Premium
A Series of MAX Phases with MA‐Triangular‐Prism Bilayers and Elastic Properties
Author(s) -
Chen Hongxiang,
Yang Dongliang,
Zhang Qinghua,
Jin Shifeng,
Guo Liwei,
Deng Jun,
Li Xiaodong,
Chen Xiaolong
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201814128
Subject(s) - isostructural , crystallography , stacking , max phases , phase (matter) , bulk modulus , diffraction , synchrotron , elastic modulus , chemistry , x ray crystallography , phase transition , materials science , series (stratigraphy) , thermodynamics , crystal structure , physics , composite material , geology , organic chemistry , nuclear physics , paleontology , optics
Abstract We report a new type of MAX phase (M=transition metals, A=main group elements, and X=C/N), Nb 3 As 2 C, designated as 321 phase. It differs from all the previous M n +1 AX n phases in that it consists of an alternate stacking of one MX layer and two MA layers in its unit cell, while only one MA layer is allowed in usual MAX phases. The new 321 phase exhibits a bulk modulus of Nb 3 As 2 C up to 225(3) GPa as determined by high‐pressure synchrotron X‐ray diffraction, one of the highest values among MAX phases. Isostructural 321 phases V 3 As 2 C, Nb 3 P 2 C, and Ta 3 P 2 C are also found to exist. First‐principles calculations reveal the outstanding elastic stiffness in 321 phases. Among all 321 phases, Nb 3 P 2 C is predicted to have the highest elastic properties. These 321 phases, represented by a chemical formula M n +1 A n X, were added as new members to the MAX family and their other properties deserve future investigations.