JPH03170603A - Manufacture of sintered powder compact - Google Patents
Manufacture of sintered powder compactInfo
- Publication number
- JPH03170603A JPH03170603A JP1307645A JP30764589A JPH03170603A JP H03170603 A JPH03170603 A JP H03170603A JP 1307645 A JP1307645 A JP 1307645A JP 30764589 A JP30764589 A JP 30764589A JP H03170603 A JPH03170603 A JP H03170603A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- additive
- powder compact
- compact
- temperature
- 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.)
- Pending
Links
- 239000000843 powder Substances 0.000 title claims abstract description 180
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 6
- 239000000654 additive Substances 0.000 claims abstract description 86
- 230000000996 additive effect Effects 0.000 claims abstract description 54
- 238000000034 method Methods 0.000 claims abstract description 34
- 239000011347 resin Substances 0.000 claims abstract description 28
- 229920005989 resin Polymers 0.000 claims abstract description 28
- 239000002184 metal Substances 0.000 claims abstract description 20
- 229910052751 metal Inorganic materials 0.000 claims abstract description 20
- 239000000919 ceramic Substances 0.000 claims abstract description 19
- 239000000203 mixture Substances 0.000 claims abstract description 14
- 239000007788 liquid Substances 0.000 claims abstract description 13
- 150000001875 compounds Chemical class 0.000 claims abstract description 8
- 238000001746 injection moulding Methods 0.000 claims description 21
- 238000009835 boiling Methods 0.000 claims description 17
- 238000002844 melting Methods 0.000 claims description 14
- 230000008018 melting Effects 0.000 claims description 14
- 239000010409 thin film Substances 0.000 claims description 13
- 238000002156 mixing Methods 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 abstract description 35
- 238000002347 injection Methods 0.000 abstract description 11
- 239000007924 injection Substances 0.000 abstract description 11
- 239000011248 coating agent Substances 0.000 abstract description 10
- 238000000576 coating method Methods 0.000 abstract description 10
- 238000005245 sintering Methods 0.000 abstract description 10
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 abstract description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 3
- BPJYAXCTOHRFDQ-UHFFFAOYSA-L tetracopper;2,4,6-trioxido-1,3,5,2,4,6-trioxatriarsinane;diacetate Chemical compound [Cu+2].[Cu+2].[Cu+2].[Cu+2].CC([O-])=O.CC([O-])=O.[O-][As]1O[As]([O-])O[As]([O-])O1.[O-][As]1O[As]([O-])O[As]([O-])O1 BPJYAXCTOHRFDQ-UHFFFAOYSA-L 0.000 abstract 2
- 238000000462 isostatic pressing Methods 0.000 abstract 1
- 238000005238 degreasing Methods 0.000 description 26
- 230000007547 defect Effects 0.000 description 20
- 230000002706 hydrostatic effect Effects 0.000 description 13
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 12
- 239000010408 film Substances 0.000 description 12
- 239000002245 particle Substances 0.000 description 12
- 229910052581 Si3N4 Inorganic materials 0.000 description 11
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 11
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 10
- 238000001816 cooling Methods 0.000 description 9
- 238000012856 packing Methods 0.000 description 9
- -1 polyethylene Polymers 0.000 description 9
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 8
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- 238000007796 conventional method Methods 0.000 description 6
- 235000011187 glycerol Nutrition 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 6
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 229910010271 silicon carbide Inorganic materials 0.000 description 5
- 239000004925 Acrylic resin Substances 0.000 description 4
- 229920000178 Acrylic resin Polymers 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 229940057995 liquid paraffin Drugs 0.000 description 4
- 238000007493 shaping process Methods 0.000 description 4
- 229920002545 silicone oil Polymers 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 3
- 238000005452 bending Methods 0.000 description 3
- 239000003822 epoxy resin Substances 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000839 emulsion Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- ZQBFAOFFOQMSGJ-UHFFFAOYSA-N hexafluorobenzene Chemical compound FC1=C(F)C(F)=C(F)C(F)=C1F ZQBFAOFFOQMSGJ-UHFFFAOYSA-N 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 229910052863 mullite Inorganic materials 0.000 description 2
- KPSSIOMAKSHJJG-UHFFFAOYSA-N neopentyl alcohol Chemical compound CC(C)(C)CO KPSSIOMAKSHJJG-UHFFFAOYSA-N 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 229920001225 polyester resin Polymers 0.000 description 2
- 239000004645 polyester resin Substances 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 229920005749 polyurethane resin Polymers 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000004663 powder metallurgy Methods 0.000 description 2
- 239000003507 refrigerant Substances 0.000 description 2
- 229920002050 silicone resin Polymers 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 229910000601 superalloy Inorganic materials 0.000 description 2
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- 230000008016 vaporization Effects 0.000 description 2
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 2
- APQIUTYORBAGEZ-UHFFFAOYSA-N 1,1-dibromoethane Chemical compound CC(Br)Br APQIUTYORBAGEZ-UHFFFAOYSA-N 0.000 description 1
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- 229910052580 B4C Inorganic materials 0.000 description 1
- 206010011224 Cough Diseases 0.000 description 1
- XBPCUCUWBYBCDP-UHFFFAOYSA-N Dicyclohexylamine Chemical compound C1CCCCC1NC1CCCCC1 XBPCUCUWBYBCDP-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- HZFDKBPTVOENNB-GAFUQQFSSA-N N-[(2S)-1-[2-[(2R)-2-chloro-2-fluoroacetyl]-2-[[(3S)-2-oxopyrrolidin-3-yl]methyl]hydrazinyl]-3-(1-methylcyclopropyl)-1-oxopropan-2-yl]-5-(difluoromethyl)-1,2-oxazole-3-carboxamide Chemical compound CC1(C[C@@H](C(NN(C[C@H](CCN2)C2=O)C([C@H](F)Cl)=O)=O)NC(C2=NOC(C(F)F)=C2)=O)CC1 HZFDKBPTVOENNB-GAFUQQFSSA-N 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 235000021355 Stearic acid Nutrition 0.000 description 1
- 239000002174 Styrene-butadiene Substances 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 229940090012 bentyl Drugs 0.000 description 1
- YSXKPIUOCJLQIE-UHFFFAOYSA-N biperiden Chemical compound C1C(C=C2)CC2C1C(C=1C=CC=CC=1)(O)CCN1CCCCC1 YSXKPIUOCJLQIE-UHFFFAOYSA-N 0.000 description 1
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 description 1
- 150000001639 boron compounds Chemical class 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- HPXRVTGHNJAIIH-UHFFFAOYSA-N cyclohexanol Chemical compound OC1CCCCC1 HPXRVTGHNJAIIH-UHFFFAOYSA-N 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 239000010720 hydraulic oil Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 229920006173 natural rubber latex Polymers 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000008117 stearic acid Substances 0.000 description 1
- 239000011115 styrene butadiene Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Producing Shaped Articles From Materials (AREA)
- Powder Metallurgy (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は焼結性粉末成形体の製造方法に関する．より詳
しくは、セラミックス焼結体あるいは焼結合金を得るた
めに、セラミックス粉末あるいは金属粉末を射出戒形法
で戒形し、次に戒形助剤として用いた添加剤を加熱・飛
散させる方法に関する．〔従来の技術〕
形状が複雑で、かつ量産されるセラ果ツクス焼結体は、
原料であるアル逅ナ、ジルコニア、炭化ケイ素、窒化ケ
イ素、ムライト、サイアロンなどの粉末を、射出戒形法
によって所望する形状に威形し、脱脂後、ついでこの粉
末成形体が焼結するに必要な温度に強熱することにより
工業的に生産されている。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a sinterable powder compact. More specifically, it relates to a method in which ceramic powder or metal powder is shaped by an injection molding method, and then an additive used as a molding aid is heated and scattered in order to obtain a ceramic sintered body or a sintered alloy. ．． [Prior art] Ceramics sintered bodies with complex shapes and mass-produced are
Raw material powders such as alumina, zirconia, silicon carbide, silicon nitride, mullite, and sialon are shaped into the desired shape using the injection molding method, and after degreasing, the powder compacts are then sintered. It is produced industrially by ignition to a certain temperature.
また、金属粉末を或形し次にこれを加熱して焼結合金を
得る方法、いわゆる粉末冶金法は、完全形状に近いもの
が得られ、また金属組織の制御が容易であるといった優
れた長所を持っている。In addition, the so-called powder metallurgy method, which is a method of forming a metal powder and then heating it to obtain a sintered alloy, has excellent advantages such as being able to obtain a nearly perfect shape and making it easy to control the metal structure. have.
しかして、上記高性能の合金部材を得る方法として、工
業的に最も期待されている方法は粉末冶金法である。す
なわち、Ｐｅ， Ｎｉ， Ｃｒ， Ｔｉ， Ｃｏ， Ｓ
ｎ，Ｃｕなどの金属粉末を所定の割合に混合し、この金
属粉末に添加剤を加えて射出成形法によって所望する形
状に或形し、脱脂した後、ついでこの金属粉末成形体が
焼結するに必要な温度に強熱することにより、高性能の
合金部材を得ることができる。Therefore, the powder metallurgy method is the most expected industrially as a method for obtaining the above-mentioned high-performance alloy members. That is, Pe, Ni, Cr, Ti, Co, S
Metal powders such as n, Cu, etc. are mixed in a predetermined ratio, additives are added to this metal powder, it is shaped into a desired shape by injection molding, degreased, and then this metal powder compact is sintered. A high-performance alloy member can be obtained by igniting to the temperature required for this.
ここでいう射出戊形法とは、上記したアルミナ、ジルコ
ニアなどのセラξツクス粉末あるいはＦｅ、Ｎｉなどの
金属粉末と混練されたとき、全体として可塑性を示し戒
形し易くなるような、例えばボリスチレン、ポリエチレ
ン、ボリブロピレン、ジエチレンフタレート、バラフィ
ン、脂肪酸エステル、ポリビニルアルコールなどの添加
剤をセラミックスや金属の粉末１００重量部に対して１
０〜３５重量部加えて混練し、この混練物を所望する形
状の金型に圧人して戊形する方法である。得られた粉末
成形体は金型から取り出され、添加剤を加熱により飛散
・除去させた後、例えば１０００〜２３００’Ｃに強熱
すれば所望する形状のセラミックス焼結体あるいは焼結
合金が得られる。The injection forming method here refers to materials such as boristyrene, which exhibits plasticity as a whole and becomes easy to form when mixed with ceramic powders such as alumina and zirconia, or metal powders such as Fe and Ni. Additives such as polyethylene, polypropylene, diethylene phthalate, paraffin, fatty acid ester, polyvinyl alcohol, etc. to 100 parts by weight of ceramic or metal powder.
This is a method in which 0 to 35 parts by weight are added and kneaded, and the kneaded product is pressed into a mold of a desired shape. The obtained powder compact is taken out of the mold, and after scattering and removing the additives by heating, it is ignited to, for example, 1000 to 2300°C to obtain a ceramic sintered body or sintered alloy in the desired shape. It will be done.
なお、本発明においては、粉末を成形し強熱すれば緻密
な焼結体を得ることが可能なセラミックスおよび金属の
粉末を焼結性粉末と称することにし、これら焼結性粉末
の成形体を粉末戊形体と称することにし、また、セラミ
ックス焼結体と焼結合金を総称して、単に、焼結体と称
することにする．更にまた、上記射出威形時に焼結性粉
末を或形するために添加する成形助剤を総称して添加剤
と称することにし、上記射出戒形法により得られた成形
体中に残存するかかる添加剤を加熱により飛散させる操
作を、該技術分野における当業者の慣例用語に従い、以
下「脱脂」と表記する。In the present invention, ceramic and metal powders that can be formed into dense sintered bodies by molding and igniting the powders are referred to as sinterable powders, and compacts of these sinterable powders are referred to as sinterable powders. This will be referred to as a powdered body, and the ceramic sintered body and sintered alloy will be collectively referred to simply as the sintered body. Furthermore, the forming aids added to shape the sinterable powder during the injection shaping process are collectively referred to as additives, and any such additives remaining in the molded product obtained by the injection shaping process are generally referred to as additives. The operation of scattering the additive by heating will be hereinafter referred to as "degreasing" according to the common terminology of those skilled in the art.
しかしながら、射出成形法によって得られた粉末成形体
を、脱脂後強熱する方法によって得られた焼結体は、亀
裂や表面剥離など欠陥のある不良品（１！品とはなし得
ないもの）が少なからず発生するという問題がある．
更に、これらの欠陥が焼結体内部に発生したものは、製
品化の段階で欠陥を発見することが困難なため一部はそ
のまま製品化されてしまい、使用中に破損し事故の原因
となるという大きな問題もある．
そしてここで特に指摘すべきは、上記亀裂や表面剥離な
ど欠陥はその殆どが脱脂工程において発生するというこ
とである．すなわち、粉末成形体に添加剤が残存してい
ると、この粉末戊形体を強熱して焼結体とする際に、該
残存添加剤が急激に気化し、この気化による膨張力のた
め粉末成形体が煽裂するという問題がある。これを防止
する目的で粉末成形体は強熱に先立って脱脂工程を設け
、添加剤を除去しておくのである。However, sintered bodies obtained by degreasing and igniting powder compacts obtained by injection molding are defective products with defects such as cracks and surface peeling (those that cannot be considered as 1! products). There is a problem that occurs quite a bit. Furthermore, if these defects occur inside the sintered body, it is difficult to detect the defects at the stage of product production, so some of the products end up being produced as is, causing damage during use and causing accidents. There is also a big problem. What should be pointed out here is that most of the defects mentioned above, such as cracks and surface peeling, occur during the degreasing process. In other words, if additives remain in the powder compact, when the powder compact is ignited to form a sintered compact, the remaining additives will rapidly vaporize, and the expansion force caused by this vaporization will cause the powder compaction to fail. There is a problem with the body being torn apart. In order to prevent this, the powder compact is subjected to a degreasing process to remove additives prior to ignition.
しかしながら、粉末成形体は上述したように、粉末１０
０重量部に対して１０重量部以上もの添加剤を含んでい
るので、このように多量の添加剤を含んだ粉末成形体か
ら、割れや亀裂を発生させることなく加熱により添加剤
を飛散・除去させることは、加熱飛散に伴う該添加剤の
膨張力が粉末成形体に強く作用するため、即ち、Ｉｌｉ
！ｉｉ！２的強度の極めて低い粉末成形体の内部の圧力
の方が粉末成形体の外部の圧力よりも高くなるために、
本質的に極めて難しい問題なのである．
したがって、従来この工程は、大気圧あるいは５ ｋｇ
７ｃｍ”程度の加圧下で粉末成形体を最高で６００℃程
度に加熱して、添加剤を気化、分解などで飛散除去させ
ることによって行われているが、添加剤の膨張力を低く
抑える必要上、粉末成形体の昇温速度は１〜３゜Ｃ／ｈ
といった極めて遅い条件で行われている．脱脂工程はこ
のように緩慢な昇温速度を採用せざるを得ないため、通
常５〜７日間もの長時間を要し、著しく生産性が阻害さ
れるといった問題があった。However, as mentioned above, the powder compact has powder 10
Since it contains more than 10 parts by weight of additives compared to 0 parts by weight, the additives can be scattered and removed by heating without causing cracks or cracks from powder compacts containing such a large amount of additives. This is because the expansion force of the additive due to heating and scattering strongly acts on the powder compact, that is, Ili
! ii! Because the pressure inside the powder compact, which has extremely low secondary strength, is higher than the pressure outside the powder compact,
This is essentially an extremely difficult problem. Therefore, traditionally this process was carried out at atmospheric pressure or at 5 kg
This is done by heating the powder compact to a maximum of about 600°C under a pressure of about 7cm" and scattering and removing the additives through vaporization, decomposition, etc., but this is done because it is necessary to keep the expansion force of the additives low. , the heating rate of the powder compact is 1 to 3°C/h.
This is done under extremely slow conditions. Since the degreasing process has no choice but to adopt such a slow temperature increase rate, it usually takes a long time of 5 to 7 days, which poses a problem in that productivity is significantly inhibited.
またこのように緩慢な昇温速度においても、肉厚が２０
１Ｉｌｍｌ以上と大きな粉末成形体になると、割れや亀
裂を発生させることなく脱脂することは従来不可能であ
った．
〔発明の要旨〕
本発明者らは、このような従来技術の欠点を解消するこ
とを目的とし、形状の大きな粉末成形体においても割れ
や亀裂などの欠陥を発生させることなく、短時間に脱脂
可能な方法を先に、特開昭６３−１４７８６９号、特開
昭６４−３０８０号において提案した。本発明は、これ
ら先に提案した方法の改良に関するものである．
〔発明の開示〕
上記百的は、焼結性粉末に添加剤を加えて粉末成形体を
得、該粉末成形体の表面の一部を露出面として残す他は
、残余を気密性がある樹脂薄膜で被覆し、該被覆した面
を静水圧加圧した状態で該粉末成形体を加熱して、該添
加剤を該露出面を通して飛散せしめることによって達威
されるが、本発明者らはかかる方法を、射出戒形法に適
応させるために鋭意検討を行い種々の条件を特定して工
業的に可能な方法にまで技術を確立したものである．
本発明において確立した技術は次の三点である．第一に
焼結性粉末を射出或形する際の、金型への流動性、第二
に射出威形して得た粉末戊形体の金型からの離脱性、第
三に添加剤を除去する隙の易Ｗｔ敗性である。Also, even at such a slow temperature increase rate, the wall thickness is 20
In the past, it was impossible to degrease large powder compacts of 1 ml or more without causing cracks or cracks. [Summary of the Invention] The present inventors aimed to eliminate the drawbacks of the prior art and have degreased a large powder compact in a short time without causing defects such as cracks or cracks. Possible methods were previously proposed in Japanese Patent Application Laid-open Nos. 147869/1986 and 3080/1982. The present invention relates to improvements to these previously proposed methods. [Disclosure of the Invention] In the above hundredth aspect, an additive is added to a sinterable powder to obtain a powder compact, and apart from leaving a part of the surface of the powder compact as an exposed surface, the rest is made of an airtight resin. This can be achieved by coating the powder body with a thin film and heating the powder compact while applying hydrostatic pressure to the coated surface to cause the additive to scatter through the exposed surface. In order to adapt the method to the Injection Kaigata method, we conducted extensive research, identified various conditions, and established the technology to an industrially possible method. The technology established in this invention consists of the following three points. Firstly, the fluidity into the mold when the sinterable powder is injected or shaped, secondly the ease with which the powder body obtained by injection molding is released from the mold, and thirdly the removal of additives. It is easy to defeat Wt.
これら本発明の目的は、次の各工程よりなる焼結性粉末
の製造方法によって達威される。These objects of the present invention are achieved by a method for producing sinterable powder comprising the following steps.
（１）焼結性粉末に、添加剤として融点が−１０゜Ｃ以
上、沸点が１４０゜Ｃ以下の性質を有する液状化合物を
、容積比率で粉末１に対して０．６〜１．１加えて混合
する．
（２）該混合して得た組戒物を射出或形するにおいて、
シリンダー温度を該添加剤の融点以上、沸点未満とし、
更に金型温度を添加剤の融点未満の温度に保持した状態
で該組成物を金型に圧入する．（３）固化した粉末成形
体を射出成形機の金型より取り出す．
（４）粉末成形体の表面を、一部の露出面を残して気密
性があり、かつ弾性のある樹脂薄膜で被覆する．（５）
該被覆した面を静水圧加圧した状態で粉末成形体を添加
剤の沸点以上に加熱し、該添加剤を該露出面を通して飛
散させる．
〔発明を実施するための具体的要件〕
以下、本発明を詳細に説明する。(1) Add a liquid compound having a melting point of -10°C or higher and a boiling point of 140°C or lower as an additive to the sinterable powder at a volume ratio of 0.6 to 1.1 to 1 powder. Mix. (2) Injecting or shaping the resulting mixture,
The cylinder temperature is set to be above the melting point and below the boiling point of the additive,
Furthermore, the composition is press-fitted into the mold while maintaining the mold temperature below the melting point of the additive. (3) Remove the solidified powder compact from the mold of the injection molding machine. (4) The surface of the powder compact is coated with an airtight and elastic thin resin film, leaving only a portion of the exposed surface. (5)
The powder compact is heated to a temperature higher than the boiling point of the additive while the coated surface is subjected to hydrostatic pressure, and the additive is dispersed through the exposed surface. [Specific Requirements for Carrying Out the Invention] The present invention will be described in detail below.
本発明ではまず、アルミナ、ジルコニア、炭化ケイ素、
窒化ケイ素、ムライト、サイアロンなどのセラミック粉
末やＦｅ， Ｎｉ， Ｃｒ．．Ｔｉ， Ｃｏ、Ｓｎ，
Ｃｕなどの金属粉末に添加剤として融点が−１０゜Ｃ以
上、沸点が１４０゜Ｃ以下の性質を有する液状化合物を
容積比率で粉末ｌに対して０．６〜１．１加えて混合す
る．ここでいう沸点はｌ気圧下におけるそれを意味し、
上記の性質を有する液状化合物には、ベンゼン、シクロ
ヘキサン、ジオキサン、ギ酸、酢酸、バラキシレン、１
．２−ジブロモエタン、ヘキサフルオ口ベンゼン、１，
１，２．２−テトラクロ口−１．２−ジフルオロエタン
、ｔｅｒｔ−ベンチルアルコール、ネオペンチルアルコ
ール、シクロへキシルア果ン、ジシクロヘキシルアミン
、ビペリジン、エチレンジアミン、水などがあり、これ
らを添加剤として用いて、容積比率で粉末１部に対して
０．６〜１．１部加えて、ボールミル、ヘンシェル果キ
サー、ニーダーなどを用いて混合する．ここで粉末成形
体よりｍ密な焼結体を得るためには焼結助剤を必要とす
る粉末においては、予め焼結助剤が添加混合された粉末
を用いるか、あるいは添加剤を混合する際に同時に焼結
助剤を混合する。焼結助剤の例としては窒化ケイ素やジ
ルコニアではＭｇ（１、ＣａＯ 、Ａ１ｇＯｓ 、’ｌ
ｘ’ｓなどがあり、これらを窒化ケイ素やジルコニアの
粉末１００重量部に対して３〜８重量部添加する．炭化
ケイ素ではＢ ， Ｂ．Ｃ、ＴｉＢ＊などのホウ素化合
物を０．２〜２重量部と単体炭素０．５〜５重量部とを
添加する。アルミナではＭｇＯ 、ＣａＯ 、Ｙ．Ｏｓ
などを０．０５〜２重量部添加する．焼結性粉末に加え
る添加剤の量は、容積比率即ち、空隙を除く実容積にお
いて、粉末ｌに対して０．６〜１．１ と特定する．添
加剤を加える目的は、粉末を射出戊形機の金型に圧入す
る際に必要な流動性を付与させるためであり、この目的
において０．６以上の添加量を必要とするが、１．１を
越えると粉末成形体の粉末充填密度が低いという問題や
、金型の間隙からのはみ出しが問題となる。In the present invention, first, alumina, zirconia, silicon carbide,
Ceramic powders such as silicon nitride, mullite, sialon, Fe, Ni, Cr. ．． Ti, Co, Sn,
A liquid compound having a melting point of -10°C or higher and a boiling point of 140°C or lower is added as an additive to metal powder such as Cu at a volume ratio of 0.6 to 1.1 per liter of powder and mixed. The boiling point here means that at 1 atmosphere,
Liquid compounds with the above properties include benzene, cyclohexane, dioxane, formic acid, acetic acid, baraxylene,
．． 2-dibromoethane, hexafluorobenzene, 1,
These include 1,2,2-tetrachloro-1,2-difluoroethane, tert-bentyl alcohol, neopentyl alcohol, cyclohexyl alcohol, dicyclohexylamine, biperidine, ethylenediamine, water, etc., and these can be used as additives. Add 0.6 to 1.1 parts by volume to 1 part of powder and mix using a ball mill, Henschel mixer, kneader, etc. In order to obtain a sintered compact that is denser than a powder compact, for powders that require a sintering aid, use a powder that has been mixed with a sintering aid in advance, or mix an additive. At the same time, the sintering aid is mixed. Examples of sintering aids include Mg(1, CaO, A1gOs, 'l) for silicon nitride and zirconia.
3 to 8 parts by weight are added to 100 parts by weight of silicon nitride or zirconia powder. For silicon carbide, B, B. 0.2 to 2 parts by weight of a boron compound such as C or TiB* and 0.5 to 5 parts by weight of elemental carbon are added. For alumina, MgO, CaO, Y. Os
Add 0.05 to 2 parts by weight of etc. The amount of additive added to the sinterable powder is specified as a volume ratio, that is, an actual volume excluding voids, of 0.6 to 1.1 per liter of powder. The purpose of adding additives is to impart the necessary fluidity when press-fitting the powder into the mold of an injection molding machine, and for this purpose, an additive amount of 0.6 or more is required, but 1. When it exceeds 1, problems arise such as low powder packing density of the powder compact and problems of protrusion from the gap in the mold.
得られた焼結性粉末と添加剤との１戒物を、次に射出成
形機を用いて金型に圧入するが、ここでシリンダー温度
は添加剤の融点以上、沸点未満とする。この理由は、シ
リンダ一部より金型へ粉末成形体が圧入されるまでは、
添加剤が液状であって、蒸発によって添加剤と粉末の＆
ＩＩ或変化を生じることなく粉末成形体に流動性を保有
させるためである。また金型温度は添加剤の融点未満の
温度に保持した状態で咳組成物を圧入する．この理由は
、粉末成形体を金型より取り出すにおいて必要な強度を
、粉末成形体に速やかに付与させるためである．即ち、
粉末成形体が金型に流入したと同じ流動性を有したまま
で、粉末成形体を金型より取り外すことは不可能であり
、取り外すためには突出しピンで粉末成形体の一部を押
したときに、全体が変形を起こさずに金型より外れるこ
とが可能な強度が粉末成形体に必要なのである，このよ
うに、焼結性粉末と添加剤との組成物は流動性を有する
状態から、固型性を有する状態へ移行することが必要で
あるが、本発明はこれを添加剤の液体より固体への相変
化を利用することによって可能にしたものである．
この目的において、本発明では金型の温度、より詳しく
はキャビティの内壁温度を添加剤の融点未満に保持し、
添加剤を凝固させた後に、粉末成形体を金型より取り外
す．自明のことながら、金型温度が低ければ低い程、添
加剤が凝固する時間は短くなり、１ショットに要する時
間は短くなるが、金型の温度が例えば−１００℃と極め
て低くなると、金型の低温脆化や、冷却に要する費用が
高くなるという問題が生じるため、本発明においては添
加剤の融点は−ｌＯ゜Ｃ以上であることを特定する．本
発明者らの実験的知見上、例えば添加剤の融点より１０
゜Ｃ低く金型の温度を保持しておけば、肉厚が２０ｍｍ
の粉末成形体は２０分間以内に金型より取り外すことが
でき、同じ＜２０℃低くしておけば１０分間以内に取り
外すことができる．本発明に使用可能な添加剤の例を前
に記したが、これらの化合物の融点は室温より低いため
、金型の温度を添加剤の融点未満に保持するためには、
金型を冷却することが必要である．冷却の方式としては
、例えば金型をジャケット構造にするか、あるいは金型
内に冷却管を貫通させた構造にして冷媒を流すことによ
って行うことが出来る。冷媒はＲｌｌ、Ｒ１２ 、Ｒ１
３ 、Ｒ２２などのフロン系やブタン、プロバンなどの
炭化水素系などから、使用温度に応じて選定すればよい
．得られた粉末成形体より、次に添加剤をＭ敗除去させ
るが、この脱脂をするに当たり、予め粉末成形体の表面
を一部露出面として残す他は、残余を気密性がある樹脂
１ａ膜で被覆する．
かかる樹脂薄膜による被覆は、例えば溶媒が揮発するこ
とや化学反応によって固化する液状の樹脂を戊形体の表
面に直接塗布、吹き付け、もしくは浸漬一引き上げ等に
より薄く塗布し、必要により乾燥や加熱等の処理を加え
ることによって表面に樹脂膜を形威せしめることにより
実施することができる．この方法に使用可能な液状の樹
脂を列記すると例えば、ポリウレタン樹脂、シリコン樹
脂、エポキシ樹脂、アクリル樹脂、ポリエステル樹脂、
クロルプレン樹脂、フェノール樹脂等や酢酸ビニル系エ
マルジョン、スチレンブタジェン系ラテックス、アクリ
ル系エマルジョン、天然ゴムラテックスなどの工業的に
製造されている樹脂を挙げることができる。The resulting mixture of sinterable powder and additives is then press-fitted into a mold using an injection molding machine, where the cylinder temperature is set to be higher than the melting point of the additives and lower than the boiling point. The reason for this is that until the powder compact is press-fitted into the mold from a part of the cylinder,
When the additive is in liquid form, the additive and powder are separated by evaporation.
II. This is to maintain fluidity in the powder compact without causing any change. The cough composition is then press-fitted into the mold while maintaining the temperature below the melting point of the additive. The reason for this is to quickly provide the powder compact with the strength necessary to take it out from the mold. That is,
It is impossible to remove the powder compact from the mold while the powder compact retains the same fluidity as when it entered the mold. Sometimes, a powder compact needs to have the strength to allow the whole to be removed from the mold without deformation. In this way, the composition of sinterable powder and additives can be made from a fluid state. , it is necessary to transition to a solid state, and the present invention makes this possible by utilizing the phase change of the additive from liquid to solid. To this end, the present invention maintains the temperature of the mold, more specifically the temperature of the inner wall of the cavity, below the melting point of the additive;
After the additive has solidified, the powder compact is removed from the mold. Obviously, the lower the mold temperature, the shorter the time it takes for the additive to solidify and the shorter the time required for one shot, but when the mold temperature is extremely low, for example -100°C, Because of the problems of low-temperature embrittlement and high cooling costs, the present invention specifies that the melting point of the additive is -1O°C or higher. Based on the experimental findings of the present inventors, for example, 10
If you keep the mold temperature low at °C, the wall thickness will be 20mm.
The powder compact can be removed from the mold within 20 minutes, and if the temperature is kept at the same temperature <20°C, it can be removed within 10 minutes. Examples of additives that can be used in the present invention have been described above, but since the melting point of these compounds is lower than room temperature, in order to maintain the mold temperature below the melting point of the additive,
It is necessary to cool the mold. Cooling can be carried out by, for example, making the mold a jacket structure, or by having a structure in which cooling pipes are passed through the mold and allowing a coolant to flow therethrough. Refrigerant is Rll, R12, R1
3. The material may be selected from fluorocarbons such as R22 and hydrocarbons such as butane and propane, depending on the operating temperature. Next, the additives are removed from the obtained powder compact, but for this degreasing, a part of the surface of the powder compact is left as an exposed surface, and the remainder is covered with an airtight resin 1a film. Cover with For coating with such a resin thin film, for example, a liquid resin that solidifies by volatilization of a solvent or a chemical reaction is applied directly to the surface of the rod, by spraying, or by dipping and pulling, and if necessary, it is applied by drying, heating, etc. This can be done by adding a treatment to form a resin film on the surface. Liquid resins that can be used in this method include, for example, polyurethane resin, silicone resin, epoxy resin, acrylic resin, polyester resin,
Examples include industrially produced resins such as chlorprene resin, phenol resin, vinyl acetate emulsion, styrene butadiene latex, acrylic emulsion, and natural rubber latex.
さらにまた、アクリル系樹脂、エボキシ樹脂、ポリエス
テル樹脂などの中には、粉末の状態で塗布しこれを加熱
すれば該粉末が融合し塗膜となるように加工された樹脂
があり、このような樹脂も使用可能である．
被覆する薄膜の厚みは、粉末成形体の形状、粉末の粒径
、静水圧加圧の圧カ、薄膜の種類などによって適宜選定
すればよく、気密性を保つに必要な最小限の厚み以上で
あればよい。Furthermore, among acrylic resins, epoxy resins, polyester resins, etc., there are resins that are processed in such a way that when applied in a powder state and heated, the powder fuses to form a coating film. Resin can also be used. The thickness of the thin film to be coated may be selected appropriately depending on the shape of the powder compact, the particle size of the powder, the pressure of hydrostatic pressurization, the type of thin film, etc., and the thickness must be at least the minimum thickness necessary to maintain airtightness. Good to have.
本発明者らの実験的知見では、薄膜の厚みは通常１０μ
一以上であることが望ましい．また、薄膜の厚みの上限
は特に規定されるものではないが、取扱の便宜上、５開
程度までが好ましい．勿論薄膜の種類によっては、これ
以下、もしくはこれ以上の厚みのものでも実施できる。According to the experimental findings of the present inventors, the thickness of the thin film is usually 10 μm.
It is desirable that it be 1 or more. Further, the upper limit of the thickness of the thin film is not particularly defined, but for convenience of handling, it is preferably up to about 5 mm. Of course, depending on the type of thin film, the thickness may be less than or greater than this.
このような樹脂薄膜で成形体表面を被覆し、後記するよ
うに該被覆膜を静水圧加圧した状態で加熱脱脂すること
により、該樹脂薄膜は該静水圧で成形体表面に常に密着
し、また該静水圧は該薄膜を通して効果的に成形体に伝
えられ、添加物が加熱されて生じる成形体の内圧以上の
圧力で成形体を等方的に加圧することによらて粉末成形
体を損傷させることなく脱脂することができるのである
．
本発明においては、粉末成形体の表面は少なくともその
一部を被覆せずにその部分を露出させておくことが必要
である。脱脂時には、該露出面より添加剤が飛散する．
露出面の位置は、粉末成形体の形状に応じて選定すれば
よいが、金型キャビティのゲート部、即ち、金型への入
り口部に位置する部分を露出面としておけば概ね問題は
ない．露出面の面積は、この面より添加剤が飛散すると
云う要請があるため、その面積が小さすぎると脱脂に要
する時間が長くなるが、本発明者らの実験的知見による
と、露出面積は目安として全表面積の０．５〜２０％、
好ましくは１〜１０％程度の範囲で実施され、１％の露
出面積であっても、従来の方法よりもはるかに短時間に
脱脂を行うことができる．
このようにして少なくとも一部を残し残部を樹脂薄膜で
被覆された粉末成形体は、次に該被覆面を静水圧加圧し
た状態で添加剤の沸点以上に加熱する．
静水圧加圧の方法は、被覆面を液体に浸漬した状態で、
この液体をボンブなとで加圧する方法でよく、加圧用液
体としては、グリセリン、流動パラフィン、シリコンオ
イル、ポリエチレングリコール、油力作動油などがある
．また高圧の空気や窒素などの気体を用いてもよい．こ
こで静水圧加圧の圧力は粉末成形体内部の加熱された添
加剤の蒸気圧以上の圧力としておけば、粉末成形体に亀
裂などの欠陥を発生させずに添加剤を蒸発・除去するこ
とができ、添加剤の種類、加熱温度、粉末成形体の形状
などによって適宜選定されるが、この目的の達戒のため
圧力はｌ ｋｇ／ｃ＋ｍ”Ｇ以上であることが好ましい
．
また、粉末成形体を高い圧力で等方圧縮することは、粉
末充填密度を高め、焼結体の強度を高めるに極めて有効
であるが、このためには圧力を５００ｋｇ／ｃａ＋”Ｇ
以上とすべきである．但しこのような高い圧力は加熱脱
脂を行う時に絶えず付加しておく必要はなく加熱する前
あるいは加熱中に３０秒〜２分間程度高圧を付加し、加
熱を行う殆どの時間は上記したような低い圧力でよい．
この高圧付加を行うには、薄膜を形成する樹脂はある程
度弾性があることが好ましい．これは、高圧付加操作時
の温度において、樹脂のガラス転移点が該操作温度以下
のものであることなどを一応の目安とすることもできる
．
粉末成形体の設置方法としては、例えば第Ｆ図に示した
ような方法がある．即ち、通気孔ｌを設けた圧力容器２
の内壁に、通気性のある多孔体３を置き、この多孔体３
の上に粉末成形体４を置いて、粉末成形体４とその周囲
の圧力容器２の内壁面に樹脂を塗布する方法である。こ
のようにすれば多孔体３に接する粉末成形体４の表面は
薄膜で被覆してない露出面となり、この状態で被覆面の
周囲を加圧媒体で満たしこれを加圧すればよい．また、
この状態で静水圧加圧すれば、樹脂被膜面はその垂直方
向より均一な圧力を受け、多孔体３との接触面は同じ圧
力によって多孔体３に押しつけられ、粉末成形体４の表
面は全て均一な圧力を受けることになる．多孔体３には
、密度を低く留めたセラ果ツクス焼結体や焼結金属、あ
るいは黒鉛などを用いることができる．加熱温度は添加
剤の沸点以上とすることを特定するが、この理由は添加
剤を速やかに飛散させるためである．自明のことながら
加熱温度を高くすればする程、添加剤の飛散速度は増し
てくるが、一方加熱温度は樹脂被膜が・気密性及び弾性
を保有する耐熱温度以上とすることはできない．この耐
熱温度は樹脂固有の性質であり、例えばポリウレタン樹
脂では１９０゜Ｃ、シリコン樹脂では２３０℃、アクリ
ル樹脂では１７０℃が現状の最高耐熱温度である．気密
性及び弾性を保有しこれ以上の耐熱温度を保有する樹脂
は工業的に入手できないのが実状であり、このため添加
剤の沸点は１４０゜Ｃ以下の化合物であることを本発明
では特定する．
本発明者等の実験的知見上、粉末戊形体が２０ｃｃの大
きさでは沸点より３０゜Ｃ高く加熱すれば約５時間で添
加剤の９９％以上を７１敗させることができ、１００ｃ
ｃの大きさでは同じく約１０時間で可能である．また沸
点より５０゜Ｃ高く加熱すれば１００ｃｃの大きさでは
約５時間で添加剤の９９％以上を飛散させることができ
、ＩＣの大きさのものであっても約１５時間で可能であ
り、次の焼結工程を問題なく行うことができる．なお昇
温温度は任意であり、２００℃／ｈとしても何ら問題は
ない．
（発明の効果〕
本発明は沸点が１４０℃以下と従来用いられてきたポリ
エチレン、ポリブロビレンなとの射出戒形用添加剤より
も、はるかに易飛散性の化合物を添加剤として用いて射
出成形し、添加剤の凝固する性質を利用して粉末成形体
の金型からの離脱を可能にし、得られた粉末成形体を等
方加圧しながら加熱することによって、粉末成形体を損
傷させることなく添加剤を飛散させる方法であり、更に
は添加剤を飛散させた粉末成形体を引続き強熱してセラ
ミックス焼結体あるいは金属焼結体とする方法である．
本発明に従えば、易飛散性の添加剤を急速に昇温して飛
散させることが可能なため、従来の方法よりもはるかに
短時間に脱脂することができる．また従来の方法では極
めて緩慢な昇温速度においても、肉厚が２０＋ｕ＋以上
の粉末成形体になると、割れや亀裂を発生させることな
く脱脂することは不可能であったが、本発明においては
粉末成形体の大きさに限界をなくすることが可能となり
、肉厚が１００ｍｍであっても何ら問題なく脱脂が可能
である．更にまた、脱脂工程中に５００ｋｇ／ｃ＋＋＋
”Ｇ以上の高い圧力で静水圧を３０秒〜２分間程度付加
す゛れば、粉末成形体の充填密度が高くなり、引き続い
て強熱して得られる焼結体の密度及び強度は従来方法で
得られた焼結体よりも顕著に向上する．以下実施例によ
って本発明を具体的に説明する．実施例ｌ
原料粉末として平均粒子径が０．２３μの窒化ケイ素粉
末を用い、これの１００重量部に対して、焼結助剤とし
て平均粒子径が０．１８μのアルミナ粉末２重量部と、
平均粒子径が０．２８μのイットリア粉末４重量部を加
え、更に添加剤としてシクロヘキサン（融点６．５℃、
沸点８０．７’Ｃ）を粉末の実容積１に対して０．９５
となるように２４重量部加えて、ボールミルを用いて１
０時間混合した．得られた粉末と添加剤との組成物を第
２図に示した射出或形機を用いて直径５０ｍｓ、長さ１
００ｍｍの円柱状に戒形した。By coating the surface of the molded object with such a thin resin film and heating and degreasing the coating film under hydrostatic pressure as described later, the thin resin film will always adhere tightly to the surface of the molded object due to the hydrostatic pressure. In addition, the hydrostatic pressure is effectively transmitted to the compact through the thin film, and the powder compact is isotropically pressed with a pressure higher than the internal pressure of the compact produced when the additive is heated. This allows for degreasing without causing damage. In the present invention, it is necessary that at least a part of the surface of the powder compact be left uncovered and exposed. During degreasing, additives scatter from the exposed surface.
The position of the exposed surface may be selected depending on the shape of the powder compact, but there is generally no problem if the exposed surface is located at the gate of the mold cavity, that is, at the entrance to the mold. The area of the exposed surface is required to prevent additives from scattering from this surface, so if the area is too small, the time required for degreasing will be longer; however, according to the inventors' experimental findings, the exposed area is a guideline. as 0.5-20% of the total surface area,
It is preferably carried out in a range of about 1 to 10%, and even with an exposed area of 1%, degreasing can be carried out in a much shorter time than with conventional methods. The powder compact, in which at least a portion of the product is coated with a thin resin film, is then heated to a temperature above the boiling point of the additive while applying hydrostatic pressure to the coated surface. In the hydrostatic pressurization method, the coated surface is immersed in liquid,
This liquid may be pressurized using a bomb, and examples of the pressurizing liquid include glycerin, liquid paraffin, silicone oil, polyethylene glycol, and hydraulic oil. Alternatively, high-pressure air or gas such as nitrogen may be used. If the pressure of the hydrostatic pressurization is set to a pressure higher than the vapor pressure of the heated additive inside the powder compact, the additive can be evaporated and removed without causing defects such as cracks in the powder compact. The pressure is preferably selected depending on the type of additive, heating temperature, shape of the powder compact, etc., but in order to achieve this purpose, the pressure is preferably 1 kg/c+m''G or more. Isotropically compressing the body at high pressure is extremely effective in increasing the powder packing density and increasing the strength of the sintered body, but for this purpose, the pressure must be increased to 500 kg/ca+”G.
It should be more than that. However, it is not necessary to constantly apply such high pressure when performing heat degreasing; high pressure is applied for about 30 seconds to 2 minutes before or during heating, and most of the heating time is at a low temperature as mentioned above. Pressure is fine. In order to apply this high pressure, it is preferable that the resin forming the thin film has some degree of elasticity. This can be based on the fact that the glass transition point of the resin is below the operating temperature at the time of high pressure application operation. As a method for installing the powder compact, there is, for example, the method shown in Figure F. That is, a pressure vessel 2 provided with a vent l.
A breathable porous body 3 is placed on the inner wall of the
In this method, a powder compact 4 is placed on top of the powder compact 4, and a resin is applied to the powder compact 4 and the inner wall surface of the pressure vessel 2 around the powder compact 4. In this way, the surface of the powder compact 4 in contact with the porous body 3 becomes an exposed surface not covered with a thin film, and in this state, the periphery of the coated surface can be filled with a pressurizing medium and pressurized. Also,
If hydrostatic pressure is applied in this state, the resin coating surface will receive uniform pressure in the vertical direction, the contact surface with the porous body 3 will be pressed against the porous body 3 with the same pressure, and the entire surface of the powder molded body 4 will be It will receive uniform pressure. For the porous body 3, a ceramic sintered body, sintered metal, graphite, or the like, which has a low density, can be used. The heating temperature is specified to be above the boiling point of the additive, and the reason for this is to quickly disperse the additive. It is obvious that the higher the heating temperature, the faster the additive will scatter, but on the other hand, the heating temperature cannot be set higher than the heat resistance temperature at which the resin coating maintains airtightness and elasticity. This heat-resistant temperature is a property specific to the resin; for example, the current maximum heat-resistant temperature is 190°C for polyurethane resin, 230°C for silicone resin, and 170°C for acrylic resin. The reality is that resins that have airtightness and elasticity and can withstand temperatures higher than this cannot be obtained industrially, so the present invention specifies that the additive has a boiling point of 140°C or lower. ．． According to the experimental findings of the present inventors, if the powder size is 20 cc, more than 99% of the additive can be destroyed in about 5 hours by heating 30°C above the boiling point;
For the size of c, it is possible to do it in about 10 hours as well. In addition, if heated 50°C above the boiling point, more than 99% of the additive can be dispersed in about 5 hours for a 100cc size, and in about 15 hours for an IC size, The next sintering process can be carried out without any problems. Note that the heating temperature is arbitrary, and there is no problem even if it is 200°C/h. (Effects of the Invention) The present invention is capable of injection molding using a compound with a boiling point of 140°C or lower, which is much more easily shattered than the conventional injection molding additives such as polyethylene and polypropylene. By utilizing the solidifying property of the additive to enable the powder compact to be released from the mold, and by heating the resulting powder compact while applying isostatic pressure, the additive can be added without damaging the powder compact. This is a method of scattering the additive, and furthermore, a method of successively igniting the powder compact with the additive dispersed thereon to form a ceramic sintered body or a metal sintered body.According to the present invention, the easily scatterable additive Because it is possible to rapidly raise the temperature of the agent and scatter it, it is possible to degrease in a much shorter time than with conventional methods.Also, even with extremely slow heating rates in conventional methods, it is possible to achieve a wall thickness of 20+u+. It has been impossible to degrease the above powder compacts without causing cracks or cracks, but with the present invention, it has become possible to remove any limitations on the size of the powder compacts, and the wall thickness can be increased. Even if it is 100mm, it can be degreased without any problem.Furthermore, during the degreasing process, 500kg/c+++
``If hydrostatic pressure is applied at a high pressure of G or more for about 30 seconds to 2 minutes, the packing density of the powder compact will increase, and the density and strength of the sintered compact obtained by subsequent ignition will be higher than that obtained by conventional methods. The present invention will be explained in detail with reference to Examples below.Example 1 Silicon nitride powder with an average particle size of 0.23μ is used as a raw material powder, and 100 parts by weight of this powder is On the other hand, 2 parts by weight of alumina powder with an average particle size of 0.18μ as a sintering aid,
4 parts by weight of yttria powder with an average particle size of 0.28μ was added, and cyclohexane (melting point 6.5℃,
Boiling point 80.7'C) is 0.95 per 1 actual volume of powder.
Add 24 parts by weight so that
Mixed for 0 hours. The resulting composition of powder and additives was molded into a mold with a diameter of 50 ms and a length of 1 mm using an injection molding machine shown in Fig. 2.
It was shaped into a cylindrical shape with a diameter of 00 mm.
ここでシリンダー４温度は３０℃、金型ｌはジャケット
構造にしてフロン系冷媒を流すことによってキャビティ
内壁温度を−１０゜Ｃとし、射出圧力は５００ ｋｇｌ
ｃｍ”Ｇとして、ｌシッットを１５分間のサイクルで威
形した．得られた粉末成形体には外観上欠陥は全く認め
られず粉末充ｆＩ！ｔ密度は５２％であった．次に第１
図に示したように５■φの通気孔１を設けた圧力容器２
の内壁に黒鉛質多孔体３（直径５０問、厚み５ｍｌＩ１
、空隙率２５％）を設置し、多孔体３の上に粉末成形体
４を置いた状態で湿式硬化型ウレタン樹脂を粉末成形体
４、多孔体３、多孔体３の周囲５一匍の圧力容器２内壁
面にハケ塗りによって塗布し、厚さ２００μの膜を被覆
した．次に圧力容器２をグリセリンで満たし、グリセリ
ンをポンプ圧縮によって５ ｋｇ／ｃｍ”Ｇに加圧した
状態でヒーターで加熱することによって粉末成形体４を
昇温し、添加剤を通気孔１を通して大気中に飛散させた
．ここでグリセリンの加熱様式は室温より１４０℃まで
２００℃／ｈの速度で昇温し、１４０℃にて１２時間保
持し、以後自然放冷により室温まで冷却した．昇温より
室温に冷却するまでの通算時間は１６時間であった．こ
の間グリセリンは５ｋｇ７ｃｍ″Ｇに保持しておいた．
圧力容器２より取り出した粉末成形体４には、亀裂の発
生や′ｆＩｌ膜の破損といった外観上の変化は全く認め
られず、シクロヘキサンは９９％以上が飛散していた．
また籾未充填率は５３％と脱脂前よりも増加していた．
次に、この粉末戊形体４を９ ｋｇ／ｃｍ！Ｇの窒素ガ
ス雰囲気下で１９００゜Ｃに２時間加熱して窒化ケイ素
質のセラ竃ツクス焼結体を得た．得られた焼結体には欠
損は認められず密度は３． １０ｇ／ｃ−であった．こ
れは窒化ケイ素の理論密度の９７％に相当する．この焼
結体より２０片の試験片を切出し、ＪＴＳＬｌ６０１の
規定に準じて曲げ強度を測定した結果、平均強度は８１
ｋｇ／問２で標準偏差は４．８ｋｇ／ｍｍ”であった．
比較例１
実施例１と全く同様にして射出威形法で得た円柱状の窒
化ケイ素質の粉末成形体を、薄膜で被覆せずにそのまま
常圧の空気中で実施例１と全く同じ加熱様式にして加熱
し脱脂を行った．脱脂後の粉末成形体は、０．５〜２ｃ
１の大きさの多数の小片に砕け散っていた．
比較例２
実施例１で用いたと同じ窒化ケイ素粉末１００重量部と
アルξ粉末２重量部とイットリア粉末４重量部からなる
原料粉末に、従来より或形助剤として用いられているポ
リプロピレン２０重量部、ポリエチレン１０重量部、ス
テアリン酸１重量部を加え、これを混練して得た混合物
を従来の射出条件であるシリンダー４温度２００ ’Ｃ
、金型ｌ温度５０℃、射出圧力７００ｋｇ／ｃｍ”Ｇの
条件で射出戒形し、実施例１と同様に直径５０ｍｍ、長
さｌ００ＩＩＩＩ＋１円柱状成形体を得た。得られた粉
末成形体には欠陥は認められず粉体充填密度は５３％で
あった。Here, the cylinder 4 temperature is 30°C, the mold l has a jacket structure, and a fluorocarbon-based refrigerant is flowed to set the cavity inner wall temperature to -10°C, and the injection pressure is 500 kgl.
cm''G, l sit was compacted in a cycle of 15 minutes.The obtained powder compact had no defects in appearance and the powder filling fI!t density was 52%.
As shown in the figure, a pressure vessel 2 with a vent hole 1 of 5 mm diameter is provided.
Graphite porous material 3 (diameter 50, thickness 5mlI1) is placed on the inner wall of
, porosity 25%), and with the powder compact 4 placed on the porous body 3, wet curing urethane resin is applied to the powder compact 4, the porous body 3, and the surrounding area of the porous body 3 at a pressure of 1 liter. It was applied to the inner wall of container 2 by brushing to form a film with a thickness of 200 μm. Next, the pressure vessel 2 is filled with glycerin, the glycerin is pressurized to 5 kg/cm"G by pump compression, and heated with a heater to raise the temperature of the powder compact 4, and the additive is passed through the vent hole 1 into the atmosphere. Here, the heating method of glycerin was to raise the temperature from room temperature to 140°C at a rate of 200°C/h, hold it at 140°C for 12 hours, and then cool it to room temperature by natural cooling. The total time it took to cool down to room temperature was 16 hours.During this time, the glycerin was maintained at 5 kg and 7 cm''G. In the powder compact 4 taken out from the pressure vessel 2, no changes in appearance such as the occurrence of cracks or damage to the 'fIl film were observed, and more than 99% of the cyclohexane was scattered.
In addition, the percentage of unfilled paddy was 53%, which was higher than before degreasing. Next, this powdered hollow body 4 has a weight of 9 kg/cm! A silicon nitride ceramic ceramic sintered body was obtained by heating at 1900°C for 2 hours in a nitrogen gas atmosphere. No defects were observed in the obtained sintered body, and the density was 3. It was 10g/c-. This corresponds to 97% of the theoretical density of silicon nitride. Twenty test pieces were cut out from this sintered body and the bending strength was measured according to the regulations of JTSLl601, and the average strength was 81.
kg/Question 2, the standard deviation was 4.8 kg/mm''. Comparative Example 1 A cylindrical silicon nitride powder compact obtained by the injection molding method in exactly the same manner as in Example 1 was coated with a thin film. Degreasing was carried out by heating in air at normal pressure without coating using the same heating method as in Example 1.The powder compact after degreasing was 0.5-2 c
It was broken into many small pieces the size of 1. Comparative Example 2 20 parts by weight of polypropylene, which has conventionally been used as a shaping aid, was added to the raw material powder consisting of 100 parts by weight of silicon nitride powder, 2 parts by weight of Al ξ powder, and 4 parts by weight of yttria powder, which were the same as those used in Example 1. , 10 parts by weight of polyethylene, and 1 part by weight of stearic acid, and the mixture obtained by kneading these was heated to the cylinder 4 temperature of 200'C, which is the conventional injection condition.
Injection molding was carried out under the conditions of a mold temperature of 50°C and an injection pressure of 700 kg/cm''G to obtain a cylindrical molded body with a diameter of 50 mm and a length of 100 III + 1 in the same manner as in Example 1. No defects were observed and the powder packing density was 53%.
次に、この粉末成形体を従来より行われている次のよう
な、高温、長時間の加熱時間で脱脂した．すなわち室温
よりｌＯＯ℃まで２０℃／ｈで昇温、１００℃より６０
０℃まで２゜Ｃ／ｈで昇温、６００゜Ｃで２時間保持、
以降自然放冷により室温まで冷却．雰囲気は６００゜Ｃ
で２時間保持した段階では、添加剤を酸化分解させるた
めに空気雰囲気とし、この段階以外は窒素ガス雰囲気と
し圧力は大気圧とした．昇温開始より室温に冷却するま
での通算時間は２７０時間という長時間を要した．
脱脂後の粉末成形体は、長さ方向に破断面が生じた状態
で、ほぼ真二つに割れていた．
実施例ｌと比較例ｌとのヰ較より、粉末成形体の樹脂被
覆面に静水圧加圧をした状態で脱脂することが粉末成形
体の割れ防止に顕著な効果があることが分かる．
また、実施例１と従来技術の脱脂法である比較例２との
比較より、本発明では極めて短時間で粉末成形体に欠損
を生じさせることなく、脱脂ができているのに対し、従
来技術でははるかに長時間での操作を行なっても、欠損
を生じさせずに脱脂することは困難であることが分かる
．
実施例２
実施例１で射出威形法によって得たと同じ窒化ケイ素質
の粉末成形体を、樹脂被覆面に付加した静水圧の加圧様
式を変化させた以外は実施例１と全く同様にして脱脂し
、続いて１９００″Ｃに２時間加熱して焼結体を得た．
脱脂時の加熱様式は実施例１と全く同様にして室温より
１４０℃まで２００゜Ｃ／ｈの速度で昇温したが、５０
″Ｃに到達した時にグリセリンの圧力を１ ｔ／ｃｍ”
Ｇでｌ分間保持し、他の時間は実施例１と同様にして５
ｋｇ／ｃ＋ｍ”Ｇの圧力に保持し、通算１６時間で脱
脂を完了した．脱脂後の粉末成形体には欠陥は認められ
ず、粉末充填密度は５９％と脱脂前より増加していた．
これを実施例１と全く同様に加熱して得た焼結体の密度
は３． １６ｇ／ｃ−であり、これは窒化ケイ素の理論
密度の９９％に相当する。Next, this powder compact was degreased using the conventional method of heating at a high temperature for a long time. In other words, the temperature is raised from room temperature to 100°C at a rate of 20°C/h, and from 100°C to 60°C.
Raise the temperature to 0°C at 2°C/h, hold at 600°C for 2 hours,
After that, let it cool naturally to room temperature. The atmosphere is 600°C
At the stage where the additives were held for 2 hours, the atmosphere was set to air in order to oxidize and decompose the additives, and at other stages, the atmosphere was set to nitrogen gas and the pressure was set to atmospheric pressure. The total time from the start of temperature rise until cooling to room temperature was a long time of 270 hours. After degreasing, the powder compact was split almost in two, with a fracture surface occurring in the length direction. A comparison between Example 1 and Comparative Example 1 shows that degreasing while applying hydrostatic pressure to the resin-coated surface of a powder compact has a remarkable effect on preventing cracking of the powder compact. In addition, a comparison between Example 1 and Comparative Example 2, which is a conventional degreasing method, shows that the present invention can degrease the powder compact in an extremely short time without causing defects, whereas the conventional technique It can be seen that it is difficult to degrease without causing defects even if the operation is performed for a much longer time. Example 2 The same silicon nitride powder compact obtained by the injection molding method in Example 1 was produced in exactly the same manner as in Example 1, except that the pressurization mode of the hydrostatic pressure applied to the resin-coated surface was changed. It was degreased and then heated to 1900"C for 2 hours to obtain a sintered body. The heating method during degreasing was exactly the same as in Example 1, and the temperature was raised from room temperature to 140 °C at a rate of 200 °C/h. However, 50
``When reaching C, increase the pressure of glycerin to 1 t/cm''
G for 1 minute, and the other times were the same as in Example 1.
The degreasing was completed in a total of 16 hours by maintaining the pressure at kg/c+m''G. No defects were observed in the powder compacts after degreasing, and the powder packing density was 59%, which was higher than before degreasing. The density of the sintered body obtained by heating in exactly the same manner as in Example 1 was 3.16 g/c-, which corresponds to 99% of the theoretical density of silicon nitride.
この焼結体の曲げ強度を実施例１と全く同様にして測定
した結果、平均強度は９５ｋｇ／ｍ−で標準偏差は３．
８ｋｇ／＋ｕ＋”であった．
実施例３
原料粉末として平均粒子径が０．２０μの炭化ケイ素粉
末を用い、これの１００重量部に対して、焼結助剤とし
て平均粒子径が０．３２μの炭化ホウ素を０．５重量部
と、平均粒子径が０．０７μの単体炭素粉末を２重量部
加え、１５時間混合した後、更に添加剤として水を粉末
の実容積１に対して０．９となるように２９重量部加え
て、ヘンシェルξキサーを用いて室温にて２時間混合し
た．
得られた粉末と添加剤との組成物を実施例ｌと同様にし
て、射出威形機を用いて、直径５０間、長さ１００ｍｍ
の円柱状に成形した．ここでシリンダー／１度は３０℃
、キャビティ内壁温度は−２０゜Ｃ、射出圧力は５００
ｋｇ／ｃｓ”［；， １ショット１５分間とした．粉
末充填密度は５３％であった．次に実施例１と全く同様
にして、圧力容器に粉末成形体を設置し、溶媒型アクリ
ル樹脂を塗布して、厚さ１５０μの膜を被覆した．次に
圧力容器をシリコンオイルで満たし、シリコオイルをポ
ンプ圧縮によって、７ｋｇ／ｃｍ”Ｇに加圧した状態で
ヒーターで加熱することによって粉末成形体を昇温し、
添加剤を大気中に飛散させた．
ここでシリコンオイルの加熱様式は、室温よりｌ５０℃
まで３００℃／ｈの速度で昇温し、１５０℃にて１５時
間保持し、以降自然放冷により室温まで冷却した．昇温
まり室温に冷却するまでの通算時間は１９時間であった
．圧力容器より取り出した粉末成形体には欠陥は認めら
れず、粉末充填密度は５４％であった．
次に、この粉末成形体を１０− ”〜１０− ’ｍａＨ
ｇの真空中にて、２０５０℃で１時間加熱し、炭化ケイ
素質のセラミックス焼結体を得た．得られた焼結体には
欠陥は認められず、密度は３． ｌｌｇ／ｃ＋ｗ’であ
った．これは炭化ケイ素の理論密度の９７％に相当する
。The bending strength of this sintered body was measured in exactly the same manner as in Example 1, and the average strength was 95 kg/m- with a standard deviation of 3.
8 kg/+u+''. Example 3 Silicon carbide powder with an average particle size of 0.20 μm was used as the raw material powder, and 100 parts by weight of this was used as a sintering aid with an average particle size of 0.32 μm. After adding 0.5 parts by weight of boron carbide and 2 parts by weight of simple carbon powder with an average particle size of 0.07μ and mixing for 15 hours, water was further added as an additive at 0.9 parts by weight per 1 part of the actual volume of the powder. 29 parts by weight of the powder were added and mixed at room temperature for 2 hours using a Henschel 50 mm in diameter and 100 mm in length
It was formed into a cylindrical shape. Here, cylinder/1 degree is 30℃
, cavity inner wall temperature is -20°C, injection pressure is 500
kg/cs"[;, 1 shot was taken for 15 minutes. The powder packing density was 53%. Next, in the same manner as in Example 1, the powder compact was placed in a pressure vessel, and the solvent-based acrylic resin was The pressure vessel was then filled with silicone oil, and the silicone oil was compressed with a pump to a pressure of 7kg/cm"G and heated with a heater to form a powder compact. raise the temperature,
The additive was dispersed into the atmosphere. Here, the heating method of silicone oil is 150℃ from room temperature.
The temperature was raised at a rate of 300°C/h to 150°C, held at 150°C for 15 hours, and then cooled to room temperature by natural cooling. The total time from heating up to cooling to room temperature was 19 hours. No defects were observed in the powder compact taken out from the pressure vessel, and the powder packing density was 54%. Next, this powder compact was heated to 10-'' to 10-'maH.
A silicon carbide ceramic sintered body was obtained by heating at 2050°C for 1 hour in a vacuum. No defects were observed in the obtained sintered body, and the density was 3. It was llg/c+w'. This corresponds to 97% of the theoretical density of silicon carbide.
この焼結体の曲げ強度を実施例１と全く同様にして測定
した結果、平均強度は８１ｋｇ／ｃｍ”で標準偏差は４
．２ｋｇ／ｃ−であった．
実施ｆ１４
原料粉末として、平均粒子径が０．２５μのアルミナ粉
末を用い、これの１００重量部に対して焼結助剤として
平均粒子径が０．２８μのＭｇＯを０．５重量部加え、
更に添加剤としてシクロヘキサンを粉末の実容積ｌに対
して０．９５となるように加え、実施例１と全く同様に
して射出戒形した．次に実施例１と全く同様にして、ウ
レタン樹脂で被覆した状態で圧力容器に設置し、７ ｋ
ｇ／ｃｍ”Ｇの加圧空気を圧力容器２に導入して粉末成
形体４の樹脂被膜面を加圧空気で等方加圧した状態で実
施例１と全く同様な加熱様式として、添加剤を通気孔１
より大気中に飛散させた．圧力容器２より取り出した粉
末成形体４には、欠陥は認められず、シクロヘキサンは
９９％以上が飛散していた．
次にこの粉末成形体４をｌ気圧の水素雰囲気中で１７０
０゜Ｃにて２時間加熱し、アルミナ質の焼結体を得た．
得られた焼結体には欠陥は認められず、密度は３．８８
ｇ／ｃｓ’であった．これはアルξナの理論密度の９９
％に相当する．
実施例５
金属粉末として、平均粒子径が１０μのＴｉ粉末１００
重量部と、平均粒子径が１．５μのＣｏ粉末ＩＯ重量部
に添加剤としてベンゼン（融点５．５℃、沸点８０．１
”Ｃ）を粉末の実容積１に対して０．９となるように１
８．５重量部加えてボールミルを用いてｌＯ時間混合し
た．得られた金属粉末と添加剤との混合物を射出威形機
を用いて直径３０■一、長さ５０＋ｎ＋の円柱状に威形
した．ここでシリンダー４温度は２５℃、金型１の牛ャ
ビティ内壁温度−１５℃、射出圧力３５０ｋｇ／ｃｍ”
Ｇとし、１シ−ｔ７トを１０分間のサイクルで戒形した
．得られた粉末成形体には外観上欠陥は全く認められず
、粉末充填密度は５４％であった。The bending strength of this sintered body was measured in exactly the same manner as in Example 1, and the average strength was 81 kg/cm'' with a standard deviation of 4.
．． It was 2kg/c-. Implementation f14 Using alumina powder with an average particle size of 0.25μ as the raw material powder, 0.5 parts by weight of MgO with an average particle size of 0.28μ as a sintering aid was added to 100 parts by weight of the powder,
Furthermore, cyclohexane was added as an additive in an amount of 0.95 liters to the actual volume of the powder, and injection molding was carried out in exactly the same manner as in Example 1. Next, in exactly the same manner as in Example 1, it was placed in a pressure vessel while being covered with urethane resin, and 7 k
g/cm"G of pressurized air was introduced into the pressure vessel 2, and the resin coating surface of the powder compact 4 was isostatically pressurized with the pressurized air. Then, the additives were heated in exactly the same manner as in Example 1. the vent 1
It was dispersed into the atmosphere. No defects were observed in the powder compact 4 taken out from the pressure vessel 2, and more than 99% of the cyclohexane was scattered. Next, this powder compact 4 was placed in a hydrogen atmosphere of 1 atm at 170 m
It was heated at 0°C for 2 hours to obtain an alumina sintered body.
No defects were observed in the obtained sintered body, and the density was 3.88.
g/cs'. This is 99 of the theoretical density of Al ξna
It corresponds to %. Example 5 Ti powder 100 with an average particle size of 10μ as metal powder
Benzene (melting point 5.5°C, boiling point 80.1
``C) is 1 so that it is 0.9 for the actual volume of powder 1.
8.5 parts by weight were added and mixed for 10 hours using a ball mill. The resulting mixture of metal powder and additives was shaped into a cylindrical shape with a diameter of 30 mm and a length of 50 mm using an injection molding machine. Here, the cylinder 4 temperature is 25℃, the cavity inner wall temperature of mold 1 is -15℃, and the injection pressure is 350kg/cm.
G, and 1 sheet to 7 sheets were admonished in a 10 minute cycle. No defects were observed in the resulting powder compact in appearance, and the powder packing density was 54%.
次に実施例１と同様にして、５問φの通気孔１を設けた
圧力容器２の内壁に、アルミナ質多孔体（直径３０−、
厚み５■園、空隙率３０％）を設置し、多孔体３の上に
粉末成形体４を置いた状態でウレタン変性エボキシ樹脂
を、粉末成形体４、多孔体３、多孔体３の周囲５ｌＩＩ
Ｉの圧力容器２内壁にスプレーによって塗布し、厚さ１
５０μの膜を被覆した．次に圧力容器２を流動バラフィ
ンで満たし、流動バラフィンをポンプ圧縮によって、１
００ｋｇ／ｃｍ”Ｇに加圧した状態で、ヒーターで加熱
することによって粉末成形体４を昇温し、添加剤を大気
中に飛散させた．流動パラフィンの加熱様式は、室温よ
り１４０℃まで２００℃／ｈの速度で昇温し１４０℃に
て５時間保持し、以降自然放冷により室温まで冷却した
．昇温まり室温に冷却するまでの通算時間は９時間であ
った．圧力容器２より取り出した粉末成形体には欠陥は
認められず、粉末充填密度は５６％であった．
次にこの粉末成形体４を１０１〜１０−’ｍｍＨｇの真
空中で１２００゜Ｃに１時間加熱して焼結合金を得た．
得られた焼結合金には欠陥は認められず、密度は理論値
の９９．３％であった．
比較例３
実施例５で射出成形して得た円柱状の金属粉末成形体を
薄膜で被覆せずに、大気圧の空気中で実施例５と全く同
じ加熱様式にして加熱し脱脂を行った。Next, in the same manner as in Example 1, an alumina porous material (diameter 30 mm,
With the powder compact 4 placed on the porous body 3, apply urethane-modified epoxy resin to the powder compact 4, the porous body 3, and the surrounding area of the porous body 3.
Coat the inner wall of the pressure vessel 2 of I by spraying to a thickness of 1
It was coated with a 50μ film. Next, the pressure vessel 2 is filled with liquid paraffin, and the liquid paraffin is compressed by a pump.
While pressurized to 00 kg/cm"G, the temperature of the powder compact 4 was raised by heating it with a heater, and the additive was dispersed into the atmosphere. The liquid paraffin was heated at 200 °C from room temperature to 140 °C. The temperature was raised at a rate of 140 °C/h and held at 140 °C for 5 hours, and then cooled to room temperature by natural cooling.The total time from temperature rise to cooling to room temperature was 9 hours.Removed from pressure vessel 2. No defects were observed in the powder compact, and the powder packing density was 56%.Next, this powder compact 4 was heated to 1200°C for 1 hour in a vacuum of 101 to 10 mmHg to sinter it. Obtained bond money.
No defects were observed in the obtained sintered alloy, and the density was 99.3% of the theoretical value. Comparative Example 3 The cylindrical metal powder compact obtained by injection molding in Example 5 was heated and degreased in air at atmospheric pressure using the same heating method as in Example 5, without covering it with a thin film. .
脱脂後の粉末成形体は５片に割れていた．実施例６
金属粉末として、平均粒子径が５μのＦｅ粉末１００重
量部と、平均粒子径が２μのＣｕ粉末４重量部を用いる
以外は実施例５と全く同様にして射出戒形、更に脱脂を
行った後、１０−’〜１０−’ｗｌｌｇの真空中で１ｌ
００゜Ｃで１時間加熱して焼結合金を得た．得られた焼
結合金には欠陥は認められず、密度は理論値の９９．５
％であった．After degreasing, the powder compact was broken into five pieces. Example 6 Injection molding and degreasing were carried out in exactly the same manner as in Example 5 except that 100 parts by weight of Fe powder with an average particle size of 5 μm and 4 parts by weight of Cu powder with an average particle size of 2 μm were used as metal powders. After that, 1l in a vacuum of 10-' to 10-'llg.
A sintered alloy was obtained by heating at 00°C for 1 hour. No defects were observed in the obtained sintered alloy, and the density was the theoretical value of 99.5.
%Met.
第１図は本発明にて得た粉末成形体が、加圧容器に設置
された状態を示す断面図である。第２図は本発明に使用
した射出成形機の一例を示した断面図である。
第１図において、
１−−−−−−−−−−一通気孔、
２ −−−−−−−−−−−・一 圧力容器、３−−−
−・・・−・・・・・・多孔体、４−−−−一一−−−
・一 粉末成形体、５・・・・−・−・−・一・樹脂膜
、
６−−−−−−−・−・・一加圧媒体ノズル、第２図に
おいて、
ｌ−・・一・・・金型、 ６−−−−ホッパ−２・
・・−・・−・−ノズル、 マ・・−一一−−−−
ヒーター３・−・・・・一 逆流防止弁、８−・−・一
油圧モーター４・−−−−−−−−シリンダー、９−
・−・−・一射出シリンダー５−−−−−・−・・スク
リューFIG. 1 is a sectional view showing a state in which a powder compact obtained according to the present invention is placed in a pressurized container. FIG. 2 is a sectional view showing an example of an injection molding machine used in the present invention. In FIG. 1, 1----------1 ventilation hole, 2----------1 pressure vessel, 3--
−・・・−・・・Porous body, 4−−−−11−−−
・1 Powder compact, 5・・・・・・・1・Resin film, 6・・・・・・・・1 pressurized medium nozzle, in Fig. 2, 1・・・1 ...Mold, 6---Hopper-2・
・・・・・−・−Nozzle, Ma・・−１１−−−−
Heater 3 -------1 Backflow prevention valve, 8----1 Hydraulic motor 4 --------- Cylinder, 9-
・−・−・Single injection cylinder 5−−−−−・−・Screw
Claims (1)
沸点が１４０℃以下の性質を有する液状化合物を容積比
率で、該焼結性粉末１に対して０．６〜１．１加えて混
合する。 （２）該混合して得た組成物を射出成形するにおいて、
シリンダー温度を該添加剤の融点以上、沸点未満とし、
更に金型温度を該添加剤の融点未満の温度に保持した状
態で該組成物を金型に圧入する。 （３）固化した粉末成形体を射出成形機の金型より取り
出す。 （４）粉末成形体の表面を一部の露出面を残して気密性
が有り、かつ弾性のある樹脂薄膜で被覆する。 （５）該被覆した面を静水圧加圧した状態で粉末成形体
を添加剤の沸点以上に加熱し、該添加剤を該露出面を通
して飛散させる。 ２）焼結性粉末がセラミックス粉末であり、添加剤が除
去されたセラミックス粉末成形体を、引き続き強熱して
セラミックス焼結体とする特許請求の範囲第１項記載の
方法。 ３）焼結性粉末が金属粉末であり、添加剤が除去された
金属粉末成形体を、引き続き強熱して金属焼結体とする
特許請求の範囲第１項記載の方法。[Claims] 1) A method for producing a sinterable powder compact comprising the following steps:
A liquid compound having a boiling point of 140 DEG C. or less is added at a volume ratio of 0.6 to 1.1 to 1 of the sinterable powder and mixed. (2) In injection molding the composition obtained by mixing,
The cylinder temperature is set to be above the melting point and below the boiling point of the additive,
Further, the composition is press-fitted into the mold while the mold temperature is maintained at a temperature below the melting point of the additive. (3) Take out the solidified powder compact from the mold of the injection molding machine. (4) The surface of the powder compact is covered with an airtight and elastic resin thin film, leaving a part of the exposed surface. (5) The powder compact is heated to a temperature higher than the boiling point of the additive while the coated surface is subjected to isostatic pressure, and the additive is scattered through the exposed surface. 2) The method according to claim 1, wherein the sinterable powder is a ceramic powder, and the ceramic powder molded body from which additives have been removed is subsequently ignited to form a ceramic sintered body. 3) The method according to claim 1, wherein the sinterable powder is a metal powder, and the metal powder compact from which additives have been removed is subsequently ignited to form a metal sintered body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1307645A JPH03170603A (en) | 1989-11-29 | 1989-11-29 | Manufacture of sintered powder compact |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1307645A JPH03170603A (en) | 1989-11-29 | 1989-11-29 | Manufacture of sintered powder compact |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03170603A true JPH03170603A (en) | 1991-07-24 |
Family
ID=17971534
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1307645A Pending JPH03170603A (en) | 1989-11-29 | 1989-11-29 | Manufacture of sintered powder compact |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03170603A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03274202A (en) * | 1990-03-26 | 1991-12-05 | Honda Motor Co Ltd | Manufacture of molded body |
-
1989
- 1989-11-29 JP JP1307645A patent/JPH03170603A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03274202A (en) * | 1990-03-26 | 1991-12-05 | Honda Motor Co Ltd | Manufacture of molded body |
| JPH0717925B2 (en) * | 1990-03-26 | 1995-03-01 | 本田技研工業株式会社 | Molded body manufacturing method |
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