Synthesis and physical properties of negative thermal expansion materials Zr1−xMxW2O8−y (M=Sc, In, Y) substituted for Zr(IV) sites by M(III) ions
✍ Scribed by Noriyuki Nakajima; Yasuhisa Yamamura; Toshihide Tsuji
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 140 KB
- Volume
- 128
- Category
- Article
- ISSN
- 0038-1098
No coin nor oath required. For personal study only.
✦ Synopsis
Zr 12x M x W 2 O 82y (M ¼ Sc, In and Y) solid solutions substituted up to x ¼ 0:04 for Zr(IV) sites by M(III) ions were synthesized by a solid-state reaction. X-ray diffraction experiments from 90 to 560 K revealed that all solid solutions had a cubic crystal structure and showed negative thermal expansion coefficients. The lattice parameters of Zr 12x M x W 2 O 82y were smaller than that of ZrW 2 O 8 probably due to oxygen defects, though the ionic radii of substituted M 3þ ions were larger than that of Zr 4þ . Order -disorder phase transition temperatures of the substituted samples drastically decreased in the order of Y, In and Sc compared to the percolation theory, and decreased with increasing M content.