Effect of Ti-Doped in (LaMn1-xTixO3)0.67(NiMn2O4)0.33 Ceramics on Microstructure and Electrical Properties

A series of NTC (Negative temperature coefficient) composite material of (LaMn1-xTixO4)(0.67)(NiMn2O4)(0.33) was prepared by solid-state method. The calcined temperature, particle size, ceramics phase structure, morphology, R-T property and electrical stability were characterized by TG/DSC, Laser particle size analyzer, XRD, SEM, resistance-temperature measurement and aging test, respectively. The results show that in the range of 1 200 similar to 1 300 degrees C sintered temperature, the electrical resistivity rho(25 C degrees) of the composite ceramics increased significantly with Ti content increased. The rho(25 degrees C) are found to be in the range of 4.4 similar to 53 179 Omega.cm and the B-25/50 values are 1 357 similar to 3 998 K. The resistance drift rate Delta R/R-0 of the composite ceramics after 1 000 h aging test at 125 degrees C was less than 0.51%. The electrical resistivity and B value of (LaMn1-xTixO3)(0.67)(NiMn2O4)(0.33) could be adjusted to desired values. The composite system has high stability. Therefore, the (LaMn1-xTixO3)(0.67)(NiMn2O4)(0.33) could be used for NTC theunistor as advanced semi-conducting materials.