Influence of inter-splat adheres on properties of HVOF-sprayed 434 stainless steel coatings on T6061 aluminum alloy

Bonding and adhesion are crucial factors determining the properties during HOVF-spraying. 434 stainless steel coatings have been applied T6061 alloy substrate using High-Velocity Oxygen Fuel (HVOF) with different spray parameters.The inter-splat adhesion of stainless steel (SS) coatings was investigated through shearing method,transmission electron microscope(TEM). The relationship between the inter-splat adheres and properties of the bonding strength, corrosion and wear resistance of SS coatings was revealed.Results showed that for thicker coatings containing more layers, the deposition temperature was higher, the coating porosity was lower, and the adhesion between splats was stronger,presented better properties. The optimum SS1-3 coated sample showed a maximum bonding strength of 52.9 MPa, a wear rate is only half of that of the SS 2-2,reach 5.94×10 -5 mm 3 /(N·m),all because of the localised metallurgical bonding at the splat interface.Compared to pure T6061 aluminium, its presented better corrosion resistance,and the corrosion current density is reduced from 18.6 μA/cm 2 to 3.5 μA/cm 2 . Finally, mechanisms for coating failure were established to explain the effects of inter-splat adhesion on the SS coatings under tension and wear.