화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.38, No.25, 10833-10838, 2013
Silver coating on porous stainless steel substrate and preparation of H-2-permeable palladium membranes
The H-2-permeable palladium membranes based on porous stainless steel (PSS) substrate are important for development of various hydrogen energy systems. To improve the surface of the PSS, a microporous silver layer was deposited successively by a coating with a suspension of silver powder in polyvinyl alcohol (PVA) solution, a heating under nitrogen at 500 degrees C for carbonization of PVA, an air treatment and a hydrogen reduction. The formation of carbon from PVA helps to maintain the porosity and integrity of the silver layer. After an activation of the resulting Ag/PSS surface through galvanic-cell reaction, palladium membranes with a thickness around 4 mu m were successfully prepared by a suction-assisted electroless plating. SEM, EDS, metallography and porometry analyzes were conducted for material characterizations. The prepared Pd/Ag/PSS membrane is permeable and selective as compared with similar those reported in literature. The permeation tests were carried out at 350, 400, 450 and 500 degrees C for 48, 48, 48 and 60 h, respectively, and the membrane was found to be unstable at 500 degrees C due to the presence of pinholes. No significant intermetallic diffusion between the silver and palladium layers was observed. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.