OPTIMIZATION OF Al-BASED AMORPHOUS COATINGS BY WARM SPRAYING BASED ON A NUMERICAL SIMULATION AND A RESPONSE-SURFACE METHODOLOGY

Al-based fully amorphous coatings with low porosity were prepared using a warm-spraying technology by combining numerical simulations and a response-surface methodology (RSM). The influences of spraying parameters (reactant flow rate, oxygen/fuel (O/F) ratio, coolant flow rate, and spraying distance) on the particle temperature and velocity were investigated using numerical simulation methods. On this basis, the response-surface equations for temperature and the velocity of the particles were established using the Box-Behnken Design (BBD) methods. The RSM was used to analyze the influence of the interactions between the spraying parameters on the temperature and the velocity of the particles. The optimum spraying parameters (OSP) predicted by the response optimizer were 0.012047 kg/s for the reactant flow rate, 0.011034 kg/s for the coolant flow rate, 2.7 for the O/F ratio, and 142 mm for the spraying distance. According to the OSP, the Al-based fully amorphous coatings with a porosity of 0.08% were obtained by warm-spraying experiments. This work provides guidance for the production of Al-based fully amorphous coatings with low porosity using warm spraying.