Evaluation the effect of process parameters on the velocity of HVOF thermally sprayed WC-Co particles

The thermal spray parameters of WC-12%Co coatings deposited using HVOF System were investigate with the purpose of particle velocity optimization. The main purpose of this study was to determine whether the Taguchi approach could be used for optimization of the particle velocity. The peening stress, bonding of particles to substrate or previously coated layer andthe deposition efficiency were directly related to the impact velocity. This, in turn, makes possible the select of the key thermal spraying parameters to have HVOF sprayed coatings with desired residual stress states and deposition efficiency together. The particle velocity in impact has been studied using spray watch system. In this study the values of particle wit h four replications for each trial and the mean effect were recorded for the 9 runs (L9 array). The Taguchi approach for experiments with replication prefers the use of signal to noise ratio (SNR). The quality characteristic was chosen to be bigger the better. Analysis of variance (ANOVA) was used to identify the most significant factors and the contribution portion of each factor.