US 11,912,879 B2
Film forming method of corrosion resistant film, corrosion resistant member on which corrosion resistant film is formed, heat exchanger, and fuel cell system
Tomoharu Kataoka, Yaizu (JP); Masao Watanabe, Okazaki (JP); and Yuya Kusano, Nagoya (JP)
Assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Filed by TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Filed on Mar. 11, 2021, as Appl. No. 17/198,490.
Claims priority of application No. 2020-066821 (JP), filed on Apr. 2, 2020.
Prior Publication US 2021/0309862 A1, Oct. 7, 2021
Int. Cl. H01M 8/04 (2016.01); C09D 1/00 (2006.01); H01M 8/04014 (2016.01); H01M 8/04029 (2016.01); F28F 19/06 (2006.01); H01M 8/04111 (2016.01); C23F 11/18 (2006.01); H01M 8/04007 (2016.01)
CPC C09D 1/00 (2013.01) [C23F 11/182 (2013.01); F28F 19/06 (2013.01); H01M 8/04014 (2013.01); H01M 8/04029 (2013.01); H01M 8/04074 (2013.01); H01M 8/04111 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A film forming method of a corrosion resistant film, comprising:
bringing a substrate made of aluminum into contact with an aqueous solution containing sulfate ions and fluoride ions; and
heating the substrate to boil the aqueous solution on a surface of the substrate to form a corrosion resistant film on the surface of the substrate, the corrosion resistant film containing oxygen, fluorine, and sulfur derived from the aqueous solution and aluminum derived from the substrate,
wherein during the heating, air bubbles are repeatedly generated in the aqueous solution on the surface of the substrate and desorbed from the surface of the substrate, resulting in repeated dissolution of an oxide film on the surface of the substrate and repeated taking of the sulfate ions and the fluoride ions into the surface of the substrate to form the corrosion resistant film.