Effect of Defect Characteristics on the Color of BaTiO3-Based PTC Ceramic

The barium titanium based PTC ceramic with two kind of colors, light blue and yellow, were obtained by changing sintering processing. In order to reveal the relationship between color and electrical properties of the ceramics. The phase structure and microstructure of as synthesized samples were investigated by powder X-ray diffraction (XRD) and scanning electron microscopic (SEM) analysis. The micro area elements were characterized by electron probe micro-analyzer (EPMA) and x-ray photoelectron spectrometer (XPS). The thermo-sensitive properties were studied by resistance-temperature measurement system. The results reveal that two kinds of PTC ceramics have the same structure, similar elements, but different microstructure and valence concentration of titanium. It is suggested that difference of color of the PTC ceramics are originated from the defect concentration of titanium.