Authors: J.W. Kim, M.S. Kwon, C.H. Han
Affilation: POSCO, Korea
Pages: 651 - 654
Keywords: non-oriented electrical steel, nano-sized colloidal silica, insulation resistance, series micro-dielectric effect
The effect of a nano-sized silica particle on the surface insulation resistivity of non-oriented electrical steel sheet was investigated. Several kinds of nano-sized colloidal silica were mixed to the chromium-free coating solution, which is consisted of mixture of metal phosphate and polyester resin. To explain the mechanism of insulation resistance in the coating layer, the series micro-dielectric effect is introduced. In well-dispersed nano-sized particle in the coating layer, the successive micro-dielectric results in the electrical insulation resistance. As a result of successive micro-dielectric, the value of insulation resistance was increased. As an experimental result, it was found that the size and solid content of a nano-sized silica particle were strongly influenced on the properties of insulation resistance. It is increased by decreasing the particle size of silica and increasing solid content of silica. It is, however, only increased to a certain extent of solid content and then it begins to decrease because an aggregation and cohesion phenomena are broken out at high percent of silica content.