Abstract: A method for preparing a membrane to be assembled in a membrane, electrode assembly includes the step of swelling an ion-conducting membrane in a liquid containing at least one solvent or to an atmosphere containing the vapor phase of at least one solvent by controlling the content of the solvent in the ion-conducting membrane. A method for manufacturing a membrane electrode assembly using an ion conducting membrane includes the steps of: providing an ion-conducting membrane in a pre-swollen state; coating the ion-conducting membrane on both sides with an electrode layer to form a sandwich; and hot-pressing the sandwich to form an ion-conducting bonding of the layers of the sandwich. Furthermore, a membrane electrode assembly is disclosed including a hot pressed sandwich having an electrode layer, a ion-conducting membrane and again an electrode layer, thereby using the ion-conducting membrane in its pre-swollen status prior to the hot-pressing.

Abstract: In a method of measuring the fill level of a reactor in continuously operated polymerization processes using measurement of the respective phase interface in the reactor by means of ionizing radiation, at least one measuring unit comprising a radiation source which emits ionizing radiation and a corresponding detector is brought to the phase interface in the reactor and flexibly installed there, with the fill level of the reactor being measured by determining the phase interface by means of the radioactive backscattering measurement.

Abstract: A bipolar plate for an apparatus having a stacked configuration, said apparatus comprised of a plurality of electrochemical cells and employing a solid electrolyte, said bipolar plate comprised of a porous titanium plate (1) having a parallel groove structure (3), said bipolar plate further comprised of a non-porous, solid titanium plate (2) strongly welded to plate (1) at contact loci (4), wherewith channels (5) are present, and said bipolar plate further comprised of a surface layer or coating (6) comprised of a material which is a catalyst for electrolytic reactions. A method of manufacturing the subject bipolar plate, comprising the following: Powder metallurgical manufacture of the porous titanium plate (1), and bonding of plate (1) to the solid titanium plate (2) by sintering.

Abstract: A depassivation layer is produced on an electrode for an electrochemical cell by applying one or more layers of a metal salt solution, containing the elements to be applied, to the substrate (1) which is to be coated and is in the form of a porous plate, by means of rolling an elastic roller (2) over the substrate, with the insertion of a solution carrier (3) in the form of felt or paper, and then drying the layer and subjecting it to a chemical/thermal treatment in air (heat treatment at 450.degree. C.). Good depassivation layers with a relatively small noble metal content can be produced in this way. The depassivation layer which, in the form of a homogeneous film, is at least partially coherent contains, as a finely divided, sub-microscopic mixture, electronically conductive sub-oxides/oxides of the substrate (1) in addition to noble metals/noble metal oxides, and it can also contain further components, such as SnO.sub.2.

Abstract: An electrically conductive layer on a solid-body electrolyte (1) is produced by swelling and impregnating an organic ion exchange material (2) with a metal salt solution, drying, converting the metal ions in a gas stream to finely distributed particles (3) which are in electrical contact with one another, renewed swelling in a solvent, converting into a brushable paste and applying same to the surface of the solid-body electrolyte and drying. Preferred embodiment: solid-body electrolyte (1) and ion exchange material (2) made of polymers containing sulphonic acids; and conductive particles (3) made of platinum metals or oxides thereof, in particular ruthenium as electrocatalyst.