| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a composition for forming a film which has excellent rust preventability on the surface of a metal substrate and further has a self-repair action without using harmful chemicals such as hexavalent chromium, and to provide a method for forming a film and a rust prevention-treated metal. <P>SOLUTION: The composition for forming a rust preventive film is used for treating the surface of a metal substrate 2, and contains as essential components: (1) ions selected from among vanadic acid ions, vanadin ions and vanadyl ions with a concentration of 0.1 to 20 g/l expressed in terms of V; (2) ions selected from titanic acid ions, fluorotitanic acid and titanium ions with a concentration of 0.1 to 50 g/l expressed in terms of Ti; (3) silicic acid ions and/or colloidal silica with a concentration of 0.1 to 50 g/l expressed in terms of Si; and (4) nitric acid ions with a concentration of 9.0 to 300 g/l supplied from a mixture of one or more kinds of nitrates selected from among NH<SB POS="POST">4</SB>NO<SB POS="POST">3</SB>, KNO<SB POS="POST">3</SB>, NaNO<SB POS="POST">3</SB>, LiNO<SB POS="POST">3</SB>and Ca(NO<SB POS="POST">3</SB>)<SB POS="POST">2</SB>, wherein pH is adjusted to the range of 0.1 to 5.5. <P>COPYRIGHT: (C)2012,JPO&INPIT |
