High temperature oxidation, hot corrosion and friction behavior of atmospheric plasma sprayed Co-Cr-Ni-W coatings

摘要

High-temperature oxidation, hot corrosion, and wear damage will occur during the service of high -temperature alloy turbine components of engines. Cobalt - based high -temperature alloy coatings have excellent oxidation resistance, hot corrosion resistance, and wear r esistance. In this study, a Co -Cr-Ni-W alloy coating was fabricated on the surface of Inconel 718 high -temperature alloy substrate using atmospheric plasma spraying (APS) technology. The microstructure, high-temperature oxidation performance, hot corrosion performance, and friction and wear performance of the coating were investigated. The results of the high-temperature oxidation test showed that the Co -Cr-Ni-W coating exhibited superior high -temperature stability, without any damage phenomena such as spal ling and delamination. With the extension of oxidation time, two new spinel oxide phases (CoCr 2O4 and Co3O4) were generated on the coating surface to resist further oxygen erosion. Internal oxidation initiated near the coating surface and propagated toward s the coating/substrate interface. In the hot corrosion test, the Co -Cr-Ni-W coating formed CoCr 2O4 spinel oxide and Cr 2O3 oxide to resist the erosion of thermal corrosion media and oxygen. With the prolongation of thermal corrosion time, the protective ox ide on the coating surface underwent a transformation from Cr 2O3 to CoCr2O4. In the wear test, as the load increased, the friction coefficient of the Co -Cr-Ni-W coating decreased, showing excellent wear resistance. The wear mechanism of the Co-Cr-Ni-W coating featured a mixed characteristic of abrasive wear, fatigue wear, and oxidation wear.