The use of carbon to improve the pressureless sintering of uranium diboride

Samples of uranium diboride were sintered in inert, reducing and vacuum conditions with and without the addition of powdered carbon to green pellets. Carbon has been shown to improve the sintering of diboride materials via the formation of gaseous phases at lower temperatures than those at which grain coarsening occurs. The addition of 0.5 wt.% carbon was seen to improve sample density in both vacuum and reducing conditions, while an increase in carbon content to 1 wt.% carbon decreased the density achieved in reducing atmosphere and had a negligible effect in vacuum.