Abstract: An inlet valve is partially coated with a protective coating to resist corrosion and gas impingement when used in an internal combustion engine. The inlet valve has a hard cladding that is shaped to function as a valve seat. The hard cladding forms an interface with the valve head body, which is typically made of a softer metallic material than the hard cladding. The protective coating is bonded to the inlet valve and covers the cladding-body interface. The protective coating is resistant to corrosion, wear from gas impingement, and can withstand the high temperatures reached in internal combustion engines. Internal engines incorporating the valves are more durable and less susceptible to catastrophic valve failure. A method for making the inlet valves generally includes masking a portion of the valve stem and the valve seat, applying a protective coating to cladding-body interface, and curing the protective coating or otherwise bonding the protective coating to the inlet valve.

Abstract: A system for applying a coating to an engine valve and curing the coating using infrared radiation includes a spraying device, an infrared oven, and a movable track. A plurality of engine valves is transported through the system on the movable track. The spraying device applies a protective coating composition on a portion of the engine valves. The coating composition has a high emissivity value that allows the coating to be rapidly and efficiently cured as the coated engine valves travel through the infrared oven.