Wear and corrosion resistant HVOF-sprayed WC-xCr3C2-8Co-6Ni coatings produced from pre-alloyed powder

In this work, a new WC-Cr3C2-CoNi coating was fabricated on steel substrate by thermal spraying the feedstock powder after an alumina-assisted pre-alloying treatment. The Cr3C2 content in the cermet coating was optimized based on the comparison of wear and corrosion properties with the conventional WC-based coating. The results showed that a (Co, Ni)6(W,Cr)6C solid-solution binder phase was formed because of the pre-alloying treatment above the eutectic temperature of feedstock powder. Moreover, sufficient diffusion of various atoms enabled the achievement of complete metallurgical bonding between carbides and the binder phase in the feedstock particles. These featured microstructures were partially retained in the resultant coatings, which thus possessed exceptional wear and corrosion resistance. The performance enhancement mechanisms of the developed coatings were proposed in terms of the unique design in composition and microstructure of the pre-alloyed feedstock powder.

Automated summary

A new WC-Cr3C2-CoNi coating was successfully fabricated on a steel substrate using thermal spraying and an alumina-assisted pre-alloying treatment. The optimized content of Cr3C2 in the cermet coating was determined based on wear and corrosion property comparisons with conventional WC-based coatings. The results showed the formation of a (Co, Ni)6(W,Cr)6C solid-solution binder phase due to the pre-alloying treatment, resulting in complete metallurgical bonding between carbides and the binder phase. The resultant coatings exhibited exceptional wear and corrosion resistance.