A study on the arc resistance and light reflectance of PTFE nozzle for circuit breaker is presented. PTFE has been used widely as a material for circuit breaker nozzle. In the arcing environment in a circuit breaker, the fraction of the radiation power is emitted out of the arc and reaches the nozzle wall by radiation, causing ablation at the surface and in the depth of the wall. In this paper, some tillers that have endurance in the high temperature arc environment were added into PTFE. Adding some tillers into PTFE was expected to be efficient in improving the endurability against radiation. The light reflectance and arc resistance of PTFE composites were investigated.

Several sol solutions were synthesized by using two kinds of nanosized boehmite and methyltrimethoxysilane (MTMS) according to the changing amount of MTMS at different reaction time. To understand their physical and chemical properties, sol-gel coating films were fabricated on glass. The sol solutions were prepared from boehmite of spherical shape (boehmite1)/MTMS and mixed boehmites of spherical and fibrous shapes (boehmite2)/MTMS. The soluble stability of boehmite1/MTMS was observed in the sol solution left for 24 h, however, that of boehmite2/MTMS was observed in the sol solution left for 48 h. The contact angle of sol-gel coating films from boehmite/MTMS increased with MTMS contents and reaction time. The films formed a flat surface with the increasing MTMS contents and decreasing reaction time. The electrical resistivity of films increased with MTMS contents. The thermal degradation of films occurred at approximately 400 oC.

Three kinds of colloidal silica (CS)=silane sol solutions were synthesized by using three kinds of CS at different reaction time. Sol solutions were prepared from 1034A CS=methyltrimethoxysilane (MTMS), HSA CS=MTMS and LS CS=MTMS materials. In order to understand their physical and chemical properties, sol-gel coating films were fabricated on glass. Coating film on glass, obtained from 1034A=MTMS sol, had high contact angle and much enhanced flat surface in comparison with those of HSA=MTMS and LS=MTMS sols. Enhanced surface properties were observed in the case of sol solutions left for 7 days. With increasing reaction time in sol solutions, surface free energy and roughness in coating films decreased. Good thermal stability was observed in all used films, i.e., no thermal degradation up to 550 C. In the case of 1034A=MTMS coating film, thermal degradation did not occur up to 600 C. In addition, microhardness of 1034=MTMS coating film was higher than those of HSA=MTMS and LS=MTMS due to active networking and surface treatment reactions between 1034A and MTMS.

No abstract

No abstract