Ceramic / inorganic-organic nano-hybrid composites for thermally stable insulation of electrical wires. Part II: Properties of the composite insulated wires

摘要

The paper Part I reported on the fabrication of high temperature capable electrical wires insulated with a new type of composite coatings comprising particulate ceramics and silicon-containing inorganic-organic nano-hybrids. This second paper studies the thermal, mechanical and dielectric properties of these composite insulated wires in accordance with relevant national standards. Techniques for materials characterization were also applied to provide information for better understanding the coatings' performance as wire insulation. Results showed that insulated wires have moderate dielectric strength comparable to ceramic insulation and excellent thermal stability, with insulation sustained for over 100 days at 500 degrees C and prolonged period at 450 degrees C under constant high temperature ageing and there is no obvious insulation degradation after thermal cycling for 20 times. The insulated wires demonstrated good mechanical properties, with interim flexibility allowing a minimal bending radius of 3 mm for 1.2 mm insulated wires. The resistance to abrasion and cutting through are also good enough to satisfy most practical applications.