鉄鋼の窒化処理への沿面放電プラズマの応用

抄録

We have been studying the surface discharge plasma generated by insulating capillary tube as an ablation gun for depositing diamond-like carbon films. It is found in our series of experiments that applying a positive voltage to the gun of the system allows us to fill the entire chamber with plasma. In this study, we propose a new application of the surface discharge technique for plasma nitriding of steel.
Nitriding experiments under various temperatures were carried out for SKH51 high speed steel substrate. The hardness of the specimen nitrided at 500°C was the highest in this work. Nitriding depth of the specimen seemed to be more than 40μm. Although X-ray diffraction measurements showed no distinguishable nitride diffraction peaks, the hard X-ray photoelectron spectroscopy (HXPS) measurements suggested the presence of Cr-N and W-N chemical bonds in the nitrided SKH51 steel. Furthermore, so-called “white layer (Fe_2-3N)” or damage were not found on the surface of nitrided specimens. It can be concluded that this technique can be one of the most superior techniques for nitriding steel.