H. Bangyou, Huazhong University of Science & Technology, Wuhan, China; Z. Haiou, W. Guilan, Huazhong University of Science and Technology, Wuhan, China
A rapid forming method was introduced to prepare porous coating and to control its porosity by changing spray parameters. Two models were constructed to simulate the flattening procedure of melting particle and the growth process of flatten particles on substrate. Considering the gap-pore and step-pore in the presented models, the influence of spray angle on porosity of coating was mainly investigated. The simulation results show that the porosity of coating increases with the decrease of the spray angle. When the spray angle is less than 30°, shield-pores appear in coating because of the shield-effect among melting particles. This situation results in the rapidly increasing of porosity in coating and the porosity of coating is up to 49% when the spray angle decrease to 15°. Besides spray angle, other spray parameters that potentially relate to the porosity of coating are discussed, such as the velocity of spray gun, the particle velocity and the particle size.
