Electrochemical Synthesis of Aluminum Nitride in Liquid Ammonia Electrolyte Solutions

Abstract

ABSTRACTAn electrochemical method for the preparation of high purity metal nitride ceramic precursors is described. Constant current electrolysis of an electrolyte solution containing NH3 and NH4Br at an Al electrode yields a solid mixture consisting of Al(NH3)6Br3 and [Al(NH2)(NH)]n after evaporation of excess NH3. Calcination of this mixture above 800 C in flowing NH3 results in sublimation of Al(NH3)6Br3 and conversion of the ceramic polymer precursor, [Al(NH2)(NH)]n, to pure, high surface area AlN. Here we discuss some electrochemical aspects of the polymer precursor synthesis, precursor processing parameters, and materials characterization of the AlN powder before and after sintering.