Prediction of orientational phase transition in boron carbide

Prediction of orientational phase transition in boron carbide

The assessed binary phase diagram of boron-carbon exhibits a single intrinsically disordered alloy phase designated “B4C” with rhombohedral symmetry occupying a broad composition range that falls just short of the nominal carbon content of 20%. As this composition range is nearly temperature independent, the phase diagram suggests a violation of the third law of thermodynamics, which typically ...

Boron carbide/n-silicon carbide heterojunction diodes

Magnetoresistance in boron carbide junctions

Orientational phase transition in NaxC60 (1<x<3).

X-ray diffraction and calorimetry data on cubic NaxC60(1<xTm above that of pure C60, e.g., Tm(x=1.3)=325 K. The ordered phases are the same as in pure C60: simple cubic, space group Pa3 ̄, but the orientations in the disordered phase are more restricted. We explain how Na stabilizes the ordered phase to rather high T, while K and Rb do not, in terms of Coulomb interactions between C60 molecu...

Shock-wave strength properties of boron carbide and silicon carbide