热处理对高温粘结石墨部件导电性能的影响

INFLUENCE OF HEAT TREATMENT ON THE CONDUCTIVITY OF GRAPHITE JOINT BONDED BY HIGH TEMPERATURE ADHESIVE

以酚醛树脂和B4C为原料制备高温粘结剂并对石墨材料进行粘接 ,测试了经不同温度热处理后接头部位的导电性能。并利用XRD和SEM对热处理后的粘接接头结构进行了表征。结果表明 ,热处理温度对粘接接头的导电性能有着决定性的作用。 10 0 0℃以下的热处理阶段 ,随温度的升高 ,石墨接头的电阻率迅速降低 ,10 0 0℃以上高温热处理后接头的导电性能良好 ,电阻率变化不大。此外 ,由于B4C的半导体特性和高温下的催化石墨化作用 。

High temperature adhesives were prepared with phenol formaldehyde resin as matrix and B 4C powders as additives. The graphite samples bonded by the above adhesives were heat treated at different temperatures ranged from 200?℃ to 1?500?℃. Subsequently their conduct electricity was tested. The structure of the joint was also characterized by means of XRD and SEM. The results showed that the heat treatment temperature had critical influence on the joints' conduct electivity. The specific resistance reach its maximum value when the graphite joints were treated at 200?℃ because of the non conduct character of phenol formaldehyde resin. But the specific resistance of the joint decreased rapidly with increasing of heat treatment temperature below 1?000?℃. With the treatment temperatures rising higher than 1?000?℃, the graphite joints showed satisfing conductivity performance with specific resistance decreased slowly. Additionally, the boron carbide also had important influenced on the electrical conductivity of the joint due to its semi conductor and graphitzation effect.