Stress and mechanical properties of Ti-Cr-N gradient coatings deposited by vacuum arc

The biaxial stress, determined from X-ray Diffraction using the sin2ψ method, was compressive and varied from −2.2 to −2.7 GPa for gradient coatings grown on silicon and from −4.1 to −4.3 GPa for the samples grown on carbon steel substrates. Gradient coatings exhibited reduced internal stresses in comparison with coatings of constant composition (−3.9 and −5.6 GPa, for samples grown on Si and steel substrate, respectively). It is established that the mechanical properties (hardness and the modulus of elasticity) of gradient coatings are the superposition of the solid solutions TixCr1 − xN of different concentration (0.60 < x < 0.84 and 0.25 < x < 0.67).