa. However, some of the abrasive particles of Comparative Example F exhibited severe deterioration such that the microhardness measurement could not be effectively performed (parts of the particles were too weak). Although the majority of the heat treated abrasive particles were beige, the colors varied. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. FIG. 19 shows an SEM electron micrograph of the abrasive particles of Comparative Example F after heating. The microstructure observed after heating was different from the microstructure observed before heating. Differences larger than those observed for the heat treatment at 1000 ° C. for 4 hours were again most prominently observed at the colony boundary.
[0146]
The average microhardness of the heated abrasive particles in the second vitrified bonding material was 13.4 GPa. However, some of the abrasive particles of Comparative Example F exhibited severe deterioration such that the microhardness measurement could not be effectively performed (parts of the particles were too weak). Although the majority of the heat treated abrasive particles were beige, the colors varied. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed after heating was different from the microstructure observed before heating. Differences larger than those observed for the heat treatment at 1000 ° C. for 4 hours were again most prominently observed at the colony boundary.
[0147]
Comparative Example G
Comparative Example A A sol-gel derived abrasive particle (commercially available from 3M @ Company of St. Paul, Minn. Under the trade name "321 CUBITRON") was used in place of the fused abrasive particle. A Comparative Example G coated abrasive disc was prepared as described above.
[0148]
Grinding performance of Comparative Examples AG
Comparative Examples AG The grinding performance of the coated abrasive disc was evaluated as follows. Each coated abrasive disc was mounted on a graded aluminum backup pad and used to grind a previously weighed 1.25 cm x 18 cm x 10 cm 1018 mild steel workpiece surface. While the disk was driven at 5,000 rpm, the portion of the disk above the inclined edge of the backup pad contacted the workpiece with a load of 8.6 kg. Each disk was used to grind individual workpieces sequentially over one minute intervals. The total cut was the sum of the amount of material removed from the workpiece throughout the test period. The total amount cut by each sample after 12 minutes of grinding and the amount cut at the twelfth time point (ie, the final amount cut) are reported in Table 1 below.
[0149]
[Table 1]
Table 1

[0150]
Comparative Example H
(A) 144.5 g of alumina powder ("APA-0.5"), 147.4 g of cerium (IV) oxide (CeO₂) Powder (obtained from Aldrich Chemical Company, Inc.), 0.6 g dispersant ("DURAMAX D-30005") and 137.5 g distilled water were charged into a polyethylene bottle; , 75 mol% Al₂O₃And 25 mol% Ce₂O₃Comparative Example H molten material and abrasive particles were prepared as described in Comparative Example A, except that they were present in an amount that resulted in The color of the molten material was dark yellow-green.
[0151]
FIG. 12 is a scanning electron microscope (SEM) photomicrograph of a polished cross section of a melted material of Comparative Example H (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5-30 micrometers. Comparative Example H Based on inspection of a polished sample using SEM in powder X-ray diffraction and backscatter mode for a portion of the material, the white portion of the micrograph shows crystalline CeAlO₃And crystalline CeO₂And the dark part is crystalline CeAl₁₁O₁₈It is thought that was. The width of these phases observed in the polished section was less than about 0.5 micrometers. Furthermore, large primary crystals (CeAlO) present in the form of dendrites₃And / or CeO₂Is observed in some areas of the polished section and CeAlO₃And / or CeO₂A possible deviation of the composition from a strict eutectic composition towards a rich composition was suggested.
[0152]
Comparative Example I
(A) 146.5 g alumina powder ("APA-0.5"), 147.4 g dysprosium oxide powder (obtained from Aldrich Chemical Company, Inc.), 0.6 g dispersant ("DURAMAX @ D- 30005 ") and 136.3 g of distilled water were charged into a polyethylene bottle, and (b) the powder contained 78 mole% Al.₂O₃And 22 mol% Dy₂O₃Comparative Example I molten material and abrasive particles were prepared as described in Comparative Example A, except that they were present in an amount that resulted in The color of the molten material was white.
[0153]
FIG. 13 is a scanning electron microscope (SEM) photomicrograph of a polished cross section of the molten material of Comparative Example I (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5-20 micrometers. Based on inspection of polished samples using SEM in powder X-ray diffraction and backscatter mode of a portion of Comparative Example I material, the white part of the micrograph was crystalline Dy.₃Al₅O₁₂And the dark part is α-Al₂O₃It is thought that was. The width of these phases observed in the polished section was less than about 1 micrometer. No primary crystals were observed.
[0154]
Comparative Example J
(A) 146.3 g of alumina powder ("APA-0.5"), 148.4 g of ytterbium oxide powder (obtained from Aldrich Chemical Company, Inc.), 0.6 g of dispersant ("DURAMAX @ D- 30005 ") and 139.6 g of distilled water were charged into a polyethylene bottle, and (b) the powder contained 78.6 mol% of Al.₂O₃And 21.4 mol% Yb₂O₃Comparative Example J molten material and abrasive particles were prepared as described in Comparative Example A, except that they were present in an amount that resulted in The color of the molten material was gray.
[0155]
FIG. 14 is a scanning electron microscope (SEM) micrograph of a polished cross section of a melted material of Comparative Example J (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5 to 25 micrometers. Comparative Example J Based on inspection of a polished sample of a portion of the material using powder X-ray diffraction and SEM in backscatter mode, the white portion of the micrograph shows crystalline Yb₃Al₅O₁₂And the dark part is α-Al₂O₃It is thought that was. The width of these phases observed in the polished section was less than about 1 micrometer. Furthermore, large primary crystals (α-Al) present in the form of dendrites₂O₃Is observed in some areas of the polished cross section and Al₂O₃A possible deviation of the composition from a strict eutectic composition towards a rich composition was suggested.
[0156]
Comparative Example K
(A) 149.5 g of alumina powder ("APA-0.5"), 149.4 g of yttria-stabilized zirconia oxide powder (94% by weight of ZrO₂(+ HfO₂) And 5.4% by weight of Y₂O₃Of the nominal composition of Zirconia @ Sales, Inc. of Marietta, Georgia. Was added under the trade name "HSY3.0", 0.6 g of a dispersant ("DURAMAX @ D-30005") and 136.5 g of distilled water to a polyethylene bottle, and (b) powder was 54.8 mol% Al₂O₃And 45.2 mol% of ZrO₂Comparative Example K molten material and abrasive particles were prepared as described in Comparative Example A, except that they were present in an amount that resulted in The color of the molten material was white.
[0157]
FIG. 15 is a scanning electron microscope (SEM) micrograph of a polished cross section of a melted material of Comparative Example K (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5 to 40 micrometers. Based on inspection of polished samples using SEM in powder X-ray diffraction and backscatter mode for a portion of Comparative Example K material, the white portion of the micrograph shows crystalline ZrO₂And the dark part is α-Al₂O₃It is thought that was. The width of these phases observed in the polished section was less than about 0.5 micrometers.
[0158]
The average microhardness of Comparative Example K was determined to be 15.3 GPa as described above in Comparative Example B.
[0159]
Some Comparative Example K particles were heated in a platinum crucible, heated at 50 ° C./hour to 1000 ° C., held at 1000 ° C. (in air) for 4 hours, then at about 100 ° C./hour to room temperature. And cooled. The color of the abrasive particles after heating was white. The average microhardness of the abrasive particles after heating was 15.0 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. An SEM micrograph of the comparative example K material before heating is shown in FIG. The microstructure observed after heating was substantially the same as the microstructure observed before heating.
[0160]
By comparing the peak intensity of 111 of cubic and / or tetragonal reflection at about 2θ = 30 degrees with the peak intensity of 111 of monoclinic reflection at about 2θ = 28 degrees, the above-mentioned comparison before and after the heat treatment is performed. Example K Another X-ray powder diffraction as described above for Comparative Example F was used to qualitatively measure the phases present in the material. The non-heat treated Comparative Example K material mainly contained cubic and / or tetragonal zirconia before and after heat treatment (ie, no significant difference was observed in the X-ray diffraction results).
[0161]
Some Comparative Example K particles were also heated in a platinum crucible, heated at 50 ° C./hour to 1000 ° C., held at 1000 ° C. (in air) for 8 hours, and then at about 100 ° C./hour. Cooled to room temperature. The color of the abrasive particles after heating was white. The average microhardness of the abrasive particles after heating was 15.0 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed after heating was slightly different from the microstructure observed before heating. An SEM micrograph of Comparative Example K after heating is shown in FIG. Generally ZrO₂Some cracks were observed in the heat-treated material near the primary crystal.
[0162]
Comparative Examples B, C, F and K Differential Scanning Calorimetry (DTA) and Thermogravimetric Analysis (TGA) of Abrasive Particles / Materials
Differential scanning calorimetry (DTA) and thermogravimetric analysis (TGA) were performed on each of Comparative Examples B, C, F and K abrasive particles / material. Each material was crushed with a mortar and pestle and sieved to retain particles in the 400-500 micron size range.
[0163]
A DTA / TGA test was performed on each of the sieved samples (using an instrument obtained from Netzsch Instruments, Selb, Germany under the trade name "NETZSCH STA 409 DTA / TGA"). 100 microliter Al₂O₃The amount of each sample sieved in the sample holder was 127.9 micrograms (Comparative Example B), 125.8 micrograms (Comparative Example K), and 127.3 micrograms (Comparative Example B). . Each sample was heated in still air from room temperature (about 25 ° C.) to 1300 ° C. at a rate of 10 ° C./min.
[0164]
Referring to FIG. 4, line 167 is the DTA data plotted for the Comparative Example B material. Line 169 is the plotted TGA data. Referring to FIG. 5, line 197 is the DTA data plotted for the Comparative Example C material. Line 199 is the plotted TGA data. Referring to FIG. 6, line 177 is the DTA data plotted for the Comparative Example K material. Line 179 is the plotted TGA data. Referring to FIG. 7, line 187 is the DTA data plotted for the Comparative Example F material. Line 189 is the plotted TGA data. The weight change of the sample through the TGA test was 0.22% for Comparative Example B, 0.22% for Comparative Example C, 0.73% for Comparative Example K, and 1.16% for Comparative Example F. Met.
[0165]
Example 1
122.4 g alumina powder ("APA-0.5"), 132.6 g ytterbium oxide powder (obtained from Aldrich Chemical Company, Inc.) instead of gadolinium oxide powder, 45 g zirconium oxide powder (100 wt. % ZrO₂(+ HfO₂) Of the nominal composition of Zirconia @ Sales, Inc. of Marietta, Georgia. DK-2), 0.6 g dispersant ("DURAMAX @ D-30005") and 140.2 g distilled water were charged to a polyethylene bottle. Example 1 A molten material and abrasive particles were prepared as described above. The color of the molten material was white-grey.
[0166]
FIG. 22 is a scanning electron microscope (SEM) micrograph of a polished cross section of the Example 1 material (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5 to 25 micrometers. Example 1 Based on examination of a polished sample of a portion of the material using powder X-ray diffraction and SEM in backscatter mode, the white portion of the micrograph shows crystalline Yb₃Al₅O₁₂And the dark part is crystalline α-Al₂O₃It is thought that was. ZrO₂The shape of the microcrystal was not easily distinguished on the micrograph. The width of these phases observed in the polished section was less than about 1 micrometer.
[0167]
Example 2
127.25 g alumina powder ("APA-0.5"), 127.75 g gadolinium oxide powder (obtained from Molycorp, Inc.), 45 g zirconium oxide powder ("DK-2"), 0.6 g Example 2 molten material, abrasive particles and disks were prepared as described in Comparative Example A, except that a dispersant ("DURAMAX @ D-30005") and 150 g of distilled water were charged to the polyethylene bottle.
[0168]
FIG. 23 is a scanning electron microscope (SEM) micrograph of a polished cross section of the molten material of Example 2 (prepared as described in Comparative Example A). The micrograph shows the eutectic-derived microstructure. Example 2 Based on inspection of polished samples using SEM in powder X-ray diffraction and backscatter mode for a portion of the material, the white portion of the micrograph shows crystalline GdAlO₃And the dark part is α-Al₂O₃It is thought that was. ZrO₂The shape of the microcrystal was not easily distinguished on the micrograph. The width of the phase crystals observed in the polished section was less than about 1 micrometer.
[0169]
Example 3
124.5 g alumina powder ("APA-0.5"), 125.3 g dysprosium oxide powder (obtained from Aldrich Chemical Company, Inc.), 45 g zirconium oxide powder ("DK-2"), 0 Example 3 Molten material and abrasive particles were prepared as described in Comparative Example A, except that 0.6 g of dispersant ("DURAMAX @ D-30005") and 140 g of distilled water were charged into a polyethylene bottle.
[0170]
FIG. 24 is a scanning electron microscope (SEM) photomicrograph of a polished cross section of the molten material of Example 3 (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5 to 15 micrometers. Example 3 Based on inspection of a polished sample using SEM in powder X-ray diffraction and backscatter mode for a portion of the material, the white portion of the micrograph shows crystalline Gy₃Al₅O₁₂And the dark part is α-Al₂O₃It is thought that was. ZrO₂The shape of the microcrystal was not easily distinguished on the micrograph. The width of the phase crystals observed in the polished section was less than about 1 micrometer.
[0171]
Some Example 3 Abrasive particles were placed in a platinum crucible and heated at 50 ° C./hour to 1000 ° C., held at 1000 ° C. (in air) for 8 hours, and then at about 100 ° C./hour to room temperature. Cool. The average microhardness of the abrasive particles of Example 3 after heating was 15.6 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed for the Example 3 abrasive particles after heating was substantially the same as the microstructure observed before heating.
[0172]
Example 4
147.9 g alumina powder ("APA-0.5"), 137.1 g lanthanum oxide powder (obtained from Molycorp, Inc.), 15 g zirconium oxide powder ("DK-2"), 0.6 g Example 4 molten material and abrasive particles were prepared as described in Comparative Example A, except that a dispersant ("DURAMAX @ D-30005") and 145 g of distilled water were charged into a polyethylene bottle.
[0173]
FIG. 25 is a scanning electron microscope (SEM) photomicrograph of a polished cross section of the molten material of Example 4 (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5-20 micrometers. Example 4 Based on inspection of a polished sample of a portion of the material using powder X-ray diffraction and SEM in backscatter mode, the white portion of the micrograph shows crystalline LaAlO₃And the dark part is crystalline LaAl₁₁O₁₈And the gray part is crystalline monoclinic ZrO₂It is thought that was. The width of these phases observed in the polished section was less than about 1.5 micrometers.
[0174]
Example 5
109 g of alumina powder ("APA-0.5"), 101 g of lanthanum oxide powder (obtained from Molycorp, Inc.), 90 g of zirconium oxide powder ("DK-2"), 0.6 g of dispersant ( Example 5 Molten material, abrasive particles and disks were prepared as described in Comparative Example A, except that "DURAMAX @ D-30005") and 145 g of distilled water were charged to the polyethylene bottle.
[0175]
FIG. 26 is a scanning electron microscope (SEM) micrograph of a polished cross section of the molten material of Example 5 (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. Example 5 Based on inspection of a polished sample of a portion of the material using powder X-ray diffraction and SEM in backscatter mode, the white portion of the micrograph shows crystalline LaAlO₃And the dark part is crystalline LaAl₁₁O₁₈And the gray part is La₂Zr₂O₇It is thought that was. Further, based on powder X-ray diffraction, the material is monoclinic ZrO₂And cubic ZrO₂And two variants. ZrO₂The shape and position of the microcrystals were not easily identified on the micrograph.
[0176]
Example 5 The average microhardness of the abrasive particles was determined to be 12.0 GPa as described above in Comparative Example B.
[0177]
Some Example 5 abrasive particles were also placed in a platinum crucible and heated at 50 ° C./hour to 1000 ° C., held at 1000 ° C. (in air) for 8 hours, then at about 100 ° C./hour to room temperature And cooled. The average microhardness of the abrasive particles of Example 5 after heating was 11.8 GPa. The polished sections prepared for microhardness measurements were examined using SEM in secondary electron mode. The microstructure observed for the Example 5 abrasive particles after heating was substantially the same as the microstructure observed before heating.
[0178]
Examples 2, 5 and Comparative Examples EG The grinding performance of the coated abrasive discs was evaluated as described above for Comparative Examples AG. The results are reported in Table 2 below.
[0179]
[Table 2]
Table 2

[0180]
Example 6
109 g alumina powder ("APA-0.5"), 101 g lanthanum oxide powder (obtained from Molycorp, Inc.), 9 g yttrium oxide powder (obtained from HC Starck, Newton, Mass.) As described in Example 1, except that 81 g of zirconium oxide powder ("DK-2"), 0.6 g of dispersant ("DURAMAX @ D-30005") and 145 g of distilled water were charged into a polyethylene bottle. Example 6 A molten material and abrasive particles were prepared.
[0181]
FIG. 27 is a scanning electron microscope (SEM) photomicrograph of a polished cross section of the fused Example 6 material (prepared as described in Example 1). The micrograph shows a eutectic-derived microstructure containing multiple colonies. Example 6 Based on inspection of polished samples using SEM in powder X-ray diffraction and backscatter mode for a portion of the material, the white part of the micrograph shows crystalline LaAlO₃And the dark part is crystalline LaAl₁₁O₁₈And the gray part is cubic ZrO₂It is thought that was. ZrO₂The shape and position of the microcrystals were not easily identified on the micrograph.
[0182]
Example 7
111 g of alumina powder ("APA-0.5"), 93 g of neodymium oxide powder (obtained from Molycorp, Inc.), 90 g of zirconium oxide powder ("DK-2"), 0.6 g of dispersant ( Example 7 Molten material and abrasive particles were prepared as described in Comparative Example A, except that "DURAMAX @ D-30005") and 138 g of distilled water were charged into a polyethylene bottle.
[0183]
FIG. 28 is a scanning electron microscope (SEM) micrograph of a polished cross section of the molten material of Example 7 (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. Example 7 Based on inspection of polished samples using powdered X-ray diffraction and SEM in backscatter mode for a portion of the material, the white part of the micrograph shows crystalline NdAlO₃And the dark part is crystalline NdAl₁₁O₁₈It is thought that was. The width of these phases observed in the polished section was less than about 0.3 micrometers. Further, based on powder X-ray diffraction, the material is cubic ZrO₂And two variants. ZrO₂The shape and position of the microcrystals were not easily identified on the micrograph.
[0184]
Example 8
106.1 g of alumina powder ("APA-0.5"), 103.9 g of cerium (IV) oxide (CeO₂) Powder (obtained from Aldrich Chemical Company, Inc., Milwaukee, Wis.), 90 g zirconium oxide powder ("DK-2"), 0.6 g dispersant ("DURAMAX @ D-30005") and 139.5 g Example 8 A molten material and abrasive particles were prepared as described in Comparative Example A, except that distilled water was added to the polyethylene bottle.
[0185]
FIG. 29 is a scanning electron microscope (SEM) photomicrograph of a polished cross section of the molten material of Example 8 (prepared as described in Comparative Example A). The micrograph shows the eutectic-derived microstructure. Based on inspection of the polished sample using SEM in some powder X-ray diffraction and backscatter modes of Example 8, the white part of the micrograph shows crystalline CeAlO₃And the dark part is crystalline CeAl₁₁O₁₈And the gray part is Ce₂Zr₂O₇It is thought that was. The width of these phases observed in the polished section was less than about 5 micrometers. Further, based on powder X-ray diffraction, the material is monoclinic ZrO₂And cubic ZrO₂And two variants. ZrO₂The shape and position of the microcrystals were not easily identified on the micrograph. Furthermore, large primary crystals (CeAlO)₃And / or CeO₂Is observed in some areas of the polished section and CeAlO₃And / or CeO₂A possible deviation of the composition from a strict eutectic composition towards a rich composition was suggested.
[0186]
Comparative Example L
(A) 155.6 g alumina powder ("APA-0.5"), 144.3 g lanthanum oxide powder (obtained from Molycorp, Inc., Blair, CA), 0.6 g dispersant ("DURAMAX" D-30005 ") and 130 g of distilled water in a polyethylene bottle; and (b) the powder was 77.5 mol% Al₂O₃And 22.5 mol% La₂O₃Comparative Example L molten material, abrasive particles and disks were prepared as described in Comparative Example A, except that they were present in an amount that resulted in The color of the molten material was white-red. However, some of the abrasive particles were redder than others.
[0187]
FIG. 30 is a scanning electron microscope (SEM) photomicrograph of a polished cross section of the molten material of Comparative Example L (prepared as described in Comparative Example A). The micrograph shows a eutectic-derived microstructure containing multiple colonies. The size of the colonies was about 5-30 micrometers. Based on inspection of polished samples using SEM in powder X-ray diffraction and backscattering mode for a portion of Comparative Example B material, the white part of the micrograph shows crystalline LaAlO₃And the dark part is crystalline LaAl₁₁O₁₈It is thought that was. The width of these phases observed in the polished section was less than about 0.5 micrometers. Furthermore, large primary crystals (LaAlO) that exist in the form of dendrites₃Is observed in some areas of the polished section and La₂O₃A possible deviation of the composition from a strict eutectic composition towards a rich composition was suggested.
[0188]
Comparative Examples EG and L The abrasive performance of the coated abrasive discs was evaluated as described above for Comparative Examples AG. The results are reported in Table 3 below.
[0189]
[Table 3]
Table 3

[0190]
Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that the invention is not unduly limited to the illustrative embodiments described herein.
[Brief description of the drawings]
FIG. 1 is a schematic partial cross-sectional view of a coated abrasive article comprising molten abrasive particles according to the present invention.
FIG. 2 is a perspective view of a bonded abrasive article comprising molten abrasive particles according to the present invention.
FIG. 3 is an enlarged schematic view of a nonwoven abrasive article comprising molten abrasive particles according to the present invention.
FIG. 4 is a differential scanning calorimetry (DTA) plot and a thermogravimetric analysis (TGA) plot of a molten material of Comparative Example B.
FIG. 5 is a DTA plot and a TGA plot of a molten material of Comparative Example C.
FIG. 6 is a DTA plot and a TGA plot of a molten material of Comparative Example K.
FIG. 7 is a DTA plot and a TGA plot of Comparative Example F abrasive particles.
FIG. 8 is a scanning electron micrograph of a polished cross section of a molten material of Comparative Example A.
FIG. 9 is a scanning electron micrograph of a polished cross section of Comparative Example B molten material.
FIG. 10 is a scanning electron micrograph of a polished cross section of Comparative Example C molten material.
FIG. 11 is a scanning electron micrograph of a polished cross section of a molten material of Comparative Example D.
FIG. 12 is a scanning electron micrograph of a polished cross section of a molten material of Comparative Example H.
FIG. 13 is a scanning electron micrograph of a polished cross section of a molten material of Comparative Example I.
FIG. 14 is a scanning electron micrograph of a polished cross section of Comparative Example J molten material.
FIG. 15 is a scanning electron micrograph of a polished cross section of Comparative Example K molten material.
FIG. 16 is a scanning electron micrograph of a polished cross section of Comparative Example F abrasive particles.
FIG. 17 is a scanning electron micrograph of the polished cross section of Comparative Example F abrasive particles after exposure to various heating conditions.
FIG. 18 is a scanning electron micrograph of a polished cross section of Comparative Example F abrasive particles after exposure to various heating conditions.
FIG. 19 is a scanning electron micrograph of a polished cross section of Comparative Example F abrasive particles after exposure to a vitrified bonding material.
FIG. 20 is a scanning electron micrograph of a polished cross section of Comparative Example K material after being exposed to various heating conditions.
FIG. 21 is a scanning electron micrograph of a polished cross section of a Comparative Example K material after being subjected to various heating conditions.
FIG. 22 is a scanning electron micrograph of a polished cross section of the molten material of Example 1.
FIG. 23 is a scanning electron micrograph of a polished cross section of the molten material of Example 2.
FIG. 24 is a scanning electron micrograph of a polished cross section of the molten material of Example 3.
FIG. 25 is a scanning electron micrograph of a polished cross section of the molten material of Example 4.
FIG. 26 is a scanning electron micrograph of a polished cross section of Example 5 molten material.
FIG. 27 is a scanning electron micrograph of a polished cross section of the molten material of Example 6.
FIG. 28 is a scanning electron micrograph of a polished cross section of the molten material of Example 7;
FIG. 29 is a scanning electron micrograph of a polished cross section of the molten material of Example 8;
FIG. 30 is a scanning electron micrograph of a polished cross section of a molten material of Comparative Example L.

Claims (99)

At least (a) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ ,
(Ii) a molten crystalline co-crystal comprising a eutectic with at least two of the first crystalline complex Al ₂ O ₃ .rare earth oxide or (iii) the second different crystalline complex Al ₂ O ₃ .rare earth oxide Crystal material. Melting crystalline eutectic material according to claim 1 content with respect containing Al ₂ O ₃ of at least 40 wt% on a theoretical oxide basis of total metal oxides of the eutectic material. The rare earth oxides include CeO ₂ , Dy ₂ O ₃ , Er ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , La ₂ O ₃ , Nd ₂ O ₃ , Pr ₆ O ₁₁ , Sm ₂ O ₃ , and Yb. _3. The molten crystalline eutectic material of claim 2 selected from the group consisting of ₂ O3 and combinations thereof on a theoretical oxide basis. 3. The molten crystalline eutectic material of claim 2, comprising the eutectic colonies having an average size of less than 100 micrometers. 5. The molten crystalline eutectic material of claim 4, wherein said colonies have an average size of less than 50 micrometers. The molten crystalline eutectic material according to claim 2, wherein the eutectic material includes the eutectic colony, and the size of a crystal constituting the colony is 10 micrometers or less on average. 7. The molten crystalline eutectic material according to claim 6, wherein the size of the crystal is 1 micrometer or less on average. The _{eutectic, Al 2 O 3 -Dy 3 Al} 5 O 12 -ZrO 2 _{eutectic, Al 2 O 3 -Er 3 Al} 5 O 12 -ZrO 2 _{eutectic, Al 2 O 3 -GdAlO 3 -ZrO} 2 Co melting crystalline eutectic material according to claim 2 which is selected from the group consisting of crystal and _{Al 2 O 3 -Yb 3 Al 5} O 12 -ZrO 2 eutectic. Melting crystalline eutectic material according to claim 8, further comprising a primary crystal Al ₂ O _3. The _{eutectic, CeAlO 3 -Ce 3 Al 11 O} 18 -ZrO 2 _{eutectic, EuAlO 3 -EuAl 11 O 18 -ZrO} 2 _{eutectic, LaAlO 3 -LaAl 11 O 18 -ZrO} 2 _eutectic, NdAlO 3 -NdAl ₁₁ O ₁₈ -ZrO _{2 eutectic, PrAlO 3 -PrAl 11 O 18 -ZrO} 2 eutectic and SmAlO ₃ -SmAl ₁₁ O ₁₈ -ZrO ₂ melting crystalline according to claim 2 which is selected from the group consisting of eutectic Eutectic material. Melting crystalline eutectic material according to claim 2 wherein the eutectic is LaAlO ₃ -LaAl ₁₁ O ₁₈ -ZrO ₂ eutectic. The molten crystalline eutectic material according to claim 2, further comprising at least one of crystalline Y ₂ O _{3 and a} crystalline complex Al ₂ O ₃ .Y ₂ O ₃ . Crystalline _{BaO, CaO, Cr 2 O 3} , CoO, Fe 2 O 3, HfO 2, Li 2 O, MgO, MnO, NiO, SiO 2, TiO 2, Na 2 O, SrO, Sc 2 O 3, V 2 The molten crystalline eutectic material according to claim 2, further comprising at least one of O ₃ , ZnO, or a complex thereof, Al ₂ O ₃ .metal oxide. 3. The molten crystalline eutectic material of claim 2, having an average microhardness of at least 13 GPa. Melting crystalline eutectic material according to claim 3 wherein the complex Al 2 _{O 3} · _REO may further include a cation in addition to the Al cations, and rare earth cations. Part of the Al cation of the complex Al ₂ O ₃ .REO is replaced with at least one cation of an element selected from the group consisting of Cr, Ti, Sc, Fe, Mg, Ca, Si, Co and combinations thereof. The molten crystalline eutectic material according to claim 3, wherein Part of the rare earth cations of the complex Al ₂ O ₃ .REO is a group consisting of Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Th, Tm, Yb, and combinations thereof. The molten crystalline eutectic material according to claim 3, wherein the material is substituted with at least one cation of an element selected from the group consisting of: Part of the rare earth cations of the complex Al ₂ O ₃ .REO is an element selected from the group consisting of Fe, Ti, Mn, V, Cr, Co, Ni, Cu, Mg, Ca, Sr and combinations thereof. 4. The molten crystalline eutectic material according to claim 3, wherein the material is substituted with at least one cation. The _{eutectic, Al 2 O 3 -Dy 3 Al} 5 O 12 -ZrO 2 _{eutectic, Al 2 O 3 -Er 3 Al} 5 O 12 -ZrO 2 _{eutectic, Al 2 O 3 -GdAlO 3 -ZrO} 2 Co The eutectic material is selected from the group consisting of eutectic and Al ₂ O ₃ —Yb ₃ Al ₅ O ₁₂ —ZrO ₂ eutectic, wherein the molten crystalline eutectic material further comprises a primary crystal of a metal oxide corresponding to the eutectic, primary crystallites _{Dy 3 Al 5 O 12, Er} 3 Al 5 O 12, GdAlO 3 and _Yb 3 _Al 5 melting crystalline eutectic material according to claim _{1, O 12} is selected from the group consisting of. The _{eutectic, CeAlO 3 -CeAl 11 O 18 -ZrO} 2 _{eutectic, EuAlO 3 -EuAl 11 O 18 -ZrO} 2 _{eutectic, LaAlO 3 -LaAl 11 O 18 -ZrO} 2 eutectic and NdAlO ₃ -NdAl ₁₁ O _18- ZrO ₂ eutectic, PrAlO ₃ -PrAl ₁₁ O ₁₈ -ZrO ₂ eutectic and SmAlO ₃ -SmAl ₁₁ O ₁₈ -ZrO ₂ eutectic, wherein the molten crystalline eutectic material is the eutectic 2. The molten crystalline material according to claim 1, further comprising a primary crystal of a metal oxide corresponding to, wherein the primary crystal is selected from the group consisting of CeAlO ₃ , EuAlO ₃ , LaAlO ₃ , NdAlO ₃ , PrAlO ₃ and SmAlO _3. Eutectic material. The _{eutectic, CeAlO 3 -CeAl 11 O 18 -ZrO} 2 _{eutectic, EuAlO 3 -EuAl 11 O 18 -ZrO} 2 _{eutectic, LaAlO 3 -LaAl 11 O 18 -ZrO} 2 _eutectic, NdAlO 3 -NdAl ₁₁ O _18- ZrO ₂ eutectic, PrAlO ₃ -PrAl ₁₁ O ₁₈ -ZrO ₂ eutectic and SmAlO ₃ -SmAl ₁₁ O ₁₈ -ZrO ₂ eutectic, wherein the molten crystalline eutectic material is the eutectic further comprising a primary crystal of the corresponding metal oxide, said primary crystals from the group consisting of _{CeAl 11 O 18, EuAl 11 O} 18, LaAl 11 O 18, NdAl 11 O 18, PrAl 11 O 18 and _SmAl 11 _{O 18} 2. The molten crystalline eutectic material of claim 1, which is selected. 2. The eutectic according to claim 1, wherein the eutectic is at least a eutectic of (a) crystalline ZrO ₂ , (b) crystalline Al ₂ O ₃ and (c) crystalline complex Al ₂ O ₃ . Melt crystalline eutectic material. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 2. The molten crystalline eutectic material according to claim 1, which is a eutectic of a material. Molten crystalline abrasive particles comprising at least 20% by volume of a eutectic material, based on the total metal oxide volume of the particles, wherein the eutectic material is at least:
(A) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ ,
(Ii) Melt crystalline polishing including a eutectic with at least two of the first crystalline complex Al ₂ O ₃ .rare earth oxide or (iii) the second different crystalline complex Al ₂ O ₃ .rare earth oxide Agent particles. 25. The molten crystalline abrasive particles of claim 24, comprising at least 50% by volume of the eutectic material, based on the total volume of the particles. Melting crystalline abrasive particles according to claim 25 containing Al ₂ O ₃ of at least 40 vol% based on the total metal oxide content of the particles on a theoretical oxide basis. The rare earth oxides include CeO ₂ , Dy ₂ O ₃ , Er ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , La ₂ O ₃ , Nd ₂ O ₃ , Pr ₆ O ₁₁ , Sm ₂ O ₃ , and Yb. ₂ O _3, and the molten crystalline abrasive particles according to claim 26, combinations thereof are selected on a theoretical oxide basis. 27. The molten crystalline abrasive particles of claim 26, wherein the molten crystalline abrasive particles comprise the eutectic colonies, wherein the colonies have an average size of less than 100 micrometers. 29. The molten crystalline abrasive particles of claim 28, wherein the colonies have an average size of less than 50 micrometers. 27. The molten crystalline abrasive particles according to claim 26, wherein the molten crystalline abrasive particles include the eutectic colonies, and the average size of the crystals constituting the colonies is 10 micrometers or less. 31. The molten crystalline abrasive particles of claim 30, wherein the size of the crystals is less than or equal to 1 micrometer on average. The _{eutectic, Al 2 O 3 -Dy 3 Al} 5 O 12 -ZrO 2 _{eutectic, Al 2 O 3 -Er 3 Al} 5 O 12 -ZrO 2 _{eutectic, Al 2 O 3 -GdAlO 3 -ZrO} 2 Co crystal and _{Al 2 O 3 -Yb 3 Al 5} O 12 -ZrO 2 melting crystalline abrasive particles according to claim 26 which is selected from the group consisting of eutectic. Melting crystalline abrasive particles according to claim 32 wherein the molten crystalline abrasive particles further includes a primary crystal Al ₂ O _3. The _{eutectic, CeAlO 3 -CeAl 11 O 18 -ZrO} 2 _{eutectic, EuAlO 3 -EuAl 11 O 18 -ZrO} 2 _{eutectic, LaAlO 3 -LaAl 11 O 18 -ZrO} 2 _eutectic, NdAlO 3 -NdAl ₁₁ O ₁₈ -ZrO _{2 eutectic, PrAlO 3 -PrAl 11 O 18 -ZrO} 2 eutectic and SmAlO ₃ -SmAl ₁₁ O ₁₈ -ZrO ₂ melting crystalline abrasive of claim 26 which is selected from the group consisting of eutectic particle. The eutectic melting crystalline abrasive particles according to claim 26, which is a LaAlO ₃ -LaAl ₁₁ O ₁₈ -ZrO ₂ eutectic. The molten crystalline abrasive particles crystalline _Y 2 _{O 3} or melt crystalline abrasive particles according to claim 26, further comprising at least one crystalline complex _{Al 2 O 3 · Y 2 O} 3. The molten crystalline abrasive particles, crystalline _{BaO, CaO, Cr 2 O 3} , CoO, Fe 2 O 3, HfO 2, Li 2 O, MgO, MnO, NiO, SiO 2, TiO 2, Na 2 O, _{SrO, Sc 2 O 3, V} 2 O 3, ZnO or melt crystalline abrasive particles according to claim 26, further comprising at least one of those complex _Al 2 _{O 3} · metal oxides. 27. The molten crystalline abrasive particles of claim 26, wherein the molten crystalline abrasive particles have an average microhardness of at least 13 GPa. The complex Al 2 _{O 3} · _REO melt crystalline abrasive particles according to claim 26, further comprising a cation in addition to the Al cations, and rare earth cations. Part of the Al cation of the complex Al ₂ O ₃ .REO is replaced with at least one cation of an element selected from the group consisting of Cr, Ti, Sc, Fe, Mg, Ca, Si, Co and combinations thereof. 27. The molten crystalline abrasive particles of claim 26, wherein Part of the rare earth cations of the complex Al ₂ O ₃ .REO is a group consisting of Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Th, Tm, Yb, and combinations thereof. 27. The molten crystalline abrasive particles of claim 26, wherein the particles are substituted with at least one cation of an element selected from: Part of the rare earth cations of the complex Al ₂ O ₃ .REO is an element selected from the group consisting of Fe, Ti, Mn, V, Cr, Co, Ni, Cu, Mg, Ca, Sr, and combinations thereof. 27. The molten crystalline abrasive particles of claim 26, wherein the particles are substituted with at least one cation. The _{eutectic, Al 2 O 3 -Dy 3 Al} 5 O 12 -ZrO 2 _{eutectic, Al 2 O 3 -Er 3 Al} 5 O 12 -ZrO 2 _{eutectic, Al 2 O 3 -GdAlO 3 -ZrO} 2 Co And the molten crystalline abrasive particles are further selected from the group consisting of eutectic and Al ₂ O ₃ —Yb ₃ Al ₅ O ₁₂ —ZrO ₂ eutectic, wherein the molten crystalline abrasive particles further comprise primary crystals of a metal oxide corresponding to the eutectic. primary crystallites _{Dy 3 Al 5 O 12, Er} 3 Al 5 O 12, GdAlO 3 and _Yb 3 _Al 5 melting crystalline abrasive particles according to claim _{25, O} of ₁₂ is selected from the group. The _{eutectic, CeAlO 3 -CeAl 11 O 18 -ZrO} 2 _{eutectic, EuAlO 3 -EuAl 11 O 18 -ZrO} 2 _{eutectic, LaAlO 3 -LaAl 11 O 18 -ZrO} 2 _eutectic, NdAlO 3 -NdAl ₁₁ O _18- ZrO ₂ eutectic, PrAlO ₃ -PrAl ₁₁ O ₁₈ -ZrO ₂ eutectic and SmAlO ₃ -SmAl ₁₁ O ₁₈ -ZrO ₂ eutectic, wherein the molten crystalline abrasive particles are eutectic. further comprising a primary crystal of the corresponding metal oxide, said primary crystals _{CeAlO 3, EuAlO 3, LaAlO 3} , NdAlO 3, PrAlO 3 and melt the crystalline of claim 25 which is selected from the group consisting of SmAlO ₃ Abrasive particles. The _{eutectic, CeAlO 3 -CeAl 11 O 18 -ZrO} 2 _{eutectic, EuAlO 3 -EuAl 11 O 18 -ZrO} 2 _{eutectic, LaAlO 3 -LaAl 11 O 18 -ZrO} 2 _eutectic, NdAlO 3 -NdAl ₁₁ O _18- ZrO ₂ eutectic, PrAlO ₃ -PrAl ₁₁ O ₁₈ -ZrO ₂ eutectic and SmAlO ₃ -SmAl ₁₁ O ₁₈ -ZrO ₂ eutectic, wherein the molten crystalline abrasive particles are eutectic. further comprising a primary crystal of the corresponding metal oxide, said primary crystals from the group consisting of _{CeAl 11 O 18, EuAl 11 O} 18, LaAl 11 O 18, NdAl 11 O 18, PrAl 11 O 18 and _SmAl 11 _{O 18} 26. The molten crystalline abrasive particles of claim 25, wherein the particles are selected. 25. The eutectic according to claim 24, wherein the eutectic is at least a eutectic of (a) crystalline ZrO ₂ , (b) crystalline Al ₂ O _3, and (c) crystalline complex Al ₂ O ₃ . Melted crystalline abrasive particles. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 2. The molten crystalline abrasive particles according to claim 1, which is a eutectic of a material. Melting crystalline abrasive particles according to claim 1 wherein at least a majority by weight of the crystalline ZrO ₂ is cubic ZrO _{2. 2.} The molten crystalline abrasive particles according to claim 1, wherein the crystalline ZrO ₂ is stabilized by an oxide other than the rare earth oxide present in the crystalline complex Al ₂ O ₃ . at least,
A molten crystalline eutectic material containing a eutectic of (a) crystalline complex Al ₂ O ₃ .rare earth oxide and (b) crystalline ZrO ₂ . Melting crystalline eutectic material according to claim 50 wherein at least a majority by weight of the crystalline ZrO ₂ is cubic ZrO _2. The crystalline ZrO _2, the melt crystalline eutectic material according to claim 50, which is stabilized by an oxide other than rare earth oxide present in the crystalline complex Al 2 _O 3 _· rare earth oxide. Molten crystalline abrasive particles comprising at least 20% by volume of a eutectic material, based on the total metal oxide volume of the particles, wherein the eutectic material is at least:
Molten crystalline abrasive particles containing a eutectic of (a) crystalline complex Al ₂ O ₃ .rare earth oxide and (b) crystalline ZrO ₂ . Melting crystalline abrasive particles according to claim 53 wherein at least a majority by weight of the crystalline ZrO ₂ is cubic ZrO _2. Molten crystalline abrasive particles wherein at least a portion of a number of particles having a particle size distribution ranging from fine particles to coarse particles comprise at least 20% by volume, based on the total metal oxide volume of the individual particles, of a eutectic material. And the eutectic material is at least:
(A) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ ,
A large number of particles containing a eutectic with at least two of (ii) the first crystalline complex Al ₂ O ₃ .rare earth oxide or (iii) the second different crystalline complex Al ₂ O ₃ .rare earth oxide. The eutectic is at least according to (a) a crystalline _ZrO 2, (b) a crystalline _Al 2 _{O 3} and (c) a crystalline complex _Al 2 _{O 3} · 55. eutectic rare earth oxides Many particles. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 56. The multiple particles of claim 55, wherein the particles are eutectic. Molten crystalline abrasive particles wherein at least a portion of a number of particles having a particle size distribution ranging from fine particles to coarse particles comprise at least 20% by volume, based on the total metal oxide volume of the individual particles, of a eutectic material. And the eutectic material is at least:
Numerous particles containing a eutectic of (a) crystalline complex Al ₂ O ₃ rare earth oxide and (b) crystalline ZrO ₂ . Number of particles of claim 58 wherein at least a majority by weight of the crystalline ZrO ₂ is cubic ZrO _2. At least a portion of the number of abrasive particles having a particle size distribution ranging from fine particles to coarse particles and having a specified nominal grade comprises at least 20% by volume of the eutectic material based on the total metal oxide volume of the individual particles. A plurality of molten crystalline abrasive particles, wherein the eutectic material is at least
(A) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ ,
Numerous abrasives containing a eutectic with at least two of (ii) the first crystalline complex Al ₂ O ₃ .rare earth oxide or (iii) the second different crystalline complex Al ₂ O ₃ .rare earth oxide particle. The eutectic is at least according to (a) a crystalline _ZrO 2, (b) a crystalline _Al 2 _{O 3} and (c) a crystalline complex _Al 2 _{O 3} · Claim 60 eutectic rare earth oxides Numerous abrasive particles. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 61. The plurality of abrasive particles of claim 60, wherein the abrasive particles are eutectic. At least a portion of the number of abrasive particles having a particle size distribution ranging from fine particles to coarse particles and having a specified nominal grade comprises at least 20% by volume of the eutectic material based on the total metal oxide volume of the individual particles. A plurality of molten crystalline abrasive particles, wherein the eutectic material is at least
Numerous abrasive particles containing a eutectic of (a) crystalline complex Al ₂ O ₃ .rare earth oxide and (b) crystalline ZrO ₂ . Numerous abrasive particle according to claim 63 wherein at least a majority by weight of the crystalline ZrO ₂ is cubic ZrO _2. At least (a) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ , (ii) first crystalline complex Al ₂ O _3. Rare earth oxide or (iii) second different crystalline a method for producing molten crystalline eutectic material comprising eutectic of at least two complex Al 2 _O 3 _· rare earth oxide, at least one of Al ₂ O ₃ source to provide a melt, at least method comprising the steps of melting a kind of rare earth oxide source and at least one ZrO ₂ source, a step of converting the melt to the molten crystalline eutectic material. 66. The method of claim 65, wherein the method includes cooling the melt using a metal plate. 67. The method of claim 65, wherein the method includes cooling the melt using metal balls. The eutectic is at least according to (a) a crystalline _ZrO 2, (b) a crystalline _Al 2 _{O 3} and (c) a crystalline complex _Al 2 _{O 3} · 65. eutectic rare earth oxides Method. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 66. The method of claim 65, wherein the product is a eutectic. At least 20% by volume, based on the total volume of the individual particles, of at least (a) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ , (ii) the first Process for producing molten crystalline abrasive particles containing a eutectic with at least two of crystalline complex Al ₂ O ₃ rare earth oxide or (iii) second different crystalline complex Al ₂ O ₃ rare earth oxide Melting at least one Al ₂ O ₃ source, at least one rare earth oxide source and at least one ZrO ₂ source to provide a melt; and providing the melt with the molten crystalline abrasive. Converting the particles into particles. 71. The method of claim 70, wherein the converting comprises cooling the melt to provide a solidified material, and crushing the solidified material to provide the molten crystalline abrasive particles. Method. 72. The method of claim 71, wherein cooling the melt comprises cooling the melt using a metal plate. 72. The method of claim 71, wherein cooling the melt comprises cooling the melt using metal balls. The eutectic material, at least, according to claim 70 comprising (a) a eutectic crystalline _ZrO 2, (b) a crystalline _Al 2 _{O 3} and (c) a crystalline complex _Al 2 _{O 3} · rare earth oxide the method of. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 71. The method of claim 70, which is a eutectic of the product. A method for producing a molten crystalline eutectic material comprising at least a eutectic of (a) a crystalline complex Al ₂ O ₃ .rare earth oxide and (b) a crystalline ZrO ₂ , A method comprising: melting at least one Al ₂ O ₃ source, at least one rare earth oxide source and at least one ZrO ₂ source; and converting the melt to the molten crystalline eutectic material. A eutectic material of at least 20% by volume, based on the total volume of the individual particles, wherein at least a eutectic of (a) crystalline complex Al ₂ O ₃ .rare earth oxide and (b) crystalline ZrO ₂ A method for producing molten crystalline abrasive particles comprising a eutectic material comprising at least one Al ₂ O ₃ source, at least one rare earth oxide source and at least one ZrO ₂ source to provide a melt And converting the melt to the molten crystalline abrasive particles. An abrasive article comprising a number of abrasive particles and a binder wherein at least a portion of the abrasive particles comprises at least 20% by volume, based on the total volume of the individual particles, of the eutectic material, wherein the eutectic material comprises at least ,
(A) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ ,
An abrasive article comprising a eutectic with at least two of (ii) a first crystalline complex Al ₂ O ₃ .rare earth oxide or (iii) a second different crystalline complex Al ₂ O ₃ .rare earth oxide. 79. The abrasive article of claim 78, wherein the article is a coated abrasive article and further comprises a backing. 79. The abrasive article of claim 78, wherein the article is a bonded abrasive article. 79. The abrasive article of claim 78, wherein the article is a nonwoven abrasive article and further comprises a nonwoven web. The eutectic is at least according to claim 78 which is eutectic of (a) a crystalline _ZrO 2, (b) a crystalline _Al 2 _{O 3} and (c) a crystalline complex _Al 2 _{O 3} · rare earth oxide Abrasive articles. The eutectic comprises at least (a) crystalline ZrO ₂ and (b) a first crystalline Al ₂ O ₃ .rare earth oxide and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 79. The abrasive article of claim 78, wherein the article is a eutectic. An abrasive article comprising a binder and a plurality of abrasive particles, wherein at least a portion of the abrasive particles comprises at least 20% by volume, based on the total volume of the individual particles, of a molten crystalline abrasive. Particles, wherein the eutectic material is at least
(A) crystalline complex Al ₂ O ₃ .rare earth oxide and (b) crystalline ZrO ₂
Abrasive article comprising a eutectic with Abrasive article of claim 84 wherein at least a majority by weight of the crystalline ZrO ₂ is cubic ZrO _2. A vitrified bonded abrasive article comprising a plurality of abrasive particles bonded together via a vitrified bonding material, wherein at least a portion of the plurality of abrasive particles is at least based on the total volume of the individual particles. Molten crystalline abrasive particles comprising 20% by volume of the eutectic material, wherein the eutectic material is at least:
(A) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ ,
Vitrification bonding polishing including eutectic with at least two kinds of (ii) first crystalline complex Al ₂ O ₃ .rare earth oxide or (iii) second different crystalline complex Al ₂ O ₃ .rare earth oxide Agent articles. 87. The vitrified bonded abrasive article of claim 86, wherein the vitrified bonding material comprises silica, alumina and boria. 91. The vitrified bonded abrasive article of claim 87, wherein the vitrified bonding material comprises at least 10% by weight of the alumina. 89. The vitrified bonded abrasive article of claim 88, wherein the vitrified bonding material comprises at least 10% by weight of the boria. The eutectic is at least according to claim 86 which is eutectic of (a) a crystalline _ZrO 2, (b) a crystalline _Al 2 _{O 3} and (c) a crystalline complex _Al 2 _{O 3} · rare earth oxide Melted crystalline abrasive particles. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 87. The molten crystalline abrasive particles according to claim 86, wherein the particles are eutectic of the material. A vitrified bonded abrasive article comprising a plurality of abrasive particles bonded together via a vitrified bonding material, wherein at least a portion of the plurality of abrasive particles is at least based on the total volume of the individual particles. Molten crystalline abrasive particles comprising 20% by volume of the eutectic material, wherein the eutectic material is at least:
A vitrified bonded abrasive article comprising a eutectic of (a) a crystalline complex Al ₂ O ₃ .rare earth oxide and (b) crystalline ZrO ₂ . Vitrified bonded abrasive article according to claim 92 wherein at least a majority by weight of the crystalline ZrO ₂ is cubic ZrO _2. Contacting at least one molten crystalline abrasive particle comprising at least 20% by volume, based on the total volume of the individual particles, of a eutectic material with a surface of a workpiece; Moving at least one of the molten abrasive particles or the surface relative to the other to polish with the agent particles, the method comprising:
The eutectic material is at least (a) crystalline ZrO ₂ and (b) (i) crystalline Al ₂ O ₃ , (ii) first crystalline complex Al ₂ O _3. Rare earth oxide or (iii) A process comprising a eutectic with at least two of _two different crystalline complexes Al ₂ O ₃ .REO. The eutectic is at least according to (a) a crystalline _ZrO 2, (b) a crystalline _Al 2 _{O 3} and (c) a crystalline complex _Al 2 _{O 3} · Claim 94 eutectic rare earth oxides Method. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 95. The method of claim 94, wherein the product is a eutectic. Contacting at least one molten crystalline abrasive particle comprising at least 20% by volume, based on the total volume of the individual particles, of a eutectic material with a surface of a workpiece; Moving at least one of the molten abrasive particles or the surface with respect to the other in order to polish with the abrasive particles, wherein the eutectic material is at least (a) A method comprising a eutectic of a complex Al ₂ O ₃ .rare earth oxide and (b) crystalline ZrO ₂ . The eutectic is at least according to (a) a crystalline _ZrO 2, (b) a crystalline _Al 2 _{O 3} and (c) a crystalline complex _Al 2 _{O 3} · 97. eutectic rare earth oxides Method. The eutectic comprises at least (a) crystalline ZrO ₂ , (b) a first crystalline complex Al ₂ O ₃ .rare earth oxide, and (c) a second different crystalline complex Al ₂ O ₃ .rare earth oxide 97. The method of claim 97, which is a eutectic of the product.

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