The Effects of the Addition of Zr on the Mechanical and Tribological Properties of TaN Coating

This work presents the modification of the morphological, structural, chemical composition, mechanical, and tribological properties of the TaN film by the Zr addition on two substrates (Ti6Al4V and Si substrates) using DC magnetron co-sputtering. As a result, the TaN film presented a dense morphology and a structure combination of c-TaN and Ta phases, with a preferential (110) plane of the c-Ta phase. Nevertheless, adding Zr changed from denser to columnar morphology and a preferential (111) plane of the c-TaN phase related to the power applied to the Zr Target (PZr). These modifications caused the reduction of the hardness (H) and elastic modulus (E*) of the films, from values of 25.8 GPa of H and 221.5 GPa of E* for the TaN films to 18 GPa of H and 155.5 GPa for the TaZrN film at PZr = 55 W. In the same way, the failure modes and load capacity properties were modified with the addition of Zr to the TaN matrix, from buckling failure mode with LC1 of 8 N for TaN film to Chevron Tension Cracks failure mode with LC1 of 12.5 N for the TaZrN film at PZr = 45 W. Nevertheless, the wear rate decreased with the addition of Zr to TaN matrix, from 0.25 and 0.15 (m(3)/mN x 10(-12)) at 1 and 2 N of load for the surfaces coated with the TaN film to 0.12 and 0.08 (m(3)/mN x 10(-12)) at the same loads for the surfaces coated with TaZrN film at PZr = 45 W.