Microstructure and oxidation resistance of a plasma sprayed Mo-Si-B multiphase alloy coating

摘要

A multiphase Mo-Si-B alloy coating can be successfully deposited onto the Mo-ZrC composite using a low pressure plasma spraying method. Microstructure of the plasma sprayed Mo-Si-B coating consists of Mo_5Si_3, Mo_3Si and Mo_5SiB_2 phases, which are the same constituents as Mo-Si-B alloy powder. Nanostructure is formed in the Mo-Si-B coating with the eutectic composition owing to the rapid quenching effect by plasma spraying. The oxidation behavior of the Mo-Si-B coating shows rapid mass loss followed by slow mass gain at 1673 K in Ar-20 percent O_2. Dense and adherent borosilicate glass formation passivates the coating against further oxidation at 1673 K.