Abstract
In the solid-state reaction between ultrafine chromia powder, which was produced by the decomposition of chromium formate, and amorphous boron powder, Cr5B3, CrB, Cr3B4, Cr2B3 and CrB2 were obtained at the mole ratios of 1.5 to 7.0 at 1600°C in vacuum for 2h. A single phase of CrB was formed at the mole ratio of 3.0 and 1600°C. A single phase of CrB2 was formed at the mole ratio of 7.0 and at temperatures above at 1000°C. Other chromium borides were not obtained as a single phase in the present study. The chemical compositions of single phases of CrB and CrB2 were Cr0.93B and Cr0.98B2, respectively. The lattice parameters of the chromium borides obtained agree fairly well with those reported previously.
