Research Of Lsco Thick Film Resistor Paste

The purpose of the topics is to lower the current high cost of thick film resistor paste. LSCO (La0.6Sr0.4CoO3) has excellent electrical properties at room temperature, it is used as functionality materials to replace traditional ruthenium and silver thick film resistor paste. The slurry modulation, screen printing and high temperature sintering were used for sample preparation. the square resistance of prepared thick film ranging from1KΩ/□to10MΩ/□. The effects of the functional phase, inorganic bonding phase and preparation process of thick film to thick film resistor was studied.LSCO was selected as functionality phase materials of resistor paste, and study its feasibility analysis on room temperature properties. The room temperature conductivity of LSCO is3.07×104S/m, it’s used as functionality phase materials to prepare thick film components, the resistance could greater than3.26Ω/□, similar to the square resistance of present thick film resistor paste on the market (1Ω/□to100MΩ/□). The LSCO has good chemical stability, does not react with the impurities and the glass phase after the high-temperature sintering, and can be good to keep its conductive properties. Thermal expansion coefficient of LSCO is13.7×10-6/K, close to the stainless steel substrate (11.0×10-6/K), so it’s applicable as the functionality phase materials of stainless steel substrate thick-film resistor paste.The glass was design as inorganic bonding to suitable for the LSCO function phase. The preparation of the glass, the influence of the electrical performance of thick film with the thermal expansion coefficient of glass and the content of glass was discussed. The results show that, the smaller the thermal expansion coefficient of the glass, the greater difference between glass and functionality phase materials, the smaller resistance of the prepared thick film. Content of glass phase in thick-film to electrical properties has a critical value of5%, when the percentage of the glass phase is less than5%, thick Film square resistance slowly increased with the increase of glass content; when the glass phase content greater than5%, the square resistance of the thick film increased dramatically with the increase of glass content.Preparation of thick film resistor paste with proportion between solid powder and terpineol-ethyl cellulose organic vehicle (terpineol:ethyl cellulose=92:8) is30:70. Screen printing was used as thick film preparation process to print the insulation layer and resistive layer on the stainless steel substrate. The effect of electrical properties of thick film resistors with the thickness of the layer of thick film, the sintering process and the additive was studied. The results show that, the square resistance and TCR of the thick film resistors has the approximate non-linear inverse relationship when the thick film resistor component and the substrate is certain. Selection of different glass as inorganic binder, there will be a corresponding optimal peak sintering temperature, when the peak sintering temperature below the optimal peak sintering temperature, the square resistance of thick film changes little, when the peak sintering temperature is higher than the optimal peak sintering temperature, the square resistance of the thick film increased dramatically. With the introduction of additives, the electrical properties of the thick film will change a lot, the square resistance and TCR of the thick film will decrease with the introduction of CuO and Bi2O3; the square resistance will increase and TCR will decrease with the introduction of MnO2.