Role of Chalcogen Atoms as an A-Site Element on the Physical Properties of 211 MAX Phases in the Hf–A–B System
M.A. Hadi
Abstract
The dual character of MAX phases with ceramic and metallic properties and their numerous technological applications continue to increase the attention of materials scientists towards them. The recent synthesis of boride MAX phases with chalcogen atoms at the A-site is an important addition to the MAX phase family and has further expanded the diversity of the physical properties of this family. Here, density functional theory calculations were employed to understand the role of chalcogen atoms at the A-site on the structural, mechanical, lattice dynamic, thermal, electronic, and optical properties of Hf 2 SB, Hf 2 SeB, and Hf 2 TeB. In the Hf–A–B system of the 211 MAX family, most of the physical properties decrease as the chalcogen atom A moves from S to Te via Se, while the lattice parameters show a gradual increase. All compounds under study are brittle in nature. Their elastic, electronic, and optical properties exhibit an anisotropic nature. They have the potential to be etched into two-dimensional MXenes and become thermal barrier coating materials. Also, they will reduce solar heating when used as a coating material.