The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 11, 2015
Filed:
Dec. 27, 2007
Jeong He-lee, Pohang-si, KR;
Young Hwan Kim, Pohang-si, KR;
Jong Hee Kim, Daejeon, KR;
POSCO, Pohang-Si, Gyeongsangbuk-do, KR;
Abstract
Disclosed is a method for improving surface properties of the stainless steels for bipolar plate of polymer electrolyte membrane fuel cell having low interfacial contact resistance and excellent corrosion resistance. The method for improving surface properties of the stainless steels according to one exemplary embodiment of the present invention includes: pickling a stainless steel with an aqueous sulfuric acid solution, the stainless steel comprising, by weight: C: 0.02% or less, N: 0.02% or less, Si: 0.4% or less, Mn: 0.2% or less, P: 0.04% or less, S: 0.02% or less, Cr: 25-32%, Mo: 0.1 to 5%, Cu: 0.1 to 2%, Ti: 0.5% or less, Nb: 0.5% or less, and the balance of Fe and other inevitable elements, and then washing the stainless steel with water, and then immersing the stainless steel in a mixture solution of nitric acid and hydrofluoric acid to form a passivation layer.