| AVS 58th Annual International Symposium and Exhibition | |
| Tribology Focus Topic | Thursday Sessions |
| Session TR-ThP |
| Session: | Tribology Focus Topic Poster Session |
| Presenter: | Petros Abraha, Meijo University, Japan |
| Authors: | P. Abraha, Meijo University, Japan J. Miyamoto, Meijo University, Japan |
| Correspondent: | Click to Email |
Tribological properties play significant role on the performance of tool steel surfaces. Here, application of electron beam excited plasma nitriding and its effect on tribological properties is described. The technique eliminates the formation of the brittle and rough compound layer that is common in nitriding processes. The hardening process is done through diffusion of the plasma species in to the subsurface of the treated material without altering the initial surface finish. The applications of the process can be in areas of hard coating where adhesion of the coating material with the tool steel is of significant importance.
The experimental tool steel material is SKD 61 with a chemical composition of 0.36% C, 5.05% Cr, 1.21% Mo, 0.83% V, 0.92% Si, 0.43% Mn, 0.008% P, >0.001% S, Fe bal. The sample was heat treated, hardened and triple tempered to a hardness of 630 Hv. The sample was then treated in a nitrogen plasma produced by a beam current of 8 A under a working pressure of 0.4 Pa. The temperature was set at 500 degrees centigrade throughout the treatment time. The experimental set up includes bias terminals that reduce the ion density within the vicinity of the tool steel material. This is done to reduce nitriding due to ion and increase the chance of nitriding due to neutral species within the plasma. The cross sectional hardness distributions and wear measurements of the nitrided tool steels were examined to determine the mechanical and tribological surface properties. The surface has no trace of the compound layer that is usually observed in the ion nitriding processes. This is also confirmed from the X-ray Diffraction peaks, as there is no visible Fe3N and Fe4N peaks observed. These results are attractive as they open new areas of application especially in the coating industry where adhesion remains to be the limiting factor in lots of the hard coatings that protect cutting and forming tools against wear.