Scratch testing of ZrN coating on Ti-6Al-4V titanium alloy surface preliminary treated by compression plasma flows impact

Abstract

Investigation of compression plasma flows preliminary impact influence on adhesion of ZrN coating deposited on Ti-6Al-4V titanium alloy was carried out. Profilometry, X-ray diffraction, and scratchtesting were used as investigation techniques. The findings showed that preliminary plasma impact led to the formation of developed surface relief and synthesis of titanium nitride on the surface of the alloy. Plasma processing provided a higher critical force Lc3 during scratch tests, which increases from 44 N (without processing) to 137 N (the density of absorbed energy 26 J/cm2, 6 pulses). With a decrease in the density of absorbed energy and a growth of the number of pulses, there was a tendency of the critical force Lc3 increase, that is mainly associated with the formation of an intermediate layer δ-TiN during plasma impact, the thickness of which increased with a growth of the number of pulses and a decrease in the density of absorbed energy.