Na2CO3 doping effect on ZnO–Pr6O11–Co3O4 ceramic varistor properties

Suitable Na2CO3 doping can enhance the varistor properties of ZnO–Pr6O11–Co3O4 ceramics. X-ray diffractometer (XRD), thermo-gravimetry analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to investigate the Na+ ion addition effects on the crystal phases, microstructure development and varistor properties of ZnO–Pr6O11–Co3O4 ceramics. The results imply that sodium ions will dissolve into praseodymium oxide and promote oxygen vacancy formation in praseodymium oxide. This phenomenon will enhance the oxygen diffusion and formation of zinc vacancies at the grain boundary. The varistor characteristics of ZnO–Pr6O11–Co3O4 ceramics can therefore be improved by adding Na2CO3.

► Na+ dissolved into praseodymium oxide and promote oxygen vacancy formation.
► Addition of Na+ enhanced the oxygen diffusion and formation of zinc vacancies.
► The varistor characteristics of ZnO–Pr6O11 can be improved by adding Na2CO3.