Hydrogen-free amorphous carbon coatings deposited by the arc ion-plating process

Abstract

Industry is very interested in the production of diamond and diamond-like coatings because of their unusual properties. In the meanwhile some deposition processes for diamond coatings are used industrially. These processes are carried out at high temperatures of 800–1000°C; therefore only some materials such as cemented carbides can be coated. Diamond-like amorphous carbon coatings are an alternative. These coatings show diamond-like properties and are very suitable for tribological applications. Some industrially used coating processes allow deposition temperatures of around 200°C. A relatively new method for the deposition on large substrates at low temperatures is the arc ion-plating process. In this process, carbon is evaporated and partially ionized by a high energy arc beam. The regulation of the coating properties, e.g. hardness and electrical resistance, can be achieved in a wide range by controlling such process parameters as the bias voltage or gas pressure. With the total absence of hydrogen and hydrogenous reactive gases, the growth of polymer-like parts in the coatings can be suppressed. This paper describes the deposition of amorphous diamond-like carbon coatings onto different substrate materials using the arc ion-plating process. Some characteristic properties of these coatings are shown by an example for a tribological application.