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 (United States)

关键词: 08 Hydrogen;    Coal;    Alloys;    Membranes;    X-Ray Diffraction;   

DOI  :  10.2172/834511
RP-ID  :  NONE
RP-ID  :  FC26-03NT41849
RP-ID  :  834511

美国|英语

来源: UNT Digital Library

【 摘 要 】

To overcome the issue of pinhole (defect) formation in membrane films over large areas, a process was developed and implemented for producing 6-12 {micro}m-thick, Pd-Cu alloy films on thermally oxidized silicon wafer substrates. The processing parameters on silicon are such that adhesion is poor and as-deposited Pd-Cu alloy films easily release from the oxidized silicon surface. Hydrogen permeation tests were conducted on 9 and 12 {micro}m-thick Pd-Cu alloy films and the hydrogen flux for 9 and 12 {micro}m-thick films were 16.8 and 8 cm{sup 3}(STP)/cm{sup 2} {center_dot} min respectively. The hydrogen permeability (corrected using data in McKinnley patent) of the 9 {micro}m-thick membrane is 7.4 {center_dot} 10{sup -5} cm{sup 3}(STP) {center_dot} cm/cm{sup 2} {center_dot} s {center_dot} cm Hg{sup 0.5} at 350 C and compares very well to permeability reported by McKinnley for a 62.5% Pd membrane; this permeability is {approx}56% of the value reported for a Pd-Cu alloy membrane with optimum 60% Pd composition. Using XRD, we confirmed the presence of a two-phase, {alpha}/{beta}, structure and that the composition of our membrane was slightly higher than the optimum composition. We are making adjustments to the compositions of the Pd-Cu alloy target in order to produce films next quarter that match the ideal Pd{sub 60}Cu{sub 40} composition.