THE INFLUENCE OF A GLOW DISCHARGE TREATMENT ON SURFACE MODIFICATION AND OUTGASSING RATE OF STAINLESS STEEL AND TITANIUM ALLOYS

摘要

The aim of these investigations is to characterize surfaces of metallic samples modified by different discharge techniques. Outgassing measurements were carried out and the results were correlated with the results of chemical surface analyses. In first experiments the influence of an ac gas discharge on the outgassing rates of titanium alloys was studied. It was shown that the applied discharge technique had nearly no influence on the outgassing rate of these alloys. Furthermore we exposed stainless steel samples to electrons, argon and oxygen ions either in a de glow discharge or ina microwave discharge. If was found that the de glow discharge in an Ar/O-2 mixture had the strongest effect on the reduction of the outgassing rate in comparison to the other plasma treatments. The surfaces of the treated samples were investigated with respect to the topography and the chemical composition (depth profile) by SEM, AES and XPS. At the treatment parameters chosen, the incorporation of oxygen by the de glow discharge is much more effective in comparison to microwave discharge. It was verified that an oxidation of Fe and Cr appeared under this reactive plasma treatment up to a depth of 15 nm. [References: 10]