Development of Zr/ZrO_2 high temperature and high pressure sensors for in-situ measuring chemical parameters of deep-sea water

In order to in situ measure chemical parameters of deep-sea water and hydrothermal fluids at midocean ridge(MOR), it is necessary to use high temperature and high pressure chemical sensors.Developing new sensors is essential to measure in-situ pH and other chemical parameters(dissolved H2, dissolved H2S) of deep-sea water and hydrothermal fluids in a wide temperature range(2℃―400℃) at MOR vents.The YSZ(Yttria Stabilized Zirconia, 9%Y2O3) ceramic-based(HgO/Hg) chemical sensors possess excellent electrochemical properties at high temperatures, which have been used to measure chemical parameters of hydrothermal fluids above 200℃.A novel Zr/ZrO2 oxidation/reduction electrode was constructed by oxidation of Zr wire in Na2CO3 melt.This Zr/ZrO2 electrode has good chemical stability while measuring pH of high-temperature aqueous solutions, combined with a Ag/AgCl reference electrode.Potentials of the Zr/ZrO2 sensor in association with a Ag/AgCl reference electrode vary linearly with pH over a wide pH range, as tested by various NaCl-HCl-H2O solutions(NaOH-NaCl-H2O for basic solutions), at temperatures in the range of 20℃―200℃.Thus, the Zr/ZrO2 sensors can be utilized in monitoring the fluids over the temperature range of 2℃―200℃.The Zr/ZrO2 electrode combined with Ag/AgCl, Ag/Ag2S, and Au electrodes has been used to measure pH and other chemical parameters(dissolved H2, dissolved H2S) of aqueous fluids from low to high temperatures and high pressures in the laboratory and to monitor those parameters of deep-sea water in South China Sea.

磁控溅射TiAlN和TiAlSiN对Zr-Fe-Cr合金600℃腐蚀性能的影响

为了提高Zr-Fe-Cr高温锆合金的耐腐蚀性能,采用磁控溅射,在Zr-Fe-Cr合金表面沉积TiAlN和TiAlSiN膜,然后对有无薄膜层的样品进行高温氧化,并对比不同表面状态样品氧化层的厚度及其增重。结果表明在Zr-Fe-Cr合金表面磁控溅射TiAlN和TiAlSiN均能明显提高基材的耐高温氧化性,其中TiAlSiN层表现出更优越的的性能。分析认为,基材的高温耐腐蚀性得到改善是因为镀层在高温下形成致密的Al 2 O 3和TiO 2膜,有效保护基体不被氧化。