JPH02116679A - Production of high-density sintered silicon nitride body - Google Patents
Production of high-density sintered silicon nitride bodyInfo
- Publication number
- JPH02116679A JPH02116679A JP63268112A JP26811288A JPH02116679A JP H02116679 A JPH02116679 A JP H02116679A JP 63268112 A JP63268112 A JP 63268112A JP 26811288 A JP26811288 A JP 26811288A JP H02116679 A JPH02116679 A JP H02116679A
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- sintering
- cordierite
- powder
- mixture
- 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 56
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 title claims abstract description 56
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 238000005245 sintering Methods 0.000 claims abstract description 46
- 239000000843 powder Substances 0.000 claims abstract description 30
- 239000000203 mixture Substances 0.000 claims abstract description 21
- 229910052878 cordierite Inorganic materials 0.000 claims abstract description 18
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 13
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000002156 mixing Methods 0.000 claims abstract description 7
- 238000000465 moulding Methods 0.000 claims abstract description 5
- 238000010298 pulverizing process Methods 0.000 claims abstract description 3
- 238000010304 firing Methods 0.000 claims description 12
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 10
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 4
- 229910052593 corundum Inorganic materials 0.000 abstract description 3
- 239000000463 material Substances 0.000 abstract description 3
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract description 3
- 239000000377 silicon dioxide Substances 0.000 abstract description 2
- 150000002910 rare earth metals Chemical class 0.000 abstract 3
- 230000001105 regulatory effect Effects 0.000 abstract 2
- 238000001354 calcination Methods 0.000 abstract 1
- 229910052681 coesite Inorganic materials 0.000 abstract 1
- 229910052906 cristobalite Inorganic materials 0.000 abstract 1
- 235000012239 silicon dioxide Nutrition 0.000 abstract 1
- 229910052682 stishovite Inorganic materials 0.000 abstract 1
- 229910052905 tridymite Inorganic materials 0.000 abstract 1
- 238000000034 method Methods 0.000 description 25
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 238000011049 filling Methods 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 5
- 238000001272 pressureless sintering Methods 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 4
- 238000005452 bending Methods 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 229910010271 silicon carbide Inorganic materials 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003779 heat-resistant material Substances 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009770 conventional sintering Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000001513 hot isostatic pressing Methods 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 150000003949 imides Chemical class 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000011863 silicon-based powder Substances 0.000 description 1
- 238000007582 slurry-cast process Methods 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
- C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- 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、高密度窒化けい素質焼結体の製造方法に関し
、と（に、新規に開発した焼結助剤の採用により、常圧
焼結法にもとづく低温焼成でも十分な高温強度を有しか
つ高密度の窒化けい素質焼結体を簡便に製造する方法に
ついての提案である。Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing a high-density silicon nitride sintered body, and the present invention relates to a method for producing a high-density silicon nitride sintered body. This is a proposal for a method for easily producing a high-density silicon nitride sintered body that has sufficient high-temperature strength even at low-temperature firing based on a sintering method.
窒化けい素は、高温強度、耐熱衝撃性、化学薬品や金属
・合金溶湯に対する耐食性などに優れていることから高
温構造材料として各種の用途にｉｌｌ用されろものであ
る。Silicon nitride has excellent high-temperature strength, thermal shock resistance, and corrosion resistance against chemicals and molten metals and alloys, so it is used as a high-temperature structural material in various applications.
（従来の技術）
さて、窒化けい素質焼結体は、通常反応焼結法、常圧焼
結法、ホットプレス法、またはこれらを組み合わせた方
法などで製造されている。(Prior Art) Silicon nitride sintered bodies are usually manufactured by reaction sintering, pressureless sintering, hot pressing, or a combination of these methods.
上言ｅ反応焼結法は、金属けい素粉にバインダーを添加
して所定の形状に成型し、その後、窒素ガスと高温で反
応させる方法である。この方法によれば、高純度の窒化
けい素質焼結体を得ることができるが、密度を高くする
ことがむずかしい。The e-reaction sintering method mentioned above is a method in which a binder is added to metal silicon powder, the powder is molded into a predetermined shape, and then reacted with nitrogen gas at a high temperature. According to this method, a highly pure silicon nitride sintered body can be obtained, but it is difficult to increase the density.
上記ホットプレス法は、高密度の焼結体を製造するため
に、高温・高圧下で焼結する方法であるが、高圧下で行
なうため、複雑な形状の焼結体を製造することができず
、また非常に高価な設備を必要とするので実用的な方法
ではなｌ／）。The hot press method described above is a method of sintering at high temperature and high pressure in order to produce a high-density sintered body, but because it is carried out under high pressure, it is not possible to produce sintered bodies with complex shapes. However, it is not a practical method as it requires very expensive equipment.
上記常圧焼結法は、窒化けい素粉に焼結助剤を添加、混
合し、さらにバインダーを加えて所定の形状に成型し、
その後、高温で焼成する方法である。この常圧焼結法に
よれば、比較的高い密度のものが製造できる。しかし、
理論密度に近い高充填率の窒化けい素質焼結体を製造す
るには、一般に、 １．７００℃以上の高温焼成を長時
間行う必要がある。ところが、このような高温焼成を行
うと、窒イヒけい素自体の分解が生ずるという問題があ
った。The above pressureless sintering method involves adding and mixing a sintering aid to silicon nitride powder, adding a binder, and molding it into a predetermined shape.
After that, it is fired at a high temperature. According to this pressureless sintering method, products with relatively high density can be manufactured. but,
In order to produce a silicon nitride sintered body with a high filling rate close to the theoretical density, it is generally necessary to perform high-temperature firing at 1.700° C. or higher for a long time. However, when such high-temperature firing is performed, there is a problem in that silicon nitride itself decomposes.
この執分解を防止し、高密度・高強度の窒化けい素質焼
結体を製造するための技術として。As a technology to prevent this decomposition and produce high-density, high-strength silicon nitride sintered bodies.
従来、低温で焼結した後、熱処理し、さらに熱間静水圧
プレス処理する方法（特開昭５８−８４１８４号公報）
、あるいは雰囲気を加圧し高温での窒化けい素の分解を
抑制して焼結するガス圧焼結法などが提案されている。Conventionally, after sintering at a low temperature, heat treatment is performed, and then hot isostatic pressing is performed (Japanese Unexamined Patent Publication No. 1984-84184).
Alternatively, a gas pressure sintering method has been proposed in which sintering is performed by pressurizing the atmosphere to suppress the decomposition of silicon nitride at high temperatures.
しかし、これらの従来技術は、製造工程が非常に複雑で
、高価な設備を必要とするという課題があった。However, these conventional techniques have problems in that the manufacturing process is very complicated and requires expensive equipment.
（本発明が解決しようとする課題）
常圧焼結法による既知の窒化けい素質焼結体の製造に際
しては、酸化アルミニウムや酸化マグネシウム、希土類
元素酸化物および酸化ジルコニウムを単独、またはそれ
らを２種以上混合した焼結助剤を用い、しかも、特に高
密度の焼結体を製造する場合には、 １，７５０〜１．
８５０℃という高い温度での焼成や雰囲気加圧などが必
要であった。しかしながら、このように努力して製造し
たものであっても、焼結助剤を使用したものは、一般に
高温強度の低下が著しいという傾向があった。(Problems to be Solved by the Present Invention) When producing a known silicon nitride sintered body by the pressureless sintering method, aluminum oxide, magnesium oxide, rare earth element oxide, and zirconium oxide are used singly or in combination. When using the sintering aid mixed above and producing a particularly high-density sintered body, the amount is 1,750 to 1.
It required firing at a high temperature of 850°C and pressurizing the atmosphere. However, even with these efforts, those using sintering aids generally tended to have a significant drop in high-temperature strength.
また、この窒化けい素それ自体は、もともと金属溶湯な
どに対する耐食性には優れているのに、焼結助剤を使用
して１．７００℃未満の低温で常圧焼結したものについ
ては、金属の溶湯などと接触すると、摩耗や破損などに
よ−で短時間で使用できなくなる欠点があった。この原
因は、窒化けい素質焼結体自体の密度が低いこと、すな
わち気孔が存在することによるものと考えられる。Furthermore, although silicon nitride itself has excellent corrosion resistance against molten metals, it cannot be used when sintered under normal pressure at a low temperature of less than 1.700°C using a sintering aid. If they come into contact with molten metal, etc., they will become unusable in a short period of time due to wear and tear. This is thought to be due to the low density of the silicon nitride sintered body itself, that is, the presence of pores.
従って、金属溶湯用部材としての用途に使用できると共
に長時間の使用に耐え得る窒化けい素質焼結体を得るに
は、理論密度に近い充填率を示す気孔のほとんどない焼
結体にする必要があるが、現実番７は種々の問題がある
ことは上述のとおりである。Therefore, in order to obtain a silicon nitride sintered body that can be used as a member for molten metal and can withstand long-term use, it is necessary to create a sintered body with almost no pores and a filling rate close to the theoretical density. However, as mentioned above, reality number 7 has various problems.
本発明の目的は、このような従来技術とくに常圧焼結法
にもとづ〈従来の窒化けい素質焼結体の製造方法が抱え
ている上述の如き問題を克服する・二とにある。The object of the present invention is to overcome the above-mentioned problems of the conventional method of manufacturing a silicon nitride sintered body based on the conventional techniques, particularly the pressureless sintering method.
（課題を解決するための手段）
本発明者らは、窒化けい素質耐熱材料、特に十分に高い
高温強度および耐熱衝撃強度を有する金属・合金溶湯用
部材として好適なセラミックスとりわけ窒化けい素質焼
結体を簡易に、かつ安価に製造するべく研究を重ねた結
果、焼結助剤として、コージェライトと、酸化アルミニ
ウムおよび希土類元素酸化物との混合物を用いると、有
効であることを知見した。すなわち、このような焼結助
剤を用いると、従来は困難とされていた低温焼成をして
も所望の性質を有する窒化けい素質焼結体を確実に製造
できることを知見し、本発明を完成したのである。(Means for Solving the Problems) The present inventors have developed a silicon nitride heat-resistant material, particularly a ceramic material having sufficiently high high temperature strength and thermal shock resistance, and particularly a silicon nitride sintered material suitable as a member for molten metals and alloys. As a result of repeated research in order to easily and inexpensively manufacture the sintering agent, it was found that it is effective to use a mixture of cordierite, aluminum oxide, and rare earth element oxide as a sintering aid. That is, the inventors discovered that by using such a sintering aid, it was possible to reliably produce a silicon nitride sintered body with desired properties even at low temperature firing, which was previously considered difficult, and the present invention was completed. That's what I did.
すなわち、本発明は、窒化けい素粉、または窒化けい素
粉と炭化けい素粉の混合物にコージェライト １０〜６
０ｗｔ％を含みかつ残部が酸化アルミニウムと希土類元
素酸化物とからなる焼結助剤を、この焼結助剤の量が混
合物全体の１０〜４０ｗｔ％となるように加えて粉砕し
、混合しそして成型し、その後１．４５０−１．６５０
°Ｃの温度で焼成することを特徴とする方法である。That is, in the present invention, cordierite 10 to 6 is added to silicon nitride powder or a mixture of silicon nitride powder and silicon carbide powder.
A sintering aid containing 0 wt% and the balance consisting of aluminum oxide and rare earth element oxide is added so that the amount of this sintering aid is 10 to 40 wt% of the entire mixture, pulverized, mixed, and Molded and then 1.450-1.650
This method is characterized by firing at a temperature of °C.
（作 用）
本発明の窒化けい素質焼結体の製造当り、原料としては
、窒化けい素粉、または窒化けい素粉と炭化けい素粉と
の混合物を用いる。前記窒化けい素粉は、金属シリコン
の直接窒化法によるもの、イミド分解法によるもの、あ
るいはシリカ還元法によるものなど、既知方法で製造さ
れた各種のものを用いることができる。もちろん、非晶
質、結晶質、のいずれのものでもよく、またα型および
β型窒化けい素の各含有比率も任意のものでよい。炭化
けい素粉についても同様に、通常の方法で製造された市
販のものを用いることができる。これは、必要に応じて
、前記窒化けい素粉に所定量混合して用いる。(Function) In producing the silicon nitride sintered body of the present invention, silicon nitride powder or a mixture of silicon nitride powder and silicon carbide powder is used as a raw material. As the silicon nitride powder, various types of silicon nitride powder manufactured by known methods can be used, such as those produced by direct nitriding of metal silicon, those produced by imide decomposition, or those produced by silica reduction. Of course, it may be either amorphous or crystalline, and the content ratios of α-type and β-type silicon nitride may also be arbitrary. Similarly, commercially available silicon carbide powder produced by a conventional method can be used. This is used by mixing a predetermined amount with the silicon nitride powder, if necessary.
さて、本発明の特徴の１．つば、焼結助剤中にコージェ
ライトを含むことであり、その他には、酸化アルミニウ
ムおよび希土類元素酸化物を混合して焼結助剤としてい
る。この焼結助剤中に含むコージェライトは、２Ｍｇ０
・２ Ａ１．０．・５ ＳｉＯ□で表わされる鉱物であ
って、一般にＭｇ０１１−１６ｗｔ％、Ａｌ２Ｏ３３３
−４１ｗｔ％、５ｉｆｔ ４３−５６ｗｔ％の組成を有
するものであるが、本発明で使用するものは理論組成（
Ｍｇ０１３．８ｗｔ％、Ａｌ２０３３４、８ｗｔ％、５
ｉＯｚ ５１．４ｖｔ％）に近いものが好適である。な
お、酸化アルミニウムと希土類元素酸化物は、単独元素
の酸化物、または混合酸化物の何れでもよいが、中でも
酸化イツトリウムは好適である。Now, the first feature of the present invention. The sintering aid contains cordierite, and the sintering aid is a mixture of aluminum oxide and rare earth element oxide. The cordierite contained in this sintering aid is 2Mg0
・2 A1.0.・5 Mineral represented by SiO□, generally Mg011-16wt%, Al2O333
-41wt%, 5ift 43-56wt%, but the one used in the present invention has a theoretical composition (
Mg013.8wt%, Al20334, 8wt%, 5
iOz 51.4vt%) is suitable. Note that the aluminum oxide and the rare earth element oxide may be either an oxide of a single element or a mixed oxide, and among them, yttrium oxide is preferred.
かかる焼結助剤は、前記コージェライトを１０〜６０ｗ
ｔ％を含有し、残部が酸化アルミニウムと希土類元素酸
化物とからなるものであるが、この酸化アルミニウムと
希土類元素酸化物は、酸化アルミニウム１重量部に対し
て希土類元素酸化物１〜３重量部の割合で配合したもの
が適当である。Such a sintering aid can reduce the cordierite by 10 to 60w.
t%, and the balance consists of aluminum oxide and rare earth element oxide, and the aluminum oxide and rare earth element oxide are 1 to 3 parts by weight of rare earth element oxide per 1 part by weight of aluminum oxide. It is appropriate to mix them in the following proportions.
次に窒化けい素質焼結体を製造するに当っては、上記窒
化けい素粉、またはその窒化けい素粉と前記炭化けい素
粉との混合物に、上述のような割合で配合した焼結助剤
を、この焼結助剤の量が混合物全体の１０〜４０ｗｔ％
を占めるように添加して粉砕し、混合しそして所定の形
状に成型し、その後１．４５０〜１．６５０℃の温度範
囲内で焼成する。Next, in producing a silicon nitride sintered body, a sintering aid mixed in the above-mentioned proportions is added to the above-mentioned silicon nitride powder or a mixture of the above-mentioned silicon nitride powder and the above-mentioned silicon carbide powder. The amount of this sintering aid is 10 to 40 wt% of the entire mixture.
is added to account for 1.450 to 1.650° C., pulverized, mixed and formed into a desired shape, and then calcined within a temperature range of 1.450 to 1.650°C.
このように焼結助剤としてコージェライトを含む酸化ア
ルミニウムと、希土類元素酸化物（例えば、酸化イツト
リウム）との混合物を用いると、その主要成分はＭｇＯ
１Ａ１□Ｏｓ 、 ＳｉＯ□およびＹ２Ｏ３となる。こ
れらの成分のうちＭｇＯ１Ａ１□Ｏｓ 、 ５ｉ（ｌａ
およびＹ２Ｏ，については、従来の焼結助剤の主要成分
と変わるところがない、しかしながら、これらの酸化物
のみからなるものを本発明焼結助剤と同じ配合割合で混
合したとしても、それだけでは、低温焼成でも高密度の
窒化けい素質焼結体が得られるという本発明の如き効果
は得られない。ことに、本発明の焼結助剤中に含む５ｉ
Ｏｚは、もともと窒化けい素質焼結体の高温強度を低下
させる物質として知られており、従来は全く使用されて
いなかったものである。When a mixture of aluminum oxide containing cordierite and a rare earth element oxide (for example, yttrium oxide) is used as a sintering aid, the main component is MgO.
1A1□Os, SiO□ and Y2O3. Among these components, MgO1A1□Os, 5i(la
and Y2O, there is no difference from the main components of conventional sintering aids. However, even if a product consisting only of these oxides is mixed in the same proportion as the sintering aid of the present invention, The effect of the present invention, in which a high-density silicon nitride sintered body can be obtained even at low temperature firing, cannot be obtained. In particular, the 5i contained in the sintering aid of the present invention
Oz is originally known as a substance that lowers the high temperature strength of silicon nitride sintered bodies, and has not been used at all in the past.
本発明は、前記コージェライトが焼結助剤として有用で
あることを知見した点に特徴がある。すなわち、コージ
ェライトといわれる鉱物組成および構造になっているも
のを焼結助剤として用いると、焼結体の高温強度の低下
がなく、 １．４５０〜ｌ、 ６５０℃程度の低い温
度域で焼成しても、高密度の窒化けい素質焼結体が製造
できることが判った。The present invention is characterized by the discovery that the cordierite is useful as a sintering aid. In other words, if cordierite, which has a mineral composition and structure, is used as a sintering aid, the high temperature strength of the sintered body will not decrease, and it can be fired at a low temperature range of 1.450 - 650℃. It was found that a high-density silicon nitride sintered body could be produced even if
本発明において、焼結助剤中のコージェライトの量を、
１０〜６０ｗｔ％とじたのは、 １０ｗｔ％未満では
、前記温度範囲内では焼結が不十分となり、また６０ｗ
ｔ％を越えると、完全に焼結はするものの、金属および
合金溶湯に対する耐食性が不十分になるためである。In the present invention, the amount of cordierite in the sintering aid is
The reason why the content was set at 10 to 60 wt% is that if it is less than 10 wt%, sintering will be insufficient within the above temperature range, and if the content is less than 10 wt%, sintering will be insufficient within the above temperature range.
If it exceeds t%, although complete sintering will occur, the corrosion resistance against molten metals and alloys will be insufficient.
また、この焼結助剤の（窒化けい素粉または窒化けい素
粉と炭化けい素粉との混合物への）配合割合は、粉末混
合物全体のうちのｌＯ〜４０１１＋Ｌ％とする。この配
合量が１０ｗｔ％未満では、前記温度範囲内での焼成で
は焼結が不十分となり、また４０ｗｔ％以上では、窒化
けい素または炭化けい素自体の性質が損なわれるだけで
なく、耐食性の劣化および強度低下が生ずるためである
。Further, the blending ratio of this sintering aid (into silicon nitride powder or a mixture of silicon nitride powder and silicon carbide powder) is 10 to 4011+L% of the entire powder mixture. If the amount is less than 10 wt%, sintering will be insufficient when fired within the above temperature range, and if it is more than 40 wt%, not only will the properties of silicon nitride or silicon carbide itself be impaired, but also the corrosion resistance will deteriorate. This is because a decrease in strength occurs.
次に、窒化けい素粉または窒化けい素粉と炭化けい素粉
および焼結助剤を配合した粉末混合物は、通常の粉砕処
理法、例えばボールミルなどを用いて湿式法または乾式
法で粉砕し混合する。このようにして調製した粉末混合
物を、ブレス成形押出成形および泥しょう鋳込法などの
方法によって所定形状に成型した後、焼成する。Next, the silicon nitride powder or the powder mixture of silicon nitride powder, silicon carbide powder, and sintering aid is pulverized and mixed using a conventional pulverization method, such as a wet or dry method using a ball mill. do. The powder mixture thus prepared is molded into a predetermined shape by methods such as press extrusion molding and mud casting, and then fired.
焼成は、成形後の成型体を必要があれば一旦乾燥した後
、 １．４５０〜１．６５０℃の温度範囲内で一定時間
保持することにより行う、保持時間は、１〜５時間とす
る。上記焼成温度が１．４５０℃以下では焼結が不完全
となり、また１、 ６５０℃以上の高温になると窒化け
い素の分解が起きやすくなる。焼成雰囲気については、
非酸化性雰囲気が好適である。Firing is carried out by once drying the molded body after molding, if necessary, and then holding it within a temperature range of 1.450 to 1.650°C for a certain period of time, and the holding time is 1 to 5 hours. If the firing temperature is below 1.450°C, sintering will be incomplete, and if it is at a high temperature of 1.650°C or above, silicon nitride will easily decompose. Regarding the firing atmosphere,
A non-oxidizing atmosphere is preferred.
以上のようにして製造した窒化けい素質焼結成型体につ
いて、その諸物性を測定した結果、はぼ理論密度に近い
充填率をもっており、高温下においても十分な強度を有
していることが判った。As a result of measuring various physical properties of the silicon nitride sintered molded body produced as described above, it was found that it had a filling rate close to the theoretical density and had sufficient strength even at high temperatures. Ta.
（実施例） 実施例ｌ ５１３Ｎ４粉、ＳｉＣ粉、コージェライト扮。(Example) Example l 513N4 powder, SiC powder, cordierite.
Ａ１□０３扮およびｙ、ｏ３粉を第１表に示した割合で
混合し、アルミナ製のボールミルで２４時間粉砕混合し
た。ついでプレス成形法を用い、４０ｋｇ／＋ｍ２の圧
力で１００ｘ ７５ｘ １０ｍｍの成形体を製作した。A1□03 powder, y, and o3 powder were mixed in the proportions shown in Table 1, and pulverized and mixed in an alumina ball mill for 24 hours. Next, a molded body of 100 x 75 x 10 mm was manufactured using a press molding method under a pressure of 40 kg/+m2.
その成型体を１気圧の窒素雰囲気中で焼成することによ
り窒化けい素質焼結成型体を得た。The molded body was fired in a nitrogen atmosphere of 1 atm to obtain a silicon nitride sintered molded body.
第１表に、５ｉＪ４粉、ＳｉＣ扮および焼結助剤の配合
比、焼結助剤中のコージェライト、Ａ１．０．の配合比
および成型体の焼成条件（温度、時間）を示し、さらに
得られた焼結体の開気孔率の指標として吸水率、密度の
指標として充填率（嵩密度の理論密度に対する割合）お
よび曲げ強度を示した。その結果、本発明方法で′ＪＡ
造したものは吸水率が小さく、充填率は９６％以上であ
り、曲げ強度も十分な値が得られた。Table 1 shows the blending ratio of 5iJ4 powder, SiC powder and sintering aid, cordierite in the sintering aid, A1.0. The mixing ratio and the firing conditions (temperature, time) of the molded body are shown, and the water absorption rate is an indicator of the open porosity of the obtained sintered body, and the filling rate (ratio of bulk density to theoretical density) and It shows the bending strength. As a result, in the method of the present invention, 'JA
The manufactured product had a low water absorption rate, a filling rate of 96% or more, and a sufficient bending strength.
さらに、これらの窒化けい素質焼結体について、アルミ
ニウム合金溶湯を用いて浸漬テストを行った。温度７５
０℃の溶湯中に該成型体を浸漬し、２４時間毎に取り出
してその状況を観察した。その結果１本発明方法による
ものは全（侵食を受けず、また気孔へのアルミニウム合
金溶湯の侵入による破損もなかった。Further, these silicon nitride sintered bodies were subjected to an immersion test using molten aluminum alloy. temperature 75
The molded body was immersed in molten metal at 0°C, and taken out every 24 hours to observe its condition. As a result, 1, all of the specimens produced by the method of the present invention were not eroded, nor were they damaged by the penetration of molten aluminum alloy into the pores.
なお、比較例の中で吸水率の小さいもの、例えば焼結助
剤としてコージェライトのみ４０ｗｔ％添加したものは
アルミニウム合金溶湯への浸漬テストでは表面が変質し
、クラックが入るという現象が生じた。Note that among the comparative examples, those with low water absorption, for example those in which only 40 wt % of cordierite was added as a sintering aid, had a phenomenon in which the surface deteriorated and cracks appeared in the immersion test in molten aluminum alloy.
実施例２
Ｓｊ、ＪＬ扮、コージェライト粉、Ａｌ２Ｏ３扮および
Ｙ２Ｏ，粉を第２表に示した割合で配合し、アルミナ製
のボールミルで２４時間粉砕・混合した。その混合粉末
から泥しよう鋳込み法を用い、８０φＸ １０ｍｍの成
型体を作成した。この成型体を、乾燥後、１気圧の窒素
雰囲気中で第２表に示した条件で焼成した。Example 2 Sj, JL, cordierite powder, Al2O3 and Y2O powder were blended in the proportions shown in Table 2, and ground and mixed in an alumina ball mill for 24 hours. A molded body of 80φ x 10mm was made from the mixed powder using a slurry casting method. After drying, this molded body was fired under the conditions shown in Table 2 in a nitrogen atmosphere of 1 atm.
得られた窒化けい素質焼結体の特性を第２表に示す、こ
の結果から判るように、実施例１と同様に吸水率、充填
率および曲げ強度ともに十分な値が得られた。The properties of the obtained silicon nitride sintered body are shown in Table 2. As can be seen from the results, as in Example 1, sufficient values for water absorption, filling rate, and bending strength were obtained.
さらに５本発明方法で得られた窒化けい素質焼結体につ
いて熱膨張係数を測定した結果。Furthermore, the results of measuring the coefficient of thermal expansion of the silicon nitride sintered body obtained by the method of the present invention.
２００〜１．０００℃の間の平均熱膨張係数が３．８７
Ｘ １０−’であり、従来の方法、例えば焼結助剤にＡ
１□０３とＹ２Ｏ３を用いて１．７５０℃で焼結させた
ものとほぼ同じ値が得られている。また曲げ強度につい
ては、本発明方法によるものは、例えば、室温強度６０
ｋｇ／ｍｍ２，８００℃で６３ｋｇ／ｍｍ”であったも
のが、さらに高温の１．０口０°Ｃでは５９ｋｇ／ｍｍ
”、 １．２００°Ｃでは３８ｋｇ／ｍｎ＋２であり、
高温下においても高い強度を保っていた。Average thermal expansion coefficient between 200 and 1.000℃ is 3.87
X 10-', and conventional methods, e.g.
Almost the same value as that obtained by sintering at 1.750° C. using 1□03 and Y2O3 was obtained. Regarding the bending strength, for example, the one made by the method of the present invention has a room temperature strength of 60
kg/mm2, 63 kg/mm at 800°C, but 59 kg/mm at a higher temperature of 1.0°C.
”, 1. At 200°C, it is 38kg/mn+2,
It maintained high strength even under high temperatures.
（本発明の効果）
以上説明したように本発明によれば窒化けい素質耐熱材
料、とくに高温強度に優れるとともに高密度の窒化けい
素質焼結体を簡易な方法で、安価に製造することができ
る。そして、得られる窒化けい素質焼結体はとくにアル
ミニウムやその合金などを好適例とする金属浴用部材と
して有効に用いられるものが提供できる。(Effects of the Present Invention) As explained above, according to the present invention, a silicon nitride heat-resistant material, particularly a silicon nitride sintered body having excellent high-temperature strength and high density, can be produced by a simple method and at low cost. . The resulting silicon nitride sintered body can be effectively used as a member for metal baths, with aluminum and alloys thereof being particularly preferred.
特許出願人 日本重化学工業株式会社Patent applicant: Japan Heavy and Chemical Industry Co., Ltd.
Claims (1)
の混合物にコージェライト１０〜６０ｗｔ％を含みかつ
残部が酸化アルミニウムと希土類元素酸化物とからなる
焼結助剤を、この焼結助剤の量が混合物全体の１０〜４
０ｗｔ％となるように加えて粉砕し、混合しそして成型
し、その後１．４５０〜１．６５０℃の温度で焼成する
ことを特徴とする高密度窒化けい素質焼結体の製造方法
。1. A sintering aid containing 10 to 60 wt% of cordierite in silicon nitride powder or a mixture of silicon nitride powder and silicon carbide powder, with the balance being aluminum oxide and rare earth element oxide, is added to the sintering aid. The amount of is 10 to 4 of the total mixture.
1. A method for producing a high-density silicon nitride sintered body, which comprises adding 0 wt%, pulverizing, mixing and molding, and then firing at a temperature of 1.450 to 1.650°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63268112A JPH02116679A (en) | 1988-10-26 | 1988-10-26 | Production of high-density sintered silicon nitride body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63268112A JPH02116679A (en) | 1988-10-26 | 1988-10-26 | Production of high-density sintered silicon nitride body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02116679A true JPH02116679A (en) | 1990-05-01 |
| JPH0555468B2 JPH0555468B2 (en) | 1993-08-17 |
Family
ID=17454058
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63268112A Granted JPH02116679A (en) | 1988-10-26 | 1988-10-26 | Production of high-density sintered silicon nitride body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02116679A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11100275A (en) * | 1997-09-26 | 1999-04-13 | Kyocera Corp | Low thermal expansion ceramic and its preparation |
-
1988
- 1988-10-26 JP JP63268112A patent/JPH02116679A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11100275A (en) * | 1997-09-26 | 1999-04-13 | Kyocera Corp | Low thermal expansion ceramic and its preparation |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0555468B2 (en) | 1993-08-17 |
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