Experimental study on corrosion resistance of metal coatings for transmission line fittings

Ceramic materials with high hardness, high melting point, high corrosion resistance and other characteristics, often used in material surface strengthening modification and remanufacturing repair. In order to test the corrosion resistance of metal ceramic coatings for transmission line fittings, this paper adopts the method of salt spray accelerated corrosion equivalent soil corrosion to test four kinds of metal coating materials of WC, TiN, NiCr, Ni60, and conducts a comparative analysis from the corrosion morphology, corrosion rate alignment. The results show that: with supersonic flame spraying of WC-Co and TiN-Ni coating in 168 hours of salt spray corrosion test has been rust, and galvanized steel surface of the galvanized layer is almost not completely corroded; NiCr coating in 144h after the appearance of the phenomenon of comprehensive corrosion, but when the coating is coated with a sealer, the coating is basically not corroded in 144h, basically pitting corrosion, corrosion protection effect is very strong; Ni60 coating in the test after 144h corrosion products for the reddish brown and brown, but its corrosion product densities relative to the NiCr coating corrosive material density is higher, its surface corrosion material is less, did not appear obvious corrosion phenomenon. From the corrosion morphology analysis, Ni60 coating can effectively improve the corrosion resistance of the substrate, NiCr coating can only improve the corrosion resistance of the substrate when the surface is coated with sealer. From the corrosion rate analysis, Ni60 coating has the best anti-corrosion effect, and its corrosion effect is half of NiCr coating, one-fourth of galvanized steel, and one-tenth of Q235 steel, respectively, and the corrosion resistance of Ni60 coating is better compared with that of existing WC and TiN metal-ceramic coatings.