In order to carry out in-situ measurement of hydrogen content in molten aluminum, a galvanic cell type hydrogen sensor was constructed using CaZr0.9In0.1O3-α as a solid electrolyte. This sensor exhibited stable electromotive force (emf) corresponding to hydrogen content (S). A linear relation was found between emf and logarithm of S2. The hydrogen content determined by this sensor was in good agreement with that measured by Telegas method.
