SrCe1-xYbxO3-α(0.05≤x≤0.15)质子导体管的制备及其铝液测氢应用

Preparation of SrCe1-xYbxO3-α(0.05≤x≤0.15) Proton Conductor Tubes and its Application on Determination of Hydrogen Content in Molten Aluminum

摘要:

采用固相合成法和等静压成型法制备了U型SrCe_1-xYb_xO_3-α(0.05≤x≤0.15)质子导体管,获得了较合理的合成和成型工艺参数；将其作为敏感元件组装成电化学氢传感器对750℃铝液进行了电动势测量和氢含量计算,探讨了管的掺Yb量、封接方式、管壁厚度、管内气室长度和参比气体的流量对传感器响应时间、灵敏性、准确性、重现性和电池阻抗特性的影响。结果表明：混合原料经1400℃煅烧4h能形成较纯的质子导体粉体；采用较高的成型压力(275MPa)或较长的保压时间(3-6min)能提高质子导体管的相对密度；采用倒U型式为合理的管封接方式；采用较高的掺Yb量、较薄的管壁厚度或较短气室长度的探头,传感器的响应时间可缩短至2-4min；参比气体流量的改变对电动势具有迅速、显著且可逆的影响,必须进行精确测量和控制。

Abstract:

5%, 10% and 15%Yb-doped SrCeO₃-base proton conducting ceramic tubes were prepared by solid reaction. The Electromotive forces (EMF) were continuously detected by the hydrogen probes which were fabricated with the tubes in molten aluminum at 750℃. Hydrogen contents were calculated as a result. Synthesis and pressed process parameters of ceramic tubes were discussed. The effect of Yb-doped amount and assembly methods, air chamber length or bottom thickness of the probes on the response time, sensitivity, accuracy, reproducibility and impedance spectrum characteristics for the hydrogen sensors were studied. The results indicated that the mixed powders were formed purer proton conductor after calcining at 1400°C for 4 hours. The relative density of the tubes can be improved at higher pressure (275MPa) or more holding pressure time (3-6min). The response time of the sensor can be reduced to 2-4 min by using probes which had more Yb doped amount, less tube wall thickness or shorter gas compartment length with inverted U-shaped sealing method. The reference gas flow or pressure had a rapid, outstanding and reversible effect on the EMF. It is necessary to measure and control the reference gas flow or pressure for acquiring the accurate hydrogen content.