Microstructural evolution of the rapidly quenched Fe-Cr-B alloy thermal spray coatings

Abstract

The microstructural development of Fe-Cr-B alloy thermal sprayings has been investigated by transmission electron microscopy (TEM), Anger electron spectroscopy and energy dispersive X-ray microanalysis. The Fe-Cr-B alloy powder was composed of both Cr-rich boride phases, such as Cr1.65Fe0.35B0.96 and Cr2B, and alpha-(Fe,Cr) solid solution phase of b.c.c. structure. The boride particles dissolved thermally during the thermal spraying process, resulting in the supersaturation of boron within the nanocrystalline alpha-(Fe,Cr) solid solution phase. Cross-sectional TEM observation for the sprayed coating layer revealed volume nucleation within a splat and the formation of FeCr2O4 oxide. These can contribute to the evolution of an equiaxed nanocrystalline alpha-(Fe,Cr) phase. (C) 2001 Elsevier Science B.V. All rights reserved.