STUDY OF THE OXYGEN-SENSITIVE BEHAVIOR OF YELLOW LEAD-OXIDE BY DEFECTCHEMISTRY

The dependence of electrical conductivity on ambient oxygen partial pr essure of yellow lead oxide ceramics is investigated. A conduction typ e transition is observed for pure PbO as the oxygen partial pressure v aries through a certain value that corresponds to the minimum conducti vity measured, and the conductivity is found to vary with - 1/4 and 1/4 power of the oxygen partial pressure in the n region and the p reg ion, respectively. It is also found that the conduction transition poi nt can be moved to lower or higher oxygen partial pressures with accep tor or donor impurities doped into PbO. A point defect model of doubly charged oxygen vacancies with concentration affected by impurities is presented for PbO in the investigation and it is demonstrated that th e theory is in good agreement with the experimental results.