【摘要】 按照ZrB2和SiC的质量比为7525配料,混料、烘干、热压烧结后,经线切割加工成ZrB2-SiC复合陶瓷直型发热体,研究了发热体的物相组成、微观形貌及在空气和氩气气氛下发热温度随电流电压的变化规律。结果表明,ZrB2-SiC复合陶瓷由均匀分布在ZrB2基体晶界处的SiC颗粒和尺寸小于10μm的等轴状基体ZrB2颗粒组成;在空气和氩气气氛下,ZrB2-SiC复合陶瓷发热体的温度均随电流、电压及加热时间的延长呈稳步增大趋势,同时空气气氛下发热体的电阻随温度升高而增大,并呈现线性变化;在空气和氩气气氛下,ZrB2-SiC复合陶瓷发热体表面温度分别达到1800和2200℃。同时,与铬酸镧和氧化锆发热体相比,其电压、电阻变化较小,电流较大。更多还原

【Abstract】 ZrB2-SiC composite ceramic straight heating elements were prepared using ZrB2 and SiC as starting materials( the mass ratio of ZrB2 SiC = 75 25),mixing,drying,hot pressing sintering,and then linear cutting. The phase compositions and microstructure of the heating elements,and the change of heating temperature with current and voltage in air and Ar atmosphere were researched. The results show that:( 1)ZrB2-SiC composite ceramics are composed of SiC grains( well distributed around the crystal boundaries of ZrB2) and the equant ZrB2grains( < 10 μm); temperature of the heating element rises gradually with voltage and electric current increasing and heating period prolonging in air and Ar atmosphere. Meanwhile,in air,the heating element resistance increases with temperature rising linearly; in air and Ar atmosphere,the surface temperatures of the heating elements reach 1 800 and 2 200 ℃,respectively. Compared with the chromate lanthanum and zirconia heating elements,the voltage and resistance change of the developed ones are smaller and the current change is larger.更多还原