Hard coatings for mechanical applications

Thin film hard coatings are produced by either intensive ion bombardment of surfaces during the deposition of hard materials or ion bombardment (primarily nitrogen) of metallic surfaces, under vacuum conditions. These techniques can be applied to mechanical tools, pieces subjected to wear and surfaces needing protective coatings such as optical recording devices and fibres. We describe an experiment combining physical and chemical vapour deposition to produce hard coatings for mechanical applications. The system comprises a hybrid plasma process combining reactive magnetron sputtering and ion beam bombardment from a capacitively coupled rf ion source in a vacuum chamber. To illustrate the results, a carbon target was used to deposit amorphous carbon (a-C) and amorphous carbon nitride (a-CN) thin films using a variable Ar and N(2) gas mixture. These were then compared with films produced by rf-plasma CVD. Single and multilayer structures of these materials were produced and characterized. The deposition techniques are compared in terms of film properties and their own parameters. (C) 2002 Elsevier Science Ltd. All rights reserved.