105060 Growth of ceramic grains during liquid-phase sintering in Ti(C,N)-based cermets prepared by in situ carbothermal reduction of TiO2

摘要

Growth behavior of two different types of ceramic grains during liquid-phase sintering in the Ti(C,N)-based cermets prepared by in situ carbothermal reduction of TiO2 was studied. After liquid phase sintering, white core/gray rim grains and black core/gray rim grains coexisted in the cermets. The growth of the near rounded white core/gray rim grains proceeded via a diffusion-controlled growth mechanism, following a cubic law. Meanwhile, the growth of the faceted black core/gray rim grains proceeded primarily through 2-D nucleation and lateral growth, which was mainly controlled by diffusion showing a pseudo-normal grain growth (PNGG), since the driving force of the majority of the grains with black cores exceeded the critical driving force (Delta Gc). In addition, the growth rate of the grains with white cores was significantly lower than that of the grains with black cores, which was attributed to the fact that the initial sizes of the white cores were considerably smaller than that of the black cores.