On the hydrogenated silicon carbide (SiCx:H) interlayer properties prompting adhesion of hydrogenated amorphous carbon (a-C:H) deposited on steel

摘要

This work reports a systematic study of physicalechemical properties of SiCx:H interlayers deposited by using tetramethlysilane on AISI 4140 at different temperatures (100 ℃e550 ℃) and its effects on the adhesion of a-C:H thin films. The bi-layers were obtained by pulsed-DC PECVD assisted by electrostatic confinement. The results show that the thickness of the SiC_x:H interlayer exponentially decreases as the deposition temperature increases, i.e., a thermally activated kinetic process controls the global chemical reaction in the interlayer. There is a transition temperature (~300 ℃) for interlayer deposition where adhesion of a-C:H is reached. Above ~300 ℃, the a-C:H thin films show critical loads to wedge spallation from 298 (300 ℃) to 478 mN (550 ℃). At higher temperatures, H and Si contents decrease whereas C content increases in the interlayer. The improved adhesion is associated with the nature of chemical bonds formed in the interlayer.