| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of forming an electrodeposition film and a method of forming multilayer coating film suitable for coating a steel material on which chemical conversion treatment is not applied or a steel material having an edge part and/or a burr part. SOLUTION: The method of forming electrodeposition film include a step of electrodepositing a cationic electrodeposition coating material composition on the steel material on which the chemical conversion treatment is not applied and heating and curing the resultant electrodeposition film to obtain a cured electrodeposition film. The cationic electrodeposition coating material composition used in the electrodeposition coating film forming step contains a complex salt, a double salt or a mixed compound comprising: (a) molybdic acid; (b) a metal or the metal oxide selected from a group comprising zinc, cerium, bismuth, zirconium and yttrium wherein the ratio (a):(b) of metal elements (a) and (b) by weight is (1:99)-(50:50). COPYRIGHT: (C)2009,JPO&INPIT
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