Corrosion and wear resistance of ultrasonic vibration-assisted laser cladded Fe-based crystal/amorphous composite coatings

The ultrasonic vibration (UV) is applied during the laser cladding process of Fe88.83Si6.21B2.51Cr2.45 (wt%) amorphous powders. The microstructure evolution and properties of the Fe-based crystal/amorphous composite coatings with and without UV were investigated in detail. The results reveal a significant decrease of 55.8 % in the average grain size within the UV coating, accompanied by a 35.9 % reduction in the length of columnar grains at the interface, which is primarily attributed to the acoustic streaming and cavitation effects of ultrasound. The average microhardness value of coatings rises from 659 +/- 33 HV0.2 to 873 +/- 48 HV0.2. Meanwhile, the coatings with UV exhibit outstanding wear resistance, with a 38.2 % reduction in wear rate compared to normal coatings. The corrosion mechanism of the coatings is pitting corrosion and the corroded surface of the coating with UV displays a relatively smaller pitting area. The enhancement mechanism for properties by U V can be the cooperative effect of the fine-grain strengthening and the amorphous phase strengthening.