A study of Cr3C2-based HVOF- and HVAF-sprayed coatings: Abrasion, dry particle erosion and cavitation erosion resistance

Abstract

Material and spray process selection are the key factors in the tailoring of thermal sprayed coatings for demanding industrial applications. In this study, four commercial Cr3C2-based feedstock materials were sprayed with gas-fuelled high-velocity oxygen-fuel (HVOF) and modern high-velocity air-fuel (HVAF) spray processes. Two materials with standard Cr3C2–25NiCr composition (porous and dense), a Cr3C2–50NiCrMoNb and Cr3C2–37WC–18NiCoCr materials were sprayed in addition to the reference WC-10Co4Cr material. The Cr3C2–50NiCrMoNb had a higher content of the Ni-based metal matrix compared to standard Cr3C2–25NiCr composition for added corrosion resistance, while the Cr3C2–37WC–18NiCoCr material contained additional tungsten carbide (WC) particles to improve the wear resistance. In abrasion and dry particle erosion, the Cr3C2–50NiCrMoNb coatings showed a higher degree of plastic deformation and increased material loss, whereas the Cr3C2–37WC–18NiCoCr coating had wear resistance between the standard Cr3C2–25NiCr and reference WC-10Co4Cr coatings. In cavitation erosion, the lower carbide content of Cr3C2–50NiCrMoNb coatings turned out to improve the resistance against fatigue wear due to higher fracture toughness. Overall, the HVAF sprayed coatings had higher elastic modulus, higher fracture toughness, equal or higher abrasion and erosion resistance, and higher cavitation erosion resistance compared to the HVOF sprayed counterparts.