Study of surface modification of steels with ion sub-implantation and carbon diffusion process producing interface in order to improve the adhesion of DLC films

Abstract

The study of DLC (Diamond-likeCarbon) films is currently of great interest in scientific and technological community due to its properties as low coefficient of friction, high hardness, chemical inertness, possibility of deposition on metallic substrates with different shapes, obtaining in large scales and especially the high adhesion obtained on ferrous material surfaces. This single set of properties can be associated with the widest area of application as solid lubricants, protective coatings for surfaces exposed to space environment. Moreover, it is resistant to ionizing radiation, can coat surfaces exposed to aggressive chemical environments, as in the oil, alcohol and cellulose industry and can also be used as coatings for prosthetic orthopedic, dental, catheters and other applications of these areas, for being a biocompatible material, and also for having bactericidal property. Currently, at INPE, it is produced DLC films with high adherence using a pretreatment of carbonitriding. However, this process modifies the surface of most steels, exposing them to more chemical corrosion. Thus, it is proposed in this work, a detailed study to modify the steel surface only using the carbon atom and silicon atom as interface former agents between the substrates and the DLC film. Furthermore, it will be studied a mixture of the carbon diffusion process with the silicon and carbon ion sub-implantation process. It is expected to obtain an interface, with mechanical property intermediate to the substrate and the DLC film, but with formation of strong chemical bonds to ensure a high adherence. This interface will be characterized via tribological studies, with the aid of profilometry and surface analysis by MEV, XPSe and Raman scattering spectroscopy. Thus, using the PECVD technique of growing DLC films, it will be studied the greatest mixture of the Ar, H2, CH4 and SiH4 gases associated with the different ion sub-implantation parameters for the best adherence condition of the DLC films without being affected their great properties. (AU)