Microstructure and thermal conductivity of Fe-based coatings prepared by wire-arc spraying

The thermal conductivity is an important parameter of Fe-based coating in many engineering field, such as boiler, dryer. In this study, a series of Fe-based cored wire (FeCrAl¡¢FeCrB¡¢FeCrSi) were designed and prepared coatings by wire-arc spraying to investigate the microstructure and thermal conductivity, in comparison with that of the traditional 3Cr13 coating. Microstructural studies show that all of the as-deposited coatings present a dense layered structure with the porosity below 4 %. It is found that the designed coatings have a significant reduction of oxides content than 3Cr13 coatings by adding Al, B, Si elements respectively, which results in an obvious variation on the thermal conductivity of coatings from 3.62W/mK to 8.99W/mK at room temperature. Moreover the FeCrB coating with the lowest oxide content exhibits the highest thermal conductivity of 8.99W/mK, as well as the average micro-hardness can be achieved approximately 828 HV0.1.