Thermal expansion of boron subnitrides

TL;DR

This study measures the thermal expansion of boron subnitrides B13N2 and B50N2 from 298 to 1273 K, finding quasi-linear expansion with no phase transitions, and provides their volume expansion coefficients.

Contribution

The paper presents the first detailed measurements of thermal expansion coefficients for B13N2 and B50N2 over a wide temperature range.

Findings

Thermal expansion is quasi-linear for both compounds.

Volume expansion coefficients are similar to boron-rich related structures.

No phase transitions observed between 298 and 1273 K.

Abstract

The lattice parameters of two boron subnitrides, B13N2 and B50N2, have been measured as a function of temperature between 298 and 1273 K, and the corresponding thermal expansion coefficients have been determined. Thermal expansion of both boron subnitrides was found to be quasi-linear, and the volume thermal expansion coefficients of B50N2 (15.7(2) 10-6 K-1) and B13N2 (21.3(2) 10-6 K-1) are of the same order of magnitude as those of boron-rich compounds with structure related to {\alpha}-rhombohedral boron. For both boron subnitrides no temperature-induced phase transitions have been observed in the temperature range under study.