Abstract: Automatic high velocity arc spraying process was used to deposit the FeCrBSiMnNbW amorphous and nanocrystalline coating on an AZ91 magnesium alloy substrate. The tribological properties of the coating under dry sliding were investigated on a UMT-2 micro tribo-tester. The microstructure of the coating was characterized by using scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDAX) and X-ray diffraction (XRD). Mechanical properties were measured on Vickers hardness tester and nanoindenter. The results show that the coating mainly consisted of amorphous phase and α-Fe(Cr) nanocrystals. The coating had low porosity, low amount of oxide, high microhardness and high elastic modulus. The relatively wear resistance of the amorphous and nanocrystalline coating is 3 times as that of the conventional 3Cr13 coating. The main wear mechanism of the coating was typical brittle spalling failure mechanism.