Abstract: An electrode comprising a gas permeable and liquid permeable coating bonded to an ion exchange membrane, said coating comprising low overvoltage electrocatalytic particles, more electroconductive electrolyte resistant particles and an electrolyte resistant binder compatible with the membrane to bond the particles thereto, the electrode coating being provided with a plurality of pores with a pore size of at least 0.1 microns.Effective porosity is imparted to the layer of particles by means of a sacrificial, pore-forming agent and by leaching out such agent after the particles have been bonded together and the layer formed is in its desired thickness, preferably after it has been deposited upon the membrane.Surface resistivity of the layer is reduced and the layer is effectively reinforced by incorporating electroconductive particles which often have a higher overvoltage than the electrocatalytic particles and also have high electroconductivity.

Abstract: An electrode comprising a gas permeable and liquid permeable coating bonded to an ion exchange membrane, said coating comprising low overvoltage electrocatalytic particles, more electroconductive electrolyte resistant particles and an electrolyte resistant binder compatible with the membrane to bond the particles thereto, the electrode coating being provided with a plurality of pores with a pore size of at least 0.1 microns.Effective porosity is imparted to the layer of particles by means of a sacrificial, pore-forming agent and by leaching out such agent after the particles have been bonded together and the layer formed is in its desired thickness, preferably after it has been deposited upon the membrane.Surface resistivity of the layer is reduced and the layer is effectively reinforced by incorporating electroconductive particles which often have a higher overvoltage than the electrocatalytic particles and also have high electroconductivity.

Abstract: A gas and electrolyte permeable metal layer is bonded to an ion-permeable membrane by electroless deposition to produce a permeable metal deposit upon the membrane or diaphragm. Advantageously, the membrane surface to be coated is pretreated with an amphoteric material. Thereafter, the treated surface is treated to deposit the coating. Typical metals deposited include platinum group metals, iron group metals, such as nickel, cobalt and others including gold and silver. The coatings are very thin, rarely in excess of about 50 to 100 microns.The coated membrane may be installed in an electrolytic cell used for producing chlorine and alkali by electrolysis of alkali metal chloride with the coating serving as one electrode and another opposed electrode on or adjacent to the opposite side of the membrane. It may also be used in water electrolysis and for other purposes.The coatings may be thickened by depositing other coatings of the same or different composition by suitable coating techniques.

Abstract: Halogen is produced by electrolyzing an aqueous halide in a specially designed cell. The cell comprises an anolyte chamber and a catholyte chamber separated by a permeable membrane or diaphragm, notably an ion exchange (generally cation exchange) polymer. At least one electrode comprises at least two sections. One section comprises a gas and electrolyte permeable layer, sheet or mat having a catalytic surface, i.e. one having a low overvoltage, (low hydrogen overvoltage if the cathode and low halogen overvoltage if the anode). This layer is spaced from the membrane by a second portion comprising an electroconductive resiliently compressible layer or mat, which is in contact with the membrane on one side thereof, the other side thereof being in contact with the main cathode.This second or spacer section advantageously has an electrode surface having a higher overvoltage than the first electrode surface. Preferably the cathode has the above construction.

Abstract: A cell is provided having an anode and cathode separated by an ion permeable membrane or diaphragm wherein an electrode layer is bonded to or otherwise embedded in on at least one and usually to both sides of the membrane. Polarity is imparted to a bonded or embedded electrode by pressing a crinkled resiliently compressible fabric against the membrane carrying the electrode layer. This fabric is substantially coextensive with the electrode layer and is constructed so that when compressed it exerts a substantially uniform elastic reaction pressure against the membrane carrying the electrode layer or a pliable foraminous sheet, i.e. screen, interposed between the membrane carrying the electrode layer and the resiliently compressible fabric. The resiliently compressible fabric has the ability of also transmitting pressure laterally so that pressure applied may distribute across the entire area of the layer and tendency to have local areas of too low of too high pressure is minimized or reduced.

Abstract: A process for preparing an electroconductive metal coating on a substrate wherein precursor compounds capable of decomposing to form an electroconductive coating are subjected to localized high intensive heat, followed by rapid cooling, while maintaining the bulk of the substrate and/or the surrounding atmosphere at a lower temperature.The process is particularly suited for preparing valve metal substrates coated with mixed oxides comprising at least one metal belonging to the platinum group and a valve metal. Such can be utilized as dimensionally stable anodes in electrolytic processes. The process is moreover useful for applying oxides coating on metal and non-metal substrates of different kinds, such as ceramics, glass, plastics and polymeric organic supports.

Abstract: Halogen is produced by electrolyzing an aqueous halide in a specially designed cell. The cell comprises an anolyte chamber and a catholyte chamber separated by a permeable membrane or diaphragm, notably an ion exchange (generally cation exchange) polymer. At least one electrode comprises at least two sections. One section comprises a gas and electrolyte permeable layer, sheet or mat having a catalytic surface, i.e. one having a low overvoltage, (low hydrogen overvoltage if the cathode and low halogen overvoltage if the anode). This layer is spaced from the membrane by a second section comprising a thin intermediate electroconductive layer, screen or coating which is in contact with the membrane on one side thereof, the other side thereof being in contact with the main cathode.This second or spacer section advantageously has an electrode surface having a higher overvoltage than the first electrode surface. Preferably the cathode has the above construction.

Abstract: A gas and electrolyte permeable metal layer is bonded to an ion-permeable membrane by electroless deposition to produce a permeable metal deposit upon the membrane or diaphragm. Advantageously, the membrane surface to be coated is pretreated with an amphoteric material. Thereafter, the treated surface is treated to deposit the coating. Typical metals deposited include platinum group metals, iron group metals, such as nickel, cobalt and others including gold and silver. The coatings are very thin, rarely in excess of about 50 to 100 microns.The coated membrane may be installed in an electrolytic cell used for producing chlorine and alkali by electrolysis of alkali metal chloride with the coating serving as one electrode and another opposed electrode on or adjacent to the opposite side of the membrane. It may also be used in water electrolysis and for other purposes.The coatings may be thickened by depositing other coatings of the same or different composition by suitable coating techniques.