AlPO_4高温高压相变研究  

AN INVESTIGATION OF THE PHASE TRANSFORMATION OF AIPO, AT HIGH PRESSURE AND HIGH TEMPERATURE

作　　者：王振杰[1] 叶大年[1] 

机构地区：[1]中国科学院地质研究所

出　　处：《地质科学》1990年第3期287-293,共7页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金

摘　　要：利用配有电阻炉外加热装置的金刚石对顶砧及紧装式六面顶高压容器,在500—1700℃和常压至17.8GPa温压范围内,对AlPO_4进行了实验研究。常压下,磷铝石(石英型AlPO_4)向鳞石英型AlPO_4转变的温度约为778℃,鳞石英型向方英石型AlPO_4转变的温度约为1100℃,块磷铝石α-β相转变的温度为586℃。在5.4 GPa和1300℃以下,块磷铝石保持稳定,在5GPa和大于1700℃时,发现AlPO_4分解为Al_2O_3,(刚玉)和P_2O_5鳞石英型AlPO_4在6GPa及500℃转变成斜方晶系新相,新相在室温常压下的晶胞参数为:a=4.930(?),b=7.200(?)和c=6.165(?),鳞石英型AlPO_4及块磷铝石在11GPa以上均变为NiSO_4型结构。文中讨论了AlPO_4与SiO_2的异同,并给出了一个AlPO_4可能的相图。By using the diamond-anvil pressure cell coupled with resistant-wire heating and the six anvil pressure vessel, the phase transformation of AlPO4 has been investigated at pressures up to -17.8 GPa and at temperatures from 500℃ to 1700℃. Under atmospheric pressure, the transition temperature from berlinite (qurtze-type AlPO4) to tridymite-type structure is about 778℃, and from tridymite-type to cristobalite-type structure-about 1100℃. Theα-β transition of berlinite takes place at 586℃. Berlinite is stable at pressures below 5.5 GPa and temperatures below 1300℃. It decomposes into the mixture of Al2O3 (Corundum) plus PaO5 at 5 GPa and over 1700℃. Tridymite-type AlPO4 is found to transform to a new phase at 6 GPa and 500℃. The new phase has been indexed on the basis of an orthorhombic cell with lattice parameters of a = 4.930, b = 7.200, c = 6.165 A at room temperature and atmospheric pressure. At pressures greater than 11 GPa, AlPO4 transforms from berlinite or tridymite-type to NiSO4-type form. A possible P-T phase diagram of AlPO4 is given in this paper.

关 键 词：磷酸铝 块磷铝石 高温高压相变 实验 石英 晶胞参数 

分 类 号：P578.925[天文地球—矿物学] P574[天文地球—地质学]