Cold-rolling and diffusion welding

In the past, dense selective Pd-Ag thin-waU tubes have been produced via cold rolling and diffusion welding procedures. According to this technique, commercial Pd-Ag foils have been cold rolled in order to reduce... 

S.Tosti, Metallic membranes prepared by cold rolling and diffusion welding, pp. 155-166, Copyright (2011), with permission from Wiley. 

Details of a thin-wall Pd-Ag permeator tube. Reprinted from Membranes for Membrane Reactors Preparation, Optimization and Selection, Basile and Gallucci Ed., Ch. 4, S.Tosti, Metallic membranes prepared by cold rolling and diffusion welding, pp. 155-166, Copyright (2011), with permission from Wiley. 

The diffusion welding and cold-rolling procedure previously described for the synthesis of the Ni-based membrane has been also applied to the production of a Pd-Ag/Nb/Pd-Ag composite membrane. In this application, two Pd-Ag foils with a thickness of 25 pm were used to cover a Nb plate with a thickness of 1 mm. This composite membrane was rolled down to a thickness of 128 pm (of which about 122 pm was Nb bulk, between two very thin Pd-Ag layers of 3 pm). The permeation tests carried out at 180°C... 

Since wind barriers are located at the cold side of the thermal insulation (in cold climates) they should combine a sufficient air and water tightness with a high vapour permeance. Materials which combine these properties and are often recommended as wind barriers are the spunbonded plastic films (also called house-wraps). These films are composed of rolled synthetic filaments (typically polypropylene or polyethylene fibres) that are welded together to form a continuous porous fabric. Measuring procedures and results of vapour transfer properties of spunbonded plastic films are reported in detail by Janssens and Hens [36]. The diffusion thicknesses of the films are a few centimetres and of the same order of magnitude as an air boundary layer. 

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