Preparation and characterization of composite membrane for high temperature gas separation. Quarterly technical report, September 1--November 30, 1994

To develop a new class of permselective inorganic membranes, the authors have identified electroless plating as a potential route to deposit a thin metal film on a porous substrate. Electroless plating is a controlled autocatalytic deposition of continuous film on the surface of a substrate by the interactions of a metal salt and a chemical reducing agent. This method can give thin films of metals, alloys and composites on both conducting and nonconducting surfaces. The objective of this project is to develop thin film palladium membranes for separation of hydrogen in high temperature applications. The authors plan to use electroless plating to deposit thin palladium films on microporous ceramic and silver substrates. They plan to characterize the membrane in terms of permeability and selectivity for gas separation. To accomplish the research objective, the project requires three tasks: Development of a process for composite membrane formation; Characterization of fabricated composite membrane; and Development of theoretical model for hydrogen gas separation. During this quarter, the authors attempted to measure the diffusivity and permeability of hydrogen gas through the palladium composite membrane. While running the diffusion measurements at elevated temperature and pressure, leakage of hydrogen was observed. This is a serious problem and it needs to be resolved. Currently, they are working on this problem. During this quarter, they also designed a diffusion cell to test thin-film palladium membrane in tubular structure. The diffusion cell is being fabricated and assembled by a local machine shop