BULK Mo2FeB2 BASED CERMETS FABRICATED BY MECHANICAL BALL MILLING AND REACTION BORONIZING SINTERING

The ternary boride based cermets Mo2FeB2 were fabricated successfully with Mo, FeB, Fe, Cr and Ni mixed-powders by mechanical ball milling and reaction boronizing sintering. The results indicate that, there is no alloying reaction between powders during milling; at milling times from 4 to 24 h, the morphology of mixed-powder becomes finer and the distribution becomes more and more uniform; however, as milling time exceeds 24 h, the morphology and distribution have no obvious change. The bulk Mo2FeB2 can be fabricated with sintering temperature increasing from 1437 K to 1517 K. The relative density, the hardness and bending strength increase with the temperature increasing from 1437 to 1477 K; however, the relative density has no obvious change and the hardness, bending strength decrease with the temperature exceeding 1477 K. The result also indicates that, when the sintering time increases from 25 to 50 min, the relative density, the hardness and bending strength of sample increase; however, the relative density has no obvious change and the hardness, bending strength decrease with the time exceeding 50 min.