Papers by Author: Chung Woo Cho

Abstract: Dry sliding wear resistance of DLC coated silicon disk with different surface roughness has been evaluated using a ball-on-disk sliding tester. It was found that the transfer layer formed on steel ball produced a low friction regime and the formation of transfer layer was more active with increasing the substrate surface roughness. The wear life of DLC coating was increased as increasing the real area of contact.

Abstract: Four different multilayered coatings with different Al concentrations were deposited on AISI D2 steel. The prepared coating samples were designated as WC-Ti0.6Al0.4N, WC-Ti0.53Al0.47N, WC-Ti0.5Al0.5N and WC-Ti0.43Al0.57N. The multilayered coatings were investigated with respect to coating surface and cross-sectional morphology, roughness, adhesion, hardness, porosity and tribological behavior. Especially, wear tests of four multilayered coatings were performed by using a ball-on-disc configuration with a linear sliding speed of 0.017 m/sec and a load of 5.38N. The tests were carried out at room temperature in air by employing AISI 52100 steel ball (HR = 66) with a diameter of 10mm. The surface morphology and topography of the wear scars of samples and balls have been determined by using scanning electron spectroscopy (SEM). Results have showed an improved wear resistance of the WC-Ti1-xAlxN coatings with increasing Al concentration.