Premium
Crystal Structure and Carbon Vacancy Hardening of (W 0.5 Al 0.5 )C 1− x Prepared by a Solid‐State Reaction
Author(s) -
Yan Junmin,
Ma Xianfeng,
Zhao Wei,
Tang Huaguo,
Zhu Changjun,
Cai Shuguang
Publication year - 2005
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200500143
Subject(s) - vacancy defect , crystallography , materials science , analytical chemistry (journal) , crystal structure , carbon fibers , solid solution , chemistry , metallurgy , composite number , composite material , chromatography
Novel solid solutions of aluminum in tungsten carbide (WC) with or without carbon vacancies, which can be expressed by the chemical formula (W 0.5 Al 0.5 )C 1− x ( x =0.0–0.5), have been synthesized by the solid‐state reaction of W 0.5 Al 0.5 alloy and the proper amount of carbon at around 1673 K in vacuum. The reaction time decreases from 73 to 50 h on increasing the carbon vacancy concentration from 0 to 50 %. The formation of the intended products is certified, by X‐ray diffraction, environmental scanning electron microscopy–energy‐dispersive X‐ray analysis, and inductively coupled plasma–atomic emission spectroscopy, even though the carbon vacancy concentration reaches the astonishing value of 50 %. The as‐prepared (W 0.5 Al 0.5 )C 1− x samples have been identified as the hexagonal WC‐type structure belonging to the space group P6m2 ( Z =1). Moreover, the crystallographic results reveal that the substituting aluminum atoms in the WC are located in the 1a site (the W atom position of the WC structure) and the cell parameters decrease slightly with increasing vacancy concentration. The hardness of the (W 0.5 Al 0.5 )C 1− x system increases up to a maximum 2659 kg mm −2 at a carbon vacancy concentration of about 35 %, and the density of (W 0.5 Al 0.5 )C 1− x is far lower than that of WC.