Effects of Boron Addition on the Structure and Properties of Cr-Al-Ti-N Coatings Obtained Using the CFUBMS System

The influence of boron on the structure and on the mechanical and tribological properties of protective coatings of the Cr-Al-Ti-N alloys obtained by magnetron sputtering in a closed unbalanced magnetic field using segmented planar ceramic SHS targets has been studied. The obtained coatings were examined using glow discharge optical emission spectroscopy, scanning electronic microscopy, X-ray diffraction phase analysis, nanoindentation, and tribological tests according to the pin-on-disk scheme. It has been shown that the introduction of B results in the suppression of the columnar structure and the reduction of the roughness of the coatings. Hardness, elasticity modulus, elastic recovery, wear resistance, and the coefficient of friction of coatings of the Cr-Al-Ti-B-N alloys have been determined. The introduction of 2.3 at % B leads to a high hardness (H= 15 GPa), stable friction coefficient (f= 0.65), and a decrease of the reduced wear (Vw= 7.5 x 10(-6)mm(3)/(N m)). It has been shown that the hard Cr-Al-Ti-B-N coatings of the optimal composition in their mechanical and tribological properties exceed the coatings without boron addition.