Hydrogen-induced degradation in CaCu3Ti4O12 ceramics

Hydrogen-induced degradation in CaCu3Ti4O12 (CCTO) ceramics was studied using an electrochemical hydrogen charging method, in which the silver electrodes of CCTO ceramic pellets were made a cathode in 0.01 M NaOH solution to deposit hydrogen through the electrolysis of water. The dielectric loss was greatly increased and the insulation resistance was greatly decreased after the treatment. X-ray diffraction analysis showed that no new phases were formed. It is proposed that atomic hydrogen is diffused into CCTO lattice and free electrons are formed through the ionization of hydrogen atoms, which lead to the observed degradation. Hydrogen-induced degradation occurs very quickly in CCTO ceramics and it is important to prevent hydrogen-induced degradation in CCTO ceramics.