Surface Modification Of Stainless Steel By Hybrid Plasma/Ion Implantation

Stainless steel has an excellent corrosion resistance and has been widely used in many industrial fields. However, its hardness is low and frictional bearing capacity is not very good. So in many conditions it cannot meet the demand for complex properties which with good frictional and anti-corrosion performance.In this thesis, plasma immersion ion implantation (PIII) technique was applied on AISI304 stainless steel substrate to enhance its surface properties, e.g., corrosion-resistance and wear-resistance, etc. The effect of the implantation pulse voltage and pulse repetition frequency on compositions and properties of the modified layers was examined. And Ti-TiC-C graded films were prepared on AISI304 stainless steel substrate making use of metal vapor vacuum arc ion source (MEVVA) combined with plasma immersion ion implantation technique.Grazing angle X-ray diffraction (GXRD) was used to exam the phase compositions and microstructures of the films. In order to measure the proportion of each element in Ti-TiC-C graded layer, X-ray Photoelectron Spectroscopy (XPS) was utilized to study the chemical state and depth profile of elements in the layer. The friction and wear behaviors of the films were evaluated on a pin-on-disc test in normal laboratorial environment, while the corrosion resistance of the films was investigated using an electrochemical corrosion method. The effect of the implantation pulse voltage and pulse repetition frequency on compositions and properties of the resulting films was focused on.It was found that the surface micro-hardness of the steel substrate was significantly increased after the modification at proper parameters. The films (the modified layers) had much lower friction coefficient reflecting anti-wear abilities than the steel substrate. Moreover, the modified films also had much better corrosion resistance than the steel substrate. The compositions and microstructures of the modified layers were closely related to the parameters such as the implantation pulse voltage and pulse frequency. Thus it was imperative to realize the best surface modification effect of the steel by properly...