Fabrication of Boron Carbide Composite Material Using Reaction Boronizing Sintering for Thermoelectrics

Abstract

Boron carbide, one of the boron icosahedra cluster compounds, exhibits attractive thermoelectric properties.

However, boron carbide is hard to sinter because of the strong covalent bonding of boron.

We focused on the Reaction Boronizing Sintering (RBS) method to sintering of boron carbide materials. In RBS, the eutectic liquid phase between metal and boron promotes the densification of the borides. In this study, the effects of metal addition on the thermoelectric properties were investigated. Boron carbide base materials were synthesized by powder metallurgy method using SPS from B, C, and metal powders, Mn and Ni.

According to XRD measurement of SPSed materials, boron carbide and metal boride, MB or MB₂, were appeared. Microstructural observation by SEM results showed that phase formations of metal boride depend on additive metal species. Higher thermoelectric performance can be expected by further optimizing of the SPS condition and grain size and introducing of a mechanical milling process.