Effects of ammonium tungstate on the properties of insulating coating for grain-oriented silicon steel

The effects of (NH4)(2)WO4 on the properties of phosphate insulating coating for grain-oriented silicon steel were studied. It is shown that, with gradually replacing CrO3 by (NH4)(2)WO4 in the coating solution, the wettability of coating solution first enhances and then degrades. The interlamination resistance, lamination factor and magnetism induction intensity of silicon steel first increase and then decrease, the core loss first decreases and then increases. When the (NH4)(2)WO4 content is 1.0 wt%, the coating solution shows the best wettability on the silicon steel substrate. The formed insulating coating is compact and smooth with improved corrosion resistance, there is a transition layer 0.6-0.8 mu m between the insulating coating and the forsterite sub-coating. Furthermore, the humidity resistance of the insulating coating is not significantly changed. The optimal interlamination resistance, lamination factor, magnetism induction intensity and core loss of grain-oriented silicon steel can be obtained, which are 18,021 Omega mm(2), 97.1%, 1.872 T and 1.113 W.kg(-1), respectively.