JPH0797254A - High-strength sintered alumina - Google Patents
High-strength sintered aluminaInfo
- Publication number
- JPH0797254A JPH0797254A JP5239483A JP23948393A JPH0797254A JP H0797254 A JPH0797254 A JP H0797254A JP 5239483 A JP5239483 A JP 5239483A JP 23948393 A JP23948393 A JP 23948393A JP H0797254 A JPH0797254 A JP H0797254A
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- zro
- less
- zirconia
- weight
- amount
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、破壊靱性および抗折強
度を向上させた切削工具用の高強度アルミナ質焼結体に
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength alumina sintered body for a cutting tool having improved fracture toughness and bending strength.
【０００２】[0002]
【従来技術】近時、工作機械は高効率化、無人化が進
み、切削工具においても多数の切削装置を同時に作動さ
せる場合が多い。しかしながら、アルミナセラミック工
具は一般に抗折強度や破壊靱性値が低く、そのため高速
切削、高切り込みおよび高送りといった高効率化におい
て、一度に多数のセラミック工具を使用すると１個のセ
ラミック工具であってもそれが急な欠損を生じた場合
に、全ての装置を停止させなければならないという不都
合が生じる。したがってこれらのセラミック工具として
破壊靱性が充分で、特に抗折強度が優れており、かつこ
れらが安定して得られるセラミック工具の焼結体が強く
要求されている。2. Description of the Related Art In recent years, machine tools are becoming highly efficient and unmanned, and in many cases, many cutting devices are operated simultaneously even in cutting tools. However, alumina ceramic tools generally have low bending strength and fracture toughness values, and therefore, in order to achieve high efficiency such as high-speed cutting, high cutting depth and high feed, even if one ceramic tool is used when many ceramic tools are used at a time. The disadvantage is that all equipment must be stopped if it causes a sudden failure. Therefore, there is a strong demand for a sintered body of a ceramic tool which has sufficient fracture toughness and is particularly excellent in bending strength as these ceramic tools, and which can stably obtain these.
【０００３】そこで、アルミナ質焼結体の破壊靱性値
（Ｋ1c）を向上させるため、アルミナ（Ａｌ2 Ｏ3 ）に
ジルコニア（ＺｒＯ2 ）を添加させるものがある。この
ような典型的な先行技術は特開昭５９−２５７４８号公
報に開示されている。これは、Ａｌ2 Ｏ3 中にＺｒＯ2
を分散させ、分散したジルコニア（ＺｒＯ2 ）が焼結後
ｔ−ＺｒＯ2 （テトラゴナル−ジルコニア）からｍ−Ｚ
ｒＯ2 （モノクリニック−ジルコニア）に相転移する際
の体積膨張変化により、焼結体中に多数のマイクロクラ
ックを発生させ、このマイクロクラックの存在により破
壊靱性を向上させようとするものである。Therefore, in order to improve the fracture toughness value (K 1c ) of the alumina-based sintered body, there is a method of adding zirconia (ZrO 2 ) to alumina (Al 2 O 3 ). Such typical prior art is disclosed in Japanese Patent Laid-Open No. 59-25748. This is due to ZrO 2 in Al 2 O 3.
Is dispersed, and the dispersed zirconia (ZrO 2 ) is sintered and then converted from t-ZrO 2 (tetragonal-zirconia) to m-Z.
The volume expansion change at the time of phase transition to rO 2 (monoclinic-zirconia) causes many microcracks in the sintered body, and the presence of these microcracks is intended to improve the fracture toughness.
【０００４】[0004]
【発明が解決しようとする問題点】しかしながら、焼結
体中に多数のマイクロクラックを存在させることは破壊
靱性が向上したとしても、逆に抗折強度が著しく劣化
し、特に高速切削、高切り込みおよび高送りといった高
速加工において焼結体に欠損を生じ易いという問題があ
った。However, even if the fracture toughness is improved, the presence of a large number of microcracks in the sintered body, on the contrary, significantly deteriorates the transverse strength, and particularly, high-speed cutting and high cutting In addition, there is a problem that defects are likely to occur in the sintered body during high-speed processing such as high feed.
【０００５】一方、ＺｒＯ2 およびＡｌ2 Ｏ3 を微粒子
にしていくと、抗折強度は上がるが破壊靱性は低下する
という問題があった。これはＺｒＯ2 の微粒化によりＺ
ｒＯ2 のｔ−ＺｒＯ2 からｍ−ＺｒＯ2 への転移が抑制
されるからである。On the other hand, when ZrO 2 and Al 2 O 3 are made into fine particles, there has been a problem that the fracture strength is reduced although the bending strength is increased. This is due to the atomization of ZrO 2.
This is because the transition of rO 2 from t-ZrO 2 to m-ZrO 2 is suppressed.
【０００６】本発明は、破壊靱性および抗折強度をとも
に向上することができる高強度アルミナ質焼結体を提供
することを目的とする。An object of the present invention is to provide a high-strength alumina sintered body which can improve both fracture toughness and transverse strength.
【０００７】[0007]
【問題点を解決するための手段】本発明者は上記現状に
鑑み鋭意研究の結果、平均結晶粒径１．５μｍ以下のＡ
ｌ2 Ｏ3 の主成分に平均結晶粒径１μｍ以下のＺｒＯ2
を一定量含有し、ＺｒＯ2 全量に対するＨｆＯ2 量を一
定量に制限し、ＺｒＯ2 の４０％以上をｔ−ＺｒＯ2 結
晶としたアルミナ質焼結体は、抗折強度を著しく向上し
つつ、しかもある程度以上の破壊靱性を有していること
を知見した。[Means for Solving the Problems] The inventors of the present invention have made earnest studies in view of the above-mentioned circumstances, and as a result, A having an average crystal grain size of 1.5 μm or less was obtained.
The main component of l 2 O 3 is ZrO 2 having an average crystal grain size of 1 μm or less.
A certain amount contained, limits the HfO 2 amount for ZrO 2 total amount a certain amount, the alumina sintered body of 40% or more of ZrO 2 was t-ZrO 2 crystals, while significantly improving the flexural strength, Moreover, they have found that they have fracture toughness above a certain level.
【０００８】また、主成分Ａｌ2 Ｏ3 中に所定量のＺｒ
Ｏ2 と、所定量のＦｅ，Ｎｉ，Ｃｏ等の酸化物とを含有
するとともに、ＺｒＯ2 全量に対するＨｆＯ2 量を一定
量制限することにより、抗折強度を著しく向上しつつ、
しかもある程度以上の破壊靱性を有していることを知見
した。Further, a predetermined amount of Zr is contained in the main component Al 2 O 3.
While containing O 2 and a predetermined amount of oxides of Fe, Ni, Co, etc. and limiting the amount of HfO 2 with respect to the total amount of ZrO 2 by a certain amount, the bending strength is significantly improved,
Moreover, they have found that they have fracture toughness above a certain level.
【０００９】即ち、本発明の高強度アルミナ質焼結体
は、平均結晶粒径１μｍ以下のジルコニア（ＺｒＯ2 ）
を５〜３０重量％、ハフニア（ＨｆＯ2 ）をＺｒＯ2 全
量に対して１．０重量％以下、残部が平均結晶粒径１．
５μｍ以下のアルミナ（Ａｌ2Ｏ3 ）および不可避不純
物からなるとともに、ジルコニア（ＺｒＯ2 ）の４０％
以上が正方晶ジルコニア（ｔ−ＺｒＯ2 ）結晶であるこ
とを特徴とする。また、平均結晶粒径１μｍ以下のジル
コニア（ＺｒＯ2 ）を５〜３０重量％、ハフニア（Ｈｆ
Ｏ2 ）をＺｒＯ2 全量に対して１．０重量％以下、Ｆ
ｅ，Ｎｉ，Ｃｏの酸化物のうち少なくとも１種を０．０
１〜５重量％、残部が平均結晶粒径１．５μｍ以下のア
ルミナ（Ａｌ2 Ｏ3 ）および不可避不純物からなるとと
もに、ジルコニア（ＺｒＯ2 ）の４０％以上が正方晶ジ
ルコニア（ｔ−ＺｒＯ2 ）結晶であることを特徴とす
る。That is, the high-strength alumina sintered body of the present invention is a zirconia (ZrO 2 ) having an average crystal grain size of 1 μm or less.
5 to 30% by weight, hafnia (HfO 2 ) is 1.0% by weight or less based on the total amount of ZrO 2 , and the balance is an average crystal grain size of 1.
Consists of alumina (Al 2 O 3 ) of 5 μm or less and inevitable impurities, and 40% of zirconia (ZrO 2 ).
The above is a tetragonal zirconia (t-ZrO 2 ) crystal. Further, zirconia (ZrO 2 ) having an average crystal grain size of 1 μm or less is included in an amount of 5 to 30% by weight, and hafnia (Hf) is included.
O 2 ) is 1.0% by weight or less based on the total amount of ZrO 2 , and F
At least one of oxides of e, Ni, and Co is 0.0
1 to 5% by weight, the balance consisting of alumina (Al 2 O 3 ) having an average crystal grain size of 1.5 μm or less and unavoidable impurities, and 40% or more of zirconia (ZrO 2 ) is tetragonal zirconia (t-ZrO 2 ). It is characterized by being a crystal.
【００１０】ここで、ＺｒＯ2 量、ＨｆＯ2 量等を上記
のように限定した理由について説明する。Here, the reason why the amounts of ZrO 2 and HfO 2 are limited as described above will be explained.
【００１１】先ず、Ａｌ2 Ｏ3 量は７０〜９５重量％と
することが望ましい。Ａｌ2 Ｏ3 量が７０重量％よりも
少ないとＺｒＯ2 の転移によりＡｌ2 Ｏ3 が破壊され抗
折強度が低下するからであり、９５重量％よりも多いと
破壊靱性が小さくなるからである。Ａｌ2 Ｏ3 量のより
好ましい含有量は７８〜８７重量％である。First, it is desirable that the amount of Al 2 O 3 is 70 to 95% by weight. This is because when the amount of Al 2 O 3 is less than 70% by weight, the transition of ZrO 2 causes destruction of Al 2 O 3 and the transverse rupture strength decreases, and when it exceeds 95% by weight, the fracture toughness decreases. . The more preferable content of Al 2 O 3 is 78 to 87% by weight.
【００１２】また、ＺｒＯ2 量を５〜３０重量％とした
のは、ＺｒＯ2 の含有量が５重量％より少ない場合で
は、ＺｒＯ2 添加によるクラック先端のエネルギー吸収
が少なく靱性向上の効果が小さい。また、抗折強度向上
の効果が小さい。３０重量％を越えると焼結体中のＺｒ
Ｏ2 結晶相のうち単斜晶ＺｒＯ2 （ｍ−ＺｒＯ2 ）量が
多くなり、クラック先端でのエネルギー吸収に関与する
ＺｒＯ2 が実質的に減少し、破壊靱性が低下したり、焼
結体の硬度が低下するので切削工具用として使用すると
摩擦量が大となるからである。ＺｒＯ2 量のより好まし
い含有量は１３〜２２重量％である。Furthermore, it had the ZrO 2 amount and 5 to 30 wt%, in the case where the content of ZrO 2 is less than 5 wt%, less effect of energy absorption of the crack tip by ZrO 2 added is small toughness improved . Further, the effect of improving the bending strength is small. Zr in the sintered body exceeds 30% by weight
The amount of monoclinic ZrO 2 (m-ZrO 2 ) in the O 2 crystal phase is increased, the ZrO 2 involved in energy absorption at the crack tip is substantially reduced, the fracture toughness is lowered, and the sintered body is This is because the hardness of is reduced and the friction amount becomes large when used as a cutting tool. The more preferable content of ZrO 2 is 13 to 22% by weight.
【００１３】また、ＺｒＯ2 全量に対するＨｆＯ2 量を
１．０重量％以下と限定したのは、１．０重量％よりも
多い場合にはＺｒＯ2 を微粒化した場合にｔ−ＺｒＯ2
からｍ−ＺｒＯ2 への転移が抑制され、靱性向上の効果
が小さくなるからである。ＺｒＯ2 全量に対するＨｆＯ
2 量は、０．０３〜１．０重量％とすることが望まし
い。ＨｆＯ2 量が０．０３重量％よりも少ないと、原料
粉末の精製が非常に困難となるからである。ＨｆＯ2 は
ＺｒＯ2 原料中に通常３〜５重量％含有されているが、
本発明のようにＨｆＯ2 含有量を少なくするためには、
ＨｆＯ2 の含有量の少ない鉱石を選んでＺｒＯ2 を精製
すると良い。ＺｒＯ2 全量に対するＨｆＯ2 量は、特に
０．０５〜０．５重量％含有することが好ましい。Ｈｆ
Ｏ2 は単体ではなく、ＺｒＯ2 との化合物として存在す
るか、ＺｒＯ2 中に固溶していても良い。The amount of HfO 2 with respect to the total amount of ZrO 2 is limited to 1.0% by weight or less. When the amount of HfO 2 is more than 1.0% by weight, t-ZrO 2 is atomized when ZrO 2 is atomized.
To m-ZrO 2 is suppressed, and the effect of improving toughness is reduced. HfO to ZrO 2 total amount
The 2 amount is preferably 0.03 to 1.0% by weight. If the amount of HfO 2 is less than 0.03% by weight, it will be very difficult to purify the raw material powder. HfO 2 is usually contained in the ZrO 2 raw material in an amount of 3 to 5% by weight.
In order to reduce the HfO 2 content as in the present invention,
It is advisable to select an ore with a low HfO 2 content and purify ZrO 2 . The amount of HfO 2 with respect to the total amount of ZrO 2 is particularly preferably 0.05 to 0.5% by weight. Hf
O 2 is not a simple substance, or present as a compound with ZrO 2, may be solved in ZrO 2.
【００１４】焼結体中のＡｌ2 Ｏ3 の平均結晶粒径が
１．５μｍを越えると母相であるＡｌ2 Ｏ3 の強度が低
くなる傾向にあり、ＺｒＯ2 を均一にＡｌ2 Ｏ3 中に分
散させても抗折強度は充分に向上しない。また、焼結体
中のＺｒＯ2 の平均結晶粒径が１μｍを越えると、粒子
径のバラツキを考慮すると粒径３μｍ以上の比較的粗大
なジルコニア粒子が焼結体中に残存することが多く、こ
れらのジルコニア粒子が抗折試験を行った場合に破壊源
となり強度が劣化する。Ａｌ2 Ｏ3 およびＺｒＯ2 の平
均結晶粒径は０．５μｍ以下が好ましい。When the average crystal grain size of Al 2 O 3 in the sintered body exceeds 1.5 μm, the strength of the matrix Al 2 O 3 tends to be low, and ZrO 2 is uniformly dispersed in Al 2 O 3. Even if it is dispersed therein, the bending strength is not sufficiently improved. Further, when the average crystal grain size of ZrO 2 in the sintered body exceeds 1 μm, relatively coarse zirconia particles having a particle size of 3 μm or more often remain in the sintered body in consideration of the variation in particle size, When these zirconia particles are subjected to the bending test, they become a fracture source and deteriorate in strength. The average crystal grain size of Al 2 O 3 and ZrO 2 is preferably 0.5 μm or less.
【００１５】また、ＺｒＯ2 中の４０％以上をｔ−Ｚｒ
Ｏ2 結晶としたのは、ｔ−ＺｒＯ2の含有量が４０％未
満であれば、抗折強度の増加量が少なく、また、切削工
具として使用した場合に靱性の顕著な向上が望めないか
らである。また、Ａｌ2 Ｏ3-ZrO2 系においては、Ｚｒ
Ｏ2 によるアルミナ強化機構の１つとして、クラックの
先端でｔ−ＺｒＯ2 がｍ−ＺｒＯ2 に相変態し、クラッ
クのエネルギーを吸収し、クラックを止めるという効果
がある。したがって、ｔ−ＺｒＯ2 が４０％未満ではク
ラック先端近傍のｔ−ＺｒＯ2 量が少なく、クラックの
エネルギーを充分に吸収できないからである。焼結体中
のＺｒＯ2 結晶相はＺｒＯ2 全量のうち、ｔ−ＺｒＯ2
は５０％以上、特に７０％以上であることが好ましい。Further, 40% or more of ZrO 2 is t-Zr.
O 2 crystal is used because if the content of t-ZrO 2 is less than 40%, the amount of increase in bending strength is small, and when it is used as a cutting tool, remarkable improvement in toughness cannot be expected. Is. Further, in the Al 2 O 3 —ZrO 2 system, Zr
As one of the alumina strengthening mechanisms by O 2, there is an effect that t-ZrO 2 undergoes a phase transformation into m-ZrO 2 at the tip of the crack, absorbs the energy of the crack, and stops the crack. Therefore, when t-ZrO 2 is less than 40%, the amount of t-ZrO 2 in the vicinity of the crack tip is small and the crack energy cannot be sufficiently absorbed. ZrO 2 crystal phase in the sintered body of the ZrO 2 total amount, t-ZrO 2
Is preferably 50% or more, and particularly preferably 70% or more.
【００１６】また、本発明においては、ＺｒＯ2 を５〜
３０重量％、ＨｆＯ2 をＺｒＯ2 全量に対して１．０重
量％以下の割合で含有させるとともに、Ｆｅ，Ｎｉ，Ｃ
ｏの酸化物のうち少なくとも１種を０．０１〜５重量％
の割合でＡｌ2 Ｏ3 中に分散含有した高強度アルミナ質
焼結体が提供される。In the present invention, ZrO 2 is added in an amount of 5 to 5.
30% by weight, HfO 2 in an amount of 1.0% by weight or less based on the total amount of ZrO 2 , and Fe, Ni, C
0.01-5% by weight of at least one of the oxides of o
A high-strength alumina-based sintered body dispersedly contained in Al 2 O 3 is provided.
【００１７】ここで、Ｆｅ，Ｎｉ，Ｃｏの酸化物を０．
０１〜５重量％の割合で分散含有したのは、Ｆｅ，Ｎ
ｉ，Ｃｏの酸化物が０．０１重量％よりも少ないと破壊
靱性の向上効果が得られず、５重量％を越えると抗折強
度が低下するからである。Here, the oxides of Fe, Ni, and Co are added to 0.
Fe, N were dispersed and contained in the proportion of 01 to 5% by weight.
This is because if the oxide of i, Co is less than 0.01% by weight, the effect of improving fracture toughness cannot be obtained, and if it exceeds 5% by weight, the flexural strength is lowered.
【００１８】本発明の高強度アルミナ質焼結体の製造に
際しては通常の方法を採用し得る。In producing the high-strength alumina sintered body of the present invention, a usual method can be adopted.
【００１９】例えば、平均粒子径１μｍ以下のＡｌ2 Ｏ
3 、ＺｒＯ2 、所望によりＦｅ，Ｎｉ，Ｃｏ酸化物もし
くは焼成により酸化物に変換しうる化合物を秤量後、こ
れらを分散材および蒸留水等の媒質とともに混合粉砕す
る。ＺｒＯ2 原料にはＨｆＯ2含有量の少ない原料を用
いる。例えば、ＨｆＯ2 含有量の少ないＺｒＯ2 鉱石か
ら化学的に抽出し、加熱によって酸化物粉末にしたもの
である。For example, Al 2 O having an average particle size of 1 μm or less
3 , ZrO 2 , and optionally Fe, Ni, Co oxides or compounds that can be converted into oxides by firing are weighed, and then mixed and pulverized with a medium such as a dispersant and distilled water. A raw material having a low HfO 2 content is used as the ZrO 2 raw material. For example, it is an oxide powder that is chemically extracted from ZrO 2 ore having a low HfO 2 content and heated to form an oxide powder.
【００２０】粉砕後公知の成形手段で成形した後１２５
０〜１６００℃で焼成する。焼成方法としては、大気中
での常圧焼成、ホットプレス、熱間静水圧法等を採用し
うるが、高密度の焼結体を得るためには、先ず１４００
〜１５００℃で常圧焼成した後、さらに１３００〜１５
００℃で熱間静水圧焼成すれば良い。125 after crushing and shaping by known shaping means
Baking at 0 to 1600 ° C. As the firing method, atmospheric pressure firing in air, hot pressing, hot isostatic pressing, etc. can be adopted, but in order to obtain a high density sintered body, first, 1400
After firing under normal pressure at ~ 1500 ° C, 1300 ~ 15
It suffices to carry out hot isostatic pressing at 00 ° C.
【００２１】[0021]
【作用】本発明の高強度アルミナ質焼結体では、クラッ
クの先端でｔ−ＺｒＯ2 がｍ−ＺｒＯ2 に相変態し、ク
ラック先端のエネルギーを吸収し、クラックの伸展を防
止し、破壊靱性を向上することが可能となる。In the high-strength alumina sintered body of the present invention, t-ZrO 2 undergoes phase transformation into m-ZrO 2 at the crack tip, absorbs energy at the crack tip, prevents crack extension, and fracture toughness. It becomes possible to improve.
【００２２】そして、本発明では、ＺｒＯ2 全量に対す
るＨｆＯ2 量を一定量に制限し、ジルコニア（Ｚｒ
Ｏ2 ）の４０％以上をｔ−ＺｒＯ2 結晶としたので、破
壊靱性および抗折強度をさらに向上する。In the present invention, the amount of HfO 2 relative to the total amount of ZrO 2 is limited to a fixed amount, and zirconia (Zr
Since 40% or more of O 2 ) is a t-ZrO 2 crystal, the fracture toughness and the bending strength are further improved.
【００２３】本発明のＦｅ，Ｎｉ，Ｃｏの酸化物の添加
効果を確認すべく焼結体破壊面を観察したところ、Ｆ
ｅ，Ｎｉ，Ｃｏ酸化物を添加した試料では、それらの酸
化物を添加していない試料に比較して、Ａｌ2 Ｏ3 粒子
の粒内破壊が多くなっている。The fractured surface of the sintered body was observed to confirm the effect of adding the oxides of Fe, Ni and Co of the present invention.
In the sample to which the e, Ni, and Co oxides were added, intragranular fracture of Al 2 O 3 particles was larger than that in the sample to which the oxides were not added.
【００２４】このことから、Ｆｅ，Ｎｉ，Ｃｏ酸化物の
添加によってＡｌ2 Ｏ3 粒子の結合が強固になり粒界で
の破壊が起こりにくくなっていると考えられる。破壊靱
性が向上した理由は、Ａｌ2 Ｏ3 粒子の結合が強固にな
り、クラックの伸展が困難になるためであると考えられ
る。From this, it is considered that the addition of Fe, Ni, and Co oxides strengthens the bonding of Al 2 O 3 particles and makes it difficult for the Al 2 O 3 particles to break at the grain boundaries. It is considered that the reason why the fracture toughness is improved is that the bond of Al 2 O 3 particles is strengthened and it is difficult to spread the crack.
【００２５】以下、本発明を次の実施例で説明する。The present invention will be described in the following examples.
【００２６】[0026]
実施例１ Ａｌ2 Ｏ3 原料とＺｒＯ2 原料とを表１に示す割合で調
合し、調合原料１００ｇを樹脂製ポットに入れ、アルコ
ールとφ１０ｍｍの高純度アルミナボールとともに密封
し、所定時間混合する。混合後の原料を乾燥した後、４
重量％バインダを添加し、所望形状に成形する。成形体
を大気雰囲気中で１５００℃で２時間仮焼し、しかる後
に１４００℃で１時間熱間静水圧焼成を行った。Example 1 An Al 2 O 3 raw material and a ZrO 2 raw material were mixed at a ratio shown in Table 1, 100 g of the mixed raw material was put into a resin pot, and the mixture was sealed with alcohol and a φ10 mm high-purity alumina ball and mixed for a predetermined time. After drying the mixed raw materials, 4
Add wt% binder and shape into desired shape. The molded body was calcined in an air atmosphere at 1500 ° C. for 2 hours, and then hot isostatic firing was performed at 1400 ° C. for 1 hour.
【００２７】これらの試料について日本工業規格（ＪＩ
Ｓ）による４点曲げ抗折強度試験を行うとともに、破壊
靱性（Ｋ1c）をビッカース圧痕法により、さらにビッカ
ース硬度については荷重２０ｋｇでビッカース硬度計に
より測定した結果を表１に示す。Regarding these samples, Japanese Industrial Standards (JI
Table 1 shows the results obtained by performing a 4-point bending bending strength test according to S), measuring fracture toughness (K 1c ) by the Vickers indentation method, and further measuring Vickers hardness by a Vickers hardness meter with a load of 20 kg.
【００２８】[0028]
【表１】 [Table 1]
【００２９】試料番号２〜１０、１２〜１４、１７〜１
９は本発明の範囲内のものであり、いずれも抗折強度７
０ｋｇ／ｍｍ2 以上、靱性値も６ＭＮ／ｍ3/2 以上と優
れている。これに対し、試料番号１及び２０は本発明の
範囲外のものであり、試料番号１は抗折強度５５ｋｇ／
ｍｍ2 および靱性値が４．０ＭＮ／ｍ3/2 と低く、試料
番号２０は抗折強度が１２０ｋｇ／ｍｍ2 と優れている
が、靱性が４．５ＭＮ／ｍ3/2 と劣化している。試料番
号４〜８は本発明のより好ましい範囲であり、抗折強度
が１００ｋｇ／ｍｍ2 以上、靱性値が６．０ＭＮ／ｍ
3/2 以上と優れている。Sample Nos. 2-10, 12-14, 17-1
9 is within the scope of the present invention, and all have a bending strength of 7
It has an excellent value of 0 kg / mm 2 or more and a toughness value of 6 MN / m 3/2 or more. On the other hand, sample numbers 1 and 20 are out of the scope of the present invention, and sample number 1 has a bending strength of 55 kg /
mm 2 and toughness value are as low as 4.0 MN / m 3/2, and Sample No. 20 has an excellent bending strength of 120 kg / mm 2 but has deteriorated toughness of 4.5 MN / m 3/2 . . Sample Nos. 4 to 8 are more preferable ranges of the present invention, and have a bending strength of 100 kg / mm 2 or more and a toughness value of 6.0 MN / m.
Excellent with 3/2 or more.
【００３０】実施例２ 更に、試料番号６についてジルコニア（ＺｒＯ2 ）の平
均結晶粒径を異ならせてｔ−ＺｒＯ2 結晶相の焼結体中
の量をＸ線回折ピークにより下記の方法で測定した。Example 2 Furthermore, with respect to sample No. 6, the amount of t-ZrO 2 crystal phase in the sintered body was measured by the following method by varying the average crystal grain size of zirconia (ZrO 2 ). did.
【００３１】ＣｕＫα線で２θ＝２７°〜３３°までＸ
線回折測定を行い、以下のピーク高さ（ｔ1 ，ｍ1 ，ｍ
2 ）を求める。With CuKα ray, 2θ = 27 ° to 33 ° X
Line diffraction measurement was performed and the following peak heights (t 1 , m 1 , m
2 ) Ask.
【００３２】 ｔ−ＺｒＯ2 （１１１） ３０．２° ｔ1 （１） ｍ−ＺｒＯ2 （１１１） ２８．２° ｍ1 （２） ｍ−ＺｒＯ2 （１１１） ３１．５° ｍ2 （３） ｔ1 ，ｍ1 ，ｍ2 より、ｔ−ＺｒＯ2 の量は数１で求め
られる。T-ZrO 2 (111) 30.2 ° t 1 (1) m-ZrO 2 (111) 28.2 ° m 1 (2) m-ZrO 2 (111) 31.5 ° m 2 (3 ) From t 1 , m 1 and m 2 , the amount of t-ZrO 2 can be calculated by Equation 1.
【００３３】[0033]
【数１】 [Equation 1]
【００３４】上記測定法によりｔ−ＺｒＯ2 結晶相の量
による抗折強度および靱性の変化を調べた結果を表２に
示す。Table 2 shows the results of examining the changes in the bending strength and the toughness depending on the amount of the t-ZrO 2 crystal phase by the above measuring method.
【００３５】[0035]
【表２】 [Table 2]
【００３６】試料番号２１〜２４はジルコニア（ＺｒＯ
2 ）の平均粒径が１μｍ以下と本発明の範囲内で、ｔ−
ＺｒＯ2 結晶相が約４０％以上であり、この程度以上の
ｔ−ＺｒＯ2 結晶相を含むアルミナ質焼結体は抗折強度
が９０ｋｇ／ｍｍ2 以上と優れている。これに対し、試
料番号２５および２６はジルコニア（ＺｒＯ2 ）の平均
粒径が１μｍを越え本発明の範囲外で、ｔ−ＺｒＯ2 結
晶相が４０％未満であり、このようなアルミナ質焼結体
は抗折強度が６５ｋｇ／ｍｍ2 未満と劣っていることが
理解される。尚、靱性値については試料番号２１〜２６
のいずれも７．２〜８．５ＭＮ／ｍ3/2 程度で特に大き
な差は生じなかった。Sample numbers 21 to 24 are zirconia (ZrO
If the average particle size of 2 ) is 1 μm or less and within the range of the present invention, t-
The ZrO 2 crystal phase is about 40% or more, and the alumina-based sintered body containing the t-ZrO 2 crystal phase having the ZrO 2 crystal phase or more is excellent in bending strength of 90 kg / mm 2 or more. On the other hand, sample numbers 25 and 26 have an average particle size of zirconia (ZrO 2 ) of more than 1 μm and outside the scope of the present invention, and the t-ZrO 2 crystal phase is less than 40%. It is understood that the body has a poor transverse strength of less than 65 kg / mm 2 . Regarding the toughness values, sample numbers 21 to 26
In each of the above cases, a large difference did not occur at about 7.2 to 8.5 MN / m 3/2 .
【００３７】実施例３ 純度９８％以上のＡｌ2 Ｏ3 粉末、ＺｒＯ2 粉末及び平
均粒子径１．０μｍ以下のＮｉＯ、ＣｏＯ、Ｆｅ2 Ｏ3
粉末を表３の量に秤量し、これを分散剤を添加した蒸留
水に入れ、アトライタで混合粉砕する。粉砕後のスラリ
ーを乾燥し、有機バインダーを添加し、さらに乾燥させ
て、成形用原料とした。Example 3 Al 2 O 3 powder having a purity of 98% or more, ZrO 2 powder and NiO, CoO, Fe 2 O 3 having an average particle diameter of 1.0 μm or less.
The powder is weighed to the amount shown in Table 3, put in distilled water to which a dispersant is added, and mixed and ground with an attritor. The slurry after crushing was dried, an organic binder was added, and further dried to obtain a molding raw material.
【００３８】この原料を用いて所定寸法に成形した後、
ポリエチレンの袋に真空パックし、４ｔ／ｃｍ2 の圧力
でＣＩＰ処理（冷間静水圧成形）した。After molding to a predetermined size using this raw material,
It was vacuum packed in a polyethylene bag and subjected to CIP treatment (cold isostatic pressing) at a pressure of 4 t / cm 2 .
【００３９】得られた成形体を脱バインダーし、大気雰
囲気中で１４５０℃で２時間予備焼成した。その後、焼
結体を１４２５℃で１時間２０００気圧で熱間静水圧焼
成した。The obtained molded body was debindered and prebaked at 1450 ° C. for 2 hours in the air atmosphere. Then, the sintered body was hot isostatically baked at 1425 ° C. for 1 hour at 2000 atmospheric pressure.
【００４０】得られた焼結体を３×４×４０ｍｍの抗折
強度試験片に研摩し、ＪＩＳＲ１６０１に従って３点曲
げ強度を測定した。また、前述の方法で同時に３×４×
４０ｍｍのタブレットを作製し、焼上がりの未研摩面で
Ｘ線回折を測定し、ＺｒＯ2の結晶を調べた。The obtained sintered body was ground into a bending strength test piece of 3 × 4 × 40 mm, and the three-point bending strength was measured according to JIS R1601. In addition, 3 × 4 × at the same time by the above method
A 40 mm tablet was prepared, and X-ray diffraction was measured on the unpolished surface after baking to examine ZrO 2 crystals.
【００４１】更に、３×４×４０ｍｍのタブレットを研
摩後、３μｍのダイヤモンドペーストでポリッシングを
行い、ビッカース硬度用ダイヤモンドコーンを用いて荷
重２０ｋｇでクラック長さを測定し、ＭＩ法によって破
壊靱性を測定した。Further, after polishing a tablet of 3 × 4 × 40 mm, polishing was performed with a diamond paste of 3 μm, the crack length was measured with a load of 20 kg using a diamond cone for Vickers hardness, and the fracture toughness was measured by the MI method. did.
【００４２】[0042]
【表３】 [Table 3]
【００４３】この表３より、ＮｉＯ、ＣｏＯ、Ｆｅ2 Ｏ
3 を全く添加しない組成（表１）よりも靱性が向上して
いることが判る。例えば、表１の試料Ｎo.６では靱性が
７MN/m3/2 、抗折強度が１３５ kg/mm2 であるのに対
し、この実施例では表３の試料Ｎo.３５のように靱性が
７．５MN/m3/2 、抗折強度が１４０ kg/mm2 を達成でき
た。From Table 3, NiO, CoO, Fe 2 O
It can be seen that the toughness is improved over the composition in which 3 is not added at all (Table 1). For example, the sample No. 6 in Table 1 has a toughness of 7 MN / m 3/2 and the bending strength is 135 kg / mm 2 , whereas in this Example, the sample No. 35 in Table 3 has a toughness. It was possible to achieve 7.5 MN / m 3/2 and a bending strength of 140 kg / mm 2 .
【００４４】[0044]
【発明の効果】以上のように本発明によれば、破壊靱性
値が少なくとも６ＭＮ／ｍ3/2 以上維持することがで
き、特に抗折強度は７０ｋｇ／ｍｍ2 以上とすることが
でき、高速切削、高切り込みおよび高送りといった高効
率加工に適したセラミック工具用のアルミナ質焼結体を
提供することができる。As described above, according to the present invention, the fracture toughness value can be maintained at least 6 MN / m 3/2 or more, and the bending strength can be 70 kg / mm 2 or more. It is possible to provide an alumina-based sintered body for a ceramic tool suitable for high-efficiency machining such as cutting, high-cutting and high-feeding.
Claims (2)
ｒＯ2 ）を５〜３０重量％、ハフニア（ＨｆＯ2 ）をＺ
ｒＯ2 全量に対して１．０重量％以下、残部が平均結晶
粒径１．５μｍ以下のアルミナ（Ａｌ2 Ｏ3 ）および不
可避不純物からなるとともに、前記ジルコニア（ＺｒＯ
2 ）の４０％以上が正方晶ジルコニア（ｔ−ＺｒＯ2 ）
結晶であることを特徴とする高強度アルミナ質焼結体。1. Zirconia (Z having an average crystal grain size of 1 μm or less
5 to 30% by weight of rO 2 ) and Z of hafnia (HfO 2 ).
1.0 wt% or less with respect to the total amount of rO 2 and the balance consisting of alumina (Al 2 O 3 ) having an average crystal grain size of 1.5 μm or less and unavoidable impurities, and the zirconia (ZrO 2
40% or more of 2 ) is tetragonal zirconia (t-ZrO 2 ).
A high-strength alumina sintered body characterized by being a crystal.
ｒＯ2 ）を５〜３０重量％、ハフニア（ＨｆＯ2 ）をＺ
ｒＯ2 全量に対して１．０重量％以下、Ｆｅ，Ｎｉ，Ｃ
ｏの酸化物の内少なくとも１種を０．０１〜５重量％、
残部が平均結晶粒径１．５μｍ以下のアルミナ（Ａｌ2
Ｏ3 ）および不可避不純物からなるとともに、前記ジル
コニア（ＺｒＯ2 ）の４０％以上が正方晶ジルコニア
（ｔ−ＺｒＯ2 ）結晶であることを特徴とする高強度ア
ルミナ質焼結体。2. Zirconia (Z having a mean crystal grain size of 1 μm or less
5 to 30% by weight of rO 2 ) and Z of hafnia (HfO 2 ).
1.0% by weight or less based on the total amount of rO 2 , Fe, Ni, C
0.01 to 5% by weight of at least one of the oxides of o,
The balance is alumina (Al 2
O 3 ) and inevitable impurities, and 40% or more of the zirconia (ZrO 2 ) is a tetragonal zirconia (t-ZrO 2 ) crystal, a high-strength alumina sintered body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05239483A JP3078430B2 (en) | 1993-09-27 | 1993-09-27 | High-strength alumina sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05239483A JP3078430B2 (en) | 1993-09-27 | 1993-09-27 | High-strength alumina sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0797254A true JPH0797254A (en) | 1995-04-11 |
| JP3078430B2 JP3078430B2 (en) | 2000-08-21 |
Family
ID=17045452
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05239483A Expired - Fee Related JP3078430B2 (en) | 1993-09-27 | 1993-09-27 | High-strength alumina sintered body |
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| Country | Link |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005211252A (en) * | 2004-01-28 | 2005-08-11 | Kyocera Corp | Biological member, method for manufacture thereof and artificial joint |
| US7247588B2 (en) * | 2002-11-22 | 2007-07-24 | Saint-Gobain Ceramics & Plastics, Inc. | Zirconia toughened alumina ESD safe ceramic composition, component, and methods for making same |
| WO2019208438A1 (en) * | 2018-04-26 | 2019-10-31 | 京セラ株式会社 | Ceramic substrate and mounting substrate using same, and electronic device |
| CN112834085A (en) * | 2020-12-29 | 2021-05-25 | 襄阳臻芯传感科技有限公司 | Elastic thin substrate of ceramic capacitive pressure sensor and manufacturing method |
-
1993
- 1993-09-27 JP JP05239483A patent/JP3078430B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7247588B2 (en) * | 2002-11-22 | 2007-07-24 | Saint-Gobain Ceramics & Plastics, Inc. | Zirconia toughened alumina ESD safe ceramic composition, component, and methods for making same |
| US8516857B2 (en) | 2002-11-22 | 2013-08-27 | Coorstek, Inc. | Zirconia toughened alumina ESD safe ceramic composition, component, and methods for making same |
| JP2005211252A (en) * | 2004-01-28 | 2005-08-11 | Kyocera Corp | Biological member, method for manufacture thereof and artificial joint |
| WO2019208438A1 (en) * | 2018-04-26 | 2019-10-31 | 京セラ株式会社 | Ceramic substrate and mounting substrate using same, and electronic device |
| JPWO2019208438A1 (en) * | 2018-04-26 | 2021-06-10 | 京セラ株式会社 | Ceramic substrate and mounting substrate and electronic device using it |
| CN112834085A (en) * | 2020-12-29 | 2021-05-25 | 襄阳臻芯传感科技有限公司 | Elastic thin substrate of ceramic capacitive pressure sensor and manufacturing method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3078430B2 (en) | 2000-08-21 |
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