Current Distribution Model and Control Principle of MgAION Composites by Spark Plasma Sintering (SPS)

摘要

The current distribution had remarkable effect on the microstructure and properties of MgAION composites in the process of spark plasma sintering (SPS). MgAlON composites, using alumina, magnesia and aluminum as starting materials, were prepared by SPS. Based on the current distribution method, the current distribution model on samples and single grain was established, and the basic electric current control principle was analyzed. It was found that the current conveyance by sample could be expressed by I_s = 0.229BI/(5 + 3.993 × 10~(-4)); the current conveyance by single Al grain could be expressed by I_(Al) =5.537 × 10~(-7)I/(B + 3.993 × 10~(-4)). In which, B was the Al volume fraction and I was the total current. When the Al volume fraction was controlled within 12%, the current conveyance by sample increased significantly with the Al addition increasing. Meanwhile, the current conveyance by single Al grain decreased significantly. The sintering speed and properties of MgAlON composites by SPS would show a significantly change.