Hardness and wear resistance improvement of ABS surface by CrN thin film

Abstract

This work aims to investigate the effect of sputtering power on the hardness and wear resistance of chromium nitride (CrN) thin films deposited on the acrylonitrile butadiene styrene (ABS) substrates. These coatings were performed by a reactive DC magnetron sputtering technique. The values of sputtering power were adjusted in the range of 125-200 W. The total pressure (Pt), nitrogen partial pressure (PN2), and sputtering time were kept constant at 4×10-3 mbar, 30%, and 120 min, respectively. The surface roughness of the thin films was characterized by atomic force microscopy (AFM). The crystalline structure of these CrN thin films was studied using X-ray diffraction (XRD). The hardness and Young’s modulus of the CrN coated ABS samples were analyzed by a nanoindentation hardness test. Wear resistance tests under ambient air condition at room temperature were carried out by pin-on-disc method. The wear scars of the samples were determined by scanning electron microscope (SEM). The results showed that the hardness values were varied from 6.65 to 9.58 GPa. Young’s modulus of the samples was changed from 30.87 to 44.25 GPa. The CrN coating deposited on the ABS substrate at 175 W exhibited the highest hardness of 9.58 GPa which value is as high as that of steel. This indicated its potential and promising applications as hard coating layers for ABS plastic parts.