Hydrogenated amorphous carbon formation with plasma-immersion ion plating

A five-step process for the formation of hydrogenated amorphous carbon (a-C:H) with plasma-immersion ion plating apparatus on substrates such as pure titanium, stainless steel, alumina, and hydroxyl apatite is presented. This process starts with the surface cleaning by Ar/CH4 plasma bombardment, followed with carbon implantation in methane, in acetylene, then the deposition of a-C:H in acetylene, and ends with surface adjustment by nitrogen plasma sputtering. As the result of the five-step process, a typical a-C:H coating is formed with approximate thickness of 0.9 μm on a mixed interface of carbon and substrate materials up to 100 nm. The average hardness of the a-C:H is 13 GPa without statistical significance of substrate influences. The a-C:H coatings without interlayer on substrates except for hydroxyl appetite scale off soon after exposing to the air to the contrast that the coatings with interlayer show the scratch strength of adhesion up to 25 N.