INVESTIGATION OF MECHANICAL AND TRIBOLOGICAL PROPERTIES OF AMORPHOUS DIAMOND-LIKE CARBON COATINGS

We investigated the mechanical and tribological properties of amorphou s diamond-like carbon (DLC) coatings deposited on Si(100) by a pulsed bias deposition technique, Tribological studies were performed using a pin-on-disc (POD) apparatus under a normal load of 6.25 N and at 10% relative humidity, with a ruby pin as a slider. Hardness measurements were performed using a nanoindenter and apparent fracture toughness us ing indentation techniques. We studied the influence of residual stres ses on apparent fracture toughness. The data revealed that the thickne ss, hardness and compressive stress of the coating play different role s in the apparent fracture toughness. Crack initiation is influenced b y the thickness and hardness of the coating, whereas crack propagation is influenced by the compressive stress in the film. The apparent fra cture toughness of DLC coatings increased with coating hardness. (C) 1 997 Elsevier Science Ltd.