JPH0428645B2 - - Google Patents
Info
- Publication number
- JPH0428645B2 JPH0428645B2 JP58184967A JP18496783A JPH0428645B2 JP H0428645 B2 JPH0428645 B2 JP H0428645B2 JP 58184967 A JP58184967 A JP 58184967A JP 18496783 A JP18496783 A JP 18496783A JP H0428645 B2 JPH0428645 B2 JP H0428645B2
- Authority
- JP
- Japan
- Prior art keywords
- aluminum nitride
- powder
- weight
- sintered body
- carbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 78
- 239000000843 powder Substances 0.000 claims description 65
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 32
- 239000002245 particle Substances 0.000 claims description 32
- 229910052799 carbon Inorganic materials 0.000 claims description 24
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 15
- 239000000203 mixture Substances 0.000 claims description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 9
- 239000002612 dispersion medium Substances 0.000 claims description 8
- 238000000227 grinding Methods 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 229920003002 synthetic resin Polymers 0.000 claims description 6
- 239000000057 synthetic resin Substances 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 5
- 229910021529 ammonia Inorganic materials 0.000 claims description 4
- 238000005245 sintering Methods 0.000 description 25
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 24
- 239000012535 impurity Substances 0.000 description 23
- 238000000034 method Methods 0.000 description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 17
- 239000001301 oxygen Substances 0.000 description 17
- 229910052760 oxygen Inorganic materials 0.000 description 17
- 239000002994 raw material Substances 0.000 description 16
- 238000002156 mixing Methods 0.000 description 15
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- 238000010304 firing Methods 0.000 description 9
- -1 Aliphatic alcohols Chemical class 0.000 description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 7
- 238000004458 analytical method Methods 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 239000006229 carbon black Substances 0.000 description 6
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 6
- 238000002834 transmittance Methods 0.000 description 6
- 239000004677 Nylon Substances 0.000 description 5
- 150000002736 metal compounds Chemical class 0.000 description 5
- 229920001778 nylon Polymers 0.000 description 5
- 238000010298 pulverizing process Methods 0.000 description 5
- 238000011109 contamination Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 241000872198 Serjania polyphylla Species 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 239000011575 calcium Substances 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 229910017052 cobalt Inorganic materials 0.000 description 3
- 239000010941 cobalt Substances 0.000 description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 229910001873 dinitrogen Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000007731 hot pressing Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 238000001272 pressureless sintering Methods 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- 229910052582 BN Inorganic materials 0.000 description 2
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 229910052779 Neodymium Inorganic materials 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 125000002091 cationic group Chemical group 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 239000011541 reaction mixture Substances 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910052712 strontium Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910052727 yttrium Inorganic materials 0.000 description 2
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- 239000011872 intimate mixture Substances 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 238000006902 nitrogenation reaction Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Landscapes
- Ceramic Products (AREA)
Description
本発明は窒化アルミニウム粉末の製造方法に関
する。
窒化アルミニウム焼結体は高熱伝導性、高耐食
性、高強度等の優れた特性を有するため各種高温
材料として注目されている。そして窒化アルミニ
ウム焼結体の性状は専ら、焼結体原料である窒化
アルミニウム粉末に依存すると言える。
窒化アルミニウム粉末は従来種々の方法で製造
されて来たが、焼結性がより良好なものの開発或
いは焼結体に透光性を与えるものの開発等が要求
されている。
本発明者等はかゝる要求を満すべく鋭意研究を
して来た。その結果、意外にも窒化アルミニウム
粉末中に含まれる不純物を極端に減少さすことに
よつてその焼結体に透光性を付与することが出来
るだけでなく焼結性を驚ろく程良くすることが出
来ることを見出した。更に窒化アルミニウム粉末
に含まれる不純物を減少さす手段について研究を
続け、本発明を完成させ提案するに至つた。
即ち、本発明は、
(i) 純度99.0重量％以上で、平均粒子径が2μｍ以
下のアルミナ粉末と、
(ii) 灰分0.2重量％以下で、平均粒子径が1μｍ以
下のカーボン粉末、
の少くとも２成分を含む粉末を、該粉末が接触す
る面が高純度アルミナ、窒化アルミニウム及び合
成樹脂からなる群から選ばれた少くとも１種の材
質で構成された粉砕混合装置を用い且つ液体分散
媒体中で混合し、次いで該混合物を窒素又はアン
モニア雰囲気下に焼成し粗窒化アルミニウム粉末
を得て、更に該粗窒化アルミニウムを酸化雰囲気
下に処理し未反応カーボンを除去することを特徴
とする窒化アルミニウム粉末の製造方法である。
本発明の最大の特徴は窒化アルミニウム焼結体
に透光性を付与する窒化アルミニウム粉末を提供
することである。従来提案されている窒化アルミ
ニウム粉末を用いても透光性を有する焼結体は得
ることが出来ず、窒化アルミニウム焼結体に透光
性を付与することが出来るとは考えられていなか
つた。ところが本発明者等の確認によれば、高純
度アルミナ及びカーボンを原料として用い、窒化
アルミニウム粉末の製造工程に於いて不可避的に
混入していた不純物の混入を防止し、しかも特定
の条件例えば液体分散媒体中で原料を混合するこ
とにより、焼結体に透光性を付与することが出来
る窒化アルミニウム粉末を得ることが出来るので
ある。かゝる知見は従来の窒化アルミニウム粉末
或いは窒化アルミニウム焼結体からは全く予想も
出来ない驚異的な現象である。
以下本発明を詳細に説明する。
従来公知の、アルミナとカーボンとを窒素又は
アンモニア雰囲気下に加熱する、いわゆるアルミ
ナ還元法は数μｍ以下の粒径の窒化アルミニウム
粉末を得ようとすれば粉砕工程の実施を回避する
ことが出来ず、また末反応アルミナ含有量を極端
に減少させることも出来なかつた。
本発明の方法によれば原料を焼成して得られる
窒化アルミニウムを粉砕する工程の実施を避ける
ことができる。粉砕工程の実施を避けることによ
つて粉砕工程で混入する不純物成分を除去出来る
し、のみならず窒化アルミニウムの表面が粉砕中
に酸化されて酸素含有量が増加することを防ぐこ
とも出来る。窒化アルミニウムの粉砕工程を省く
メリツトは以外にも極めて大きい。上記粉砕工程
を省いてしかも良好な性状の窒化アルミニウムを
得るには、前記製造工程に於けるアルミナ微粉末
とカーボン微粉末の混合を液体分散媒体中で行う
所謂湿式混合方式を採用することが肝要である。
湿式混合方式によれば、原料相互の混合を緊密に
実施出来るだけでなく、意外にも原料粒子が凝集
して粗大化する傾向を防ぐことが出来る。得られ
た緊密混合物は焼成により結果的に細粒子で且つ
粒子がそろつた窒化アルミニウムを与える。しか
も本発明方法によれば前記したように粉砕工程な
どで混入する不純物成分を完全に防ぐことが出
来、また窒化アルミニウム表面の酸化防止が出来
るので、従来方法に比べれば焼結性にすぐれ、且
つ高純度で透光性を備えた焼結体を与えることが
できる、すぐれた性状の窒化アルミニウム粉末を
製造することができる。
前記湿式混合で使用することができる液体媒体
は特に限定されず湿式混合溶媒として公知のもの
が使用出来る。一般に工業的には水、炭化水素、
脂肪族アルコール、又はこれらの混合物等が好適
に採用される。炭化水素は例えばリグロイン、石
油エーテル、ヘキサン、ベンゼン、トルエン等で
あり、脂肪族アルコールは例えばメタノール、エ
タノール、イソプロパノール等である。
また上記湿式混合は窒化アルミニウムに、焼成
したのちにも残存する不純物成分の混入を避ける
ことが出来る材質の装置中で実施することが必要
である。一般に該湿式混合は常温、常圧下で実施
することができ、温度及び圧力によつて悪影響を
うけることはない。また混合装置としては、アル
ミナやカーボンの二次凝集などの粗粒をほぐし、
更には必要により一層細かく粉砕することが有効
であるため通常粉砕混合の機能を有する構造のも
のが用いられ、更に材質から焼成後においても残
存する不純成分を生じないものを選ぶ限り、公知
の装置、例えばボールミル、ロツドミル、振盪ミ
ル、パンミル、コロイドミル、インパクトミル、
ニーダー攪拌摩砕ミル、流体エネルギーミルなど
粉砕と混合とを同時に達成し得る装置、手段を採
用しうる。例えば混合装置として球状物又は棒状
物を内臓したミルを使用するのが一般的である
が、ミルの内壁、球状物又は棒状物等の材質は、
得られる窒化アルミニウム中に焼成後においても
残存する不純物成分が混入するのを避けるため
に、窒化アルミニウム自身あるいは高純度アルミ
ナ例えば99.9重量％以上とするのがよい。また混
合装置の原料と接する面を全て合成樹脂製とする
か合成樹脂でコーテイングとすることも好適な手
段である。該合成樹脂としては焼成温度で焼失す
る限り特に限定されず例えばポリエチレン、ポリ
プロピレン、ナイロン、ポリエステル、ポリウレ
タン等が使用出来る。この場合、合成樹脂中には
安定剤として種々の金属成分を含む場合があるの
で、予めチエツクして使用するようにすべきであ
る。
また本発明方法では、その製造工程で窒化アル
ミニウム粉末の粉砕工程を省き且つ焼結性のよい
平均粒子径が2μｍ以下で且つ高純度の窒化アル
ミニウム微粉末を得るために、アルミナとカーボ
ンは特定の性状のものを使用するのが肝要であ
る。アルミナ微粉末としては平均粒子径が2μｍ
以下の微粉末のものを用いる必要があり、好まし
くは少くとも99.0重量％、より好ましくは少くと
も99.9重量％の純度のものが用いられる。カーボ
ン微粉末は灰分の含有量が最大0.2重量％、好ま
しくは最大0.1重量％の純度のものとして用いる
必要がある。また該カーボンの平均粒子径は得ら
れる窒化アルミニウムの粒子径に影響を与えるの
で、平均粒子径が1μｍ以下の微粒子として用い
る必要がある。該カーボンとしては、カーボンブ
ラツク、黒鉛化カーボンブラツク等が使用されう
るが一般にはカーボンブラツクが好ましい。
前記アルミナとカーボンの原料使用割合は、ア
ルミナおよびカーボンの純度および粒子径等の性
状によつて異なるので、予め予備テストを行い決
定するとよい。通常はアルミナとカーボンとをア
ルミナ対カーボンの重量比で１：0.36〜１：１、
好ましくは１：0.4〜１：１の範囲で湿式混合す
ればよい。該湿式混合された原料は必要により乾
燥を経て、窒素又はアンモニア雰囲気下に例えば
1400〜1700℃の温度で焼成する。該焼成する温度
が上記温度より低い場合は工業的に十分な還元窒
素化反応が進行しない傾向があり、また該焼成温
度が前記温度より高くなると得られる窒化アルミ
ニウムの一部が焼結を起し、粒子間の凝集が起る
ため目的の粒子径の窒化アルミニウムが得られ難
くなる傾向があるので予め該焼成温度は他の条件
に応じて決定するのがよい。
焼成により得られた粗窒化アルミニウム粉末
は、本発明によれば次いで酸素を含む雰囲気下で
例えば600〜900℃の温度で加熱処理され、該粗窒
化アルミニウム粉末に含まれる未反応のカーボン
を酸化して除去にする工程に付される。
かくして本発明によれば、AlN含量が少くと
も94重量％であり、結合酸素含量が最大３重量％
であり、不純物含量が最大0.5重量％（金属とし
て）である。平均粒子径2μｍ以下の高純度窒化
アルミニウム微粉末が提供される。
本発明の高純度窒化アルミニウム微粉末は
AlN含量が少くとも94重量％のものを得ること
が出来る。特にAlN含量が少くとも97重量％で
ある窒化アルミニウム微粉末は特に透光性の良好
な焼結体を与える。
本発明の窒化アルミニウム微粉末は結合酸素含
量が最大３重量％であり、不純物含量が最大0.5
重量％（金属として）のものを得ることが出来
る。該結合酸素は不純物として混入する金属と結
合した形態或いは酸化アルミニウムの形態で存在
するものと信じられる。結合酸素含量および不純
物含量は窒化アルミニウムの焼結性と得られる焼
結体の透光性に大きく影響する。結合酸素含量は
好ましくは1.5重量％であり、不純物含量は好ま
しくは最大0.3重量％（金属として）のがよい。
不純物としての金属化合物は、例えば窒化アル
ミニウムの製造原料であるアルミナおよびカーボ
ンに含有される不純物、製造工程中に溶媒・混合
装置あるいは配管等から混入する可能性がある。
かかる不純物は、例えば炭素、珪素、マンガン、
鉄、クロム、ニツケル、コバルト、銅、亜鉛又は
チタン等の金属化合物である。
本発明の窒化アルミニウム微粉末は特に好まし
くは上記の如き金属化合物を最大0.1重量％（金
属として）含有するものが好ましい。これらの不
純物のうち、未反応のアルミナ、カーボン或いは
窒化アルミニウムの表面が酸化されて酸化アルミ
ニウムに変化したもの等は本発明の窒化アルミニ
ウムの性状を、極端に悪化させるものではなく、
例えばアルミナ、カーボン、シリカ等の陽イオン
不純物が0.3〜0.5重量％程度存在しても、常圧焼
結性、焼結体の透光性等にはそれ程極端に悪い影
響を与えない。
一方、不純物としての鉄、クロム、ニツケル、
コバルト、銅、及びチタンの各成分は窒化アルミ
ニウムの焼結体の透光性に悪影響を与えるので、
これらの成分の混入を出来るだけ減少させるのが
よい。
それ故、窒化アルミニウム焼結体に十分な透光
性を与えるためには、本発明の窒化アルミニウム
微粉末は鉄、クロム、ニツケル、コバルト、銅及
びチタンを合計量で0.1重量％以下でしか含有し
ないものが好ましい。
本発明の窒化アルミニウム微粉末は、平均粒子
径が2μｍ以下のものが得られる。平均粒子径が
これより大きいと焼結性が低下する傾向が大きく
なる。本発明の窒化アルミニウム微粉末は好まし
くは平均粒子径が2μｍ以下で且つ粒径3μｍ以下
の粒子を70容量％以上の割合で含有するものとす
るのが好ましい。
本発明の窒化アルミニウムは上記の如く極めて
高純度であり、例えば結合酸素含量は好ましくは
最大1.5重量％である。従来、結合酸素含量が２
重量％より少ない窒化アルミニウム微粉末は焼結
性が充分でなく、良好な焼結性を得るためには結
合酸素含量が少くとも２重量％必要であると信じ
られていた技術水準を考慮すると、本発明の高純
度窒化アルミニウム微粉末が優れた焼結性を示す
ことは真に意外なことである。
本発明の高純度窒化アルミニウム微粉末から高
純度且つ高密度の窒化アルミニウム焼結体が提供
される。そのような窒化アルミニウム焼結体は、
本発明の高純度窒化アルミニウム微粉末を成形
し、得られた成形体を1700〜2100℃の温度で不活
性雰囲気下で焼結し、かくして窒化アルミニウム
含量が少くとも94重量％であり、結合酸素の含量
が最大1.5重量％であり、不純物としての金属化
合物の含量が金属として最大0.5重量％であり且
つ密度が少くとも2.9ｇ／cm2である本発明の窒化
アルミニウム焼結体を生成せしめることによつて
製造される。
また、上記の高密度且つ高純度窒化アルミニウ
ム焼結体は、焼結助剤を存在せしめて焼結を実施
する方法によつて製造することも好適な手段であ
る。
かかる方法は、例えば、Be，Mg，Ca，Sr，
Ba等のアルカリ土類金属；La，Ce，Pr，Nd，
Pm，Sm，Eu，Gd，Tb，Dy，Ho，Er，Tm，
Yb，Luランタン族金属およびイツトリウムより
成る群から選らばれる少くとも１種の金属の単体
又はその化合物の含量が最高原子価の酸化物とし
て0.02〜5.0重量％であり且つ前記窒化アルミニ
ウム微粉末を成形し、得られた成形体を例えば
1600〜2100℃の温度で不活性雰囲気下で焼結し、
かくして密度が少くとも3.0ｇ／cm2であり且つ透
光性を有する窒化アルミニウム焼結体を生成せし
めることによつて実施される。
本発明によれば前記焼結助剤は前記本発明の原
料であるアルミナ及びカーボンと一緒に混合して
使用することが出来る。このように焼結助剤を原
料と混合して得られる窒化アルミニウム粉末を焼
結するときも後述する焼結助剤と窒化アルミニウ
ム粉末との混合物を焼結するときと同じ焼結条件
で焼結出来る。前記焼結助剤のうち特に工業的に
しかも焼結体に透光性を付与するものを具体的に
例示すれば、カルシウム（Ca）、ストロンチウム
（Sr）、バリウム（Ba）、ランタン（La）、ネオジ
ム（Nd）、セリウム（Ce）、イツトリウム（Ｙ）
等である。
前記焼結はいわゆるホツトプレス焼結および常
圧焼結のいずれによつて行うことも出来る。ホツ
トプレス焼結に際しては加圧モールドの強度が限
界圧力となり通常は350Kg／cm2以下の圧力が選ば
れる。工業的には一般に少くとも20Kg／cm2、好ま
しくは50〜300Kg／cm2の圧力が採用される。
常圧焼結は焼結時に成形体に機械的圧力を何ん
ら加えないで、焼結を実質的に非加圧下で実施さ
れる。常圧焼結により焼結を行う場合には、生の
成形体は少くとも200Kg／cm2の加圧下、好ましく
は500〜2000Kg／cm2の加圧下で成形される。焼結
は不活性雰囲気、特に非酸化性の雰囲気、例えば
窒素等の雰囲気の下で実施される。
焼結温度は、焼結助剤を用いない方法では一般
に1700〜2100℃、好ましくは1800〜2000℃であ
り、焼結助剤を用いる第２の方法ではより低温に
おいても焼結が可能となり、1600〜2100℃、好ま
しくは1650〜2000℃である。
本発明の窒化アルミニウム粉末は透光性を有す
る窒化アルミニウム焼結体の原料となる他に例え
ばサイアロン（Sialon）系材料の原料として好適
に使用され、α−Sialon，β−Sialon，AlNポリ
タイプ（polytypes）の原料として従来のAlNを
用いては達成できなかつた高純度で特性の優れた
サイアロン化合物を与える。また透光性材料であ
るβ−Sialon，Al2O3−AlNスピネル（Spinel），
シリコンオキシナイトライドガラス
（Siliconoxynitride glass）の原料としてその透
光性の改良に寄与する。また本発明の窒化アルミ
ニウム粉末は分散性の良い均一な微粉末であるた
め、例えば炭化ケイ素などの各種セラミツクスへ
の添加助剤として、あるいはシリコーンゴム等の
ポリマーとの複合体用粉末として効果的な作用を
有する。
以下、本発明を実施例により詳細に説明するが
本発明はこれらの実施例に限定されるものではな
い。
なお、以下の実施例および比較例で用いた各種
の分析法又は分析装置は以下のものである。
陽イオン分析：プラズマ発光分光装置（第二精工
社製ICP−AES）
炭素分析：金属中炭素分析装置（堀場製作所製
EMIA−3200）
酸素分析：金属中酸素分析装置（堀場製作所製
EMGA−1300）
窒素分析：融解分離中和滴定法
Ｘ線回折装置：日本電子JRX−12VB
走査型電子顕微鏡：日本電子JSM−T200
比表面積測定装置：BET法
平均粒子径および粒度分布測定器：堀場製作所
CAPA−500
熱伝導率測定装置：理学電機レーザー法熱定数測
装置PS−７
光透過率測定装置：日立製作所製
自記分光光度計330型
赤外分光光度計260−30型
また、焼結体の光透過率は次の式で算出した。
Ｉ／Io＝（１−Ｒ）2e-〓t ……(1)
ここでIoは入射光の強さ、Ｉは透過光の強さ、Ｒ
は反射率、ｔは焼結体の厚み、μは吸収係数であ
る。Ｒは焼結体の屈折率によつて決まるもので屈
折率をｎとすれば空気中の測定ではＲは次式で表
わされる。
Ｒ＝（１−ｎ）2／（１＋ｎ）2 ……(2)
(1)式中のμが焼結体の透光性を表わす指標とな
るもので、後述の実施例において示したμの値は
(1)式に従つて計算した。
実施例 １
純度99.99％（不純物分析値を表１に示す）で
平均粒子径が0.52μｍで3μｍ以下の粒子の割合が
95vol％のアルミナ20ｇと、灰分0.08wt％で平均
粒子径が0.45μｍのカーボンブラツク10ｇとを、
ナイロン製ポツトとナイロンコーテイングしたボ
ールを用い、エタノールを分散媒体として均一に
ボールミル混合した。得られた混合物を乾燥後、
高純度黒鉛製平皿に入れ、電気炉内に窒素ガスを
３／minで連続的に供給しながら1600℃の温度
で６時間加熱した。得られた反応混合物を空気中
で750℃の温度で４時間加熱し、未反応のカーボ
ンを酸化除去した。得られた白色の粉末はＸ線回
折分析の結果、単相のAlNでありAl2O3の回析ピ
ークは無かつた。また該粉末の平均粒子径は
1.31μｍであり、3μｍ以下が90容量％を占めた。
走査型電子顕微鏡による観察ではこの粉末は平均
0.7μｍ程度の均一な粒子であつた。また比表面積
の測定値は4.0m2／ｇであつた。この粉末の分析
値を表２に示す。
The present invention relates to a method for producing aluminum nitride powder. Aluminum nitride sintered bodies are attracting attention as various high-temperature materials because they have excellent properties such as high thermal conductivity, high corrosion resistance, and high strength. It can be said that the properties of the aluminum nitride sintered body depend exclusively on the aluminum nitride powder that is the raw material for the sintered body. Aluminum nitride powder has conventionally been produced by various methods, but there is a demand for the development of a powder with better sintering properties or a powder that imparts translucency to a sintered body. The inventors of the present invention have conducted extensive research in order to meet these requirements. As a result, by dramatically reducing the impurities contained in the aluminum nitride powder, we were able to not only impart translucency to the sintered body, but also surprisingly improve sinterability. I discovered that it is possible. Furthermore, they continued their research on means of reducing impurities contained in aluminum nitride powder, and came to complete and propose the present invention. That is, the present invention provides at least the following: (i) alumina powder with a purity of 99.0% by weight or more and an average particle size of 2 μm or less; (ii) carbon powder with an ash content of 0.2% by weight or less and an average particle size of 1 μm or less A powder containing two components is mixed in a liquid dispersion medium using a grinding and mixing device in which the surface in contact with the powder is made of at least one material selected from the group consisting of high-purity alumina, aluminum nitride, and synthetic resin. An aluminum nitride powder characterized in that the mixture is mixed in a nitrogen or ammonia atmosphere to obtain a crude aluminum nitride powder, and the crude aluminum nitride is further treated in an oxidizing atmosphere to remove unreacted carbon. This is a manufacturing method. The most important feature of the present invention is to provide aluminum nitride powder that imparts translucency to aluminum nitride sintered bodies. Even with the use of aluminum nitride powders that have been proposed in the past, it has not been possible to obtain a sintered body that has translucency, and it has not been thought that it is possible to impart translucency to an aluminum nitride sintered body. However, according to the inventors' confirmation, by using high-purity alumina and carbon as raw materials, it is possible to prevent the contamination of impurities that are unavoidable in the manufacturing process of aluminum nitride powder, and under certain conditions such as liquid By mixing the raw materials in a dispersion medium, it is possible to obtain aluminum nitride powder that can impart translucency to a sintered body. Such findings are a surprising phenomenon that could not be expected from conventional aluminum nitride powder or aluminum nitride sintered bodies. The present invention will be explained in detail below. The conventionally known alumina reduction method, in which alumina and carbon are heated in a nitrogen or ammonia atmosphere, cannot avoid a pulverization step if an aluminum nitride powder with a particle size of several μm or less is to be obtained. Also, it was not possible to significantly reduce the content of end-reacted alumina. According to the method of the present invention, it is possible to avoid the step of pulverizing aluminum nitride obtained by firing raw materials. By avoiding the grinding process, impurity components mixed in during the grinding process can be removed, and it is also possible to prevent the surface of aluminum nitride from being oxidized during grinding and increasing the oxygen content. The advantages of omitting the step of crushing aluminum nitride are also extremely large. In order to obtain aluminum nitride with good properties while omitting the above-mentioned pulverization step, it is important to adopt a so-called wet mixing method in which the fine alumina powder and the fine carbon powder are mixed in a liquid dispersion medium in the manufacturing process. It is.
According to the wet mixing method, not only can the raw materials be closely mixed with each other, but also surprisingly it is possible to prevent the raw material particles from agglomerating and becoming coarse. The resulting intimate mixture is then calcined to yield fine-grained and uniformly grained aluminum nitride. Moreover, as mentioned above, the method of the present invention can completely prevent impurity components mixed in during the pulverization process, etc., and can also prevent oxidation of the aluminum nitride surface, resulting in superior sinterability compared to conventional methods. It is possible to produce aluminum nitride powder with excellent properties that can provide a sintered body with high purity and translucency. The liquid medium that can be used in the wet mixing is not particularly limited, and any known wet mixed solvent can be used. Generally, industrially, water, hydrocarbons,
Aliphatic alcohols, mixtures thereof, and the like are preferably employed. Hydrocarbons are, for example, ligroin, petroleum ether, hexane, benzene, toluene, etc., and aliphatic alcohols are, for example, methanol, ethanol, isopropanol, etc. Further, the above-mentioned wet mixing must be carried out in an apparatus made of a material that can avoid contamination of the aluminum nitride with impurity components that remain even after firing. In general, the wet mixing can be carried out at normal temperature and pressure, and is not adversely affected by temperature and pressure. In addition, as a mixing device, it loosens coarse particles such as secondary aggregation of alumina and carbon,
Furthermore, since it is effective to grind even finer if necessary, a device with a structure that has a grinding and mixing function is usually used, and furthermore, as long as the material is selected so that it does not produce any impurity components that remain even after firing, any known device can be used. For example, ball mill, rod mill, shaking mill, pan mill, colloid mill, impact mill,
Apparatus and means capable of simultaneously achieving grinding and mixing, such as a kneader stirring grinding mill and a fluid energy mill, may be employed. For example, it is common to use a mill with a built-in spherical or rod-shaped object as a mixing device, but the material of the inner wall of the mill, the spherical object, or the rod-shaped object, etc.
In order to avoid contamination of the resulting aluminum nitride with impurity components that remain even after firing, it is preferable to use aluminum nitride itself or high-purity alumina, for example, 99.9% by weight or more. It is also a suitable means to make all the surfaces of the mixing device that come into contact with the raw materials made of synthetic resin or coated with synthetic resin. The synthetic resin is not particularly limited as long as it is burned out at the firing temperature, and for example, polyethylene, polypropylene, nylon, polyester, polyurethane, etc. can be used. In this case, since the synthetic resin may contain various metal components as stabilizers, it should be checked before use. In addition, in the method of the present invention, in order to omit the pulverizing step of aluminum nitride powder in the manufacturing process and obtain high-purity aluminum nitride fine powder with an average particle size of 2 μm or less with good sinterability, alumina and carbon are It is important to use one with the same properties. The average particle size of fine alumina powder is 2μm.
It is necessary to use the following fine powder, preferably with a purity of at least 99.0% by weight, more preferably at least 99.9% by weight. The fine carbon powder must be used in a purity with an ash content of at most 0.2% by weight, preferably at most 0.1% by weight. Furthermore, since the average particle size of the carbon affects the particle size of the aluminum nitride obtained, it is necessary to use fine particles with an average particle size of 1 μm or less. As the carbon, carbon black, graphitized carbon black, etc. can be used, but carbon black is generally preferred. The raw material usage ratio of alumina and carbon varies depending on the properties of the alumina and carbon, such as their purity and particle diameter, and is therefore preferably determined by conducting a preliminary test in advance. Usually, alumina and carbon are mixed at a weight ratio of alumina to carbon of 1:0.36 to 1:1.
Preferably, wet mixing may be carried out in a range of 1:0.4 to 1:1. The wet-mixed raw materials are dried if necessary, and then dried under a nitrogen or ammonia atmosphere, for example.
Calcinate at a temperature of 1400-1700℃. If the firing temperature is lower than the above temperature, industrially sufficient reduction and nitrogenation reaction tends not to proceed, and if the firing temperature is higher than the above temperature, a part of the aluminum nitride obtained may undergo sintering. Since it tends to be difficult to obtain aluminum nitride having the desired particle size due to agglomeration between particles, it is preferable to determine the firing temperature in advance according to other conditions. According to the present invention, the crude aluminum nitride powder obtained by firing is then heat-treated at a temperature of, for example, 600 to 900°C in an atmosphere containing oxygen to oxidize unreacted carbon contained in the crude aluminum nitride powder. It is then subjected to a process of removal. Thus, according to the invention, the AlN content is at least 94% by weight and the bound oxygen content is at most 3% by weight.
with an impurity content of up to 0.5% by weight (as metal). High purity aluminum nitride fine powder with an average particle size of 2 μm or less is provided. The high purity aluminum nitride fine powder of the present invention is
AlN contents of at least 94% by weight can be obtained. In particular, aluminum nitride fine powder having an AlN content of at least 97% by weight provides a sintered body with particularly good translucency. The aluminum nitride fine powder of the present invention has a combined oxygen content of up to 3% by weight and an impurity content of up to 0.5%.
% by weight (as metal). It is believed that the bound oxygen exists in the form of a combination with a metal as an impurity or in the form of aluminum oxide. The bound oxygen content and impurity content greatly affect the sinterability of aluminum nitride and the translucency of the resulting sintered body. The bound oxygen content is preferably 1.5% by weight and the impurity content is preferably at most 0.3% by weight (as metal). Metal compounds as impurities may be, for example, impurities contained in alumina and carbon, which are raw materials for producing aluminum nitride, or may be mixed in from solvents, mixing equipment, piping, etc. during the production process.
Such impurities include, for example, carbon, silicon, manganese,
Metal compounds such as iron, chromium, nickel, cobalt, copper, zinc or titanium. The aluminum nitride fine powder of the present invention particularly preferably contains at most 0.1% by weight (in terms of metal) of the above-mentioned metal compounds. Among these impurities, unreacted alumina, carbon, or those in which the surface of aluminum nitride is oxidized and turned into aluminum oxide do not extremely deteriorate the properties of the aluminum nitride of the present invention.
For example, even if cationic impurities such as alumina, carbon, and silica are present in an amount of about 0.3 to 0.5% by weight, they do not have such an extremely negative effect on the pressureless sinterability, the translucency, etc. of the sintered body. On the other hand, iron, chromium, nickel as impurities,
Cobalt, copper, and titanium components have a negative effect on the translucency of aluminum nitride sintered bodies, so
It is preferable to reduce contamination of these components as much as possible. Therefore, in order to provide sufficient translucency to the aluminum nitride sintered body, the aluminum nitride fine powder of the present invention must contain iron, chromium, nickel, cobalt, copper, and titanium in a total amount of 0.1% by weight or less. Preferably one that does not. The aluminum nitride fine powder of the present invention has an average particle size of 2 μm or less. If the average particle diameter is larger than this, there is a greater tendency for sinterability to decrease. The aluminum nitride fine powder of the present invention preferably has an average particle size of 2 μm or less and preferably contains particles with a particle size of 3 μm or less in a proportion of 70% by volume or more. The aluminum nitride of the present invention is, as mentioned above, of very high purity, for example the combined oxygen content is preferably at most 1.5% by weight. Conventionally, the combined oxygen content is 2
Considering the state of the art, it was believed that fine aluminum nitride powder with less than 2% by weight does not have sufficient sinterability, and that a combined oxygen content of at least 2% by weight is required to obtain good sinterability. It is truly surprising that the high purity fine aluminum nitride powder of the present invention exhibits excellent sinterability. A high-purity and high-density aluminum nitride sintered body is provided from the high-purity aluminum nitride fine powder of the present invention. Such an aluminum nitride sintered body is
The high-purity aluminum nitride fine powder of the present invention is compacted and the obtained compact is sintered under an inert atmosphere at a temperature of 1700-2100°C, so that the aluminum nitride content is at least 94% by weight and the combined oxygen producing an aluminum nitride sintered body of the present invention having a content of at most 1.5% by weight of metal compounds as impurities, a content of metal compounds as impurities of up to 0.5% by weight as metal, and a density of at least 2.9 g/cm 2 Manufactured by. It is also preferable to manufacture the above-mentioned high-density and high-purity aluminum nitride sintered body by a method in which sintering is performed in the presence of a sintering aid. Such methods include, for example, Be, Mg, Ca, Sr,
Alkaline earth metals such as Ba; La, Ce, Pr, Nd,
Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm,
The content of at least one metal selected from the group consisting of Yb, Lu lanthanum group metals, and yttrium is 0.02 to 5.0% by weight as the highest valence oxide, and the aluminum nitride fine powder is molded. For example, the obtained molded body is
Sintered under an inert atmosphere at a temperature of 1600-2100℃,
This is carried out by producing a sintered aluminum nitride body having a density of at least 3.0 g/cm 2 and translucency. According to the present invention, the sintering aid can be used in combination with alumina and carbon, which are the raw materials of the present invention. When sintering the aluminum nitride powder obtained by mixing the sintering aid with the raw material in this way, the sintering conditions are the same as when sintering the mixture of the sintering aid and aluminum nitride powder, which will be described later. I can do it. Among the above-mentioned sintering aids, specific examples of those which are industrially applicable and which impart translucency to the sintered body include calcium (Ca), strontium (Sr), barium (Ba), and lanthanum (La). , neodymium (Nd), cerium (Ce), yttrium (Y)
etc. The sintering can be performed by either so-called hot press sintering or pressureless sintering. In hot press sintering, the strength of the pressure mold becomes the limiting pressure, and a pressure of 350 kg/cm 2 or less is usually selected. Industrially, pressures of at least 20 Kg/cm 2 are generally employed, preferably from 50 to 300 Kg/cm 2 . Pressureless sintering is performed without applying any mechanical pressure to the compact during sintering, and sintering is performed substantially without pressure. When sintering is performed by pressureless sintering, the green compact is molded under a pressure of at least 200 kg/cm 2 , preferably 500 to 2000 kg/cm 2 . Sintering is carried out under an inert atmosphere, in particular a non-oxidizing atmosphere, such as nitrogen. The sintering temperature is generally 1,700 to 2,100°C, preferably 1,800 to 2,000°C in the method that does not use a sintering aid, and the second method that uses a sintering aid allows sintering even at lower temperatures. The temperature is 1600-2100°C, preferably 1650-2000°C. The aluminum nitride powder of the present invention can be used not only as a raw material for translucent aluminum nitride sintered bodies, but also as a raw material for Sialon-based materials, such as α-Sialon, β-Sialon, AlN polytype ( This method provides sialon compounds with high purity and excellent properties that could not be achieved using conventional AlN as a raw material for polytypes. In addition, the transparent materials β-Sialon, Al 2 O 3 -AlN Spinel,
As a raw material for silicon oxynitride glass, it contributes to improving its translucency. In addition, since the aluminum nitride powder of the present invention is a uniform fine powder with good dispersibility, it is effective as an additive to various ceramics such as silicon carbide, or as a powder for composites with polymers such as silicone rubber. It has an effect. EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples. The various analytical methods and analytical devices used in the following Examples and Comparative Examples are as follows. Cation analysis: Plasma emission spectrometer (Daini Seiko ICP-AES) Carbon analysis: Carbon in metal analyzer (Horiba, Ltd.)
EMIA-3200) Oxygen analysis: Metal oxygen analyzer (manufactured by Horiba, Ltd.)
EMGA-1300) Nitrogen analysis: Melting separation neutralization titration method Manufacturer
CAPA-500 Thermal conductivity measuring device: Rigaku laser method thermal constant measuring device PS-7 Light transmittance measuring device: Hitachi Self-recording spectrophotometer model 330 Infrared spectrophotometer model 260-30 The light transmittance was calculated using the following formula. I/Io=(1-R) 2 e - 〓 t ...(1) Here, Io is the intensity of incident light, I is the intensity of transmitted light, and R
is the reflectance, t is the thickness of the sintered body, and μ is the absorption coefficient. R is determined by the refractive index of the sintered body, and if the refractive index is n, R is expressed by the following equation when measured in air. R=(1-n) 2 /(1+n) 2 ...(2) μ in formula (1) is an index representing the translucency of the sintered body, and μ is shown in the examples below. value is
Calculated according to formula (1). Example 1 The purity is 99.99% (impurity analysis values are shown in Table 1), the average particle diameter is 0.52 μm, and the proportion of particles of 3 μm or less is
20 g of alumina of 95 vol% and 10 g of carbon black with an ash content of 0.08 wt% and an average particle size of 0.45 μm,
Using a nylon pot and a nylon-coated ball, the mixture was uniformly mixed in a ball mill using ethanol as a dispersion medium. After drying the resulting mixture,
It was placed in a flat plate made of high-purity graphite and heated at a temperature of 1600° C. for 6 hours while continuously supplying nitrogen gas at a rate of 3/min into an electric furnace. The resulting reaction mixture was heated in air at a temperature of 750° C. for 4 hours to oxidize and remove unreacted carbon. As a result of X-ray diffraction analysis, the obtained white powder was found to be single-phase AlN and had no Al 2 O 3 diffraction peak. Also, the average particle size of the powder is
The diameter was 1.31 μm, and 90% of the volume was 3 μm or less.
When observed using a scanning electron microscope, this powder has an average
They were uniform particles of about 0.7 μm. Further, the measured value of the specific surface area was 4.0 m 2 /g. The analytical values of this powder are shown in Table 2.
【表】【table】
【表】
上記と同様な方法で得られた窒化アルミニウム
粉末1.0ｇを直径20mmのBN（窒化ホウ素）でコー
テイングした黒鉛ダイスに入れ高周波誘導加熱炉
を用い１気圧の窒素ガス中100Kg／cm2の圧力下で、
2000℃の温度で２時間ホツトプレスした。得られ
た焼結体はやや黄味を帯びたち密な半透明体であ
つた。この焼結体の密度は3.26ｇ／cm2であり、又
Ｘ線回折分析によれば単相のAlNであつた。こ
の焼結体の分析値を表３に示す。この焼結体の熱
伝導率は67W／ｍ・Ｋでり、またこの焼結体を厚
さ0.5mmに加工研摩したものの光透過率は6μｍの
波長に対して16％（吸収係数μ＝34cm-1）であつ
た。また上記と同条件でホツトプレスした直径40
mm、厚さ約３mmの円板から切り出した約2.8×３
×35mmの角柱状試料の３点曲げ強度をクロスヘツ
ドスピード0.5mm／min、スパン30mm、1200℃の
条件で測定した結果平均41.5Kg／mm2であつた。[Table] 1.0 g of aluminum nitride powder obtained in the same manner as above was placed in a graphite die coated with BN (boron nitride) with a diameter of 20 mm, and heated to 100 kg/cm 2 in nitrogen gas at 1 atm using a high-frequency induction heating furnace. under pressure,
Hot pressing was carried out at a temperature of 2000°C for 2 hours. The obtained sintered body was a slightly yellowish, dense, translucent body. The density of this sintered body was 3.26 g/cm 2 , and according to X-ray diffraction analysis, it was single-phase AlN. Table 3 shows the analytical values of this sintered body. The thermal conductivity of this sintered body is 67 W/m・K, and the light transmittance of this sintered body processed and polished to a thickness of 0.5 mm is 16% for a wavelength of 6 μm (absorption coefficient μ = 34 cm -1 ). In addition, diameter 40 was hot pressed under the same conditions as above.
mm, approximately 2.8×3 cut from a disk approximately 3 mm thick
The three-point bending strength of a 35 mm x 35 mm prismatic sample was measured at a crosshead speed of 0.5 mm/min, a span of 30 mm, and 1200°C, and the average was 41.5 Kg/mm 2 .
【表】
実施例 ２
実施例１で用いたものと同じアルミナ20ｇとカ
ーボン８ｇをポリエチレン製ポツトとボールを用
い水を分散媒体として用いた以外は実施例１と同
様に均一に混合した。得られた混合物を乾燥後、
高純度黒鉛製平皿に入れ炉内に窒素ガスを３／
minで連続的に供給しながら1550℃の温度で６時
間加熱した。得られた反応混合物を空気中で800
℃の温度で４時間加熱し未反応のカーボンを除去
した。得られた粉末のAlN含有量は95.8wt％で酸
素含有量は2.1wt％であつた。また該AlN粉末の
陽イオン不純物量は実施例１の表２に示したもの
とほぼ同レベルであつた。またこの粉末の平均粒
子径は1.22μで、3μｍ以下が92容量％を占めた。
上記で得られたAlN粉末（１ｇ）を実施例１
で用いた同一の焼結装置および条件でホツトプレ
スした。得られた焼結体はやや黄味を帯びた密度
3.25ｇ／cm2の半透明体であり、AlN含有量が
96.8wt％、酸素含有量が1.3wt％であつた。この
焼結体の熱伝導率は52W／ｍ・Ｋであり、また該
焼結体を厚さ0.5mmに加工研摩したものの光透過
率は6μｍの波長に対して11％（μ＝41cm-1）であ
つた。さらに該焼結体の曲げ強度を実施例１と同
条件で測定した結果、1200℃で平均35.5Kg／mm2で
あつた。
実施例 ３
純度99.3％で平均粒子径が0.58μｍのアルミナ
20ｇと灰分0.15wt％で平均粒子径が0.44μｍのカ
ーボンブラツク16ｇとをナイロン製ポツトとボー
ルを用い、ヘキサンを分散媒体として実施例１と
同様に均一に混合した。得られた混合物を乾燥
後、高純度黒鉛製平皿に入れ、炉内にアンモニア
ガスを１／minで連続的に供給しながら1650℃
の温度で４時間加熱した。得られた反応物を空気
中で750℃の温度で６時間加熱し未反応のカーボ
ンを酸化除去した。該粉末の平均粒子径は1.42μ
ｍであり3μｍ以下が84容量％を占めた。該粉末
の分析結果を表４に示す。
上記で得られたAlN粉末（１ｇ）を実施例１
で用いたと同じ焼結装置および焼結条件でホツト
プレスした。得られた焼結体は灰色がかつた半透
明体で密度は3.26ｇ／cm3，AlN含有量が97.9％、
酸素含有量が0.8％であつた。またこの焼結体の
熱伝導率は50W／ｍ・Ｋであり、0.5mmの厚みに
加工研摩したものの6μｍの光に対する透過率は
６％（μ＝53cm-1）であつた。[Table] Example 2 20 g of alumina and 8 g of carbon, which were the same as those used in Example 1, were mixed uniformly in the same manner as in Example 1, except that a polyethylene pot and ball were used and water was used as the dispersion medium. After drying the resulting mixture,
Place it in a high-purity graphite flat plate and fill the furnace with nitrogen gas.
The mixture was heated at a temperature of 1550°C for 6 hours while being continuously fed at a temperature of 1550°C. The resulting reaction mixture was heated in air for 800 min.
C. for 4 hours to remove unreacted carbon. The AlN content of the obtained powder was 95.8 wt% and the oxygen content was 2.1 wt%. Further, the amount of cationic impurities in the AlN powder was approximately at the same level as shown in Table 2 of Example 1. The average particle diameter of this powder was 1.22 μm, and particles of 3 μm or less accounted for 92% by volume. Example 1 The AlN powder (1 g) obtained above was
Hot pressing was performed using the same sintering equipment and conditions used in . The obtained sintered body has a slightly yellowish density.
It is a semi-transparent body with a weight of 3.25g/ cm2 and an AlN content of
The oxygen content was 96.8wt%, and the oxygen content was 1.3wt%. The thermal conductivity of this sintered body is 52 W/m・K, and the light transmittance of the sintered body processed and polished to a thickness of 0.5 mm is 11% for a wavelength of 6 μm (μ = 41 cm -1 ). Further, the bending strength of the sintered body was measured under the same conditions as in Example 1, and as a result, it was found to be an average of 35.5 Kg/mm 2 at 1200°C. Example 3 Alumina with a purity of 99.3% and an average particle size of 0.58 μm
20 g of carbon black with an ash content of 0.15 wt% and an average particle diameter of 0.44 μm were uniformly mixed in a nylon pot and ball in the same manner as in Example 1 using hexane as a dispersion medium. After drying the resulting mixture, it was placed in a flat plate made of high-purity graphite and heated at 1650°C while continuously supplying ammonia gas at a rate of 1/min into the furnace.
The mixture was heated at a temperature of 4 hours. The resulting reaction product was heated in air at a temperature of 750° C. for 6 hours to oxidize and remove unreacted carbon. The average particle size of the powder is 1.42μ
3 μm or less accounted for 84% by volume. The analysis results of the powder are shown in Table 4. Example 1 The AlN powder (1 g) obtained above was
Hot pressing was performed using the same sintering equipment and sintering conditions as used in . The obtained sintered body was a grayish semi-transparent body with a density of 3.26 g/cm 3 and an AlN content of 97.9%.
The oxygen content was 0.8%. The thermal conductivity of this sintered body was 50 W/m·K, and the transmittance for light of 6 μm was 6% (μ=53 cm -1 ) even though it was processed and polished to a thickness of 0.5 mm.
【表】【table】
【表】
実施例 ４
実施例１で用いたのと同じ純度（99.99wt％）
のアルミナ130ｇと灰分0.08wt％のカーボンブラ
ツク65ｇおよび平均粒子径1μｍのY2O30.52ｇを
ポリウレタン樹脂でコーテイングしたポツトとボ
ールを用いてエタノールを分散媒体として均一に
ボールミル混合した。この混合物を乾燥後、実施
例１と同じ条件で反応、酸化しAlN粉末を得た。
得られた粉末の平均粒子径は1.50μｍであり3μｍ
以下が83容量％を占めた。この粉末の分析値を表
５に示す。[Table] Example 4 Same purity as used in Example 1 (99.99wt%)
130 g of alumina, 65 g of carbon black with an ash content of 0.08 wt%, and 0.52 g of Y 2 O 3 with an average particle size of 1 μm were uniformly mixed in a ball mill using ethanol as a dispersion medium using a pot and ball coated with a polyurethane resin. After drying this mixture, it was reacted and oxidized under the same conditions as in Example 1 to obtain AlN powder.
The average particle size of the obtained powder was 1.50 μm and 3 μm.
The following accounted for 83% of the capacity. Table 5 shows the analytical values of this powder.
【表】【table】
【表】
実施例 ５
実施例１に於けるナイロン製ポツトの代りに実
施例１と同様にして得られた窒化アルミニウム粉
末を用いて成形焼結した窒化アルミニウム製ポツ
トを用いた以外は実施例１と同様に実施した。そ
の結果は実施例１で得られた窒化アルミニウム粉
末とほゞ同じものが得られた。次いでこの窒化ア
ルミニウム粉末を用いて実施例１と同様にして焼
結体を得た。得られた窒化アルミニウム焼結体を
厚さ0.5mmに加工研摩したものの光透過率は6μｍ
の波長に対して16％であつた。
また上記窒化アルミニウム製ポツトに代り
99.99％の高純度アルミナ製のポツトを用い上記
同様に実施した。その結果は上記と同様であつ
た。
実施例 ６
実施例４に於けるY2O3に代つて表６に示す添
加物をそれぞれ加えた以外は実施例４と同様に実
施した。その結果は表６に示す窒化アルミニウム
焼結体を得た。[Table] Example 5 Example 1 except that instead of the nylon pot in Example 1, an aluminum nitride pot formed and sintered using aluminum nitride powder obtained in the same manner as in Example 1 was used. It was carried out in the same way. The results were almost the same as the aluminum nitride powder obtained in Example 1. Next, a sintered body was obtained in the same manner as in Example 1 using this aluminum nitride powder. The obtained aluminum nitride sintered body was processed and polished to a thickness of 0.5 mm, and the light transmittance was 6 μm.
It was 16% for the wavelength of Also, instead of the aluminum nitride pot mentioned above,
The same procedure as above was carried out using a pot made of 99.99% high purity alumina. The results were the same as above. Example 6 The same procedure as Example 4 was carried out except that the additives shown in Table 6 were added in place of Y 2 O 3 in Example 4. As a result, aluminum nitride sintered bodies shown in Table 6 were obtained.
Claims (1)
ｍ以下のアルミナ粉末と、 (ii) 灰分0.2重量％以下で、平均粒子径が1μｍ以
下のカーボン粉末、 の少くとも２成分を含む粉末を、該粉末が接触
する面が高純度アルミナ、窒化アルミニウム及
び合成樹脂からなる群から選ばれた少くとも１
種の材質で構成された粉砕混合装置を用い且つ
液体分散媒体中で混合し、次いで該混合物を窒
素又はアンモニア雰囲気下に焼成し粗窒化アル
ミニウム粉末を得て、更に該粗窒化アルミニウ
ムを酸化雰囲気下に処理し未反応カーボンを除
去することを特徴とする窒化アルミニウム粉末
の製造方法。[Claims] 1 (i) Purity of 99.0% by weight or more and average particle size of 2μ
(ii) carbon powder with an ash content of 0.2% by weight or less and an average particle size of 1 μm or less; and at least one selected from the group consisting of synthetic resins.
The mixture is mixed in a liquid dispersion medium using a grinding mixer made of different materials, and then the mixture is fired in a nitrogen or ammonia atmosphere to obtain a crude aluminum nitride powder. A method for producing aluminum nitride powder, characterized by treating it to remove unreacted carbon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58184967A JPS6077111A (en) | 1983-10-05 | 1983-10-05 | Production of aluminum nitride powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58184967A JPS6077111A (en) | 1983-10-05 | 1983-10-05 | Production of aluminum nitride powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6077111A JPS6077111A (en) | 1985-05-01 |
| JPH0428645B2 true JPH0428645B2 (en) | 1992-05-14 |
Family
ID=16162480
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58184967A Granted JPS6077111A (en) | 1983-10-05 | 1983-10-05 | Production of aluminum nitride powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6077111A (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61178409A (en) * | 1985-01-30 | 1986-08-11 | Nippon Cement Co Ltd | Production of aluminum nitride powder |
| JPS61286266A (en) * | 1985-06-13 | 1986-12-16 | 住友電気工業株式会社 | Manufacture of aluminum nitride base sintered body |
| JPH0647447B2 (en) * | 1985-09-30 | 1994-06-22 | 株式会社東芝 | Method for producing aluminum nitride powder |
| CA1276775C (en) * | 1986-12-16 | 1990-11-27 | Hachiro Ichikawa | Process for producing an aluminum nitride powder |
| JPH01100006A (en) * | 1987-10-14 | 1989-04-18 | Nippon Light Metal Co Ltd | Production of aluminum nitride powder |
| US4975260A (en) * | 1988-04-18 | 1990-12-04 | Toshiba Ceramics Co., Ltd. | Process for preparing metal nitride powder |
| US5049367A (en) * | 1988-10-05 | 1991-09-17 | Sumitomo Chemical Co., Limited | Aluminum nitride powder and process for preparation of the same |
| US4983553A (en) * | 1989-12-07 | 1991-01-08 | The Dow Chemical Company | Continuous carbothermal reactor |
| US5112579A (en) * | 1989-12-07 | 1992-05-12 | The Dow Chemical Company | Continuous carbothermal reactor |
| US5100846A (en) * | 1990-09-13 | 1992-03-31 | The Dow Chemical Company | Purification of carbothermally produced aluminum nitride |
| WO2017079878A1 (en) * | 2015-11-09 | 2017-05-18 | 深圳市博世知识产权运营有限公司 | Method for preparing composite powder of aluminium oxide and aluminium nitride |
| KR102175711B1 (en) * | 2017-08-11 | 2020-11-06 | 주식회사 엘지화학 | Method of Preparing the Spherical Shape Aluminum Nitride Powder |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6060910A (en) * | 1983-09-14 | 1985-04-08 | Tokuyama Soda Co Ltd | Manufacture of aluminum nitride |
-
1983
- 1983-10-05 JP JP58184967A patent/JPS6077111A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6060910A (en) * | 1983-09-14 | 1985-04-08 | Tokuyama Soda Co Ltd | Manufacture of aluminum nitride |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6077111A (en) | 1985-05-01 |
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