CHARACTERIZATION OF CR3C2-NICR CERMET POWDER FOR HIGH-VELOCITY OXYFUEL SPRAYING

The structural characteristics of a commercial high velocity oxyfuel t hermal spraying powder containing chromium carbides and a Ni-Cr metall ic matrix have been determined using a variety of experimental techniq ues including X-ray diffraction, SEM, and electron probe microanalysis . The powders were prepared in such a way that a liquid phase was form ed. In some cases the liquid phase surrounded the original carbides bu t in other cases the liquid did not surround the carbide particles, gi ving rise to a mixture of both spherical and irregular granules. Apart from the original Cr3C2, secondary Cr3C2 has been found together with Cr7C3 and Cr23C6 with some nickel replacement for chromium in these c arbides. The results have been interpreted in relation to the C-Cr equ ilibrium diagram with appropriate modifications for the presence of ni ckel.