A hydrogen separation module based on wafer-scale micromachined palladium-silver alloy membranes

A thin but strong and defect free palladium-silver (Pd-Ag) alloy membrane is fabricated with a sequence of well-known thin film and micromachining techniques. A microfabrication process also creates a robust wafer-scale membrane module, which is easy to be integrated into a membrane holder to have gastight connections to the outer world. The microfabricated membranes have been tested to determine the mechanical strength, hydrogen permeability and hydrogen selectivity. The membranes have high mechanical strength and can withstand pressures up to 3 bars at room temperature. High flow rates of up to 3.6 mol H/sub 2//m/sup 2/.s have been measured with a minimal selectivity of 1500 for H/sub 2//He. The membranes survived operation at 450/spl deg/C, which is a temperature relevant for practical application in industry, for more than 1000 hours.