摘要 |
1,218,678. Modifying steel surfaces. KAWASAKI SEITETSU K.K. April 16, 1969 [Oct.28, 1968], No.19527/69. Heading C7U. A silicon steel sheet for use in transformers is formed with an insulating coating by contacting with an aqueous solution consisting of (parts by weight) 100 monobasic magnesium phosphate, 5 to 30 chromic anhydride, and 0À4 to 2À1 based on aluminium of aluminium nitrate or amorphous aluminium hydroxide. The solution may also contain a surface active agent and colloidal silica or mica. The coating may be baked at 300 to 600‹C. The steel sheet may first be provided with a nitreous coating of e. g. MgO-SiO 2 . |