JPH04219373A - Production of silicon nitride-based sintered compact - Google Patents
Production of silicon nitride-based sintered compactInfo
- Publication number
- JPH04219373A JPH04219373A JP2410991A JP41099190A JPH04219373A JP H04219373 A JPH04219373 A JP H04219373A JP 2410991 A JP2410991 A JP 2410991A JP 41099190 A JP41099190 A JP 41099190A JP H04219373 A JPH04219373 A JP H04219373A
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- firing
- si3n4
- atm
- powder
- 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
- 229910052581 Si3N4 Inorganic materials 0.000 title claims abstract description 57
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 title claims description 50
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 239000000843 powder Substances 0.000 claims abstract description 23
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910001873 dinitrogen Inorganic materials 0.000 claims abstract description 11
- 238000010304 firing Methods 0.000 claims description 31
- 230000001590 oxidative effect Effects 0.000 claims description 6
- 230000000737 periodic effect Effects 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 238000005245 sintering Methods 0.000 abstract description 17
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 8
- 239000001301 oxygen Substances 0.000 abstract description 6
- 229910052760 oxygen Inorganic materials 0.000 abstract description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 5
- 230000003647 oxidation Effects 0.000 abstract description 5
- 238000007254 oxidation reaction Methods 0.000 abstract description 5
- 229910052681 coesite Inorganic materials 0.000 abstract description 3
- 229910052906 cristobalite Inorganic materials 0.000 abstract description 3
- VQCBHWLJZDBHOS-UHFFFAOYSA-N erbium(III) oxide Inorganic materials O=[Er]O[Er]=O VQCBHWLJZDBHOS-UHFFFAOYSA-N 0.000 abstract description 3
- 239000000377 silicon dioxide Substances 0.000 abstract description 3
- 235000012239 silicon dioxide Nutrition 0.000 abstract description 3
- 229910052682 stishovite Inorganic materials 0.000 abstract description 3
- 229910052905 tridymite Inorganic materials 0.000 abstract description 3
- FIXNOXLJNSSSLJ-UHFFFAOYSA-N ytterbium(III) oxide Inorganic materials O=[Yb]O[Yb]=O FIXNOXLJNSSSLJ-UHFFFAOYSA-N 0.000 abstract description 3
- 229910001404 rare earth metal oxide Inorganic materials 0.000 abstract 2
- 239000011369 resultant mixture Substances 0.000 abstract 2
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- 239000002994 raw material Substances 0.000 description 18
- 239000002245 particle Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 6
- 238000000465 moulding Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 description 2
- -1 For comparison Inorganic materials 0.000 description 1
- 229910007277 Si3 N4 Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000009694 cold isostatic pressing Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000013022 formulation composition Substances 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000004584 weight gain Effects 0.000 description 1
- 235000019786 weight gain Nutrition 0.000 description 1
Landscapes
- Ceramic Products (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、ガスタービン等の熱機
関構造用部品として用いられる室温、高温における強度
に優れ、且つ高温におけるクリープ特性に優れた窒化珪
素質焼結体の製法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a silicon nitride sintered body, which is used as structural parts of heat engines such as gas turbines and has excellent strength at both room and high temperatures, as well as excellent creep properties at high temperatures.
【０００２】0002
【従来技術】従来から、窒化珪素質焼結体は高温におけ
る強度、硬度、熱的化学的安定性に優れた材料として注
目され、エンジニアリングセラミックスとして特に熱機
関用構造材料としての応用が進められている。[Prior Art] Silicon nitride sintered bodies have long attracted attention as materials with excellent strength, hardness, and thermal and chemical stability at high temperatures, and their application as engineering ceramics, particularly as structural materials for heat engines, has been progressing. There is.
【０００３】一般に、窒化珪素はそれ自体、難焼結性で
あることから焼結助剤としてＹ２ Ｏ３ 等の希土類元
素酸化物をはじめ、Ａｌ２Ｏ３ 等の添加が必要とされ
ている。Generally, since silicon nitride itself is difficult to sinter, it is necessary to add rare earth element oxides such as Y2O3 and Al2O3 as sintering aids.
【０００４】また、窒化珪素質焼結体は、特にターボロ
ータやガスタービンロータ等の熱機関用構造材料として
用いる場合には、高温における抗折強度が高いこと、ま
た耐酸化性に優れ、室温から高温までの強度の劣化が小
さいことが要求される。In addition, silicon nitride sintered bodies, especially when used as structural materials for heat engines such as turbo rotors and gas turbine rotors, have high flexural strength at high temperatures, excellent oxidation resistance, and It is required that there is little deterioration in strength from low to high temperatures.
【０００５】このような窒化珪素質焼結体は、通常、窒
化珪素粉末に対して前述したような焼結助剤を添加した
混合物を所望の形状に成形し、窒素を含有する非酸化性
雰囲気中で常圧焼成、ホットプレス焼成、窒素ガス加圧
焼成、熱間静水圧焼成等の手法により緻密化が図られて
いる。これらの中でも窒素ガス加圧焼成、熱間静水圧焼
成は熱機関部品のように複雑形状品の高強度の焼結体を
得るに適した焼成法として多用されつつある。[0005] Such a silicon nitride sintered body is usually produced by molding a mixture of silicon nitride powder with the above-mentioned sintering aid into a desired shape and placing it in a non-oxidizing atmosphere containing nitrogen. Among them, densification is achieved by methods such as normal pressure firing, hot press firing, nitrogen gas pressure firing, and hot isostatic pressure firing. Among these, nitrogen gas pressure firing and hot isostatic pressure firing are increasingly being used as firing methods suitable for obtaining high-strength sintered bodies of complex-shaped products such as heat engine parts.
【０００６】また、窒化珪素は、その焼結性の点から用
いる原料粉末としてα型窒化珪素を多量に含むものほど
焼結性が高く、強度の高い焼結体が得られるとして９０
％以上のα型窒化珪素を含有する原料が一般に用いられ
ている。[0006] In addition, from the viewpoint of sintering properties of silicon nitride, it is said that the more α-type silicon nitride is contained in the raw material powder used, the higher the sinterability is, and the higher the strength, the higher the sintered body can be obtained.
% or more of α-type silicon nitride is generally used.
【０００７】[0007]
【発明が解決しようとする問題点】これまで窒化珪素質
焼結体は、添加される焼結助剤や焼成条件に対してあら
ゆる検討がなされているが、これらのほとんどは室温お
よび高温での強度や耐酸化性の改良を目的として研究さ
れている。しかしながら、窒化珪素質焼結体はそれ自体
、高温で荷重が付加された状態で長時間保持した時に焼
結体が塑性変形を示すという特性（クリープ特性）があ
ることが知られており、特に熱機関構造用としては、こ
のようなクリープ特性において塑性変形の小さい材料が
要求されている。[Problems to be solved by the invention] Until now, various studies have been made regarding the sintering aids added and firing conditions for silicon nitride sintered bodies, but most of these have been conducted at room and high temperatures. Research is being conducted to improve strength and oxidation resistance. However, it is known that silicon nitride sintered bodies themselves exhibit plastic deformation (creep characteristics) when held at high temperatures and under load for long periods of time. For heat engine structures, materials with such creep characteristics and low plastic deformation are required.
【０００８】しかし、このクリープ特性については、あ
まり検討されておらず、その具体的な解決策もないのが
現状である。例えば、従来のようにα型窒化珪素を多量
に含む原料を用いて焼成すると、焼結過程においてα型
からβ型の窒化珪素へ転移するのに伴い窒化珪素粒子が
粒成長し粒径の大きい粒子が生じ、組織的に不均一にな
り、これによりクリープ特性が劣化し易くなるという問
題があった。[0008] However, this creep property has not been studied much and there is currently no concrete solution to it. For example, when firing a raw material containing a large amount of α-type silicon nitride as in the past, the silicon nitride particles grow as the α-type transitions to β-type silicon nitride during the sintering process, resulting in a large particle size. There is a problem in that particles are generated and the structure becomes non-uniform, which tends to deteriorate creep characteristics.
【０００９】[0009]
【問題点を解決するための手段】本発明者等は、このク
リープ特性について検討を加えた結果、焼結助剤として
Ｙｂ２ Ｏ３ 、Ｅｒ２ Ｏ３ を用い、これをβ型窒
化珪素を比較的多量に含有する窒化珪素粉末に添加混合
し、それを高圧の窒素ガス雰囲気中で焼成することによ
り高温における強度および耐酸化性に優れるとともに、
耐クリープ性に優れた焼結体が得られることを知見し、
本発明に到った。[Means for Solving the Problems] As a result of studying this creep property, the present inventors used Yb2 O3 and Er2 O3 as sintering aids, and combined these with a relatively large amount of β-type silicon nitride. By adding it to the silicon nitride powder and firing it in a high-pressure nitrogen gas atmosphere, it has excellent strength and oxidation resistance at high temperatures.
It was discovered that a sintered body with excellent creep resistance could be obtained.
We have arrived at the present invention.
【００１０】即ち、本発明の窒化珪素質焼結体の製法は
、β型窒化珪素を３０％以上含有する窒化珪素粉末にＹ
ｂ２ Ｏ３ および／またはＥｒ２ Ｏ３ を添加混合
し、所定の形状に成形した後、窒素ガス圧力３０〜１０
０ａｔｍにて１８００〜２１００℃の非酸化性雰囲気中
で焼成することを特徴とするもので、さらにかかる焼結
体を５００〜２０００ａｔｍにて１５００〜２０００℃
で熱間静水圧焼成することを特徴とするものである。That is, the method for producing a silicon nitride sintered body of the present invention involves adding Y to silicon nitride powder containing 30% or more of β-type silicon nitride.
After adding and mixing b2 O3 and/or Er2 O3 and molding into a predetermined shape, the nitrogen gas pressure is 30 to 10
It is characterized by firing in a non-oxidizing atmosphere at 1800 to 2100°C at 0 atm, and further firing the sintered body at 1500 to 2000°C at 500 to 2000 atm.
It is characterized by hot isostatic pressure firing.
【００１１】窒化珪素は、その結晶構造から大きくα型
とβ型の２種に大別されるが、本発明の製法によれば、
用いる原料中の比率により高温でのクリープ特性が変化
するという見地から、窒化珪素原料粉末としてβ型の窒
化珪素を３０％以上、特に４０〜７０％含有する原料を
用いることを大きな特徴とする。[0011] Silicon nitride is roughly divided into two types, α-type and β-type, depending on its crystal structure, but according to the manufacturing method of the present invention,
From the viewpoint that the creep characteristics at high temperatures change depending on the ratio in the raw material used, a major feature is that a raw material containing 30% or more, particularly 40 to 70%, of β-type silicon nitride is used as the silicon nitride raw material powder.
【００１２】この窒化珪素原料中のβ型窒化珪素量を上
記の範囲に設定したのは、その量が３０％未満では、耐
クリープ特性、特に１４００℃でのクリープ特性が大き
く劣化するからである。また窒化珪素粉末は、通常、酸
素を含有していることが知られているが、この酸素は焼
結性に寄与するものであり、その量が０．８〜１．５重
量％であることが望ましく、さらに平均粒径が０．３〜
０．６μｍ 程度のものが好適に使用される。The reason why the amount of β-type silicon nitride in this silicon nitride raw material is set within the above range is that if the amount is less than 30%, the creep resistance, especially the creep property at 1400° C., will be significantly deteriorated. . Furthermore, it is known that silicon nitride powder usually contains oxygen, but this oxygen contributes to sinterability, and the amount of oxygen should be 0.8 to 1.5% by weight. It is desirable that the average particle size is 0.3~
A material having a diameter of about 0.6 μm is preferably used.
【００１３】また、窒化珪素粉末に対して添加混合され
る焼結助剤としてはＹ２ Ｏ３ をはじめとする周期律
表第３ａ族元素酸化物の他にＡｌ２ Ｏ３ 等の各種の
ものが知られているが、本発明によれば、これらの中で
もＹｂ２ Ｏ３ および／またはＥｒ２Ｏ３ を必須成
分として添加する。これらの焼結助剤は窒化珪素粉末に
対して０．５〜３．５モル％の割合で添加されることが
望ましい。[0013] In addition to oxides of Group 3a elements of the periodic table such as Y2O3, various kinds of sintering aids such as Al2O3 are known as sintering aids to be added and mixed with silicon nitride powder. However, according to the present invention, among these, Yb2O3 and/or Er2O3 are added as essential components. These sintering aids are desirably added in a proportion of 0.5 to 3.5 mol % based on the silicon nitride powder.
【００１４】また、調合組成に関しては、上記窒化珪素
粉末およびＹｂ２ Ｏ３ および／またはＥｒ２ Ｏ３
粉末の系に対して酸化珪素を添加混合することもでき
る。この酸化珪素は、窒化珪素原料粉末中の酸素量をＳ
ｉＯ２ 換算した量も含め、１〜１０モル％以下の割合
となるように添加することが望ましく、特にこのＳｉＯ
２ 量と前記Ｙｂ２ Ｏ３ 、Ｅｒ２ Ｏ３ を含む周
期律表第３ａ族元素酸化物（ＲＥ２ Ｏ３ ）量とのモ
ル比（ＳｉＯ２ ／ＲＥ２ Ｏ３ ）が１〜２であるこ
とが好ましい。[0014] Regarding the formulation composition, the above silicon nitride powder and Yb2 O3 and/or Er2 O3
Silicon oxide can also be added and mixed into the powder system. This silicon oxide reduces the amount of oxygen in the silicon nitride raw material powder by S
It is desirable to add it in a proportion of 1 to 10 mol%, including the amount converted to iO2.
It is preferable that the molar ratio (SiO2 /RE2 O3) between the amount of SiO2 and the amount of the oxide of Group 3a element of the periodic table (RE2 O3) containing Yb2 O3 and Er2 O3 is 1 to 2.
【００１５】これらの原料粉末は、前述した所定の割合
で秤量混合された後に公知の成形手段、例えばプレス成
形、射出成形、押し出し成形、鋳込み成形、冷間静水圧
成形等の方法により所定の形状に成形後、焼成される。[0015] These raw material powders are weighed and mixed in the predetermined proportions described above, and then shaped into a predetermined shape by known molding means such as press molding, injection molding, extrusion molding, cast molding, and cold isostatic pressing. After being shaped, it is fired.
【００１６】次に、この成形体を窒素ガス圧力が３０〜
１００ａｔｍ、特に３０〜７０ａｔｍの高圧力雰囲気下
でで焼成する。この焼成における窒素ガス圧力を上記の
範囲に限定したのは、圧力が３０ａｔｍ以下では高温強
度が向上せず、１００ａｔｍを越えると試料に表面荒れ
が発生するからである。また、焼成温度は、本発明の原
料粉末がβ型窒化珪素を多量に含有していることに起因
し、１８００℃より低い温度では緻密化するのが難しい
。一方、焼成温度が２１００℃より高いと窒化珪素自体
の分解が生じ焼結体の表面が荒れ強度が劣化する。よっ
て、焼成温度は１８００〜２１００℃、特に１９００〜
２０００℃に設定される。Next, this molded body is heated to a nitrogen gas pressure of 30 to
Firing is performed under a high pressure atmosphere of 100 atm, particularly 30 to 70 atm. The reason why the nitrogen gas pressure in this firing is limited to the above range is because if the pressure is less than 30 atm, the high temperature strength will not improve, and if it exceeds 100 atm, surface roughness will occur on the sample. Furthermore, since the raw material powder of the present invention contains a large amount of β-type silicon nitride, it is difficult to densify the firing temperature at a temperature lower than 1800°C. On the other hand, if the firing temperature is higher than 2100° C., silicon nitride itself will decompose and the surface of the sintered body will become rough and its strength will deteriorate. Therefore, the firing temperature is 1800-2100°C, especially 1900-2100°C.
The temperature is set at 2000°C.
【００１７】かかる焼成によれば、対理論密度比９５％
以上の高密度の焼結体を得ることができるが、本発明に
よれば、上記の焼成によって得られた焼結体をさらに窒
素ガス圧力５００〜２０００ａｔｍの高圧雰囲気下で１
５００〜１９００℃の温度で熱間静水圧焼成することに
より、より高密度化が達成されるとともに、強度、およ
び高温での耐クリープ特性をも向上することができる。According to such firing, the theoretical density ratio is 95%.
According to the present invention, the sintered body obtained by the above sintering is further heated under a high pressure atmosphere of nitrogen gas pressure of 500 to 2000 atm.
By hot isostatic firing at a temperature of 500 to 1900° C., higher density can be achieved, and strength and creep resistance at high temperatures can also be improved.
【００１８】さらに、場合によっては、上記の方法によ
り得られた焼結体を適宜１４００〜１８００℃の非酸化
性雰囲気中で処理することにより粒界の結晶化を図り高
温特性を改善することもできる。Furthermore, in some cases, the sintered body obtained by the above method may be treated in a non-oxidizing atmosphere at 1400 to 1800°C to crystallize grain boundaries and improve high-temperature properties. can.
【００１９】[0019]
【作用】クリープ特性は、焼結体の組織の均質性に大き
く影響される特性であり、特に組織内に粒成長により大
きな粒子が不均一に存在するとクリープ特性は大きく劣
化する。[Operation] Creep characteristics are greatly affected by the homogeneity of the structure of the sintered body, and in particular, if large particles are unevenly present in the structure due to grain growth, the creep characteristics are greatly deteriorated.
【００２０】本発明によれば、原料粉末としてβ型窒化
珪素を多量に含有する窒化珪素原料粉末を用いることに
より、焼成過程でα−β転移による粒成長が小さくなり
、窒化珪素粒子が均一にそろった組織が形成されるため
に、高温クリープ特性を大きく向上することができる。According to the present invention, by using a silicon nitride raw material powder containing a large amount of β-type silicon nitride as a raw material powder, grain growth due to α-β transition is reduced during the firing process, and silicon nitride particles are uniformly formed. Since a uniform structure is formed, high temperature creep properties can be greatly improved.
【００２１】また、焼結助剤として含有されるＹｂ２
Ｏ３ 、Ｅｒ２ Ｏ３ は、そのほとんどが焼結体中の
粒界に存在するが、これらの酸化物は一般的に用いられ
ているＹ２ Ｏ３ と比較して粒界の高温での粘性を高
めることができるために、窒化珪素粒子の滑りを抑制す
る作用を成しこれによっても高温クリープ特性を向上す
ることができる。[0021] Furthermore, Yb2 contained as a sintering aid
Most of O3 and Er2 O3 exist at the grain boundaries in the sintered body, but these oxides can increase the viscosity of the grain boundaries at high temperatures compared to the commonly used Y2 O3. Because of this, it has the effect of suppressing the slippage of silicon nitride particles, which also improves high-temperature creep characteristics.
【００２２】また、焼成時の窒素ガス圧力を３０ａｔｍ
以上とした理由は、Ｎ２ が窒化珪素粒界相に溶け込み
粒界相の高温での粘性を高めるため、それにより高温ク
リープ特性および高温強度の向上につながるためである
。[0022] Also, the nitrogen gas pressure during firing was set to 30 atm.
The reason for the above is that N2 dissolves into the silicon nitride grain boundary phase and increases the viscosity of the grain boundary phase at high temperatures, thereby leading to improvements in high temperature creep properties and high temperature strength.
【００２３】[0023]
【実施例】窒化珪素原料粉末として、α型、β型の窒化
珪素原料の含有量の異なる原料を用意した。これらの原
料はいずれも酸素含有量１．０〜１．２重量％であり、
平均粒径０．４〜０．６μｍ である。[Example] As silicon nitride raw material powder, raw materials having different contents of α-type and β-type silicon nitride raw materials were prepared. All of these raw materials have an oxygen content of 1.0 to 1.2% by weight,
The average particle size is 0.4 to 0.6 μm.
【００２４】この窒化珪素原料に対して平均粒径が０．
５〜０．６μｍ のＹｂ２ Ｏ３ 、Ｅｒ２ Ｏ３ 、
また比較のためにＹ２ Ｏ３ の粉末を表１、表２に示
す割合で秤量混合した。[0024] The average particle size of this silicon nitride raw material is 0.
5-0.6μm Yb2O3, Er2O3,
For comparison, Y2O3 powder was weighed and mixed in the proportions shown in Tables 1 and 2.
【００２５】この混合粉末に適宜バインダーを添加後、
１ｔｏｎ／ｃｍ２の圧力でプレス成形した。次にこの成
形体を表１、表２に示した焼成条件で焼成し各種の焼結
体を得た。After adding a suitable binder to this mixed powder,
Press molding was performed at a pressure of 1 ton/cm2. Next, this molded body was fired under the firing conditions shown in Tables 1 and 2 to obtain various sintered bodies.
【００２６】なお、表１、表２中、試料Ｎｏ，１１、１
５、１６、２１に対して表３に示す条件でさらに熱間静
水圧焼成を行った。[0026] In Tables 1 and 2, sample Nos. 11 and 1
No. 5, 16, and 21 were further subjected to hot isostatic firing under the conditions shown in Table 3.
【００２７】[0027]
【表１】[Table 1]
【００２８】[0028]
【表２】[Table 2]
【００２９】[0029]
【表３】[Table 3]
【００３０】得られた各焼結体に対して、ＪＩＳＲ１６
０１に基づき、１４００℃４点曲げ抗折強度、酸化性雰
囲気中に１４００℃において２４時間保持後の酸化重量
増を測定し、さらに１４００℃で１Ｈｒ保持できる最大
の荷重を求めた。結果は、表４および表５に示した。[0030] For each obtained sintered body, JISR16
01, the 4-point bending strength at 1400°C and the oxidized weight gain after being held at 1400°C for 24 hours in an oxidizing atmosphere were measured, and the maximum load that could be held at 1400°C for 1 hour was determined. The results are shown in Tables 4 and 5.
【００３１】[0031]
【表４】[Table 4]
【００３２】[0032]
【表５】[Table 5]
【００３３】表１〜表５の結果によれば、原料中のβ−
Ｓｉ３ Ｎ４ の含有量が３０％よりも少ない試料Ｎｏ
，１では、室温強度、高温強度に関してはある程度高い
値を示したが、クリープ特性が特性上低いものである。
また、焼成時の圧力が３０ａｔｍより低い試料Ｎｏ，３
および焼成温度が２１００℃より高い試料Ｎｏ，４では
、いずれも焼結体の表面に窒化珪素の分解によると思わ
れる表面荒れが生じた。また、焼成温度が１７５０℃で
は焼結することができず、圧力が２００ａｔｍと高い試
料Ｎｏ，１４でも焼結体の表面に荒れが生じた。According to the results in Tables 1 to 5, β-
Sample No. with Si3N4 content less than 30%
, 1 exhibited somewhat high values for room temperature strength and high temperature strength, but the creep properties were characteristically low. In addition, sample No. 3 where the pressure during firing was lower than 30 atm
In both samples No. 4 in which the firing temperature was higher than 2100° C., surface roughness appeared on the surface of the sintered body, which was thought to be due to decomposition of silicon nitride. In addition, sintering could not be performed at a firing temperature of 1750° C., and roughness occurred on the surface of the sintered body even in sample No. 14 where the pressure was as high as 200 atm.
【００３４】なお、焼結助剤としてＹ２ Ｏ３ を用い
た試料Ｎｏ，２０では、β−Ｓｉ３ Ｎ４ を含有する
原料を用いても、焼結体表面にシミが観察され、特性的
にも低いものであった。In addition, in sample No. 20 in which Y2 O3 was used as a sintering aid, stains were observed on the surface of the sintered body even if a raw material containing β-Si3 N4 was used, and the characteristics were also poor. Met.
【００３５】これに対して高β−Ｓｉ３ Ｎ４ 含有の
原料を用いて所定の高温高圧下で焼成した本発明の試料
は、いずれも室温強度、高温強度および高温クリープ特
性のいずれにおいても優れた特性を有してした。さらに
、焼結体を熱間静水圧焼成することにより特性を向上す
ることができた。In contrast, the samples of the present invention, which were fired at a predetermined high temperature and high pressure using raw materials containing high β-Si3N4, had excellent properties in terms of room temperature strength, high temperature strength, and high temperature creep properties. I had a Furthermore, the properties could be improved by subjecting the sintered body to hot isostatic pressure firing.
【００３６】[0036]
【発明の効果】以上詳述した通り、本発明の窒化珪素質
焼結体の製法によれば、高β型窒化珪素含有の窒化珪素
粉末に対して特定の焼結助剤を添加し、これを高圧下で
焼成することにより、高温強度、高温耐酸化性に優れる
とともに高温での耐クリープ特性に優れた焼結体を得る
ことができる。これにより、ガスタービン等の熱機関材
料としてその作動温度が１４００℃を越える使用条件下
でも優れた耐久性を発揮され、より実用化を促進するこ
とができる。Effects of the Invention As detailed above, according to the method for producing a silicon nitride sintered body of the present invention, a specific sintering aid is added to silicon nitride powder containing high β-type silicon nitride. By firing under high pressure, it is possible to obtain a sintered body that has excellent high-temperature strength and high-temperature oxidation resistance, as well as excellent creep resistance at high temperatures. As a result, it exhibits excellent durability as a material for heat engines such as gas turbines even under conditions of use where the operating temperature exceeds 1400° C., thereby further promoting its practical use.
Claims (2)
素粉末にＹｂ２ Ｏ３ および／またはＥｒ２ Ｏ３
を添加混合し、所定の形状に成形した後、窒素ガス圧力
３０〜１００ａｔｍにて１８００〜２１００℃の非酸化
性雰囲気中で焼成することを特徴とする窒化珪素質焼結
体の製法。Claim 1: Yb2 O3 and/or Er2 O3 in silicon nitride powder containing 30% or more of β-type silicon nitride.
A method for producing a silicon nitride sintered body, which comprises adding and mixing the following, forming into a predetermined shape, and then firing in a non-oxidizing atmosphere at a temperature of 1800 to 2100° C. under a nitrogen gas pressure of 30 to 100 atm.
素粉末に周期律表第３ａ族元素酸化物を添加混合し、所
定の形状に成形した後、窒素ガス圧力３０〜１００ａｔ
ｍにて１８００〜２１００℃の非酸化性雰囲気中で焼成
し、その後５００〜２０００ａｔｍにて１５００〜２０
００℃で熱間静水圧焼成することを特徴とする窒化珪素
質焼結体の製法。2. Silicon nitride powder containing 30% or more of β-type silicon nitride is mixed with an oxide of a Group 3a element of the periodic table, and after being molded into a predetermined shape, the mixture is heated to a nitrogen gas pressure of 30 to 100 at.
m in a non-oxidizing atmosphere at 1800-2100°C, and then fired at 500-2000 atm at 1500-20°C.
A method for producing a silicon nitride sintered body characterized by hot isostatic firing at 00°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2410991A JP2710865B2 (en) | 1990-12-14 | 1990-12-14 | Manufacturing method of silicon nitride sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2410991A JP2710865B2 (en) | 1990-12-14 | 1990-12-14 | Manufacturing method of silicon nitride sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04219373A true JPH04219373A (en) | 1992-08-10 |
| JP2710865B2 JP2710865B2 (en) | 1998-02-10 |
Family
ID=18520067
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2410991A Expired - Fee Related JP2710865B2 (en) | 1990-12-14 | 1990-12-14 | Manufacturing method of silicon nitride sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2710865B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102795859A (en) * | 2012-08-17 | 2012-11-28 | 湖北红花高温材料有限公司 | SiC-Si3N4 high temperature ceramic furnace bottom plate for annular furnace and preparation method thereof |
| CN114988882A (en) * | 2022-07-11 | 2022-09-02 | 中材高新氮化物陶瓷有限公司 | Silicon nitride high-temperature ceramic part with complex shape and preparation method thereof |
-
1990
- 1990-12-14 JP JP2410991A patent/JP2710865B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102795859A (en) * | 2012-08-17 | 2012-11-28 | 湖北红花高温材料有限公司 | SiC-Si3N4 high temperature ceramic furnace bottom plate for annular furnace and preparation method thereof |
| CN114988882A (en) * | 2022-07-11 | 2022-09-02 | 中材高新氮化物陶瓷有限公司 | Silicon nitride high-temperature ceramic part with complex shape and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2710865B2 (en) | 1998-02-10 |
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