High-temperature oxidation behavior of PbTe and oxidation-resistive glass coating

Oxidation of lead telluride (PbTe) is a serious issue for thermoelectric applications. In the present study, the oxidation behavior of PbTe was studied at oxygen partial pressures of 10 Pa to 0.1 MPa in the temperature range between 700 and 900 K. At moderately low oxygen partial pressures and high temperatures, mass loss was observed and the oxide layers (Pb/sub 3/TeO/sub 5/ or Pb/sub 5/TeO/sub 7/) formed on the PbTe surface. At high oxygen partial pressures and low temperatures, mass gain was observed and PbTeO/sub 3/ or Pb/sub 2/TeO/sub 4//PbTeO/sub 3/ oxide layers formed on the PbTe surface. When the temperature was higher than 819 K, PbTeO/sub 3/ melted and dropped down from the specimen. Oxidation-resistive glasses were coated on the PbTe surface. The glass-coated PbTe showed excellent oxidation resistance showing no mass change at 773 K.