THERMODYNAMIC INVESTIGATION OF CERAMIC MATERIALS AT ELEVATED TEMPERATURES
CINCINNATI UNIV OHIO
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Electromotive forces from the change of partial free energy of O in TiO varied from 100 to 5 mv after 4 hr at 1375 K. Fairly constant values of electromotive force were obtained for the reaction of 2 Zr ZrO2 3 ZrCr2 equals 2 Zr3Cr3O18 mv at 1510K and 21 mv at 1550K. The half cells were ZrZrO2 and Zr2ZrZr3Cr3O.All the transition metals Ta, V, Nb, Mo, Cr, and W stabilize c-ZrO2 with TiO2 and another metal. Nb2O5 and Ta2O5 were substituted for TiO2 in 2 experiments no c-ZrO2 was formed. Similar compounds 6ZrO2.Nb2O5 and 6ZrO2.Ta2O5 were formed in each experiment and the d values in the 2 structures coincided some reduction occurred with the Nb2O5 but not with Ta2O5. After heating for 4 hr at 1200 C, Zr2Cr2O is present in large quantities when prepared with Cr, Zr, and Cr2O3 or Cr, Zr, and ZrO2. High purity boron phosphide, prepared from BCl3 and PH3 and degassed at 1200 K to constant weight, had a smaller residue than that stoichiometrically calculated for the expected end product, B6P.