反応性プラズマ溶射法による窒化アルミニウム皮膜の作製と特性評価

摘要

Aluminum nitride (A1N) has excellent properties such as high corrosion resistance, hardness and thermal conductivity. In this study, A1N coatings were fabricated by reactive plasma spraying by using A1-A1N mixed powder for feedstock. The optimal mixing ratio of A1-A1N particles and spray conditions were investigated. A1-A1N particles were injected into Ar/N_2 plasma and were deposited onto graphite substrate. It was possible to fabricate the coatings using Al-10～40 wt.%AlN powders for feedstock. Especially, using Al-20 wt.%AlN and Al-30 wt.%AlN powders enabled to fabricate dense coatings which consisted of almost completely A1N phase. The nitride phase concentration in the coatings was controlled by RF power and N_2 gas flow rate in the plasma gas. Furthermore, it became clear that the hardness of the coatings depended on the nitride concentration in the coatings. The thermal conductivity of the coating was achieved 71.2 (W/m·K). Therefore, it was possible to fabricate A1N based coatings with high thermal conductivity by reactive plasma spraying by using Al-AlN mixed powder.%窒化アルミニウム（AlN）は化学的安定性，ハロゲンプラ ズマ等への耐性，高硬度，高熱伝導性および低熱膨張係数な どの優れた特性をもつことから，半導体製造装置やヒートシ ンク等へ応用されている．従来，AIN部材は焼結体が用い られてきたが，焼結法では大型部品や複雑形状部品への適用 は困難であり，多くの場合，AlNの持つ耐食性や熱伝導率 は部材表面に付与するだけでよい．そのため，高速成膜が可 能な溶射法によるAIN皮膜作製の需要が高まっている．し かし，AlNは安定した溶融状態をもたず高温で分解するこ とから，原料の溶融を前提とする溶射法による成膜は実質不 可能である．