Observations of grain boundary chemistry variations in a boron carbide processed with oxide additives

Abstract

Analytical electron microscopy was used to examine the grain boundary chemistry in boron carbide containing Al-O-rich phases at triple junctions. In this study, SiO2, Al2O3, and B2O3 additives were used to synthesize an aluminoborosilicate glass on the grain boundaries with the long-term goal to enhance fracture resistance. Nanolayer films were not observed using high-angle annular dark field imaging; however, energy-dispersive spectroscopy quantification revealed grain boundaries with varying excess of Si and Al. Overall, it was concluded variations in grain boundary chemistry depend upon the intrinsic grain boundary character and spatial heterogeneity of the oxide additives.