Key Factors Influencing the Gas and Nozzle Outlet Temperature in Cold Spray

Cold spray is comparatively novel thermal spray process with high potential for the additive manufacturing of metallic materials. It has several unique characteristics - most notably, the process does not require any melting or fusion of the processed materials and the substrate. The powder is accelerated by a gas flow and forms dense layers on impact due to the high kinetic energy. The chamber temperature is the most known parameter in cold spray alongside the pressure of the process gas. The set chamber temperature has a crucial effect on the gas flow and its velocity and, thus, the build quality. However, in addition to the chamber temperature, other parameters, such as the nozzle material and the powder gas flow rate, also influence the parameters of the gas flow. The cause-effect relationships are not yet fully understood. This paper describes the influence of the nozzle material on the outlet gas temperature and its effect on the particle velocity.