Mechanical and tribological properties of hard aluminium-carbon multilayer films prepared by the Laser-Arc technique

The method of laser-induced vacuum arc (Laser-Arc) combines the good controllability of pulsed laser deposition with the high efficiency of a vacuum arc technique. One advantage of this technique is the reduction of droplets, allowing the deposition of high-quality amorphous carbon films. These hydrogen-free films, with a very high hardness, exhibit excellent wear resistance and low friction. Multilayer films consisting of aluminium and carbon were deposited on a metallic substrate (90MnV8). A Rockwell C tester was used to assess and the adhesion of the coatings to the substrate. Young moduli of around 420 GPa were measured by the non-destructive ultrasonic surface wave method (US-SAW). The coefficient of friction was investigated by using two different fretting wear tests with the same load but different frequencies and stroke lengths, and values between 0.1 and 0.25 were recorded against steel. The coatings showed an increase in adhesion and a decrease in the tribological properties with increasing aluminium content.