| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electromagnetic steel sheet having a chromium-free insulation coating film which has various required properties such as rust prevention, adhesiveness, and heat resistance and does not produce sticking even if it is subjected to stress-relief annealing in an oxidizing atmosphere after blanking. <P>SOLUTION: The insulation coating film is composed only of an oxide layer formed from one or two or more oxides selected from the group consisting of SiO<SB POS="POST">2</SB>and oxides (for example, CaO and Al<SB POS="POST">2</SB>O<SB POS="POST">3</SB>) capable of vitrifying in cooperation with silica. Alternatively, the insulation coating film has, on the oxide layer, an upper layer formed by applying a liquid containing a water-soluble polyvalent metallic salt followed by baking. The adhesion amount of the oxide layer is 0.3-1.5 g/m<SP POS="POST">2</SP>as the total adhesion amount of the oxides, and the adhesion amount of the upper layer is 1.5 g/m<SP POS="POST">2</SP>or less. The upper layer may be a semi-organic coating film containing a synthetic organic resin. <P>COPYRIGHT: (C)2012,JPO&INPIT |
