Development of YSZ pH sensor for Use in High Temperature Solutions

研制了一种用于高温水溶液pH测量的氧化钇稳定氧化锆（YSZ）固体电解质pH传感器。用离子束溅射法在YSZ板的一侧沉积一层Ni-NiO混合物薄膜作为固态内参比电极。在368- 523 K范围内考察了该传感器的pH响应特性，发现在各个温度下，传感器的电位均随pH值的升高而线性下降，随温度的升高，电位-pH关系的梯度逐渐增大，当温度超过423 K时，与预测的能斯特值基本一致。通过电位与pH关系的外推估计的，接近于Ni-NiO参比电极的热力学计算值。当温度低于473 K时，传感器的pH响应缓慢，当温度超过473 K时，传感器的pH响应加快，在523 K时，传感器的电位在1小时内达到稳定。

A solid-electrolyte pH sensor using a yittria-stabilized zirconia (YSZ) has been developed for pH measurements in high temperature aqueous solutions. A thin film of Ni-NiO mixture, which was deposited on one side of the YSZ plate by ion-beam-sputtering, was used as a solid-state internal reference electrode. The pH response of the sensor was examined at temperatures in the range of 368-523K.It was found that at every temperatures examined, the potential of the pH sensor decreases linearly with increasing pH.The gradient of the potential vs. pH relationship increased with increasing temperatures, and it almost agreed with the predicted Nernstian value when the temperature exceeded 423K.The response potentials at pH0, which were estimated by extrapolation of the potential vs. pH relationships, were close to those calculated thermodymanically for a Ni-NiO reference electrode. The pH response of the sensor was slow at temperatures lower than 473K,but became faster when the temperature exceeded 473K ; the stationary potentials of the sensor were reached within one hour at 523K.