scholarly journals Transparent MgAl2O4 Spinel Ceramics Produced by HIP Post-Sintering

2006 ◽  
Vol 114 (1334) ◽  
pp. 802-806 ◽  
Author(s):  
Koji TSUKUMA
Keyword(s):  
Mgal2o4 Spinel

scholarly journals Thermodynamics of Mg–Al Order-Disorder Reaction in MgAl2O4-Spinel: Constrained by Prolonged Annealing Experiments at 773–1123 K

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 872
Author(s):  
Yunlu Ma ◽  
Xinjian Bao ◽  
Xi Liu
Keyword(s):  
Spinel Structure ◽  
Structural Model ◽  
Molar Fraction ◽  
Thermodynamic Models ◽  
Mgal2o4 Spinel ◽  
Cation Order ◽  
Prolonged Annealing ◽  
Wide Range ◽  
History Of ◽  
Annealing Experiments

MgAl2O4-spinel has wide industrial and geological applications due to its special structural and physical–chemical features. It is presumably the most important endmember of complex natural spinel solid solutions, and therefore provides a structural model for a large group of minerals with the spinel structure. There exists a well known but still inadequately understood phenomenon in the structure of MgAl2O4-spinel, the Mg–Al cations readily exchanging their positions in response to variations of temperature, pressure, and composition. A large number of experiments were performed to investigate the Mg–Al cation order-disorder process usually quantified by the inversion parameter x (representing either the molar fraction of Al on the tetrahedral T-sites or the molar fraction of Mg on the octahedral M-sites in the spinel structure), and some thermodynamic models were thereby constructed to describe the x-T relation. However, experimental data at some key T were absent, so that the different performance of these thermodynamic models could not be carefully evaluated. This limited the interpolation and extrapolation of the thermodynamic models. By performing some prolonged annealing experiments with some almost pure natural MgAl2O4-spinel plates and quantifying the x values with single-crystal X-ray diffraction technique, we obtained some critical equilibrium x values at T down to 773 K. These new x-T data, along with those relatively reliable x values at relatively high T from early studies, clearly indicate that the CS94 Model (a model constructed by Carpenter and Salje in 1994) better describes the Mg–Al cation order-disorder reaction in MgAl2O4-spinel for a wide range of T. On the basis of the CS94 Model, a geothermometer was established, and its form is T-closure = 21362 × x3 − 12143 × x2 + 6401 × x − 10 (T-closure standing for the closure temperature of the Mg–Al cation exchange reaction). This geothermometer can be used to constrain the thermal history of the geological bodies containing MgAl2O4-spinel.

scholarly journals Dynamic Wetting of CaO-Al2O3-SiO2-MgO Liquid Oxide on MgAl2O4 Spinel

2014 ◽  
Vol 46 (1) ◽  
pp. 208-219 ◽  
Author(s):  
Hamed Abdeyazdan ◽  
Neslihan Dogan ◽  
M. Akbar Rhamdhani ◽  
Michael W. Chapman ◽  
Brian J. Monaghan
Keyword(s):  
Dynamic Wetting ◽  
Mgal2o4 Spinel ◽  
Liquid Oxide

Synthesis of nanocrystalline MgAl2O4 spinel powders by a novel chemical method

2007 ◽  
Vol 61 (17) ◽  
pp. 3585-3588 ◽  
Author(s):  
Guo-jun Li ◽  
Zhan-ru Sun ◽  
Chun-huan Chen ◽  
Xue-jun Cui ◽  
Rui-ming Ren
Keyword(s):  
Chemical Method ◽  
Mgal2o4 Spinel

Controlled fabrication of hierarchical MgAl2O4 spinel/carbon fiber composites by crystal growth and calcination processes

2015 ◽  
Vol 41 (9) ◽  
pp. 12504-12508 ◽  
Author(s):  
Tao Zhang ◽  
Yuming Zhou ◽  
Xiaohai Bu ◽  
Yongjuan Wang ◽  
Fengxian Qiu
Keyword(s):  
Crystal Growth ◽  
Carbon Fiber ◽  
Fiber Composites ◽  
Carbon Fiber Composites ◽  
Mgal2o4 Spinel

scholarly journals THE OPTICAL SPECTRA OF Co2+ IN MgAl2O4 SPINEL

1991 ◽  
Vol 01 (C7) ◽  
pp. C7-279-C7-283 ◽  
Author(s):  
P. J. DEREN ◽  
W. STREK ◽  
B . JEZOWSKA-TRZEBIATOWSKA ◽  
I. TRABJERG
Keyword(s):  
Optical Spectra ◽  
Mgal2o4 Spinel

The nature of Cr(III) luminescence in MgAl2O4 spinel

1988 ◽  
Vol 40-41 ◽  
pp. 421-422 ◽  
Author(s):  
W. Strȩk ◽  
P. Dereń ◽  
B. Jezowska-Trzebiatowska
Keyword(s):  
Mgal2o4 Spinel
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