Study On Tape Casting Of Chip Thermistors And Co-fired Technology

With the rapid development of modern electrical and communication technology, miniaturization, portability, high speed, multifunction and high reliability have become the main demand of the electrical device. Modern electronic component development gradually turned to multilayer and chip type. For the advantage of reducing size and low room temperature resistance, the co-firing multilayer ceramic PTCR component research became hot point recently. The paper researched the key technology about fabricating co-firing multilayer PTCR component by the national"863"project financed, the main content included as follows.For the first time introduced tape casting for fabricating PTCR ceramic tapes based BaTiO3, the viscosity of non-aqueous slurry and the cast tape thickness were also analyzed, a cast tape with the thickness of 100μm and well mechanics performance was prepared. Based on the research of sintering curve, material which sintered at 1300℃with the lowest room resistivity of 38.8?·cm, ratio of maximum to minimum of resistance of 6.30 and temperature coefficient of 15.56%℃-1 was prepared. For the demand of environmental protection, the aqueous tape casting also was researched. Through the comparison between PAA latex blinders and PVA blinders, found that PAA blinders excelled PVA blinders whether solid loading, viscosity and electrical performance after sintering, and therefore more suited to aqueous tape casting.Discussed the characteristics and difficulties of high temperature co-fired ohmic electrode, and introduced the composition and performance of common Ni-Pd compound ohmic electrode. Corresponding to it, the physical chemical properties, oxidation resistance and microstructure of Ni-Cr cheap electrode were investigated.The defect chemistry knowledge and oxygen diffusion kinetics base were studied when BaTiO3 sintering in various atmosphere. Through the research on electrical performance of ceramic which sinter in two kind atmosphere, discussed the principle of the reduce atmosphere composition. After the trial of co-fired multilayer chip type component, found the difficulties were oxidation resistance of interior electrode and interface contact between the electrode and ceramic.