IRON CORE EXHIBITING EXCELLENT INSULATING PROPERTY AT END FACE, AND METHOD FOR COATING END FACE OF IRON CORE

摘要

An iron core having an insulating coating film on the end face thereof which comprises a dried coating film of a pure silicon polymer, a modified silicon polymer and/or a mixed silicon polymer, the silicon polymers being defined i n the specification, has an average film thickness of 0.5 .mu.m or more, and exhibits a withstand voltage of 30 V or more and a heat resistance temperatu re in air of 400~C or higher; and a method for producing the iron core, which comprises forming an iron core and then subjecting the core to an immersion or spraying treatment using one or more of a pure silicon polymer, a modified silicon polymer and a mixed silicon polymer. The iron core is greatly excellent in insulating characteristics, corrosion resistance, adhesion of a coating to base iron, heat resistance, the effect to improve magnetic characteristics, and the like, and the method allows the practice of an insulating treatment for the iron core with no pre-treatment such as degreasing, annealing or the like at a low temperature in a short time.