COST-EFFECTIVE METHOD FOR PRODUCING SELF SUPPORTED PALLADIUM ALLOY MEMBRANES FOR USE IN EFFICIENT PRODUCTION OF COAL DERIVED HYDROGEN

Lanning, B. ; Arps, J.

Southwest Research Institute

关键词: 08 Hydrogen;    Repair;    Substrates;    Membranes;    Phase Diagrams;   

DOI  :  10.2172/882510
RP-ID  :  none
RP-ID  :  FC26-03NT41849
RP-ID  :  882510

美国|英语

来源: UNT Digital Library

【 摘 要 】

During the last quarter, new procedures were developed and implemented to improve reliability and repeatability of release characteristics from the temporary substrate (i.e., silicon wafer) and to minimize through-thickness defects in a 6-inch diameter film, 3 microns in thickness. With the new procedures, we have been able to consistently produce essentially stress free films, with zero or minimal defects (less than 5) across a 6-inch diameter area. (It is important to note that for those films containing pinholes, a procedure has been developed to repair the pinholes to form a gas tight seal). The films are all within the identified tolerance range for composition (i.e., 60 {+-} 0.2 % Pd). A number of these films have subsequently been shipped to IdaTech for evaluation and integration into their test module. Colorado School of Mines continued their high temperature evaluation of 6 micron thick, sputtered Pd-Cu films. Pure hydrogen permeability increased up to 400 C while the membrane was in the {beta}-phase and dropped once the temperature increased to over 450 C. Above this temperature, as confirmed by the binary phase diagram, the film transforms into either a mixed {alpha}/{beta} or pure {alpha} phase. The same trend was observed for a baseline 25 micron-thick foil (from Wilkinson) where the pure hydrogen permeability increased with temperature while the membrane was in the {beta}-phase and then decreased upon transformation to the {alpha} phase.