Preparation of composite electroheat carbon film
(College of Materials Science and Engineering, Hunan University,
Changsha 410082, China)
Changsha 410082, China)
Abstract: A kind of conductive and heating unit, which can reach a high surface electroheat temperature at a low voltage, was developed in view of the traditional electroheat coating which has a low surface electroheat temperature and an insufficient heat resistance of its binder. The coating molded electroheat carbon film(CMECF) was prepared by carbonizing the coating which was prepared by adding modified resin into flake graphite and carbon fiber, coating molded onto the surface of the heat resisting matrix after dried, while the hot pressing molded electroheat thick carbon film(HPMETCF) was prepared by carbonizing the bodies whose powders were hot pressing molded directly. The surface and inner microstructure of the carbon film was characterized and analyzed by SEM and DSC/TG, while electroheat property was tested by voltage-current volume resistivity tester and electrical parameter tester. The results show that, close-packed carbon network configuration is formed within the composite electroheat carbon film which yields a volume resistivity of 0.5×10-2-10.0×10-2Ω•cm at room temperature. The electroheat carbon film after anti-oxidizable treatment reaches a higher surface electroheat temperature than that of the existing electroheat coatings at a low voltage, and has excellent electroheat property, high thermal efficiency as well as stable physicochemical property. It is found that, at room temperature(19±2℃) and 22V for 5min, the surface electroheat temperature of the self-produced CMECF (mfiller/mresin=1.8/1) reaches 112℃ while HPMETCF (mfiller/mresin=3.6/1) reaches 265℃.
Key words: electroheat carbon film; electroheat property; modified resin; preparation process