Thermal stresses in surface-coated Fe-3%Si sheet

The aim of the paper is to present a model of thermal stresses in a layered plane system, and consequently to verify the model validity by comparing calculated thermal stresses with measured thermal stresses. The paper deals thus with thermal stresses in the Fe-3%Si sheet for magnetic applications, having a surface coating of the 2MgO.TiO2, ZrO2, TiO2, Al2O3, 2MgO.SiO2, MgO.Al2O3 oxides. The thermal stresses, originating during a cooling process as a consequence of the difference in thermal expansion coefficients between the Fe-3% Si sheet and the surface coating, degrade hysteresis losses of the Fe-3%Si sheet. Magnetic properties of the presented coating-Fe-3%Si systems, as the magnetic induction and the hysteresis losses before and after coating formation, are presented. The theoretical background, including the model of the thermal stresses in anisotropic and isotropic two-layered plane systems, consequently transformated to the three-layered plane system, is presented. Calculated thermal stresses are compared with those of a tension measurement of the presented coating-Fe-3%Si systems, numerical equality of the calculated and measured thermal stresses is observed. (C) 2003 Kluwer Academic Publishers.