Study of the operational properties of strengthening metal-ceramic coating

The use of alternative fuels, including compressed natural gas, for piston internal combustion engines leads to an increased level of exhaust gas temperatures and is characterized by the absence of condensed lubricants, which leads to premature failure of the surface of the working chamfer of the timing valve. One of the options for solving this problem is the use of strengthening metal-ceramic coating of the working chamfer consisting of a nickel matrix with the addition of silicon carbide and zirconium dioxide. To assess the possibility of using this coating in real working conditions, it is necessary to conduct comprehensive tests to determine the operational properties and durability. Thus, the main purpose of the work is to study the performance properties and durability of the ceramic-metal coating in the conditions of an engine powered by compressed natural gas. The coating was formed on a short-pulse laser unit using the powder composition of the components. We carried out tribological studies and determined microhardness, surface roughness, heat resistance and durability on the stand developed by us. The studies showed an increase in the values of the performance properties of the metal-ceramic coating compared to the coating used for serial valves, which, as a result, led to a twofold increase in the durability of the exhaust valve.