Effect of ultrasonic peening on the surface properties of nano-layered CrN/CrAlN coating deposited by CAPVD method on D3 tool steel

Abstract

Hard coatings are widely used in industrial applications to protect the workpiece from mechanical and chemical damage. Due to the high hardness and internal stress of most hard coatings, there is a deterioration in adhesion strength and coating performance. The aim of this study is to investigate the effect of the ultrasonic peening pre-treatment on the surface properties of a nano-layered CrN / CrAlN coating that is deposited on the AISI D3 cold-work tool steel. Cathodic arc physical vapor deposition (CAPVD) was used to apply the coating. To evaluate the surface properties of the coatings, Rockwell-C and Vickers microhardness testers, potentiodynamic polarization, and pin-on-disk were utilized. The obtained results show that the ultrasonic peening pre-treatment process has caused the compressive residual stress, reduced the surface roughness, and increased the surface hardness of the uncoated substrate. Ultrasonic peening pre-treatment of the D3 cold work steel samples has increased the wear resistance on the surface of the coated specimens by an average of 47% and, an ultrasonic power of 25% has the best conditions in terms of wear resistance. Also, in the peened sample with a power of 20%, the adhesion of the nano-layered CrN/CrAlN coating to the substrate is optimal (HF1 level), its average surface roughness has a minimum value (Ra=0.36 μm), and its corrosion resistance is improved about 33.2% rather than the base coated sample in the 3.5 wt.% NaCl solution.