COATING FLUID FOR INSULATING COATING OF GRAIN-ORIENTED SILICON STEEL SHEET EXCELLENT IN ADHESION RESISTANCE AND SPACE FACTOR AND FORMATION OF INSULATION COATING

摘要

PROBLEM TO BE SOLVED: To form an insulation coating capable of suppressing the adhesion of steel sheets to each other without reducing space factor by coating a finish- annealed grain-oriented silicon steel sheet with a coating fluid contg. a specified amt. of inorg. mineral particles of a specified average particle diameter, drying and baking the fluid. ;SOLUTION: A coating fluid for a tension applying insulation coating contg. 0.02-20 wt.% inorg. mineral particles of 2 to ≤20 μm average particle diameter on solid basis is prepd. A finish-annealed grain-oriented silicon steel sheet is coated with the coating fluid and this fluid is dried and baked to form the objective tension applying insulation coating excellent in space factor and resistance to adhesion due to strain relief annealing. The coating fluid contains a phosphate, chromic acid and colloidal silica as principal components and is prepd., e.g. by formulating about 50 wt.% aq. aliminum phosphate soln. contg. chromic acid with an aq. dispersion of colloidal silica having about 20% concn. and aluminum particles of about 0.6 μm average particle diameter.;COPYRIGHT: (C)2000,JPO