Toward a new PTCR material based on the Na2Ti6O13/Na2Ti3O7 system

Mixed phases of sodium titanate ceramics are obtained using both conventional and laser sintering methods. It was observed a clear dependence on the structural, microstructural and electrical resistivity with the employed sintering method. The temperature dependence of the resistivity in the ceramics shows an increase of three orders of magnitude in a narrow range of temperatures, thereby indicating a noticeable positive temperature coefficient of resistivity (PTCR) effect. To explain this observed abnormal behavior, a model based on the structure of the Na2Ti6O13/Na2Ti3O7 composite is proposed. A new class of PTCR materials is reported.Postprint (author's final draft