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AssigneesHitachi, Ltd., Hitachi Engineering Co., Ltd.
InventorsYasumasa Furutani, Yasuo Hira, Takashi Hasegawa, Akira Minato, Saburo Shoji, Osao Sumita
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The present invention provides a process for removing a metal surface oxide from a metallic substance by contacting the metal surface oxide layer with a deterging liquid to introduce electrons into the metal surface oxide in contact with the deterging liquid to dissolve the metal surface oxide, which process is characterized in that a metal piece or carbon piece is immersed in the deterging liquid into which gaseous hydrogen has been introduced and the metal piece or carbon piece is electrically connected to the metal surface oxide on the metallic substance. The metal piece is preferably platinum or vanadium. A preferred deterging liquid is one having a pH of about 5 to 7 and containing a complexing agent.
A process for removing a metal surface oxide layer from a metallic substance by contacting the metal surface oxide layer with a gaseous hydrogen containing deterging liquid to introduce electrons into the metal surface oxide in contact with the deterging liquid and to dissolve the metal surface oxide, wherein the metal surface oxide layer is composed mainly of an iron oxide, the electrons are formed on the metal surface oxide layer, and the deterging liquid contains at least one of an organic acid, an organic salt or an organic complexing agent, and further wherein a metal piece selected from at least one of platinum, palladium, nickel, iron, copper and stainless steel or a carbon piece is immersed in the deterging liquid and the metal piece or the carbon piece is electrically connected with the metal surface oxide layer of the metallic substance.
A process for removing a metal surface oxide layer from a stainless steel pipe by contacting the metal surface oxide layer with a deterging liquid containing gaseous hydrogen to introduce electrons into the metal surface oxide layer in contact with the deterging liquid and to dissolve the metal surface oxide, wherein the metal surface oxide layer is composed mainly of an iron oxide, the electrons are formed on the metal surface oxide layer, and the deterging liquid contains a complexing agent, and further wherein a stainless steel plate plated with one of platinum, palladium or nickel is immersed in the deterging liquid and the plated stainless steel plate is electrically connected to the metal surface oxide on the stainless steel pipe.
Dependencies are inferred from the claim text.