DETERMINATION OF OXYGEN IN OXIDE CERAMICS BY INERT-GAS FUSION ANALYSIS - EFFECT OF BATH METALS

Oxygen in four kinds of oxide ceramics (Y2O3, ZrO2, TiO2 and Al2O3) was determined by the inert gas fusion method. To examine the gas extraction, Fe, Ni, Cu, Sn and Ti were used as a bath metals. From the analytical values and the gas extraction curves, it was considered that the promoting ability of these metals was higher in the order, Ti<Sn<Cu-Ni<Fe. The analytical results of ZrO2, TiO2 and Al2O3 obtained with Fe (or Ni), Cu and Fe, respectively, did not agree with the theoretical values, though the gas extraction curves showed rapid and complete decomposition. In the crucible after measurement, the metal bath formed a dome. Above results suggest that both bath metal and the sample were pushed up to the top of crucible by the generated CO gas, and that the decomposition was stopped or CO gas was adsorpted on the bath metal, by cooling down of the bath temperature. Use of Sn-Ni or Sn-Fe bath suppressed the dome formation and the analytical results were agreed well with the theoretical values.