Synthesis of titanium diboride by electric arc plasma in air

Abstract

The paper reports data that demonstrate the feasibility of vacuum-free electric arc synthesis of titanium diboride. An optimal energy mode was found to synthesize submicron titanium diboride powder with the hexagonal lattice parameters a = 3.03 ± 0.04 Å, c = 3.23 ± 0.04 Å with no impurity crystal phases in its composition. A bulk ceramic sample with relative density of 99.1 % and hardness of 18 GPa was consolidated from the synthesized powder. The powder and bulk ceramic samples were analyzed by scanning electron microscopy and transmission electron microscopy. Structure of the synthesized material has a positive effect on the densification of the material. The sintered grains already formed in the process of synthesis under the influence of external pressure and heating from the current flow sinter each other, forming a single target structure with a minimum number of pores, of oxide impurities. Raman spectroscopy was employed to analyze the homogenized precursor mixture, synthesized powder, and TiB2-based bulk ceramic sample. The obtained Raman spectrum of sintering powder is characteristic of TiB2-based materials with a low concentration.