Process for manufacturing a proton conducting membrane having an alumina matrix

Process for manufacturing a porous body, in particular suitable as a membrane, e. g. for use a fuel cell. To provide membranes with higher inertia, the process comprises the following steps: a) providing a thin substrate having the geometrical base of the body which is to be produced, b) providing an alumina film by an electrochemical process on the substrate, c) separation of the substrate from the alumina film, and d) drying and chemical etching of the alumina film.