Wear resistance of HVOF- and HVAF-sprayed (Ti,Mo)(C,N)–Ni coatings from an agglomerated and sintered powder

(Ti,Mo)(C,N)-25 wt% Ni coatings obtained by spraying an agglomerated and sintered feedstock powder using different high velocity air-fuel (HVAF) and high velocity oxygen-fuel (HVOF) deposition processes are comparatively analysed for their sliding, abrasion and impact resistance. All HVOF-sprayed coatings are particularly dense, with ≈800 HV hardness (tested at 100 gf, 300 gf and 500 gf). In-flight oxidation resulted in some embrittlement, as revealed by scratch tests. In ball-on-disk sliding against an Al 2 O 3 counterpart, they maintained a mild wear regime (wear rates ≤10 −6 mm 3 /(N m)) from room temperature up to 600 °C, with better performance in comparison to Cr 3 C 2 –NiCr reference coatings. At room temperature, the Ti(C,N) hard phase limited the abrasive cutting by counterbody asperities. At 400 °C and 600 °C, the coatings developed a thin, protective oxide tribofilm. They also exhibited no interface delamination in cyclic impact tests. However, they suffered higher wear (≈3–5 × 10 −3 mm 3 /(N m)) in high-stress particle abrasion testing, particularly when compared to HVAF-sprayed Cr 3 C 2 –NiCr. Gaining improved control over in-flight oxidation of (Ti,Mo)(C,N)–Ni during spraying is probably the key to overcome this limitation. The HVAF-sprayed (Ti,Mo)(C,N)–Ni coating exhibited severe interlamellar decohesion under all test conditions, as the limited melting degree of the feedstock did not compensate for the intrinsic microstructural inhomogeneity of the powder particles. • HVOF (Ti,Mo)(C,N)–Ni exhibited better sliding wear resistance than Cr 3 C 2 –NiCr up to 600 °C. • HVOF (Ti,Mo)(C,N)–Ni is not sensitive to the p × V factor over a tested range of 1–25 MPa × m/s. • Oxide inclusion and ensuing brittleness worsened the resistance of HVOF coatings to high-stress particles' abrasion. • The coatings did not delaminate under cyclic impact conditions. • The HVAF coating is less homogeneous and weaker because the Ni matrix did not melt under the chosen deposition conditions.