Otherwise ,Al2O3 also played an important role in B4C composite ceramic densification. The Fig. 6 was the XRD result of B4C composite ceramic .Except the initial raw material, AlB12C2 was detected , which was reported to enhance the densification of B4C by lowering the diffusion barrier [7,8]. The improved sinterability was therefore partly attributable to the phases at the boundaries, either Al2O3 or AlB12C2.