Fabrication of Aluminium Nitride by Electrophoretic Deposition

Abstract

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 N2 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.