Surface Treatment of Tool Steel in Controlled Plasma Nitriding Environment

Abstract

Nitriding of tool steel was investigated in a controlled electron beam excited nitrogen plasma environment. The samples were nitrided in two distinct regions, a region with high plasma density and a region with low plasma density called the irradiated and non-irradiated region, respectively. The experimental results confirm the formation of the brittle compound layer in treating the sample in the irradiated region of the process chamber whereas, the samples treated in the non-irradiated region produced diffusion based nitriding without the compound layer. The hardness measurements of the samples nitrided in both regions were more than two times the hardness of the untreated samples. The overall results of our experiments show that nitriding of tool steels can be performed in a controlled plasma nitriding environment to produce surfaces with or without the compound layer depending on the required surface.

Keywords

• plasma nitriding
• tool steel
• electron beam
• compound layer
• diffusion layer
• floating potential