烧结温度对碳陶瓷线性电阻相组成及性能影响

Effect of Sintering Temperature on Phase Composition and Performance of Carbon-Ceramic Linear Resistor

碳-陶瓷线性电阻是由碳黑导电材料、粘土和煅烧矾土骨料在还原氛下高温烧结制成。研究了碳陶瓷线性电阻结过程中相组成及断口微观形貌的变化规律,研究了烧结温度对电阻气孔率、烧结收缩率、力学强度及电学性能的影响规律。实验结果表明,电阻相组成变化主要由粘土相变化引起,烧结过程中粘土的分解及莫来石相的形成影响导电材料的分布,从而影响电阻的电性能、力学强度。烧结温度在700~1500℃时,电阻率呈先下降后上升趋势,力学强度在1400℃时达最高,烧结温度继续升高,莫来石相二次结晶长大造成电阻力学强度下降。

Carbon-ceramic linear resistors are made of carbon black conductive material,clay and calcined bauxite aggregate under high-temperature sintering in a reducing atmosphere.The author studied the changes of phase composition and fracture micromorphology during the sintering process of carbon-ceramic linear resistance,and made research on the influence of sintering temperature on the resistance porosity,sintering shrinkage,mechanical strength and electrical properties.The results show that the change of resistive phase composition is mainly caused by the change of clay phase.The decomposition of clay and the formation of mullite phase during sintering affect the distribution of conductive materials,thereby affecting the electrical properties and mechanical strength of the resistor.When the sintering temperature is 700~1500℃,the electrical resistivity decreases firstly and then increases;the mechanical strength reaches the highest at 1400℃.As the sintering temperature continues to increase,the secondary crystallization of mullite phase causes a decrease in the mechanical strength of the resistor.