Effects of reduction atmosphere and nano carbon powder addition on the deoxidization of injection molded aluminum nitride parts

Injection molded aluminum nitride parts processed using a multi-component binder yielded a residual carbon content of 1 wt.% when the parts were debound in solvent, and then thermally debound in an atmosphere of N2–3%H2 to a temperature of 500 °C. Subsequent heating in an atmosphere of N2–3%H2 to a temperature of 1500 °C caused the loss of residual carbon that was derived from the decomposition of binder. The residual carbon content consequently was insufficient to reduce the surface oxide of the aluminum nitride powder at temperatures higher than 1500 °C. Accordingly, nano carbon powder was added to enhance the deoxidization from the powder surface prior to sintering densification. A correlation between the added carbon content and the residual oxygen content in the parts could be found.