Oxygen self‐diffusion in quartz under hydrothermal conditions
Oxygen self‐diffusion in quartz under hydrothermal conditions
复制标题
水热条件下氧在石英中的自扩散
DOI：
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发表时间：
1984
期刊：
影响因子：
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通讯作者：
P. Dennis
中科院分区：
文献类型：
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作者：
P. Dennis
在水热条件下，在515°-850°C的温度范围内，对单晶石英中的氧自扩散Dox进行了监测。在700°和850°C之间的β场中，数据由平行和垂直于C的两个线性Arrhenius关系表示。Do （m2 s−1）的值平行于C的2.09×10−11和垂直于（101¯0）的3.16×10−10。ΔH （kJ mol−1）的值与c平行为138.54，与（101¯0）垂直为203.72。在700°C下，在11.5-100 MPa的总压力范围内，Dox与Ni-NiO和Fe3O4-Fe2O3缓冲液之间的水（f(H2O)）和氧（f(O2)）逸度无关。结果与外源点缺陷下的简单带电空位扩散机制一致。需要进一步的实验来确认流动氧缺陷的性质。结果的一个关键方面是观察到，在本实验的低水逸度下，含氢缺陷似乎在氧运输机制中不起作用。这与其他已发表的数据集形成对比，并直接导致需要进行详细的实验室间比较。
Oxygen self-diffusion, Dox, has been monitored in single-crystal quartz in the temperature range 515°–850°C under hydrothermal conditions. In the beta field, between 700° and 850°C, the data are represented by two linear Arrhenius relations for transport parallel and perpendicular to c. Values for Do (m2 s−1) are 2.09×10−11 parallel to c and 3.16×10−10 perpendicular to ( 101¯0). Values for ΔH (kJ mol−1) are 138.54 parallel to c and 203.72 perpendicular to ( 101¯0). At 700°C, in the total pressure range 11.5–100 MPa, Dox is independent of water (f(H2O)) and oxygen (f(O2)) fugacities between the Ni-NiO and Fe3O4-Fe2O3 buffers. The results are consistent with diffusion via a simple charged vacancy mechanism under an extrinsic point defect regime. Further experiments are required to confirm the nature of the mobile oxygen defect. A key aspect of the results is the observation that at the low water fugacities of the present experiments a hydrogen-containing defect appears to play no role in the oxygen transport mechanism. This is in contrast to other published sets of data and leads directly to the requirement for detailed interlaboratory comparisons.