Oxidation Behavior and Structural Transformation of (CrTaTiVZr)N Coatings

(CrTaTiVZr)N coatings were prepared on Si substrates through the reactive magnetron sputtering system to investigate the oxidation behaviors and structural evolution of the coatings at different annealing temperatures in air. The (CrTaTiVZr)N coating had a face-centered cubic structure with an oxidation temperature of up to 300 °C, but its surface changed into the amorphous oxide phase and then into the rutile TiO2 phase when the annealing temperature was increased to 500 °C. The rutile TiO2 phase continued to grow, and an additional solid solution phase of body-centered tetragonal I41/amd was formed at annealing temperatures beyond 600 °C. The high annealing temperature promoted the oxidation to progress along the thickness direction and synergistically developed the porosity. As a result, the hardness and the electrical performance of the coating deteriorated. The hardness decreased from 34.30 GPa to 1.52 GPa, and the electrical resistivity increased from 142 µΩ·cm to 17.5 Ω·cm.