THE ELECTRICAL BEHAVIOR OF REFRACTORY OXIDES
SYSTEMS RESEARCH LABS INC DAYTON OHIO
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Polycrystalline disc shaped samples for conductivity and polarization measurements were made of ZrO2. The discs were coated with Pt paste and fired, yielding Pt electrodes measuring less than 1 ohm across each face. Conductivity mea urements were made from 200 to 1360 C the monoclinic-tetragonal phase transformation caused a hysteresis loop in the conductivity curve. The inversion occurred near 1170 C on heating and 1030 C on cooling. Conductivity was greater at the same temperature in the tetragonal modification. the activation energy for conduction of ZrO2 in the tetragonal modification was 1.05 e.v., lower than the 1.5 e.v. in the monoclinic phase at the same temperature. Polarization data yielded a transport number of 0.2 for electrons in monoclinic ZrO2 at 907 C. Attempts to grow single crystal ZrO2 are discussed. Several small platelets too small for x-ray diffraction analysis were presumed to be ZrO2 through indirect tests.