Sliding wear behavior of plasma sprayed NiCrAlY-WC based composite coatings on AA5083 alloy

Abstract

WC based coatings was deposited by thermal spray process have been extensively used in industrial application to counter abrasive type of wear. In this study, for the first time NiCrAlY-WC based composite coatings were deposited on AA5083 substrate by plasma sprayed coating technique. The composite coatings were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and microhardness. Sliding wear behavior of coated and uncoated samples was carried out on pin-on-disc tribometer as per ASTM standards G99-05 by varying loads (10, 15 and 20 N), sliding distance and sliding velocity were kept constant. The results show that the high level of porosity, crack formation across the coating thickness and improved hardness. The wear resistance was increased for coated sample, irrespective of applied load. Analysis of worn surface of coated samples tested under normal loads of 10, 15 and 20 N suggest that gradual transition of adhesive to delamination type of mild wear. Whereas, uncoated samples exhibit ploughing are predominant at lower loads and severe metal flow at higher loads.
Keywords: Plasma sprayed coatings, AA5083, sliding wear behavior, NiCrAlY, WC.