JP2631108B2 - Manufacturing method of silicon nitride sintered body - Google Patents
Manufacturing method of silicon nitride sintered bodyInfo
- Publication number
- JP2631108B2 JP2631108B2 JP62247035A JP24703587A JP2631108B2 JP 2631108 B2 JP2631108 B2 JP 2631108B2 JP 62247035 A JP62247035 A JP 62247035A JP 24703587 A JP24703587 A JP 24703587A JP 2631108 B2 JP2631108 B2 JP 2631108B2
- Authority
- JP
- Japan
- Prior art keywords
- sintered body
- silicon nitride
- mol
- temperature
- group iiia
- 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.)
- Expired - Fee Related
Links
Landscapes
- Ceramic Products (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はガスタービン等に使用される窒化珪素質焼結
体に関するものである。Description: TECHNICAL FIELD The present invention relates to a silicon nitride sintered body used for a gas turbine or the like.
窒化珪素から成る焼結体は原子の結合様式が共有結合
を主体として成り、強度、硬度、熱的化学的安定性にお
いて、優れた特性を有することからエンジニアリングセ
ラミックス、特に熱機関として例えばガスタービン等へ
の応用が進められている。Sintered bodies made of silicon nitride are mainly composed of covalent bonds in the bonding mode of atoms, and have excellent properties in strength, hardness, and thermal and chemical stability. Application to is being promoted.
近年、熱機関はその高効率化に伴い熱機関の作動温度
が1400℃以上となることが予測され、この条件での使用
が可能な材料が望まれている。このような熱機関に使用
可能な材料として窒化珪素質焼結体が最も期待されてい
る。In recent years, it has been predicted that the operating temperature of a heat engine will be 1400 ° C. or higher as the efficiency of the heat engine increases, and materials that can be used under these conditions are desired. As a material usable for such a heat engine, a silicon nitride sintered body is most expected.
従来より、窒化珪素質焼結体を製造する方法として
は、窒化珪素に対して焼結助剤としてY2O3などの周期律
表第III a族酸化物やAl2O3などを添加しこれを窒素雰囲
気中で焼成することが行われている。また、窒化珪素質
焼結体の高温特性を高める上でAl2O3などの酸化物を低
減させて、窒化珪素−周期律表第III a族酸化物−SiO2
系の結晶を粒界に生成させた焼結体も提案されているま
た、高密度化の手法としては、これまでの常圧焼成や、
ホットプレス法、窒素ガス加圧焼成法に代わり、1000〜
3000気圧もの超高圧下で焼成する、熱間静水圧プレス焼
成法が知られている。Conventionally, as a method for producing a silicon nitride-based sintered body, a silicon nitride is added with a Group IIIa oxide of the periodic table, such as Y 2 O 3 , or Al 2 O 3 as a sintering aid. This is fired in a nitrogen atmosphere. Further, in order to enhance the high-temperature characteristics of the silicon nitride-based sintered body, oxides such as Al 2 O 3 are reduced, and silicon nitride—a group IIIa oxide of the periodic table—SiO 2
A sintered body in which a system crystal is generated at a grain boundary has also been proposed.
Instead of hot press method and nitrogen gas pressure firing method, 1000 ~
A hot isostatic press sintering method in which sintering is performed under an ultra-high pressure of 3000 atm is known.
この熱間精水圧プレス焼成法によれば、相対密度90%
以上に一次焼成された焼結体に対して、熱間静水圧プレ
ス焼成を施すことが多用されるが、かかる方法では、焼
結体の周囲の雰囲気を厳密に制御する必要があり、粒界
結晶相の制御や、特性の安定化が難しいという問題があ
る。According to this hot water pressure press firing method, the relative density is 90%
As described above, hot isostatic pressing is often used for the primary fired sintered body. However, in such a method, it is necessary to strictly control the atmosphere around the sintered body, and the There is a problem that it is difficult to control the crystal phase and stabilize the characteristics.
これに対して、被処理物をガラス容器やガラス浴中に
入れてガラスを圧力媒体として超高圧を印加して焼成す
る、いわゆるガラスシールHIP法が知られている。この
方法は、被処理物を雰囲気から完全に遮断して焼成する
ために雰囲気の制御を必要とせず、しかも比較的低温で
焼成できるために微細な組織の高強度焼結体が得られる
という利点を有する。例えば、特開昭60−155576号で
は、Al2O3−第III a族酸化物添加系の成形体を仮焼、ガ
ラスシールHIPすることにより高緻密質でしかも靱性の
優れた窒化珪素質焼結体を製造する方法が提供されてい
る。On the other hand, a so-called glass seal HIP method is known in which an object to be processed is placed in a glass container or a glass bath, and sintering is performed by applying an ultra-high pressure using glass as a pressure medium. This method has the advantage that a high-strength sintered body with a fine structure can be obtained because firing is performed at a relatively low temperature without requiring control of the atmosphere in order to completely block the workpiece from the atmosphere and firing. Having. For example, in Japanese Patent Application Laid-Open No. 60-155576, a silicon nitride-based sintered body having high density and excellent toughness is obtained by calcination and glass sealing HIP of an Al 2 O 3 -group IIIa oxide-added molded body. A method is provided for making a compact.
しかしながら、このガラスシールHIP法では、微細な
組織によって高強度の焼結体が作製できる反面、通常法
によって得られる焼結体に比較して靱性が低いという問
題があった。また、特開昭60−155576号に記載された焼
結体、Al2O3を含むために1400℃以上の高温域における
強度、耐酸化性が劣るという問題があった。そこで本発
明の目的はHIP後の焼結体の靱性が優れ、且つ1400℃以
上の高温域においても強度、耐酸化性が優れた焼結体を
作成することにある。However, in the glass seal HIP method, although a high-strength sintered body can be manufactured with a fine structure, there is a problem that the toughness is lower than that of a sintered body obtained by a normal method. Further, there is a problem that the sintered body described in Japanese Patent Application Laid-Open No. 155576/1985 contains Al 2 O 3 , resulting in poor strength and oxidation resistance at a high temperature of 1400 ° C. or higher. Therefore, an object of the present invention is to prepare a sintered body having excellent toughness after HIP and excellent strength and oxidation resistance even in a high temperature range of 1400 ° C. or higher.
本発明によれば、3成分基準で窒化珪素粉末を85〜95
モル%と、周期律表第III a族元素から選ばれる少なく
とも1種の元素(M)の化合物を酸化物換算(M2O3)で
0.5〜5モル%と過剰酸素とを含有し、かつ(過剰酸素
のSiO2換算モル数/M2O3モル数)の比が1以上である混
合粉末を出発原料として成形し、その成形体を1550℃〜
1850℃の範囲にて熱処理を行い針状結晶を成長させた
後、さらにその熱処理した成形体を1650℃〜2000℃、10
00〜3000気圧の範囲でガラスを圧力媒体として熱間静水
圧プレス焼結させることを特徴とする窒化珪素質焼結体
の製造法が提供される。According to the present invention, silicon nitride powder is 85 to 95 on a three-component basis.
Mol%, and a compound of at least one element (M) selected from Group IIIa elements of the periodic table in terms of oxide (M 2 O 3 )
A mixed powder containing 0.5 to 5 mol% and excess oxygen and having a ratio of (mol number of excess oxygen in terms of SiO 2 / mol number of M 2 O 3 ) of 1 or more is molded as a starting material, and the molded body is formed. 1550 ℃ ~
After performing a heat treatment in the range of 1850 ° C. to grow needle-like crystals, the heat-treated compact was further heated to 1650 ° C. to 2000 ° C., 10
A method for producing a silicon nitride-based sintered body, characterized in that hot isostatic press sintering is performed using glass as a pressure medium in the range of 00 to 3000 atm.
即ち、本発明の焼結体を製造する場合には、まずSi3N
4粉末としてはα型、β型のいずれでも良く、特にBET比
表面積が10m2/g以上、酸素含有量3重量%以下のものを
用いるのが望ましい。That is, when producing the sintered body of the present invention, first, Si 3 N
4 The powder may be either α-type or β-type, and it is particularly desirable to use a powder having a BET specific surface area of 10 m 2 / g or more and an oxygen content of 3% by weight or less.
上記のSi3N4粉末と周期律表第III a族元素から選ばれ
る金属の化合物を焼結体中においてβ−Si3N4が85〜95
モル%、上記金属元素化合物を酸化物換算で0.5〜5モ
ル%となるように秤量し、調合する。なお調合の際に用
いる金属化合物としては、酸化物、炭化物、窒化物、酸
窒化物、ホウ化物、硝酸塩、炭酸塩又はシュウ酸塩等の
化合物を用いることができるが、これらの中でも酸化物
が好ましい。Above the Si 3 N 4 powder and periodic table III a group β-Si 3 N 4 in the sintered body in a compound of a metal selected from the elements 85 to 95
The metal element compound is weighed and mixed so as to be 0.5 to 5 mol% in terms of oxide in terms of oxide. As the metal compound used in the preparation, compounds such as oxides, carbides, nitrides, oxynitrides, borides, nitrates, carbonates, and oxalates can be used. preferable.
調合後、混合した粉末に適当なバインダ等を混合し、
公知の成形方法、例えばプレス成形、鋳込み成形、押し
出し成形、インジェクション成形等によって所望の形状
に成形した後、熱処理される。After blending, mix a suitable binder etc. into the mixed powder,
After molding into a desired shape by a known molding method, for example, press molding, casting molding, extrusion molding, injection molding or the like, heat treatment is performed.
熱処理は1550〜1850℃の範囲にて行う。1550℃より低
いと窒化珪素が針状結晶に発達せず、HIP後の靱性が低
く、1850℃より高いとHIP後の比重が上らないためであ
る。The heat treatment is performed in the range of 1550 to 1850 ° C. If the temperature is lower than 1550 ° C, silicon nitride does not develop into needle-like crystals, and the toughness after HIP is low. If the temperature is higher than 1850 ° C, the specific gravity after HIP does not increase.
さらに、良好な針状組織をこの被熱処理物に生成する
ために要求される要件として、被熱処理物の密度を理論
密度の30〜75%の範囲にすることが必要である。このこ
とは、針状に伸びるだけの空間を成形体中に保持するこ
とを意味する。30%より低いと針状化は果たせるが、そ
の後の焼結の際の変形・収縮が大きく、寸法の制御等が
困難となる。また75%以上の密度となると熱処理時の針
状化が十分とならない。Further, as a requirement required for producing a good needle-like structure in the heat-treated material, it is necessary that the density of the heat-treated material is in the range of 30 to 75% of the theoretical density. This means that a space enough to extend like a needle is kept in the molded body. If it is lower than 30%, acicularization can be achieved, but deformation and shrinkage during subsequent sintering are large, making it difficult to control dimensions and the like. On the other hand, if the density is 75% or more, needle formation during heat treatment is not sufficient.
熱処理体はその後1650℃〜2000℃、1000〜3000気圧の
範囲でガラスを圧力媒体として、熱間静水圧プレス焼結
させる。処理温度は1650℃〜2000℃であり、1650℃以上
では焼結体の比重が上らず2000℃以上では粒生長のため
強度が劣化する。The heat-treated body is then subjected to hot isostatic press sintering at 1650 ° C. to 2000 ° C. and 1000 to 3000 atm using glass as a pressure medium. The processing temperature is 1650 ° C. to 2000 ° C. When the temperature is 1650 ° C. or higher, the specific gravity of the sintered body does not increase, and when the temperature is 2000 ° C. or higher, the strength deteriorates due to grain growth.
また(過剰酸素のSiO2換算モル数/M2O3モル数)(モ
ル比)は1以上であり、これ未満では耐酸化性が劣化す
る。Further, (molar ratio of excess oxygen in terms of SiO 2 / mol number of M 2 O 3 ) (molar ratio) is 1 or more, and if it is less than 1, the oxidation resistance deteriorates.
なお、ここで過剰酸素とは焼結助剤として周期律表第
III a族元素酸化物を加えた場合、焼結体中の全酸素量
から第III a族酸化物に結合している酸素分を差し引い
た残りの酸素である。Here, excess oxygen is defined as the sintering aid in the periodic table
When a group IIIa element oxide is added, it is the remaining oxygen obtained by subtracting the oxygen bound to the group IIIa oxide from the total oxygen content in the sintered body.
比表面積14m2/g、酸素含有量2重量%以下のα−Si3N
4粉末に第III a族元素から選ばれた金属の酸化物と、過
剰酸素量調整用としてSiO2と、比較例としてAl2O3とを
適宜配合し、これらをボールミルにて24時間混合した。
得られたスラリーを乾燥造粒した後プレス成形し、真空
中で脱バインダ後第1表に示す条件で熱処理して針状結
晶を成長させた後に、その焼結体をガラスを圧力媒体と
して第1表に示す条件において焼結させ第1表の試料番
号1〜17の組成の焼結体を得た。Α-Si 3 N with a specific surface area of 14 m 2 / g and an oxygen content of 2% by weight or less
4 Powder oxide of a metal selected from Group IIIa elements, SiO 2 for excess oxygen adjustment, and Al 2 O 3 as a comparative example were appropriately blended, and these were mixed for 24 hours in a ball mill. .
The obtained slurry is dried and granulated, press-formed, debindered in a vacuum, and then heat-treated under the conditions shown in Table 1 to grow needle-like crystals. Sintering was performed under the conditions shown in Table 1 to obtain sintered bodies having the compositions of Sample Nos. 1 to 17 in Table 1.
得られた各試料につき常温及び1400℃におけるJIS−R
1601四点曲げ抗折強度試験と、1400℃×24時間経過後に
おける重量増(mg/cm2)による焼結体の酸化重量増即
ち、高温の耐酸化性を測定し、第1表に示した。JIS-R at room temperature and 1400 ℃ for each sample obtained
1601 Four-point flexural strength test and increase of oxidized weight of sintered body by weight increase (mg / cm 2 ) after 1400 ° C × 24 hours, that is, oxidation resistance at high temperature was measured. Was.
尚、過剰酸素量はLECO社の酸素、窒素同時分析装置に
よってまず全酸素量を測定し、次にICP分析によって焼
結体中の第III a族化合物を測定し、それに基づき酸化
物換算における酸素量を算出し、全酸素量からその酸素
量を差し引くことによって算出した。The amount of excess oxygen was measured by first measuring the total oxygen content using an oxygen and nitrogen simultaneous analyzer from LECO, and then measuring the Group IIIa compound in the sintered body by ICP analysis. The amount was calculated and calculated by subtracting the oxygen amount from the total oxygen amount.
第1表から理解されるように、試料番号13は第III a
族元素の酸化物が7モル%と多くかつSiO2/M2O3(モル
比)が0.85と小さいため靱性が劣化しかつ高温における
酸化重量増が多く耐酸化性が劣化している。試料番号14
は第III a族元素の酸化物が0.4モル%と少ないため高温
抗折強度が35Kg/mm2、靱性が5.7MPa・m1/2と劣ってい
る。さらに、試料番号17はAl2O3が1モル%添加されて
おり、そのため高温抗折強度及び高温における耐酸化性
が著しく劣化している。 As can be seen from Table 1, sample no.
Since the oxides of group elements are as large as 7 mol% and the SiO 2 / M 2 O 3 (molar ratio) is as small as 0.85, the toughness is deteriorated and the oxidation weight at high temperature is increased, and the oxidation resistance is deteriorated. Sample No. 14
Has an inferior high-temperature flexural strength of 35 kg / mm 2 and a toughness of 5.7 MPa · m 1/2 because the oxide of the Group IIIa element is as small as 0.4 mol%. Further, in sample No. 17, 1 mol% of Al 2 O 3 was added, so that high-temperature bending strength and oxidation resistance at high temperature were significantly deteriorated.
さらに、試料番号15及び16から理解されるように、さ
らに熱処理の工程を加えることによりHIP後の焼結体の
破壊靱性は向上し、その処理温度は1550℃以上であるこ
とが必要であることが理解される。Furthermore, as can be understood from Sample Nos. 15 and 16, the fracture toughness of the sintered body after HIP is improved by adding a further heat treatment step, and the processing temperature must be 1550 ° C. or higher. Is understood.
本発明においては高温強度及び高温耐酸化性に優れた
しかも靱性の高い窒化珪素質焼結体を得ることができ
る。In the present invention, a silicon nitride sintered body having excellent high-temperature strength and high-temperature oxidation resistance and high toughness can be obtained.
Claims (2)
と、周期律表第III a族元素から選ばれる少なくとも1
種の元素(M)の化合物を酸化物換算(M2O3)で0.5〜
5モル%と過剰酸素とを含有し、かつ(過剰酸素のSiO2
換算モル数/M2O3モル数)の比が1以上である混合粉末
を出発原料として成形し、その成形体を1550℃〜1850℃
の範囲にて熱処理を行い針状結晶を成長させた後、さら
にその熱処理した成形体を1650℃〜2000℃、1000〜3000
気圧の範囲でガラスを圧力媒体として熱間静水圧プレス
焼結させることを特徴とする窒化珪素質焼結体の製造
法。(1) 85-95 mol% of silicon nitride powder based on three components
And at least one selected from Group IIIa elements of the periodic table
The compound of the element (M) is 0.5 to 0.5 in oxide equivalent (M 2 O 3 ).
5 mol% and excess oxygen, and (excess oxygen SiO 2
The mixed powder having a ratio of (converted mole number / M 2 O 3 mole number) of 1 or more is molded as a starting material, and the molded body is formed at 1550 ° C. to 1850 ° C.
After growing a needle-shaped crystal by performing a heat treatment in the range of 1650 ℃ ~ 2000 ℃, further heat-treated molded body, 1000 ~ 3000
A method for producing a silicon nitride-based sintered body, wherein hot isostatic press sintering is performed using glass as a pressure medium in a range of atmospheric pressure.
yの群から選ばれる特許請求の範囲第1項記載の窒化珪
素質焼結体の製造法。2. The method according to claim 2, wherein said Group IIIa element is Sc, Er, Yb, Ho and D.
2. The method for producing a silicon nitride-based sintered body according to claim 1, which is selected from the group of y.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62247035A JP2631108B2 (en) | 1987-09-30 | 1987-09-30 | Manufacturing method of silicon nitride sintered body |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62247035A JP2631108B2 (en) | 1987-09-30 | 1987-09-30 | Manufacturing method of silicon nitride sintered body |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6487566A JPS6487566A (en) | 1989-03-31 |
JP2631108B2 true JP2631108B2 (en) | 1997-07-16 |
Family
ID=17157442
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP62247035A Expired - Fee Related JP2631108B2 (en) | 1987-09-30 | 1987-09-30 | Manufacturing method of silicon nitride sintered body |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2631108B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2771335B2 (en) * | 1990-12-07 | 1998-07-02 | 京セラ株式会社 | Silicon nitride sintered body for cutting tools |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0772105B2 (en) * | 1985-10-31 | 1995-08-02 | 京セラ株式会社 | Silicon nitride sintered body and method for manufacturing the same |
-
1987
- 1987-09-30 JP JP62247035A patent/JP2631108B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPS6487566A (en) | 1989-03-31 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0493802A1 (en) | Silicon nitride-silicon carbide composite sintered material | |
JP2631108B2 (en) | Manufacturing method of silicon nitride sintered body | |
JP3454993B2 (en) | Silicon nitride sintered body and method for producing the same | |
JP3034100B2 (en) | Silicon nitride sintered body and method for producing the same | |
JP2631104B2 (en) | Silicon nitride sintered body | |
JP2662863B2 (en) | Method for producing silicon nitride based sintered body | |
JPH09110533A (en) | Silicon nitride-based sintered material and its production | |
JP2631105B2 (en) | Silicon nitride sintered body | |
JP2691295B2 (en) | Silicon nitride sintered body | |
JPH09157028A (en) | Silicon nitride sintered compact and its production | |
JP3445345B2 (en) | High heat-resistant water sialon-based sintered body | |
JP2742622B2 (en) | Silicon nitride sintered body and method for producing the same | |
JP2710865B2 (en) | Manufacturing method of silicon nitride sintered body | |
JP2771335B2 (en) | Silicon nitride sintered body for cutting tools | |
JPH10279360A (en) | Silicon nitride structural parts and its production | |
JPH06287066A (en) | Silicon nitride sintered compact and its production | |
JP2584996B2 (en) | Silicon nitride sintered body | |
JPH078746B2 (en) | Silicon nitride ceramics and method for producing the same | |
JP2708136B2 (en) | Silicon nitride sintered body and method for producing the same | |
JPH10212167A (en) | Silicon nitride-base composite sintered compact and its production | |
JP2691285B2 (en) | Silicon nitride sintered body | |
JPH06316465A (en) | Silicon nitride-based sintered compact and production thereof | |
JP2783711B2 (en) | Silicon nitride sintered body | |
JPH03153574A (en) | High strength sialon-based sintered body | |
JPH0686331B2 (en) | High-strength sialon-based sintered body |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
LAPS | Cancellation because of no payment of annual fees |