Microstructure and wear-resistance of Fe-Cr-B base metamorphic alloys

Metamorphic (crystalline-to-amorphous) transition and consequent microstructural change were investigated In relation with the wear-resistance during the wear process of Fe-base metamorphic coating layer, The spray coating was accomplished using a detonation gun with various fuel gas conditions. The spray coated layer exhibited significantly improved wear resistance, which is about 45 times higher than that of the noncoated substrate. The significantly low friction coefficient and high hardness, resulting from the presence of amorphous surface film, seems to be. the main cause of the improved wear-resistance. Electron microscopy on the cross-section of the coated layer exhibited intra-particle micro-segregations associated with rod-shape Cr and B rich particles and Fe-Cr solid solution phase. From the observations using TEM and EDS, Fe-Cr solid solution with supersaturated B and Si content seems to be the main phase contributing to the crystalline-to-amorphous transition during wear.