KENBIKYO Vol.50▶No.3 2015
â– Researches Today

Microstructural Analysis of a Negative Thermal Expansion Material ZrW2O8

Yukio Satoa, Yasuhisa Yamamurab and Yuichi Ikuharac

aDepartment of Materials Science and Engineering, Graduate School of Engineering, Kyushu University
bFaculty of Pure and Applied Sciences, University of Tsukuba
cInstitute of Engineering Innovation, The University of Tokyo

Abstract: Zirconium tungstate (ZrW2O8) exhibits negative coefficient of thermal expansion, which is not the case for most materials. It is believed that the negative thermal expansion should be closely related with geometrical alignment of WO4 tetrahedra in ZrW2O8. In this article, we introduce our recent study that revealed the spatial distribution of WO4 geometrical ordering state using dark-field transmission electron microscopy. It was found that the WO4 geometrical ordering is partly inverted and is partly disordered on the nanoscale.

Key words: ZrW2O8, Negative Thermal Expansion, Dark-Field, TEM, Electron Diffraction