A galvanic cell type of hydrogen sensor was developed using proton conductor, indium doped calcium zirconate, as a solid electrolyte. Highly dense solid electrolyte and glass sealing improved the reliability (stable EMF value) of an electrochemical hydrogen probe and solid reference material instead of a gas reference serves to measure hydrogen concentration in atmospheres containing hydrogen.
Solid reference ($Ti/TiH_2$) sealed by glass could survive up to 900℃. The validity of the probe was confirmed by both experiments in a closed chamber using a controlled atmosphere and in molten aluminum . These results showed that the probe was very useful to monitor the hydrogen contents in the industrial plants.
