Abstract
Aluminum nitride (AlN) has emerged as an important material due to its outstanding electrical and mechanical properties. Aluminum nitride is applicable for heat sink, semiconductor equipment and several structural and electrical applications. Aluminum nitride has hexagonal and cubic structures. Cubic AlN (c-AlN) is a metastable structure and an unexplored material whose properties may be quite different from those of wurtzite AlN. Synthesis of c-AlN is more difficult than h-AlN because it is metastable phase. In this study c-AlN based coatings were fabricated through the nitridation reaction between Al feedstock powders and N2 plasma in Atmospheric Plasma Spray (APS) process. The influence of changing the particle size of Al feedstock powders on nitriding rate was investigated in this study by using three different particle sizes of commercial Al powders (with average particle sizes of 30, 15 and 3 micron). The results showed that cubic AlN based coating was fabricated through nitriding of Al powder in APS process. The nitriding reaction was enhanced by using smaller particle size of Al powers that the fine particles react easier with N2 plasma than larger particles. However spraying of fine particles was more difficult than larger particles and the fabricated coating incase of finer particles have heterogeneous structure.
