Method of producing annealing separator, annealing separator, and grain-oriented magnetic steel

Abstract

The invention provides a method of producing an annealing separator, an annealing separator and a grain-oriented magnetic steel. An annealing separator obtained by the method has high purity and excellent dispersibility and bonding strength, thus allowing formation of a uniform, dense forsterite layer on the surface of a grain-oriented magnetic steel. The method of producing an annealing separator comprises the following steps: step (1) in which magnesium oxide and an ammonium salt solution are mixed and reacted to prepare a magnesium salt solution and ammonia, and then the purified magnesium salt solution and the ammonia are reacted to obtain magnesium hydroxide, step (2) in which one portion of the obtained magnesium hydroxide is subjected to high temperature ageing at 155 to 230° C. while another portion of the obtained magnesium hydroxide is subjected to low temperature ageing at 10 to 100° C., and step (3) in which the magnesium hydroxides aged under the different conditions are mixed and burned to obtain magnesium oxide for use as an annealing separator.

Dependencies are inferred from the claim text.