| 摘要 |
PROBLEM TO BE SOLVED: To make it possible in a coating composition for a silicon steel sheet to lower iron loss by reducing eddy current loss almost without lowering the space factor of a silicon steel laminate iron core and to thereby form an iron core inexpensively. SOLUTION: Calcium silicate and/or zinc phosphate as a curing agent is added to an alkali silicate, and the resultant mixture is mixed with a natural glass based on colemanite (2CaO, 3B<SB>2</SB>O<SB>3</SB>, 5H<SB>2</SB>O) and/or natural glass based on ulexite (Na<SB>2</SB>O, 2CaO, 5B<SB>2</SB>O<SB>3</SB>, 16H<SB>2</SB>O) as an inorganic filler in the form of fine flakes having an average particle diameter of 30μm and a thickness of 1.0μm or less for several hours in a ball mill. The obtained coating composition is applied to a 0.35 mm thick silicon steel sheet to form an about 5μm thick or thinner film thereon followed by drying with hot air of around 200°C for about 20-30 min. The obtained coating film is excellent in insulation properties, hardness, adhesion, water resistance, etc., is free of cracks and defects, and is tough, so that the coated silicon steel sheet can constitute a silicon steel laminate iron core realizing a space factor of 98.6% or higher and reduced eddy current generation. COPYRIGHT: (C)2008,JPO&INPIT
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