Investigation of the Microstructural, Mechanical, and Tribological Properties of HVOF-Sprayed 434 Stainless Steel Coatings on T6061 Aluminum Alloy
摘要
To improve the hardness and wear resistance of aluminum alloys, 434 stainless steel coatings on aluminum substrates were deposited with different spraying parameters (number of sprayed-layers and spray distance) via high-velocity oxygen–fuel (HVOF) flame spraying. The Young’s modulus (E) of the SS coatings was calculated via three-point bending and measured the hardness by Vickers indentation tests. The tribological properties of SS coatings were discussed by the H/E and H3/E2, as well as the influence of different iron oxide types on the abrasion of stainless steel coatings was investigated via thermodynamics and kinetics. The results showed that best match of a hard phase (martensitic transformation provides) with Young’s modulus of the coating, high H/E and H3/E2 ratio, SS1-2 coated sample presented better wear resistance, which have a lowest average friction coefficient, and the wear rate is reduced from 11.21 × 10−5 mm3/(N m) − 6.01 × 10−5 mm3/(N m) to 7.67 × 10−5 mm3/(N m) − 4.96 × 10−5 mm3/(N m). In addition, compared with the first set of deposition conditions, SS2-2 coated sample have a higher average friction coefficient as spray distance increased, and the wear rate is increased by nearly two times, due to formation the hard and brittle Fe3O4 phase. The tribological properties of SS coatings can well revealed by calculating the ratio of Young’s modulus to hardness (H/E and H3/E2).