Effect of copper on the electrical properties of K-1.6(Mg1-yCuy)(0.8)Ti7.2O16 ceramics

摘要

The electrical conductivity of the K-1.6(Mg1-yCu)(0.8)Ti7.2O16 ceramics has been investigated as a function of copper fraction (0 less than or equal to y less than or equal to 1). At the calcination temperature of 1000 degrees C, a tetragonal-single phase was obtained for the all compositions. In the specimens sintered at 1100 degrees C for 4 h, the electrical conductivity of the specimens increased with the increasing copper fraction, y. This result can be explained by the weakness of the K-O bonding and the increase of the bulk density and grain size. For the specimens with copper fraction (0 less than or equal to y < 0.8), the electrical conduction was developed mainly by ionic conduction while electronic conduction abruptly occurred at copper fraction y greater than or equal to 0.8. This resulted from the valence transition of copper ions associated with the formation of oxygen vacancies. [References: 18]