| 其他摘要 | The discovery of black chimney, hydrothermal ore deposits and the symbiotic related biotic community, is one of the most scientific achievements over the past few decades in the field of ocean science. To submarine hydrothermal, the value of oxygen fugacity carry lots of information about materials and mechanisms of the earth's interior, so, how to get the parameter of oxygen fugacity of hydrothermal systems under high temperature and high pressure (HTHP), has been a prerequisite for reveal their interaction mechanisms of the hydrothermal existing in the different mid-ocean ridges. In recent years, our research group concentrated on the study of hydrothermal under HTHP, and had designed and manufactured a good Nernst response YSZ oxygen sensor, however, the YSZ oxygen sensor previously developed exist some defects, such as, higher inner resistance (when used above 500 oC) and fractional structure. To solve the above defects, we optimized the sensor structure and manufacture process, the improved sensor has the qualities of lower inner (can used above 200 oC), superior resistant to thermal-shock, pressure, corrosion and Nernst response, furthermore, its dimensions of outlines match the deep-diving vehicle probe of Alvin, American. Detailed contents of this thesis are shown as following: (1) During the beginning stage of the thesis research, we used hot-isostatic press and wire-cutting to get the cylindrical Cr/Cr2O3 as the basal body, then, coating, slip casting, or slip casting combine gradient materials measures were used on the surface of Cr/Cr2O3 to get the different thickness YSZ ceramic membranes. But the membranes we got, either too thin cannot meet the needed mechanical strength of the sensor, or too thick resulting in ceramic membrane arise from YSZ membrane and Cr/Cr2O3 body has different properties and organizations, coefficient of thermal expansions and stress relief, and so on. So, we changed the experimental program. (2) The YSZ ceramic tube was fabricated by plaster casting method, then poured into Cr/Cr2O3 power buffering agents, which were mixed well through ball milling, after these progress, the tube was firing as a whole. Depending on the above method, we got the composite ceramic YSZ-Cr/Cr2O3, which possess the characteristic of no crack on the YSZ tub surface, no seam between oxygen buffering power (Cr/Cr2O3) and YSZ ceramic tube. (3) Depending on Pt slurry method and coating combined roasting progress, we prepared the electrode film for sensor, which has loose structure, plenty of blowholes, abundant of active sites, and high catalytic activity. (4) Related to the sensor resistant to thermal-shock, compressive, and electrode tolerate corrosion experiments were carried in laboratory. Results show that the self-developed YSZ oxygen sensor had superior resistant to thermal-shock, mixed with a small amount of Al2O3 can improve the YSZ ceramic tube’s mechanical properties; the YSZ had high pressure resistance, and the electrode film had strong corrosion resistance. (5) Depending on connected the sensor and HTHP hydrothermal systems test platform in our research group, we investigated the sensor to ensure whether it had Nernst respond. The results show, when enough Ni/NiO solid oxygen buffering power was putted into the autoclave to control the HTHP hydrothermal oxygen fugacity, the sensor measured electrodynamics’ potential value is close to the theoretical calculated results according to handbook of thermodynamic data at 450 oC, and the relative error is less than 2.5%. The results demonstrated the YSZ oxygen sensor developed in this work had perfect Nernst response. (6) Depending on the developed sensor, we measured the HTHP hydrothermal oxygen fugacity of 3.5% NaCl solution. The results show, when repeated increased or increased the temperature in an experiment, the experimental data can well reappearance at the same temperature; moreover, when used Keithley 6430 (its biggest in |
修改评论