电泳沉积制备氮化铝陶瓷的研究

采用电泳沉积法成功制备相对密度达到61.9%的均匀氮化铝素坯, 经无压烧结后可获得热导率为200W/(m·K)的氮化铝陶瓷. 研究表明, 以无水乙醇为溶剂、加入0.1wt%聚丙烯酸（PAA）做分散剂、pH值控制在9.7左右的悬浮液具有最佳分散性. 电泳沉积（EPD）成型比干压成型制备的预烧体孔容减小, 比湿法成型制得的预烧体大孔显著减少. 用扫描电子显微镜（SEM）对三种不同成型方法制得氮化铝陶瓷的显微结构进行了研究, 结果表明, EPD法所得氮化铝陶瓷的显微结构均匀, 晶粒尺寸5μm左右.

Fabrication of Aluminium Nitride by Electrophoretic Deposition

The electrophoretic deposition (EPD) technique was developed to prepare AlN green body with a relative density of 61.9%. The thermal conductivity of the fabricated AlN ceramics was 200W/(m·K) by pressureless sintering at 1800℃ for 4h in N_2 atmosphere. Well-dispersed, stable suspensions were obtained using ethanol as suspension media and polyacrylic acid (PAA) as dispersant, the pH value being around 9.7. In the case of the EPD of AlN green body, the dependence of the deposit mass on the experimental parameters was investigated in detail. By EPD from the AlN suspension, green body with a high homogeneity of the particle coordination was produced. Pore size distribution indicated that AlN calcined body prepared by EPD had smaller pore size and lower cumulative volume than those fabricated by slip casting or CIP. SEM observations show that microstructure of the AlN ceramics prepared by EPD was homogeneous and the grain size was about 5μm. The results show that electrophoretic deposition is a promising way to obtain AlN ceramics.