Suppression effect of decarburization by dry-ice blasting on plasma-sprayed steel coatings: Structure, wear performance and magnetic properties

Steel coatings prepared by atmospheric thermal spraying with dry-ice blasting were studied in terms of phase structure, magnetic and wear behaviors. It was found that dry-ice blasting could suppress the volatilization of carbon during spraying process due to the exclusion effect of carbon dioxide gas sublimated from dry-ice pellets on the oxygen. Moreover, the fractographic observation of the deposited coatings proved the removal effect of dry-ice blasting on the splashing particulates which were distributed with poor bonding strength between the splat layers. In addition, it has been found that the magnetic properties are sensitive to the direction in the coating, although steel coating presents a ferromagnetic character in the parallel and vertical directions. Steel coating deposited with dry-ice blasting possesses a relatively lower saturation magnetization but has a superior wear resistance because of the suppression of decarburization during the spraying process.