SELF-LUBRICATING THIN FILMS FOR TOOL STEELS

Specimens made from Vanadis 6 cold work tool steel were machined, ground, heat processed by standard regime and finally mirror polished. After that, they were layered with CrAgN. The Ag-content in the layers was chosen to 3 wt% and 15 wt% respectively. Microstructural analysis revealed that the addition of 3 wt%Ag did not influence the growth manner of the films but the addition of 15 wt%Ag has made considerable changes in the film growth. The layer with 3 wt%Ag had excellent adhesion on the steel substrate. On the other hand, the addition of 15%Ag had strongly negative impact on the coating adhesion. Similar effect of different Ag addition has been established also to both the hardness and the Young modulus of the films, also. Both films have superior tribological properties against hard material (alumina) as well as against soft counterpart (CuSn6 as-cast bronze).