Comparative microstructure characteristics and properties of arc-sprayed Fe-based and HVOF-sprayed Ni-based coatings on ASME SA 210 C steel tube

SA 210C is the material for tube boiler which is generally coated with Fe-based and Ni-based to increase its resistance at high temperature. The methods of thermal spray coating which is mostly performed on the material is wire arc (WA) spray and high velocity oxy-fuel (HVOF) have different cost and coating characteristics. Thermal spray coating with Ni-based is used more. In this study, Fe-based and Ni-based were deposited using WA and HVOF spray, respectively. Compared to Ni-based, Fe-based coating had more porosity. The amount of the porosity supports the findings stating that abrasion rate of Fe-based is higher than Ni-based. The hardness values of Fe-based (200.15 HV) and Ni-based (201.36 HV) are almost the same. The coating quality was assessed based on the evaluation of micro and crystal structure and the effect is revealed in this paper. The Fe-based coating with WAS can be the alternative technique to replace Ni-based with HVOF method.