Reactive Sintering Of B-C Ceramics By Spark Plasma Sintering

In this study, the processing of preparation of B-C ceramic materials by Spark Plasma Sintering (SPS) technique with raw boron and carbon element powders was investigated. The density, chemic component, microstructure, chemic surroundings and phase structure of materials have been researched. Relative density up to 90% were achieved with sintering at 1700℃, 95% at 1900℃, the sintering temperature of SPS was lower than traditional process.The boron carbide fabricated by SPS has a fine-grain microstructure. The stripes in grain were observed by TEM, the reason of observation of the stripes in grain is presence of stacking faults.With series experiments, the experience formula of component of B-C has been founded to control the component of materials.The effect of SPS process on the phase structure of material and chemic surroundings of the atoms were analyzed via X-Ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The C atom has been taken place by B atom with the increasing of the B/C ratio. Amount of B-B chains has got large, both in the icosahedrons and chief chains. Contrarily, the amount of C-B and C-C chains was getting disappear.The analysis of XRD patterns and Rietveld method have been taken, parameters of lattice was calculated and phase structure was confirmed. The B₁₃C₂ structure fitting is better than B4C, and the main phases of material are B₁₃C₂ and B₄C.After analysis of specimens via series testing methods, the sintering mechanism of was gained. The process of boron carbide reactive sintering is composed by 4 parts: Raw element powders are mixing and surface effect is coming up; Reaction; Producing of new phase; Growth of crystal.