| AVS 62nd International Symposium & Exhibition | |
| Tribology Focus Topic | Thursday Sessions |
| Session TR-ThP |
| Session: | Tribology Poster Session |
| Presenter: | Takuma Matsuda, Meijo UnUniversity, Japan |
| Authors: | P. Abraha, Meijo University, Japan T. Matsuda, Meijo UnUniversity, Japan |
| Correspondent: | Click to Email |
Hard thin films such as titanium nitride and titanium aluminum nitride films are widely used to improve the durability of cutting tools, punches, and dies that are extensively used in the manufacturing industries. In general, the hardness of hard coating films is about three to five times that of tool steel surfaces causing a remarkably high stress that would eventually lead to the detachment of the hard coating. One way of improving the adhesion of hard coatings is to increase the surface hardness of the tool steel, narrowing the gap, to maintain a reasonably stronger bondage.
In this research, neutral nitriding operation was performed on the SKH 51 tool steel surface before TiAlN coating. Neutral nitriding is a plasma process that allows only the neutral species to diffuse into the interstitial layer of the tool steel surface. The process delimits the formation of the undesirable brittle compound layer to a much higher treatment time while keeping the as-finished surface conditions. The scratch test was performed to provide a measure of coating/tool steel adhesion.
The results of our experiments show that in nitriding SKH 51 tool steel for 6 hours, the hardness of the tool steel surface was increased by about two times, 1400 Hv compared to the untreated sample (750 Hv). The scratch tests show that a well-defined failure of the coating occur at a higher critical load in tool steel samples that are neutral nitrided compared to samples without the pre-treatment. Our results demonstrate that neutral species based nitriding is effective for high adhesion of hard coating materials on tool steel surfaces.