Study on microstructure of the coatings sprayed in low pressure condition and its post-treatment technology

In order to make clear the effect of the spraying technology on the coatings microstructure formation in the low pressure spraying, the wires of 4Cr13, Al and Ti were adopted to prepare the spraying coatings in air and low pressure condition, respectively.The microstructure, the amount of the compounds and their distribution pattern in both coatings were compared by the micro-analysis and microarea chemical analysis.Static press test was used to investigate the closing possibility of the porosities.After the press test, the coatings was heated to certain temperature to analyze the effect of the recrystallization heat treatment on the coatings microstructure.As a result, the amount of the oxide in 4Cr13 and Al coatings has been reduced obviously in the low pressure condition, and metallurgy combination between the splat particles can be formed by pressing and heating.However the low pressure condition can not provide sufficient protection for the Ti coatings, the following recrystallization heat treatment can not get metallurgy combination between the particles.