Effect of heat treatment on erosion–corrosion of Fe-based amorphous alloy coating under slurry impingement

In order to investigate the effect of vacuum heat-treatment (VHT) on the erosion−corrosion performance of Fe-based amorphous alloy coating (Fe-AAC) under alkaline sand-containing NaCl slurry impingement, Fe48Cr15Mo14C15B6Y2 at.% amorphous alloy coatings were first prepared via a high-velocity air fuel (HVAF) spraying process and then vacuum heat-treated at several different temperatures. Experimental results show that the fraction of the amorphous phase in the coating decreases with increasing VHT temperature. The heat-treated coatings exhibit a higher hardness of ∼994 HV0.1 with good wear resistance but lower corrosion potentials of ∼ -0.607 V and a larger corrosion current density of ∼7.98 × 10−6 A. Erosion−corrosion tests show that the mass loss increases as the temperature of the heat-treatment increases under the same conditions of slurry pH. However, as the slurry pH values increase, the mass loss of the sample treated at the same VHT temperature tends to decrease. The mechanism of erosion−corrosion failure of the Fe-AAC is the synergy of wear by fluidity particles on coatings and corrosion of corrosive media during erosion. •After VHT, the hardness of Fe-AACs exceeds 1000 HV0.1.•VHT affects the wear resistance and corrosion resistance of the Fe-AACs.•The degradation of the corrosion resistance caused by crystallization has a great impact on the erosion performance.