JPH0437653A - Production of ceramics sintered body - Google Patents
Production of ceramics sintered bodyInfo
- Publication number
- JPH0437653A JPH0437653A JP2140378A JP14037890A JPH0437653A JP H0437653 A JPH0437653 A JP H0437653A JP 2140378 A JP2140378 A JP 2140378A JP 14037890 A JP14037890 A JP 14037890A JP H0437653 A JPH0437653 A JP H0437653A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- carbon
- aluminum
- sintered body
- aluminum oxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000919 ceramic Substances 0.000 title claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims abstract description 46
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 31
- JXOOCQBAIRXOGG-UHFFFAOYSA-N [B].[B].[B].[B].[B].[B].[B].[B].[B].[B].[B].[B].[Al] Chemical compound [B].[B].[B].[B].[B].[B].[B].[B].[B].[B].[B].[B].[Al] JXOOCQBAIRXOGG-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000000843 powder Substances 0.000 claims abstract description 25
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 24
- 239000000203 mixture Substances 0.000 claims abstract description 14
- 238000000465 moulding Methods 0.000 claims abstract description 12
- 238000010304 firing Methods 0.000 claims description 30
- 150000001875 compounds Chemical class 0.000 claims description 10
- 239000000463 material Substances 0.000 abstract description 15
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract description 3
- 239000005011 phenolic resin Substances 0.000 abstract description 2
- 238000001354 calcination Methods 0.000 abstract 3
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 abstract 1
- 229910052593 corundum Inorganic materials 0.000 abstract 1
- 229920001568 phenolic resin Polymers 0.000 abstract 1
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract 1
- 239000002245 particle Substances 0.000 description 17
- 238000005245 sintering Methods 0.000 description 13
- 239000000126 substance Substances 0.000 description 12
- 229910052810 boron oxide Inorganic materials 0.000 description 11
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 11
- 238000000034 method Methods 0.000 description 9
- OJMOMXZKOWKUTA-UHFFFAOYSA-N aluminum;borate Chemical compound [Al+3].[O-]B([O-])[O-] OJMOMXZKOWKUTA-UHFFFAOYSA-N 0.000 description 8
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 7
- 229910052796 boron Inorganic materials 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 229910052782 aluminium Inorganic materials 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 239000013078 crystal Substances 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 229910016459 AlB2 Inorganic materials 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 101000693961 Trachemys scripta 68 kDa serum albumin Proteins 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000002309 gasification Methods 0.000 description 2
- 238000007731 hot pressing Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000009694 cold isostatic pressing Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 238000001513 hot isostatic pressing Methods 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Ceramic Products (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、耐摩耗性および靭性に優れた特に切削工具を
はじめとする各種構造材料として適したセラミックス焼
結体の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a ceramic sintered body that has excellent wear resistance and toughness and is particularly suitable as a variety of structural materials including cutting tools.
（従来技術及びその問題点）
アルミナ（Ａ１２０３）質焼結体をはじめとするセラミ
ック材料は、従来から金属材料などに比較して耐摩耗性
等の機械的特性に優れていることから金属材料に代わる
材料として各種の構造用部品として使用されている。(Prior art and its problems) Ceramic materials such as alumina (A1203) sintered bodies have traditionally been used as metal materials because they have superior mechanical properties such as wear resistance compared to metal materials. It is used as an alternative material for various structural parts.
しかしながら、最近に至ってはセラミックスに対してさ
らに高い特性が要求されており、アルミナ質焼結体に対
しても他のセラミックスとの複合化により各種特性の改
善を図ることが提案されている。However, in recent years, ceramics have been required to have even higher properties, and it has been proposed to improve various properties of alumina sintered bodies by combining them with other ceramics.
また、セラミックスの中でも特に耐摩耗性に優れた材料
として、硼化チタンや硼化ジルコニウムなどの硼化物の
研究開発が盛んに行われている。Further, among ceramics, research and development of borides such as titanium boride and zirconium boride are being actively conducted as materials with particularly excellent wear resistance.
（発明が解決しようとする問題点）
このような硼化物を生体とするセラミックスは高い硬度
を有する反面、強度や靭性が低く応用分野が限られてい
た。(Problems to be Solved by the Invention) Although such ceramics containing boride as a living body have high hardness, their strength and toughness are low, and the fields of application thereof are limited.
硼化チタンは硬度が高く、熱伝導性が良いことから切削
工具用材料として有望と考えられていたが、靭性を改善
する方法を見出すことが出来ず実用には到っていない。Titanium boride has high hardness and good thermal conductivity, so it was thought to be a promising material for cutting tools, but it has not been put into practical use because no method has been found to improve its toughness.
硼化ジルコニウムは金属との反応性が低いことから、金
属溶湯用るつぼ等としての応用が期待されているが、強
度が低いことから構造材料としての応用分野は限られて
いる。Since zirconium boride has low reactivity with metals, it is expected to be used as crucibles for molten metal, but its low strength limits its application as a structural material.
また、硼化アルミニウムは酸化アルミニウムに比較して
硬度に優れた材料であるが未知の部分が多く、焼結体と
して優れた特性を有するものは未だ開発されていなかっ
た。Furthermore, although aluminum boride is a material with superior hardness compared to aluminum oxide, there are many unknown aspects, and a sintered body with excellent properties has not yet been developed.
そこで、本発明者等は、先に上記の硼化物中から硼化ア
ルミニウムを選択し、その焼結性や特性の改善について
検討を進めたところ、硼化アルミニウムに対して酸化ア
ルニウム成分を混合して成形、焼成することにより、硼
化アルミニウムの一部あるいは全部を分解せしめること
により酸化アルミニウムを含有する高い硬度を有し且つ
高い靭性を有する特異的な材料が得られることを提案し
た（特願平１−３１２７３５号）。しかしながら、この
材料は焼結中に硼素が揮散しやすいことから焼結体組成
のコントロールが難しいために特性が安定せず、特に大
型の焼結体を作成する場合に該焼結体内の各元素、特に
硼素が偏析し焼結体の内部と周辺部で特性のバラツキが
生しるという問題があった。Therefore, the present inventors first selected aluminum boride from among the borides mentioned above and proceeded with studies on improving its sinterability and properties. We proposed that a unique material containing aluminum oxide, which has high hardness and high toughness, could be obtained by decomposing some or all of the aluminum boride by molding and firing the aluminum boride (patent application). No. 1-312735). However, with this material, boron easily volatilizes during sintering, making it difficult to control the composition of the sintered body, resulting in unstable properties. In particular, there was a problem in that boron segregated, resulting in variations in properties between the inside and the periphery of the sintered body.
（問題点を解決するための手段）
そこで、本発明者等は硼化アルミニウムの焼結性ならび
にその特性改善について検討を進めた結果、上記の系に
対して炭素粉末を特定の割合で添加することにより大型
品においても全体として特性が均質で且つ高い硬度、靭
性を有する焼結体が得られることを知見した。(Means for Solving the Problems) Therefore, the present inventors investigated the sintering properties of aluminum boride and the improvement of its properties.As a result, the present inventors added carbon powder at a specific ratio to the above system. It has been found that by doing this, even in large-sized products, a sintered body having homogeneous properties as a whole and high hardness and toughness can be obtained.
即ち、本発明は、硼化アルミニウムと、酸化アルミニウ
ムあるいは焼成により酸化アルミニウムを生成しうる化
合物からなる組成物１００重量部に対して炭素あるいは
焼成により炭素を生成する化合物を炭素換算で０．０５
〜８重量部を添加した混合物を成形後、１２００〜１９
００ ’Ｃの温度で焼成することを特徴とするもので、
さらに上記構成において、酸化アルミニウムあるいは焼
成によって酸化アルミニウムを生成する物質として針状
の結晶粒子からなるものを用いること乙こよって焼結体
中に酸化アルミニウムの針状晶の粒子を存在させ、これ
により焼結体の靭性をさらに向上させることができる。That is, the present invention provides 0.05 parts by weight of carbon or a compound that produces carbon when fired, in terms of carbon, per 100 parts by weight of a composition consisting of aluminum boride, aluminum oxide, or a compound that can produce aluminum oxide when fired.
After molding the mixture to which ~8 parts by weight was added, the temperature was 1200 ~ 19
It is characterized by being fired at a temperature of 00'C,
Furthermore, in the above configuration, aluminum oxide or a substance that generates aluminum oxide by firing is made of needle-shaped crystal particles. The toughness of the sintered body can be further improved.
以下、本発明を詳述する。The present invention will be explained in detail below.
本発明のセラミックス焼結体の製造方法は、原料の調製
、成形、焼成の三つの工程により構成される。The method for manufacturing a ceramic sintered body of the present invention includes three steps: preparation of raw materials, molding, and firing.
〔原料の調製］
出発原料としては硼化アルミニウム粉末及び酸化アルミ
ニウム粉末あるいは焼成によって酸化アルミニウムを生
成する化合物粉末および炭素を用いる。[Preparation of Raw Materials] As starting materials, aluminum boride powder and aluminum oxide powder, or compound powders that produce aluminum oxide upon firing, and carbon are used.
硼化アルミニウム粉末は、平均粒径２００メンシユ以下
、望ましくは３μｍ以下、最適には１μｍ以下の粉末で
あり、一般に化学式ＡＩＢ、□、ＡｌＢ２もしくは非化
学量論組成の硼化アルミニウムであってもよく、またこ
れらの混合物であってもよい。現在市販されているＡｌ
Ｂ１２は部分的にＡＩＢ＋ｏを含んでいるものもあるが
その場合も問題は生じない。The aluminum boride powder is a powder with an average particle size of 200 mensius or less, preferably 3 μm or less, optimally 1 μm or less, and may generally be aluminum boride with the chemical formula AIB, □, AlB2 or a non-stoichiometric composition. , or a mixture thereof. Currently commercially available Al
B12 may partially contain AIB+o, but no problem occurs in that case either.
一方、酸化アルミニウム粉末或いは焼成により酸化アル
ミニウムを生成する物質は、いずれも平均粒径３μｍ以
下、特に１μｍ以下の微細な粒子を用いるのが望ましい
。なお、焼成により酸化アルミニウムを生成する物質と
しては、金属アルミニウム、硼酸アルミニウムなどが挙
げられ、硼酸アルミニウムは９Ａ＋□０３・Ｂ ｚ Ｏ
］または２Ａ１２０３ ・２Ｂ２０：ｌの化学式で表
される。On the other hand, for the aluminum oxide powder or the substance that produces aluminum oxide by firing, it is desirable to use fine particles with an average particle size of 3 μm or less, particularly 1 μm or less. In addition, examples of substances that generate aluminum oxide by firing include metal aluminum, aluminum borate, etc. Aluminum borate is 9A+□03・B z O
] or represented by the chemical formula 2A1203 ・2B20:l.
また、本発明によれば酸化アルミニウムあるいは焼成に
より酸化アルミニウムを生成する物質として針状形態か
らなるものを用いることにより焼結体の靭性をさらに高
めることができる。具体的には、針状晶酸化アルミニウ
ム、あるいは焼結時の加熱により針状晶酸化アルミニウ
ムを生成する物質として９ＡＩ□０３ ・２ＢｚＯｉの
化学式を有する針状晶硼酸アルミニウムが用いられる。Furthermore, according to the present invention, the toughness of the sintered body can be further improved by using aluminum oxide or a substance that produces aluminum oxide upon firing that has a needle-like shape. Specifically, acicular aluminum borate having the chemical formula 9AI□03.2BzOi is used as acicular aluminum oxide or as a substance that generates acicular aluminum oxide upon heating during sintering.
なお、これらの針状物質は、平均径（短径）が２μｍ以
下、特に０．２乃至０．７μｍであることが好ましく、
また長径／短径で表わされるアスペクト比の平均が３〜
１００、特に１０乃至３０のものが好適に用いられる。In addition, it is preferable that these acicular substances have an average diameter (minor axis) of 2 μm or less, particularly 0.2 to 0.7 μm,
Also, the average aspect ratio expressed by major axis / minor axis is 3~
100, particularly 10 to 30, is preferably used.
上記平均径を２μｍ以下に特定したのは焼結時の粒成長
が過大にならず、高い抗折強度を維持できるからであり
、２μｍより大きいと焼結時の結晶粒子の粒成長が著し
く、粒子径のコントロールが難しくなり、靭性にばらつ
きが生じ、また切削工具として用いた際に逃げ面の境界
摩耗が大きくなる傾向にあるためである。The above average diameter is specified to be 2 μm or less because grain growth during sintering does not become excessive and high bending strength can be maintained.If it is larger than 2 μm, grain growth of crystal grains during sintering becomes significant This is because it becomes difficult to control the particle size, variations in toughness occur, and boundary wear on the flank surface tends to increase when used as a cutting tool.
一方、アスペクト比の平均が３より小さいと繊維強化の
効果が少ないために靭性の向上効果はなく、１００より
大きいと原料の取扱が難しく、均一に分散できないため
に靭性が低下する傾向にある。On the other hand, if the average aspect ratio is smaller than 3, there is no effect of improving the toughness because the effect of fiber reinforcement is small, and if it is larger than 100, the raw material is difficult to handle and cannot be uniformly dispersed, so the toughness tends to decrease.
なお、この場合でもウィスカーの一部を粉砕しながら混
合すれば問題なく使用できる。Even in this case, it can be used without any problem if the whiskers are mixed while pulverizing some of them.
上述の硼化アルミニウム粉末および酸化アルミニウム粉
末あるいは焼成により酸化アルミニウムを生成する物質
の調合は、硼化アルミニウム粉末が５〜９５重量％、好
ましくは３０〜８０重量％、酸化アルミニウム粉末ある
いは焼成により酸化アルミニウムを生成する物質が酸化
アルミニウムに換算して３〜９０重量％、好ましくは２
０〜７０重量％の割合で混合される。また特に高硬度の
材質を得るためには、硼化アルミニウム５５〜８０重量
％、酸化アルミニウム２０〜４５重量％が最適であり、
特に高靭性の材質を得るためには、硼化アルミニウム３
０〜５５重量％、酸化アルミニウム４５〜７０重量％が
最適である。The above-mentioned formulation of aluminum boride powder and aluminum oxide powder or a substance that produces aluminum oxide by firing is such that aluminum boride powder is 5 to 95% by weight, preferably 30 to 80% by weight, and aluminum oxide powder or aluminum oxide is produced by firing. 3 to 90% by weight, preferably 2% by weight in terms of aluminum oxide.
They are mixed in a proportion of 0 to 70% by weight. In addition, in order to obtain a material with particularly high hardness, 55 to 80% by weight of aluminum boride and 20 to 45% by weight of aluminum oxide are optimal.
In order to obtain a material with particularly high toughness, aluminum boride 3
0 to 55% by weight and 45 to 70% by weight of aluminum oxide are optimal.
混合割合を上記の範囲に設定したのは、硼化アルミニウ
ムが９５重量％を越えると焼結が難しく、また、硼化ア
ルミニウムが５重量％を下回ると焼結体の硬度が低下す
るからである。酸化アルミニウムが３重量％を下回ると
強靭化の効果がなく、９０重量％を越えると硬度が低下
する。The reason for setting the mixing ratio within the above range is that if the aluminum boride content exceeds 95% by weight, sintering will be difficult, and if the aluminum boride content falls below 5% by weight, the hardness of the sintered body will decrease. . If the aluminum oxide content is less than 3% by weight, there is no toughening effect, and if it exceeds 90% by weight, the hardness decreases.
また、高靭性化を目的に酸化アルミニウム粉末の代わり
に添加される針状粒子は、全量中に３〜７５体積％の割
合で含有することが望ましい。Further, it is desirable that the acicular particles added in place of the aluminum oxide powder for the purpose of increasing toughness be contained in a proportion of 3 to 75% by volume in the total amount.
本発明によれば、系の焼結性および均質化を図る上で、
上記硼化アルミニウムと酸化アルミニウム成分からなる
組成物１００重量部に対して炭素粉末あるいは焼成によ
り炭素を生成する化合物を炭素換算で０．０５〜８重量
部、特に１〜３重量部の割合で混合する。炭素量を上記
の範囲に限定したのは、炭素量が０６０５重量部未満で
は焼結体の硬度および強度の均一化が達成されず、８重
量部を越えると逆に焼結性が低下し緻密体が得られない
からである。According to the present invention, in order to improve the sinterability and homogenization of the system,
Carbon powder or a compound that generates carbon by firing is mixed at a ratio of 0.05 to 8 parts by weight, especially 1 to 3 parts by weight in terms of carbon, to 100 parts by weight of the composition consisting of aluminum boride and aluminum oxide components. do. The reason why the carbon content is limited to the above range is that if the carbon content is less than 0.605 parts by weight, uniform hardness and strength of the sintered body will not be achieved, and if it exceeds 8 parts by weight, the sinterability will decrease and the density will be reduced. This is because the body cannot be obtained.
なお、炭素成分としてはフェノール樹脂等の焼成により
炭素を生成する化合物の他、カーボン型を用いたホット
プレス焼成時に型から混入する場合もあるためにこれら
を総合して炭素添加量を調整することが望ましい。In addition to compounds that generate carbon when fired, such as phenol resins, the carbon component may also be mixed in from the mold during hot press firing using a carbon mold, so the amount of carbon added should be adjusted by taking these into account. is desirable.
さらに、本発明によれば、焼結性を改善する目的で上記
の混合物に酸化硼素を２０重量％以下の割合で添加する
こともできる。この酸化硼素はその量が２０重量％を越
えると焼結体の硬度および靭性が低下するため好ましく
ない。また、この酸化硼素は、硼化アルミニウム粉末表
面の酸化膜から生成されたものであってもよく、硼化ア
ルミニウムの一部を酸化させてもよい。Furthermore, according to the present invention, boron oxide can be added to the above mixture in a proportion of 20% by weight or less for the purpose of improving sinterability. If the amount of boron oxide exceeds 20% by weight, the hardness and toughness of the sintered body will decrease, which is not preferable. Further, this boron oxide may be generated from an oxide film on the surface of the aluminum boride powder, or a part of the aluminum boride may be oxidized.
Ｃ成形〕
硼化アルミニウム、酸化アルミニウム成分、炭素、所望
により酸化硼素を上記の割合で混合後、衆知の成形手段
で所望の形状に成形できる。成形手段は、例えばプレス
成形、押し出し成形、射出成形、鋳込み成形、冷間静水
圧成形等が用いられる。成形性を向上させるため公知の
バインダーや分散剤を用いてもよい。C-forming] After mixing aluminum boride, an aluminum oxide component, carbon, and, if desired, boron oxide in the above proportions, it can be molded into a desired shape by a well-known molding means. As the shaping means, for example, press molding, extrusion molding, injection molding, cast molding, cold isostatic pressing, etc. are used. Known binders and dispersants may be used to improve moldability.
次に、これらの成形体を所望により真空中もしくは窒素
ガスもしくはアルゴンガス等の不活性ガス中で脱脂した
のち焼成を行う。焼成は１２００乃至１９００℃の温度
でＡｒ、Ｈｅ等の不活性ガスもしくはカーボン等の存在
する還元性雰囲気およびそれらの加圧もしくは減圧雰囲
気で０．５乃至６．０時間程度行えばよい。焼成手段と
しては、常圧焼成、ホットプレス法および熱間静水圧焼
成法（ＨＩ Ｐ法）等が適用され、特に高密度の焼結体
を得るために、普通焼成、ホットプレス法によって対理
論密度比９６％以上の焼結体を作成し、さらに５００〜
２０００気圧の高圧下で１２００〜１９００°Ｃの焼成
温度で熱間静水圧焼成すればよい。焼成温度を上記の範
囲に設定したのは、焼成温度が１２００°Ｃより低いと
焼結が不十分でボイド等が発生するために十分な特性が
得られず、１９００ ”Ｃを越えると酸化アルミニウム
が粒成長してボアが発生し強度が低下するためである。Next, these molded bodies are degreased in vacuum or in an inert gas such as nitrogen gas or argon gas, if desired, and then fired. Firing may be carried out at a temperature of 1200 to 1900° C. for about 0.5 to 6.0 hours in a reducing atmosphere in which an inert gas such as Ar or He or carbon is present, and in a pressurized or reduced pressure atmosphere thereof. As the firing method, normal pressure firing, hot pressing method, hot isostatic pressing method (HIP method), etc. are applied. Create a sintered body with a density ratio of 96% or more, and further
Hot isostatic firing may be performed at a firing temperature of 1200 to 1900°C under a high pressure of 2000 atm. The reason why the firing temperature was set in the above range is that if the firing temperature is lower than 1200°C, sufficient properties will not be obtained due to insufficient sintering and voids will occur, and if the firing temperature exceeds 1900°C, aluminum oxide will be formed. This is because grains grow and bores occur, reducing strength.
上記の焼成によれば、原料中の硼化アルミニウムは一部
または全部がアルミニウムと硼素に分離するとともに系
中の酸素と反応し酸化アルミニウムや硼酸アルミニウム
と、アルミニウム、酸素、硼素からなるガラス状物質を
生成する。これに対し、酸化アルミニウムはそのままの
状態で残存し焼結される。一方、酸化アルミニウムの代
わりに硼酸アルミニウムを用いた場合は、１４００°Ｃ
付近で一部または全部が酸化アルミニウムと酸化硼素と
に分離し、それぞれを添加した場合と同様な効果をもた
らす。他方、アルミニウム金属を用いた場合は、系中の
酸素もしくは硼素と反応しＡｌＢ２等の硼化アルミニウ
ム、酸化アルミニウムあるいは硼酸アルミニウムを生成
しそれぞれを添加した場合と同様な効果をもたらす。According to the above firing, part or all of the aluminum boride in the raw material is separated into aluminum and boron, and reacts with oxygen in the system to form a glassy substance consisting of aluminum oxide, aluminum borate, aluminum, oxygen, and boron. generate. In contrast, aluminum oxide remains as it is and is sintered. On the other hand, when aluminum borate is used instead of aluminum oxide, the temperature is 1400°C.
Some or all of the aluminum oxide separates into aluminum oxide and boron oxide in the vicinity, producing the same effect as when each is added. On the other hand, when aluminum metal is used, it reacts with oxygen or boron in the system to produce aluminum boride such as AlB2, aluminum oxide, or aluminum borate, producing the same effect as when each is added.
上記の焼成過程において各化合物の分離、反応によって
生成した酸化硼素は１５００°Ｃ以上では蒸発するが、
いずれも焼結助剤としての効果を示し焼結体の高緻密化
を促進する。しかし、酸化硼素が焼結体中に多く含有さ
れると硬度や強度が低下するので、含有量は２０重量％
以下、望ましくは１０重量％以下にするのがよい。The boron oxide produced by the separation and reaction of each compound in the above firing process evaporates at temperatures above 1500°C.
Both exhibit the effect of sintering aids and promote high densification of the sintered body. However, if a large amount of boron oxide is contained in the sintered body, the hardness and strength will decrease, so the content should be 20% by weight.
The content below is desirably 10% by weight or less.
（作用）
上述した本発明の焼結体が高強度、高靭性且つ高硬度を
有する理由についてはおよそ次の３つの要因が考えられ
る。(Function) The following three factors are considered to be the reason why the sintered body of the present invention described above has high strength, high toughness, and high hardness.
■粒子結合力の向上
焼結時、硼化アルミニウムの一部または全部が分解し活
性なアルミニウムと硼素が生成される。■Improvement of particle bonding strength During sintering, part or all of aluminum boride decomposes and active aluminum and boron are generated.
このアルミニウムと硼素により強固に結合された新たな
粒子が形成され粒子結合力の向上が図られる。New particles are formed that are strongly bonded to each other by this aluminum and boron, and the bonding force of the particles is improved.
■粒子形状の複雑化
従来の酸化アルミニウムでは結晶粒子は球形に近いもの
が多く、破壊はそれらの粒界から起こっていた。本発明
の材料では■に記述した分解生成反応を伴って焼結され
るため粒子形状は複雑に入り組んだ形状となっている。■Complicated particle shapes In conventional aluminum oxide, many of the crystal particles were close to spherical, and fracture occurred at their grain boundaries. Since the material of the present invention is sintered with the decomposition and production reaction described in (2), the particle shape is complicated.
このため新たなりラックの進展が阻止されその結果破壊
靭性が向上する。なお、針状の酸化アルミニウムもしく
は分解により針状の酸化アルミニウムを生成する物質を
添加すると粒子形状の複雑化は更に促進され、針状結晶
が入り組んだ組織を持つようになるため靭性は更に向上
する。Therefore, new rack development is prevented, and as a result, fracture toughness is improved. Furthermore, if acicular aluminum oxide or a substance that generates acicular aluminum oxide through decomposition is added, the particle shape will become more complex, and the acicular crystals will have an intricate structure, which will further improve the toughness. .
■酸化硼素のガス化の促進
上記の焼成過程において各化合物の分離、反応によって
生成し７た酸化硼素は１５００“Ｃ以上では蒸発するが
、いずれも焼結助剤としての効果を示し焼結体の高緻密
化を促進する。しかし、大型品においては構成元素、特
に化合物として酸化硼素が焼結体中に偏在しやすく、特
に焼結体の内部と外部において硬度や靭性の特性のバラ
ツキが生じる。炭素成分の存在により還元雰囲気中、過
剰な酸化硼素の酸化硼素のガス化が促進されるために成
分の偏析が少なくなり均一な特性を有する焼結体が得ら
れる。■Promotion of gasification of boron oxide The boron oxide produced by the separation and reaction of each compound in the above firing process evaporates at temperatures above 1500"C, but all of them are effective as sintering aids and the sintered body However, in large products, constituent elements, especially boron oxide as a compound, tend to be unevenly distributed in the sintered body, resulting in variations in hardness and toughness, especially between the inside and outside of the sintered body. The presence of the carbon component promotes gasification of excess boron oxide in a reducing atmosphere, resulting in less segregation of components and a sintered body with uniform properties.
以下、本発明を次の例で説明する。The invention will now be explained with the following examples.
（実施例１）
原料として、酸化アルミニウム粉末（平均粒径１μｍ以
下、純度９９．９％以上）と、ＡＩＢ＋ｚ粉末（粒径２
００メツシユ以下）と、針状酸化アルミニウム（平均粒
径０．７μｍ、平均アスペクト比１５）と、硼酸アルミ
ニウム（平均粒径０．７μｍ、平均アスペクト比２０）
並びに平均粒径が１．０μｍの炭素粉末を用いて第１表
に示す割合に秤量後、回転ミルで１２時間混合粉砕した
。混合後のスラリーを乾燥してホットプレス用原料とし
た。 この原料をカーボン型に充填し、１５００〜１８
００′Ｃで１時間、３００ ｋｇ／ｃｍ２の圧力でホッ
トプレス焼成した。(Example 1) As raw materials, aluminum oxide powder (average particle size 1 μm or less, purity 99.9% or more) and AIB+z powder (particle size 2
00 mesh or less), acicular aluminum oxide (average particle size 0.7 μm, average aspect ratio 15), and aluminum borate (average particle size 0.7 μm, average aspect ratio 20)
Carbon powder having an average particle size of 1.0 μm was weighed in the proportions shown in Table 1, and then mixed and ground in a rotary mill for 12 hours. The slurry after mixing was dried and used as a raw material for hot pressing. Fill a carbon mold with this raw material and
Hot press firing was carried out at 00'C for 1 hour at a pressure of 300 kg/cm2.
得られた各試料を研磨して鏡面状態にポリッシングして
焼結体の内部および周辺部をＩＭ法でＫＩＣを、さらに
ビッカース硬度を測定した。Each of the obtained samples was polished to a mirror-like state, and the inside and peripheral parts of the sintered bodies were measured for KIC and Vickers hardness using the IM method.
結果は第１表に示す。The results are shown in Table 1.
（以下余白）
第１表によれば、硼化アルミニウムー酸化アルミニウム
系に対して炭素を全く添加しなかった試料Ｎｏ、 １で
は、硬度については内部が高く、靭性については周辺部
が高くなる傾向を示し、焼結体の特性に内外で差が生じ
た。これに対して炭素を添加した系については内外差は
２０％以内に抑えることができるが、炭素量が８重量％
を越えた試料Ｎｏ、 ７については、焼結不良が発生し
、抗折強度等の特性の劣化を招いた。(Margins below) According to Table 1, in sample No. 1, in which no carbon was added to the aluminum boride-aluminum oxide system, the hardness tended to be higher in the interior, and the toughness tended to be higher in the periphery. , and there was a difference in the properties of the sintered body between the inside and outside. On the other hand, for systems with added carbon, the difference between the inside and outside can be suppressed to within 20%, but the carbon content is 8% by weight.
Regarding sample No. 7, which exceeded the above, sintering failure occurred, resulting in deterioration of properties such as flexural strength.
また、硼化アルミニウム単体からなる試料Ｎｏ、 ２０
では、焼成温度を高めても焼結不良を越し特性も低いも
のであった。酸化アルミニウム単体の試料Ｎｏ、 ２１
Ｌこおいては特性上不十分であった。In addition, sample No. 20 consisting of aluminum boride alone
However, even if the firing temperature was increased, the properties were poor beyond sintering failure. Single aluminum oxide sample No. 21
Regarding L, the properties were insufficient.
さらに、焼成温度に関しては、１３００°Ｃより低い試
料Ｎｏ、２３は焼結不良により、また１９００°Ｃより
高い試料階２２は酸化アルミニウムの粒成長によってい
ずれも焼結体中にボイドが発生し、特性が劣化した。Furthermore, regarding the firing temperature, voids were generated in the sintered body in Sample No. 23, which was lower than 1300°C, due to poor sintering, and in Sample No. 22, which was higher than 1900°C, due to grain growth of aluminum oxide. Characteristics have deteriorated.
これらの比較例に対して、本発明の試料はいずれも硬度
、靭性とも特性の内外差がなく、抗折強度６０ ｋｇ／
ｍｍ２以上、靭性４． ＯＭＰａ −ｍ””以上、ビア
カース硬度１８． ＯＭＰａ−ｍ””以上が達成された
。In contrast to these comparative examples, the samples of the present invention had no difference in hardness or toughness, and had a bending strength of 60 kg/
mm2 or more, toughness 4. OMPa -m"" or more, via cast hardness 18. OMPa-m"" or higher was achieved.
特に、焼結体中に針状の硼酸アルミニウムや酸化アルミ
ニウムを添加したものでは、靭性が最大１０ＭＰａ
−ｇ”’の焼結体が得られた。In particular, sintered bodies with needle-shaped aluminum borate or aluminum oxide added have a toughness of up to 10 MPa.
-g"' sintered body was obtained.
（発明の効果）
以上詳述した通り、本発明によれば硼化アルミニウムに
、酸化アルミニウム成分を添加した系にさらに炭素成分
を適量添加し、成形焼成することにより高い硬度、靭性
を維持しつつ焼結体の内外の特性を均一化することがで
きる。(Effects of the Invention) As detailed above, according to the present invention, an appropriate amount of carbon component is further added to a system in which an aluminum oxide component is added to aluminum boride, and high hardness and toughness are maintained by molding and firing. The internal and external properties of the sintered body can be made uniform.
これにより、工具材料をはじめとする大型形状の各種産
業機械部品用材ｆ）としての応用範囲をさらに拡大する
ことができる。As a result, the range of applications can be further expanded as a material f) for various large-sized industrial machine parts including tool materials.
Claims (1)
いは焼成により酸化アルミニウムを生成しうる化合物と
からなる組成物１００重量部に対して炭素粉末あるいは
焼成により炭素を生成する化合物を炭素に換算して０．
０５〜８重量部添加し、これを成形後、１２００〜１９
００℃の温度で焼成することを特徴とするセラミックス
焼結体の製造方法。For 100 parts by weight of a composition consisting of aluminum boride powder and aluminum oxide powder or a compound capable of producing aluminum oxide upon firing, the amount of carbon powder or a compound capable of producing carbon upon firing is 0.0% in terms of carbon.
05 to 8 parts by weight was added, and after molding, 1200 to 19
A method for producing a ceramic sintered body, characterized by firing at a temperature of 00°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2140378A JP2931917B2 (en) | 1990-05-30 | 1990-05-30 | Manufacturing method of ceramic sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2140378A JP2931917B2 (en) | 1990-05-30 | 1990-05-30 | Manufacturing method of ceramic sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0437653A true JPH0437653A (en) | 1992-02-07 |
| JP2931917B2 JP2931917B2 (en) | 1999-08-09 |
Family
ID=15267432
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2140378A Expired - Fee Related JP2931917B2 (en) | 1990-05-30 | 1990-05-30 | Manufacturing method of ceramic sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2931917B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015078078A (en) * | 2013-10-15 | 2015-04-23 | 独立行政法人産業技術総合研究所 | Low-friction, low-wear sliding member for water lubrication and production method thereof |
| CN116041070A (en) * | 2022-12-27 | 2023-05-02 | 北京理工大学 | High-toughness boron-aluminum composite material |
-
1990
- 1990-05-30 JP JP2140378A patent/JP2931917B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015078078A (en) * | 2013-10-15 | 2015-04-23 | 独立行政法人産業技術総合研究所 | Low-friction, low-wear sliding member for water lubrication and production method thereof |
| CN116041070A (en) * | 2022-12-27 | 2023-05-02 | 北京理工大学 | High-toughness boron-aluminum composite material |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2931917B2 (en) | 1999-08-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPS6256104B2 (en) | ||
| CN114736022B (en) | High-density, high-strength and ultrahigh-hardness boron carbide/high-entropy diboride complex phase ceramic and preparation method thereof | |
| EP0347920B1 (en) | High strength high toughness TiB2 ceramics | |
| US5360772A (en) | Ceramic material reinforced by the incorporation of TiC, TiCN and TiN whiskers and processes for production thereof | |
| JPH04130065A (en) | Method of forming high-density metal boride complex | |
| JPH0437653A (en) | Production of ceramics sintered body | |
| JP2651935B2 (en) | Method for producing composite material and raw material composition | |
| JP2742620B2 (en) | Boride-aluminum oxide sintered body and method for producing the same | |
| JP3051603B2 (en) | Titanium compound sintered body | |
| JP2759290B2 (en) | Manufacturing method of aluminum oxide sintered body | |
| JPH07172919A (en) | Titanium-compound sintered material | |
| JP2997320B2 (en) | Fiber reinforced ceramics | |
| JP2931916B2 (en) | Ceramic sintered body | |
| JP2840688B2 (en) | Manufacturing method of aluminum oxide sintered body | |
| JP2720093B2 (en) | Fiber reinforced ceramics | |
| JP2779454B2 (en) | Aluminum oxide sintered body | |
| JP2533854B2 (en) | ZrO2-based ceramics sintered body for wear resistant structural material | |
| JP2794122B2 (en) | Fiber reinforced ceramics | |
| JP2997334B2 (en) | Fiber reinforced ceramics | |
| Bengisu et al. | Densification and mechanical properties of shock-treated alumina and its composites | |
| JPH0517210A (en) | Production of alumina-based composite sintered body and the sintered body | |
| JPH0710747B2 (en) | Boride-zirconium oxide-carbonitride ceramic materials | |
| JPH04132658A (en) | Ceramic sintered compact and production thereof | |
| JP2700925B2 (en) | Fiber reinforced ceramics and manufacturing method | |
| CA1189094A (en) | Ceramic composition |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |