Thermal expansion of kyanite at ambient pressure:An X-ray powder diffraction study up to 1000℃  

作　　者：Xi Liu Qiang He Hejing Wang Michael E. Fleet Xiaomin Hu 

机构地区：[1]The Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education of China, Beijing 100871, China [2]School of Earth and Space Sciences, Peking University, Beijing 100871, China [3]Department of Earth Sciences, University of Western Ontario, London, Ontario, N6A 5B7, Canada

出　　处：《Geoscience Frontiers》2010年第1期91-97,共7页地学前缘（英文版）

基　　金：financially supported by the Natural Science Foundation of China(Grant 40872033);the Fundamental Research Funds for the Central Universities(to XL);the Natural Sciences and Engineering Research Council of Canada(to MF)

摘　　要：The thermal expansion coefficients of kyanite at ambient pressure have been investigated by an X-ray powder diffraction technique with temperatures up to 1000 ℃. No phase transition was observed in the experimental temperature range. Data for the unit-cell parameters and temperatures were fitted empirically resulting in the following thermal expansion coefficients： αa = 5.8（3） × 10^-5, αb = 5.8 （1）× 10^-5, αc = 5.2（1）× 10^-5, and αv = 7.4（1） × 10^-3 ℃ 1 in good agreement with a recent neutron powder diffraction study. On the other hand, the variation of the unit-cell angles α, β and γ of kyanite with increase in temperature is very complicated, and the agreement among all studies is poor. The thermal expansion data at ambient pressure reported here and the compression data at ambient temperature from the literature suggest that, for the kyanite lattice, the most and least thermally expandable directions correspond to the most and least compressible directions, respectively.The thermal expansion coefficients of kyanite at ambient pressure have been investigated by an X-ray powder diffraction technique with temperatures up to 1000 ℃. No phase transition was observed in the experimental temperature range. Data for the unit-cell parameters and temperatures were fitted empirically resulting in the following thermal expansion coefficients： αa = 5.8（3） × 10^-5, αb = 5.8 （1）× 10^-5, αc = 5.2（1）× 10^-5, and αv = 7.4（1） × 10^-3 ℃ 1 in good agreement with a recent neutron powder diffraction study. On the other hand, the variation of the unit-cell angles α, β and γ of kyanite with increase in temperature is very complicated, and the agreement among all studies is poor. The thermal expansion data at ambient pressure reported here and the compression data at ambient temperature from the literature suggest that, for the kyanite lattice, the most and least thermally expandable directions correspond to the most and least compressible directions, respectively.

关 键 词：High temperature KYANITE Thermal expansion X-ray powder diffraction 

分 类 号：TP274[自动化与计算机技术—检测技术与自动化装置] TG115.23[自动化与计算机技术—控制科学与工程]