*2.1. Materials*

A commercially-available AZ91D powder (WeiHao Magnesium Powder Co., Ltd., Tangshan, China) and SiC powder (Sulzer Metco, Bron, France) were used to produce coatings. The AZ91D particles presented a spherical shape (Figure 1a), and the grain orientation is random (Figure 1b). SiC particles show dendritic morphology with sharp edges (Figure 1c). Size distribution of the powder was examined using a MASTERSIZER 2000 system (Malvern Panalytical Ltd., Royston, UK). The size distribution of the AZ91D powder was in the range from 34 μm to 81 μm, and averaged 52 μm (Figure 1d). The size distribution of SiC powder is from of 4 μm to 55 μm, and averaged 15 μm (Figure 1e). The content of SiC particles in the feedstock powder was 30 vol %. Stainless steel and magnesium plates with a dimensions of 60 mm × 20 mm × 2 mm were used as substrates. The substrates were sandblasted using alumina grits (ISO 6344, Grit designation, P100) prior to spraying.

**Figure 1.** Morphology of the original AZ91D powder (**a**); sectional microstructure of an AZ91D particle after etching (**b**); and the morphology of SiC powder (**c**). Size distribution of the AZ91D powder particles (**d**) and SiC powder particles (**e**).
