Experimental investigation of erosion corrosion performance and slurry erosion mechanism of HVOF sprayed WC-10Co coatings using design of experiment approach

Abstract

Slurry erosion poses a serious threat which causes damage to slurry handling equipment, as it leads to substantial expenditure owing to faults, downtime and material alternative costs. High velocity oxy fuel (HVOF) spraying method engaged to deposit defensive coating, particularly cermet coating, which can enhance substrates resistance to slurry erosion. In this analysis, HVOF coated conventional composite WC-10Co coatings on the steel substrate are used. The coating structures were analysed by SEM and XRD techniques. Furthermore, micro hardness, porosity and roughness were determined. Slurry erosion testing was conducted upon this coating to investigate the effects of rotating speed, impingement angle, slurry concentration, and exposure period on erosion behaviour. Empirical correlations have been developing through RSM approaches to anticipate the loss of mass in coating. Using the five levels, central composite design matrix, four variables has been employed to reduce the number of experimental runs. The relationship established may be efficiently used to assessment of the coating erosion rate with ninety five percent level of certainty. The research outcome indicates that the rotational speed is the predominant factor preceded by impinging angle, slurry composition and time.