Near-Zero Thermal Expansion and Phase Transitions in HfMg1−xZnxMo3O12

Frontiers in Chemistry

Erjun Liang¹  Juan Guo¹  Huanli Yuan²  Ruofan Shen³  Dongxia Chen⁴  Xianghong Ge⁴  Mingju Chao⁴  Sailei Li⁴ 

[1] Engineering and Key Laboratory of Materials Physics of Ministry of Education, Zhengzhou University, Zhengzhou, China;College of Science, Zhongyuan University of Technology, Zhengzhou, China;Department of Physics and Electronic Engineering, Zhoukou Normal University, Zhoukou, China;;School of Physical Science &

关键词: thermal expansion;    near-zero thermal expansion;    phase transition;    X-ray diffraction (XRD);    Raman spectrum;   

DOI  :  10.3389/fchem.2018.00115

来源: DOAJ

【 摘 要 】

The effects of Zn2+ incorporation on the phase formation, thermal expansion, phase transition, and vibrational properties of HfMg1−xZnxMo3O12 are investigated by XRD, dilatometry, and Raman spectroscopy. The results show that (i) single phase formation is only possible for x ≤ 0.5, otherwise, additional phases of HfMo2O8 and ZnMoO4 appear; (ii) The phase transition temperature from monoclinic to orthorhombic structure of the single phase HfMg1−xZnxMo3O12 can be well-tailored, which increases with the content of Zn2+; (iii) The incorporation of Zn2+ leads to an pronounced reduction in the positive expansion of the b-axis and an enhanced negative thermal expansion (NTE) in the c-axes, leading to a near-zero thermal expansion (ZTE) property with lower anisotropy over a wide temperature range; (iv) Replacement of Mg2+ by Zn2+ weakens the Mo–O bonds as revealed by obvious red shifts of all the Mo–O stretching modes with increasing the content of Zn2+ and improves the sintering performance of the samples which is observed by SEM. The mechanisms of the negative and near-ZTE are discussed.

【 授权许可】

Unknown