Tribological behavior under high temperature of BCN films deposited by sputtering-PBII hybrid system

Abstract

In this article, the results obtained from a study on the tribological behavior of boron carbon nitride (BCN) films under high temperature are reported. BCN films with different carbon concentrations (from 0 to 66.7 at%) were deposited by a sputtering-PBII hybrid system. The hardness and Young's modulus of the films were evaluated using a nanoindenter. The friction and wear behaviors of the films measured under room and high temperatures were characterized using ball-on-disk friction testing and an optical microscope. The element composition of the transfer layer formed on the ball and wear track surfaces was analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy. The results indicated that the nanohardness and Young's modulus of BCN films increased with increasing carbon concentration. A higher carbon concentration led to a lower friction coefficient when measured at room temperature. However, only the BC2.4N1.3 film showed a very low friction coefficient with a low specific wear rate when measured under high temperature. This behavior can be confirmed by the agglomerated debris and wear scars formed on the ball and wear track surfaces. Therefore, the BC2.4N1.3 film is a promising material as a protective coating to be applied in high temperature lubricating applications due to its good wear resistance and thermal stability.