Study of the Behavior of Mo40Si40B20 Coatings in the Temperature Range of 1000-1200 degrees C

摘要

The resistance of Mo40Si40B20 magnetron coatings to high-temperature oxidation in the 1000-1200 degrees C temperature range is investigated. The main phases of the initial coating are high-temperature beta-MoSi2 with a hexagonal lattice and t-MoB. The phase transition of beta-MoSi2 phase into the low-temperature tetragonal alpha-MoSi2 one proceeds at 1000 degrees C. After annealing, the main structural components of the coating are the t-MoSi2, t-Mo5Si3, and t-MoB phases. The size of the formed crystallites' of the t-MoSi2, t-Mo5Si3, and t-MoB phases increases 1.5-fold at 1000-1200 degrees C. The coatings oxidation is studied at 1200 degrees C in the isothermal and non-isothermal modes. After annealing on the surface, a dense oxide SiO2 layer formed and prevented the diffusion of oxygen to the substrate and its subsequent oxidation. In the case of non-isothermal annealing, the protective oxide layer's thickness increases 2.6-3.6-fold compared to that during isothermal holding for the same holding time.