Mechanical properties of TiN-TiC mixed crystal films

Deposited films of TiN-TiC systems with solid solutions were prepared over the range 0.2-0.8 in x defined by , using a RF magnetron sputtering method. Tribological properties of the samples were examined as a function of x. Microhardness increased with x, and reached maximum at around 0.7. Adhesive force between the deposited film and the substrate (high-speed steel) were measured by a scratch test. It was obtained that the adhesive force increased with x and reached maximum at about 0.5. The friction coefficient decreased monotonously with x, but showed a tendency to become minimum at 0.4-0.5. The wear rate showed a complex phenomena with the x-value, indicating two maximums at about 0.2 and 0.8.

X-ray diffraction analyses were conducted with the film samples. The change in microhardness with x was clearly associated with the physical breadth. It was found that the major part of physical breadth was due to lattice distortion in all samples. The decrease in I(111)/I(200) also related to the increase in the microhardness. Stacking faults were found to form in the film during the sputtering deposition, suggesting that vacancy platelets were generated in the sample depending on the value of the stacking probability.