Salt spray corrosion test of micro-plasma oxidation ceramic coatings on Ti alloy

摘要

Ceramic coatings were prepared on Ti-6Al-4V alloy in NaAlO_2 solution by micro-plasma oxidation (MPO). The salt spray tests of the coated samples and the substrates were carried out in a salt spray test machine. The phase composition and surface morphology of the coatings were investigated by XRD and SEM. Severe corrosion occurred on the substrate surface, while there were no obvious corrosion phenomena on the coated samples. The coatings were composed of Al_2TiO_5 and a little α-Al_2O_3 and rutile TiO_2, and the salt spray test did not change the composition of the coatings. The weight loss rate of the coatings decreased with increasing MPO time because of the increase in density and thickness of the coatings. The surface morphology of the coatings was influenced by salt spray corrosion test. Among the coated samples, the coating prepared for 2 h has the best corrosion resistance under salt spray test.