Surfaces of metallic Ti have been modified successfully to thick layers of metalceramic, TiC, by reactive plasma processing. The carbonized surfaces consist of mixed layers of TiC and metallic Ti. TiC grains grow up on the Ti substrate with island forms. The metal Ti acts as a "paste" between the growing TiC grains. The hardness of the modified surface layers increases with processing temperature. The hardness reaches 5000 k g/mm(2) at a processing temperature of about 1300 degrees C, which is a value comparable to bulk TiC. Analysis of the XAFS spectrum and the diffraction profiles for the fabricated layers shows a reduction of the Ti-Ti distance from a distance of 3.07 angstrom for the bulk TiC to 3.025 angstrom. Using the results of the local structures around a Ti element by XAFS analysis, we will try to elucidate the abnormal hardness of the newly fabricated TiC by an analytical model.

Keywords: TiC; cermets; XAFS; electron-nuclear interaction