Formation Mechanism of Al₂O₃/HfO₂ Eutectic Coating on SiC Substrate Using Light Focusing Method

Abstract

In this paper, we discuss our previous experimental results and recent considerations on the preparation of solidified oxide eutectic coating on non-oxide ceramics by unidirectional solidification method using light focusing apparatus. As an example, an explanation is given here with regard to the formation mechanism of Al2O3-HfO2 eutectic coatings on SiC substrate. The Al2O3 component in oxide melt easily reacts with SiC and primary HfO2 phase solidified on SiC substrate. However, the solidified HfO2 phase also react with SiC substrate and HfC-HfO2 graded functional layer is formed on SiC substrate and Al2O3-HfO2 eutectic microstructure is formed on the graded functional layer