scholarly journals Substitutions of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12 for Less Hygroscopicity and Low Thermal Expansion Properties

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3945 ◽  
Author(s):  
Qiang Ma ◽  
Lulu Chen ◽  
Heng Qi ◽  
Qi Xu ◽  
Baohe Yuan ◽  
...  

In this investigation, ZrxY2−xVxMo3−xO12 (0 ≤ x ≤ 1.4) is developed and the effects of the substitutions of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12 on the hygroscopicity and thermal expansion property are investigated. For the smaller substitution content (x ≤ 0.5), their crystal structures remain orthorhombic, while there is crystal water still in the lattice. The linear coefficients of thermal expansions (CTEs), for x = 0.1, 0.3, 0.5, and 0.7, are about −4.30 × 10−6, −0.97 × 10−6, 0.85 × 10−6, and 0.77 × 10−6 K−1, respectively, from 476 to 773 K, which means that the linear CTE could be changed linearly with the substitution content of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12. As long as the substitution content reaches x = 1.3/1.4, almost no hygroscopicity and low thermal expansion from room temperature are obtained and are discussed in relation to the crystal structure and microstructure.

2014 ◽  
Vol 599 ◽  
pp. 89-92 ◽  
Author(s):  
Sha Ding ◽  
Zhong He Shui ◽  
Teng Pan ◽  
Wei Chen

The low-thermal expansion coefficient (CTE) of cement paste and concrete are designed and prepared with fly ash in this study. The thermal expansion property and pore structure of cement/concrete are tested by Thermal Dilatometer, MIP, and SEM. The test results show that the addition of fly ash lowers the thermal expansion rate and coefficient of hardened paste. The increase of addition level is accompanied by the decrease of the thermal expansion coefficient. The introduction of fly ash could improve the pore structure of concrete, thus improve the thermal expansion property of cement concrete.


2017 ◽  
Vol 28 (7) ◽  
pp. 1600-1606
Author(s):  
Ying-Zhi Cheng ◽  
Xiu-Yu Sun ◽  
Xiao-Ling Xiao ◽  
Xiang-Feng Liu ◽  
Li Xue ◽  
...  

2011 ◽  
Vol 21 (14) ◽  
pp. 5338 ◽  
Author(s):  
Norihiro Suzuki ◽  
Shosuke Kiba ◽  
Yuichiro Kamachi ◽  
Nobuyoshi Miyamoto ◽  
Yusuke Yamauchi

1992 ◽  
Vol 46 (2) ◽  
pp. 273-276 ◽  
Author(s):  
G. Chen ◽  
R. G. Haire ◽  
J. R. Peterson

We have investigated the Eu3+ ion luminescence spectra from different host crystals of the lanthanide sesquioxides exhibiting either the A, B, or C form. The Eu3+ ion luminescence spectra from B-type Eu2O3 and from Eu3+-doped A-type La2O3 and C-type Lu2O3 were obtained at room temperature. It is suggested that the luminescence from f-f transitions in the Eu3+ ion can be used to determine the crystal structure, because the different Eu3+ ion site symmetries in the different crystal structures give rise to different characteristic spectral splitting patterns.


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