大洋中脊热水探测与新型传感器

Exploration for Hydrothermal Fluids of Mid-Ocean Ridge and Novel Chemical Sensors

对大洋中脊的探测带来了大量科学发现。在大洋中脊热水喷口的极端条件下,在大的温度梯度范围内,一方面在喷口(黑烟囱)周围形成巨量金属硫化物快速堆积;另一方面在喷口周围由内向外形成一个生物晕。为了研究洋中脊极端条件下的水热过程,模拟洋中脊水—岩相互作用条件下生命过程,需要在高温高压环境中原位获取数据,必须利用先进、灵敏的化学传感器。由于新材料技术的发展,美国和西方国家深海探测时广泛使用YSZ电化学传感器(氧化钇稳定的氧化锆陶瓷,YSZ:Yttria Stabilized Zirconia),这种传感器的优点是在温度大于200℃的高温时性能良好,在低于200℃条件下灵敏度降低,而且在国际市场上没有这些高温高压化学传感器出售。“十五”期间,科技部863计划,首次将发展深海高温高压传感器的海底多参数检测技术之一列入我国计划。根据863计划,中国科学家通过努力研制成功一系列具有中国自主知识产权的高温高压化学传感器,在自主研制了YSZ传感器的同时,发明了国际上首次可以在大温度范围、在海上实用的Zr/ZrO2高温化学传感器,可部分替代YSZ传感器。这两类集成式化学传感器可以探测大洋中脊400℃/40MPa热水的pH、H2、H2S、Eh等,并在2004年的南海的海试中取得成功。

Lots of new discoveries from Mid-Ocean Ridge bring forward many significant problems for scientists, such as rapid sediments of sulphide deposits and formation of new biological species at large temperature- pressure ranges. To study hydrothermal fluids at extreme conditions, we need to obtain in-situ obervation data utilizing high temperature-pressure chemical sensors. Recent advances in materials synthesis make great progress in the developments of sensor technology. YSZ （Yttria Stabilized Zirconia） ceramic-based chemical sensors have been applied in testing chemical parameters （pH, H2, H2S） of hydrothermal vents in Mid-Ocean Ridge. This kind of chemical sensors possesses excellent electrochemical properties at high temperatures, which are not sensitive below 200℃. With the support of 863 Sea Project from Ministry of Science and Technology, we made considerable efforts to develop high temperature-pressure chemical sensors of independent intellective property rights, especially novel type chemical sensors Zr/ZrO2 sensors for measurements of deep ocean in a large variety temperature range of 2℃ to 400℃. In July and December of 2004, this high temperature chemical sensor assemblage was successfully used in the investigations of Southern China sea and recorded lots of data of chemical parameters （pH and dissolved H2 and H2S concentrations） of the sea from the surface to 3300 m depth.