Influence of Surface Treatment before Coating on Magnetic Properties of TiN-Coated Grain Oriented Silicon Steel Sheet

In order to clarify the influence of the pre-treatment on the magnetic properties of TiN-coated silicon steel sheets, various acid treatments on the silicon steel sheets were done prior to the TiN coating by the HCD method.With chemical polishing prior to TiN coating, the iron loss W17⁄50(W/kg) of the TiN-coated silicon steel sheets was dramatically improved by 0.20-0.24 W/kg. In contrast, with the pre-treatments with 10%H2SO4 and 10%HCl solutions, the improvement of W17⁄50(W/kg) was reduced to 0.1-0.14 W/kg. Also, the improvement of W17⁄50(W/kg) in the pre-treatment with the H2SO4 solution was less than that with the HCl solution.By the pre-treatments with 10%H2SO4 and 10%HCl solutions, the value of W17⁄50(W/kg) became lower than that of a silicon steel product, but by subsequent TiN coating both We and Wh were improved. However, the improvement of W17⁄50(W/kg) due to the pre-treatment with these acid solutions showed 60-70% of that in the case of chemical polishing.The thin-film X-ray diffraction in the 111 peak intensity of TiN became weaker in the order of chemical polishing, the 10%HCl solution and the 10%H2SO4 solution, and in the latter case showed 200, 220 and 311 peaks of TiN.