Fracture Toughness of HVOF Thermally Sprayed WC-12Co Coating in Optimized Particle Temperature

In this paper the fracture toughness of WC-12Co coatings in optimum particle temperature in high velocity oxy fuel (HVOF) process have been studied by means of Vickers indentation. Multiple linear regression model applying Minitab, were used to determine the relationship and interaction between HVOF parameters and particle temperature. For genetic algorithm optimization, the signal to noise ratio was applied as a functional output of design of experiments. The results of validation test show a good agreement between obtained optimum condition and the results of genetic algorithm. The fracture toughness obtained by Vickers indentation shows the direct effect of particle temperature on coating toughness. The maximum amount of signal-to-noise using the genetic algorithm for velocity and temperature is 53.07 and -64.62, which equals 450.2 m/s and 1702 ºC respectively. The results show that the Fracture toughness of WC-12Co deposited by LPG fuel in smallest level of temperature is 2.83MPa(m)1/2 compared to 1.32MPa(m)1/2 in highest temperature. The spray watch diagnostic system, micro-hardness test, Vickers indentation, X-Ray diffraction, EDS and scanning electron microscopy have been used for this purpose.