Valve metal electrode with valve metal oxide semi-conductive face
AssigneeOronzio de Nora Impianti Elettrochimici S.p.A.
InventorsGiuseppe Bianchi, Vittorio De Nora, Patrizio Gallone, Antonio Nidola
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Abstract
Describes chlorine resistant metal electrodes, preferably of valve metals such as titanium and tantalum, having coatings of mixed metal oxides, preferably valve metal oxides, which have been doped to provide semi-conducting surfaces on the electrodes, which coatings also have the capacity to catalyze chlorine discharge from the electrodes and to resist corrosive conditions in a chlorine cell.
Claims10
An electrode comprising a chlorine resistant metal base from the group consisting of titanium and tantalum, having a coating thereon containing an oxide of a platinum group metal and a mixture of metal oxides forming a semi-conductor coating on said base, said mixture of metal oxides forming the semi-conducting coating comprising a material from the group consisting of titanium dioxide and tantalum pentoxide and at least one doping oxide from the group consisting of an oxide of silver, tin, chromium, lanthanum, aluminum, cobalt, antimony, molybdenum, nickel, iron, tungsten, vanadium, phosphorus, boron, beryllium, sodium, calcium, strontium, lead, copper and bismuth, and mixtures thereof, the percentage of doping oxide being between 0.10 and 50% of the material from the group consisting of titanium dioxide and tantalum pentoxide and the ratio of platinum group metals to the non-precious metals in said oxide coating being between 20:100 and 85:100, all said percentages being based upon the metal in said oxides.
An electrode comprising a chlorine resistant metal base from the group consisting of titanium and tantalum, having a semi-conductor coating thereon containing (a) a platinum group metal oxide, (b) a metal oxide from the group consisting of titanium dioxide or tantalum pentoxide and (c) a doping oxide for said titanium dioxide or tantalum pentoxide from the group consisting of oxides of silver, tin, chromium, lanthanum, aluminum, cobalt, antimony, molybdenum, nickel, iron, tungsten, vanadium, phosphorus, boron, beryllium, sodium, calcium, strontium, lead, copper and bismuth, and mixtures thereof, the percentage of doping oxide being between 0.10 and 50% of the metal oxide from the group consisting of titanium dioxide and tantalum pentoxide and the ratio of platinum group metals to the non-precious metals in said oxide coating being between 20:100 and 85:100, all said percentages being based upon the metal in said oxides.
An electrode comprising a chlorine resistant metal base from the group consisting of titanium and tantalum having a semi-conductor coating thereon containing (a) a platinum group metal oxide, (b) a metal oxide from the group consisting of titanium dioxide and tantalum pentoxide and (c) at least one doping oxide for said titanium dioxide and tantalum pentoxide from the group consisting of oxides of vanadium, tantalum, tin, cobalt, lanthanum and aluminum.
An electrode comprising a chlorine resistant metal base from the group consisting of titanium and tantalum having a semi-conductor coating containing (a) ruthenium oxide, (b) titanium dioxide and (c) at least one doping oxide for said titanium dioxide from the group consisting of oxides of tantalum, tin, lanthanum, cobalt, vanadium and aluminum.
Dependencies are inferred from the claim text.