Coated fuel injector valve

An electromagnetic fuel injector having improved wear characteristics comprises a body (11) having a fuel inlet (16) and a fuel outlet (17). A valve seat (12) is sealably connected to the body (11), and a moveable valve member (13) positioned at the fuel outlet for controlling the flow of fuel from the outlet comprises a valve outlet element (20) that provides a sealing interface with the valve seat (12). The valve member (13) and included valve outlet element (20) further comprise wear surfaces (21, 23, 24) that are subject to repeated impact and/or sliding contact; at least a portion of these wear surfaces (21, 23, 24) comprise an applied layer of diamond-like carbon (DLC) (26) stabilized by inclusion of greater than 30 weight percent of a carbide-forming material selected from the group consisting of silicon, titanium, and tungsten.