The Dow Chemical Company

Donald L Caldwell

Mark J Hazelrigg

John M McIntyre

Kenneth A Poush

Raymond John Fuchs, Jr

Mark Jonathan Hazelrigg, Jr

Raul A Castillo

Ralph W Parham, Jr

Impressed current cathodic protection systems employing an anode having a cobalt spinel type surface, said surface having the formula: M.sub.x Z.sub.y Co.sub.(3-(x+y)) O.sub.4, where M is a metal or a mixture of two or more metals selected from the group of metals contained in Groups IB, IIA, and IIB of the periodic table of the elements, where Z is a metal or a mixture of two or more metals selected from the group of metals contained in Group IA of the periodic table of the elements, where 0.ltoreq.x.ltoreq.1, where 0.ltoreq.y.ltoreq.0.5, and where 0.ltoreq.(x+2y).ltoreq.1.

Impressed current cathodic protection system employing cobalt spinel

An electrochemical cell having a hydraulically impermeable permselective membrane is operated more efficiently by (1) separating the anode and the cathode of such a cell from the permselective membrane by a spacing means which is porous, hydrophilic, and electrically non-conductive, or alternatively, (2) providing a coating on the metal electrodes of said cell which is hydrophilic, porous, and electrically non-conductive. Said spacing means is of a material selected from the group consisting of at least one of mineral fibers, synthetic organic polymers, and ceramics and glasses.

Electrochemical cell with improved energy efficiency

Porous separators for electrolytic processes are designed which are characterized by an N.sub.mac t value, where N.sub.mac is the ratio of the resistance (r) of the electrolyte-saturated separator to the resistance (r.sub.o) of an equivalent volume of electrolyte and t is the thickness, in inches, of the separator. The N.sub.mac value is referred to here as the MacMullin Number.

Porous separators for electrolytic processes

Hypochlorite ions in aqueous solution are catalytically decomposed by the action of a poly-metal spinel of cobalt preferably coated on an inert, stable support. The spinel catalyst may contain dispersed therein, optionally, other 'modifier' metal oxides which contribute better adherence of the spinel to the substrate and improve the toughness of the spinel coating. The substituted cobalt spinel conforms generally to the empirical formula

Substituted cobalt oxide spinels for catalytic decomposition of

Catalytic decomposition of hypochlorite using substituted cobalt oxide

Electroconductive substrates for use as oxygen electrodes are coated with an optional interface layer and then with cobalt oxide spinels conforming substantially to the empirical formula

Electrodes for oxygen manufacture

Electroconductive substrates are coated with an interface layer and then with cobalt oxide spinels conforming substantially to the empirical formula

Substituted cobalt oxide spinels

Electroconductive substrates are coated with substituted cobalt oxide spinels conforming substantially to the empirical formula

Electroconductive substrates are coated with substituted cobalt oxide spinels conforming substantial to the empirical formula

An electrolytic cell and its method of operation is described. The cell comprises an anode, a cathode and iron-containing metals exposed to the interior portions of the cell which are maintained at about the same electrical potential as the cathode. These materials are covered with a protective coating to minimize corrosion during operation of the cell.

Corrosion resistant electrolytic cell

Electrodes with porous coatings are produced using an inorganic compound which is soluble in an aqueous solution, as the pore former in the coating. The inorganic pore former may be removed from the coating while the electrode is being used in an electrolytic cell without contaminating the electrolyte. Such electrodes are particularly useful in electrolytic cells, wherein they operate at a significantly lower voltage and have a longer life span than conventional electrodes.

Preparation of porous electrodes

Electrodes particularly suitable for use as anodes in electrolytic cells are prepared by coating an electrically-conductive substrate with a thermally-decomposable inorganic cobalt compound and then thermally oxidizing the inorganic cobalt compound under conditions at which the single-metal spinel, Co.sub.3 O.sub.4, is formed.

Process for preparing an electrode for electrolytic cell having a

Hypochlorite ions in aqueous solution are catalytically decomposed by the action of a single-metal spinel of Co.sub.3 O.sub.4, preferably coated on an inert, stable support. The Co.sub.3 O.sub.4 catalyst may contain dispersed therein, optionally, other 'modifier' metal oxides which do not affect the single-metal spinel structure of the Co.sub.3 O.sub.4, but which contribute better adherence of the Co.sub.3 O.sub.4 to the substrate and improve the toughness of the Co.sub.3 O.sub.4 coating.

Catalytic decomposition of hypochlorite

Anodes particularly suitable for use in electrolytic cells are prepared by coating an electrically-conductive substrate with a bimetallic oxide having a spinel structure of the formula M.sub.x Co.sub.3-x O.sub.4 where O&lt;X.ltoreq.1 and where M is a metal of Periodic Group IB, IIA or IIB. Also the coating contains therein, optionally, a modifier oxide, such as ZrO.sub.2.

Electrolytic cell anode structures containing cobalt spinels

Electrodes are prepared by coating electrically conductive substrates with an electrically conductive film comprising a single-metal spinel of the formula Co.sub.3 O.sub.4. The coating can include modifier oxides selected from Groups III-B through VII-B, Groups III-A through V-A, and the Lanthanides and Actinides. Particularly suitable as modifier oxides are the oxides of zirconium, vanadium, titanium, lead, tantalum, tungsten, niobium, cerium, or molybdenum. These electrodes are particularly suitable for, but not limited to, use as the anode in an electrolytic chlorine cell wherein a diaphragm is interposed between an anode and a cathode in an aqueous electrolyte solution containing sodium chloride.

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Lake Jackson, TX, United States of America

Donald L Caldwell