Synthesis of Dense, High‐Defect‐Concentration B ₄ C through Mechanical Activation and Field‐Assisted Combustion

Abstract

Dense fine‐grained B 4 C was synthesized by the spark plasma sintering (SPS) method using mechanically activated elemental powders. Relative densities of up to 95% were achieved. When characterized by X‐ray line broadening methods, the grains of the resulting product were determined to be nanometric in scale. However, transmission electron microscopy (TEM) observations showed the product to be composed of a mixture of fine (nanometric) crystallites and grains in the micrometer range. The TEM images showed a highly defective structure containing a high density of twins. Their presence is the reason for the discrepancy between the X‐ray and TEM results.