Development of SO_x gas sensor utilizing the improved beta-alumina solid electrolyte

研究了-氧化铝与稀土氧化物（Nd_2O_3,CeO_2,Pr_6O_<11>）的反应。以稀土氧化物薄膜和Na^+- β -氧化铝球团为样品，可以得到以下实验结果：在1073 K下，Pr_6O_<11>与β -氧化铝反应，证实了一些新化合物的存在。在CeO_2中，没有发现除CeO_2和-氧化铝特征外的其他模式，因此CeO_2不与-氧化铝反应，Nd_2O_3与-氧化铝反应，形成c型化合物，然后转化为a型化合物。利用电池电导率随时间的变化，研究了-氧化铝球团与空气- so_x混合气体在1023 K下的反应。电导率随气体的进入而急剧变化，并基本保持恒定值，证实了Na^+- β -氧化铝球团表面在1小时内被稳定的Na_2SO_4相覆盖。从以上实验结果可以得出，最佳固体电解质是覆盖CeO_2的Na^+- β -氧化铝。构建了覆盖CeO_2固体电解质的Na^+- β -氧化铝SO_x气体传感器，并研究了该传感器在873和1023偶联钾下的响应性。发现平衡电动势随P_<so2>的变化而可靠地变化。在特别。利用CeO_2包覆的Na^+- bte -氧化铝促进了低温下对P_<so2>变化的响应表征。得到了许多对研制实用SO_x传感器有用的实验结果。

The reaction between beta-alumina and rare-earth oxides (Nd_2O_3,CeO_2,Pr_6O_<11>) have been investigated. By using the thin film of rare-earth oxide and Na^+- beta-alumina pellet as samples, the following experimental results could be found. At 1073ﾟK,Pr_6O_<11> reacted with beta-alumina and the existence of some new compounds were confirmed. In the case of CeO_2 the extra pattern except the characteristic ones of CeO_2 and beta-alumina were not found and it was concluded that CeO_2 was not reacted with beta-alumina Nd_2O_3 reacted with beta-alumina and C-type compound was found and follows transformed to A-type one.The reaction between beta-alumina pellet and air-SO_x gas mixture have been investigated based on the variation of electritic conductivity of cell with time at 1023 K. The electritic conductivity changed suddenly with the gas flowing into the cell and follows kept nearly constant value it was confirmed that the surface of Na^+-beta-alumina pellet was covered by stable Na_2SO_4 phase within one hour.From above experimental results, it could be concluded that the best solid electrolyte is the Na^+-beta-alumina covered with CeO_2. The SO_x gas sensor employing Na^+-beta-alumina covered with CeO_2 solid electrolyte was constructed and the responsivility of this sensor at 873 and 1023ﾟK have been investigated. The equilibrium e.m.f. wasfound to change reliably with the change in P_<so2>. In particularly. the characterization of response to a change in P_<so2> at lower temperature was promoted by means of utilizing the Na^+-bate-alumina diskcovered by CeO_2. Many useful experimental results have been obtainedfor development the practical SO_x sensor.