Microstructure and Tribological Performances of 25NiCr-Cr3C2 Coatings Prepared by Laser-Hybrid Plasma Spraying Technology

摘要

In this paper, the 25NiCr-Cr3C2 coatings are deposited on 38CrMoAl substrate by air plasma spraying and laser-hybrid plasma spraying (LHPS)technologies, the coatings microstructures and tribological performances were studied using an optical microscope, a scanning electron microscope, an X-ray diffraction, and a SRV high-temperature friction and wear tester. At the same time, the coatings bonding strength, microhardness are tested and analyzed. The test results indicate that the LHPS 25NiCr-Cr3C2 coating achieves metallurgy bonding and has higher bonding strength and higher microhardness than the air plasma spraying coating for the addition of the laser power. The laser power makes the 25NiCr-Cr3C2 powders melt more sufficiently and has good fluidity and uniformity and therefore the LHPS 25NiCr-Cr3C2 coatings microstructures become more compact and there are no big cracks and cavities in it. For the above changes, the LHPS 25NiCr-Cr3C2 coating has more excellent anti-high temperature abrasion performance and its friction coefficient is low and very stableits main failure mechanism is a good combination of mild scratching and plastic deformation.