Application of RSM to Study the Parametric Effects on Erosion of Flame Sprayed Coatings

In the present work, Ni-base powder (EWAC1004 EN) was modified with the addition of 5%wt., and 10%wt of WC in order to develop three compositions namely 1004+0%wt WC (pure EWAC1004 EN), 1004+5%wt WC and 1004+10%wt WC respectively. These three compositions were deposited by flame spraying process. The effect of WC addition on Vickers hardness and erosive wear behavior of the deposited coatings was studied. The erosive wear behavior of flame sprayed coatings was investigated by Response Surface Methodology (RSM). To investigate and develop the erosive wear model of the flame sprayed coatings five factors; namely composition (C), velocity (V), impact angle (A), temperature (T) and feed rate (F), were used each of which was varied at three levels. Analysis of variance (ANOVA) was carried out to determine the significant factors and interactions. Investigation showed that the composition, velocity, impact angle, temperature and feed rate were the main significant factors while the composition-velocity, velocity-temperature and velocity-feed rate were the main significant interaction. Thus an erosive wear model was developed in terms of main factors and their significant interactions. The validity of the model was evaluated by conducting experiments under different wear conditions. A comparison of modeled and experimental results showed 4 - 9 % error. The WC addition improves the erosive wear resistance of the coatings. This is due to increase in hardness of the coatings.