Effects of substrate temperature on physical properties of amorphous carbon film synthesized under atmospheric pressure

There has been growing demands for amorphous carbon film which is well known as diamond-like carbon film, to be used in sliding parts of mechanical components due to their excellent physical properties. They are generally synthesized under low-pressure using expensive vacuum technology. Therefore the demand for films grows at a sluggish pace. However, the demand for films can expand substantially if it is possible to synthesize films which have excellent physical properties under atmospheric pressure.In this paper, we synthesized amorphous carbon films on high-speed steel substrates under atmospheric pressure and used C2H2 and He mixture gas for process gas. From our previous study, the films synthesized under atmospheric pressure were not hard enough to apply for mechanical components. Therefore, we synthesized amorphous carbon films by heating the substrate to drive surface reaction and improve their hardness. In the result, we succeeded to synthesize the film of which the hardness was 2.6 GPa.