A method of hardfacing a metal body, including the steps of flame spraying a metallic material onto a surface of the metal body to produce a layer of the metallic material on the metal body and fusing the layer of metallic material to provide a hardfacing layer, is improved by roughening the surface of the metal body prior to the step of flame spraying to provide a mechanical bond between the metal body and the hardfacing layer. The roughening is carried out to achieve a surface roughness adjusted to the thickness of the hardcoating. The surface roughness is preferably 40%-90% of the thickness of the hardfacing layer. A rotor for a progressing cavity pump/motor, including a metallic rotor body having a surface, and a layer of hardfacing on the surface, the hardfacing comprising of fused flame sprayed metallic material, the surface of the rotor body having an average surface roughness of at least substantially 6 mils with irregular protrusions for providing a mechanical bond between the rotor body and the hardfacing.