Effect of the Shape Factor on the Cold-Spraying Dynamic Characteristics of Sprayed Particles

Silicon powder was chosen to be deposited by cold spraying for the consideration of possible applications in lithium ion batteries. The influence of the silicon particle shapes other than spherical on the impact velocity and temperature for different working parameters of the gas streams have been numerically investigated by using computational fluid dynamics modeling. The results show that, for same equivalent diameter, the particle impact velocities increase to a maximum velocity when the shape factor increases to a certain value and then decreases to the impact velocity of spherical particles. In the cold-spraying process, the particle velocity profile for smaller shape factors is much closer to that of the gas stream due to the larger particle surface area. Furthermore, the particle impact velocity increment for smaller shape factors is much more remarkable with a higher main propulsion gas temperature and higher carrier gas pressure. The effect of raising the main propulsion gas pressure on the impact velocity of the particles with very smaller shape factors is negligible. The particle impact velocity and temperature can be altered by not only the change of the working parameters of the gas steams but also the change of the sizes and shapes of the sprayed particles.