Numerical investigation into the nanostructure and mechanical properties of amorphous SiBCN ceramics

Abstract

Siliconboron carbonitride ceramics possess exceptional high-temperature stability, creep resistance and electrical properties, thus are promising materials for use as coatings, membranes, high temperature fibers and in microelectronics. However, using experiments to investigate the nanostructures and high temperature mechanical properties of SiBCN ceramics is very challenging. In this work, large-scale molecular dynamics simulations were used to study the effects of N content on the structural and mechanical properties of SiBCN ceramics. A melt-quench method was used to generate amorphous structures of SiBCN, and the resulting nanostructure, pair distribution functions and angular distribution functions are consistent with the experimental results from XPS, X-ray diffraction and TEM. The calculated Young's moduli are close to the experimental data values, and the structure with the optimal N content presents the largest Young's modulus. The simulation results give a key insight into the nanostructure and mechanical properties of SiBCN ceramics with different compositions.