On the contrary, HF2 presents
a much finer microstructure with much smaller splats compared with
HF3, as shown in Fig. 6(a) and (b). Why? It positively attributes to the
particle breakages (“A” in Fig. 5(a)) and deformations of particles (“B”
in Fig. 5(a)) and the previously-deposited coating portion (“C” in
Fig. 5(a)) upon high-velocity-particle impacts.