Effect of deposition temperature on the microstructure and tribological properties of Si-DLC coatings prepared by PECVD

Abstract

The tribological properties of diamond-like carbon (DLC) coatings were influenced by their microstructure, which was controlled by the preparation technology and parameters. In this study, Si-DLC coatings were prepared on cemented carbide (YG10C) and stainless steel (316L) substrates by plasma enhanced chemical vapor deposition with various deposition temperatures. The effect of the deposition temperature on the microstructure and tribological properties was systematically investigated. The results showed that the sp3/sp2 values and hardness of the Si-DLC coatings increased firstly and then decreased as the deposition temperature increased from 60 °C to 180 °C, while the tendency in toughness, adhesion strength and residual stress is not consistent with it. The performance of the coatings obtained at 120 °C was best, while the coatings obtained at 150 °C had the lowest toughness due to the volume expansion caused by the transformation of sp3 to sp2. A graphite transfer layer was observed on the wear tracks of friction pairs. Thereinto, O-Si-C on the transfer layer could further reducing shear resistance and plays a role as a lubricant. Therefore, the coating prepared at the preferred deposition temperature had excellent tribological properties.