Characterizations the deposition behavior and mechanical properties of detonation sprayed Fe-based amorphous coatings

In this study, the spreading morphologies and deposition behaviors of molten droplet in a single detonation sprayed shot under different oxygen-fuel ratio conditions are characterized in detail to reveal the formation mechanism of Fe-based amorphous coatings. Additionally, the porosities, micro-hardness, amorphous phase content and wear behavior of the coatings were also carefully evaluated to correlate the relationship between preparation process parameters, particle deposition behavior, spreading morphology, and mechanical properties. The results indicate that the spraying oxygen-fuel ratio (OF) parameter can determine the microstructure change of the coating, which is considered to be a reflection of the molten state of the sprayed particles. The low OF reduces the combustion efficiency, making the coating particles deposited in a form similar to cold spraying, resulting in uneven coating structure. In the case of medium OF (2.00), amorphous particles can form completely melted droplets and spread well on the substrate, and produce a good metallurgical bond with the substrate. Thanks to the good spread of the amorphous droplets, the OF-2.00 coating displays a very uniform and dense structure and uniformly distributed microhardness, which also makes its wear resistance (0.63 × 10−6 mm3 N−1 m−1) increased by about 8 times compared with OF-1.43 coating.