Accurate and rapid measurements of thermodynamic properties of minerals by microcalorimetric method.

采用微量热法准确快速测量矿物的热力学性质。

基本信息

批准号：
60840023
负责人：
AKAOGI Masaki
金额：
$ 2.94万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60840023/
关键词：
Calorimetry Heat capacity Enthalpy High pressure mineral Rapid measurement Accurate measurement 迅速測定

项目摘要

1. Heat capacities of high-pressure silicate minerals were measured by the differencial scanning calorimeter which was installed by the grant-in-aid for scientific research. The data processing system using the personal computor was made for rapid and accurate calculation of the heat capacity measured by the differencial scanning calorimeter. Garnet solid solutions containing pyroxene components are stable in the pressure-temperature conditions in the mantle transition zone. Heat capacities of the garnet solid solutions in the system <Mg_4> <Si_4> <O_(12)> - <Mg_3> <Al_2> <Si_3> <O_(12)> , which represent the garnets in the transition zone, were measured by the present heat capacity measurement system. It was observed that heat capacity of the garnet solid solution at each temperature changed very little with increasing <Mg_4> <Si_4> <O_(12)> component. The Gruneisen parameter and Debye temperature of the garnet solid solutions were estimated from the heat capacity data.2. Enthalpies of silicates and germanates stable at high pressures were measured. Enthalpies of transition of the silicates and germanates were obtained for the following systems:(1) rhodonite-clinopyroxene-garnet transitions in MnSi <O_3> , (2) wollastonite-garnet-perovskite transitions in CaGe <O_3> , (3) pyroxenoid-garnet-ilmenite-perovskite transitions in CdGe <O_3> , (4) pyroxene-garnet transition in the system <Mg_4> <Si_4> <O_(12)> - <Mg_3> <Al_2> <Si_3> <O_(12)> .Phase boundaries for the above transitions were calculated from the measured enthalpies.They were almost consistent with the boundaries determined by the phase equilibrium experiments. It was established that the pyroxene(or pyroxenoid)- garnet transitions have generally gentle positive dP/dT slopes, while the ilmenite (or garnet)-perovskite transitions have negative slopes.

1、高压硅酸盐矿物的热容采用科研补助金安装的差示扫描量热仪进行测定。使用个人计算机的数据处理系统是为了快速、准确地计算差示扫描量热计测量的热容量而设计的。含有辉石成分的石榴石固溶体在地幔过渡带的压力-温度条件下是稳定的。测量了体系中石榴石固溶体<Mg_4><Si_4><O_(12)>-<Mg_3><Al_2><Si_3><O_(12)>代表过渡区石榴石固溶体的热容通过现有的热容量测量系统。观察到随着<Mg_4><Si_4><O_(12)>组分的增加，各个温度下石榴石固溶体的热容变化很小。根据热容数据估算了石榴石固溶体的格鲁内森参数和德拜温度。 2．测量了在高压下稳定的硅酸盐和锗酸盐的焓。获得了以下体系的硅酸盐和锗酸盐的转变焓：(1) MnSi <O_3> 中的蔷薇辉石-单斜辉石-石榴石转变，(2) CaGe <O_3> 中的硅灰石-石榴石-钙钛矿转变，(3) 辉石- CdGe <O_3> 中的石榴石-钛铁矿-钙钛矿转变，(4)体系中辉石-石榴石相变 <Mg_4> <Si_4> <O_(12)> - <Mg_3> <Al_2> <Si_3> <O_(12)> 。上述转变的相界是根据测量的焓计算的。它们与相平衡实验确定的边界几乎一致。已确定辉石（或类辉石）-石榴石转变通常具有平缓的正 dP/dT 斜率，而钛铁矿（或石榴石）-钙钛矿转变具有负斜率。