Preparation and Properties of Composite Oxide Hydrogen Blocking Coatings by Sintering Method

The α-Al2O3/Cr2O3/SiO2 composite coating was prepared on a 316L stainless steel sheet using ceramic sintering method. The effect of sintering temperature on the forming of the coating was studied, and the microstructure, thermal shock resistance and electrochemical hydrogen permeation of the coating were observed by XRD, SEM, thermal shock method and electrochemical hydrogen permeation test apparatus. The main research results are as follows: When sintering at 725℃ and slurry ratio is 1:5, the coating surface is uniform, no pores and cracks occur, and the average thickness is about 64μm. The microstructure analysis showed that Cr2O3 and SiO2 were uniformly distributed in the coating, Al2O3 segregation existed outside the coating, and a new phase of Al2SiO5 was produced. Compared to 316L, the coating in slurry ratio 1:5 has best hydrogen stability and thermal shock resistance with permeability reduction factor (PRF) is 15.31. In addition, the composite coating has good thermal shock resistance and can withstand 20 thermal cycles at 450℃.