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US 5,334,293 AGranted
Electrode comprising a coated valve metal substrate
AssigneeImperial Chemical Industries Public Limited Company
InventorsJohn F. Cairns, David R. Hodgson
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AssigneeImperial Chemical Industries Public Limited Company
InventorsJohn F. Cairns, David R. Hodgson
Estimating the term…
An electrode which comprises a substrate of a valve metal or an alloy thereof having properties similar to those of the valve metal and a coating comprising an outer layer which comprises RuO.sub.2, an oxide of at least one non-noble metal and at least one other noble metal or oxide thereof and an intermediate layer having a composition different from that of the outer layer and which comprises RuO.sub.2 and an oxide of at least one non-noble metal. The electrode is particularly useful as an anode for an electrolytic cell, eg a chlor-alkali cell, it has a lifetime therein which is greater than the sum of the operational life-times of electrodes which comprise a valve metal substrate and which separately comprise one of the above layers which together form a part of the coating of that electrode.
An electrode which comprises a substrate of a valve metal or an alloy thereof having properties similar to those of the valve metal and a coating comprising an outer layer which comprises RuO.sub.2, an oxide of at least one non-noble metal and at least one other noble metal or oxide thereof and an intermediate layer having a composition different from that of the outer layer and which comprises RuO.sub.2 and an oxide of at least one non-noble metal wherein the ruthenium oxide provides a minor portion of at least one of the intermediate layer and the outer layer.
An electrode which comprises a substrate of a valve metal or an alloy thereof having properties similar to those of the valve metal and a coating comprising an outer layer which comprises RuO.sub.2, an oxide of at least one non-noble metal and at least one other noble metal or oxide thereof and an intermediate layer having a composition different from that of the outer layer and which comprises RuO.sub.2 and an oxide of at least one non-noble metal wherein the loading of the outer layer is less than the loading of the intermediate layer.
An electrode which comprises a substrate of a valve metal or an alloy thereof having properties similar to those of the valve metal and a coating comprising an outer layer which comprises RuO.sub.2, an oxide of at least one non-noble metal and at least one other noble metal or oxide thereof and an intermediate layer having a composition different from that of the outer layer and which comprises RuO.sub.2 and an oxide of at least one non-noble metal, wherein the oxide of the other noble metal of which the outer layer is comprised is an oxide of iridium.
An electrode which comprises a substrate of a valve metal or an alloy thereof having properties similar to those of the valve metal and a coating comprising an outer layer which comprises RuO.sub.2, an oxide of at least one non-noble metal and at least one other noble metal or oxide thereof and an intermediate layer having a composition different from that of the outer layer and which comprises RuO.sub.2 and an oxide of at least one non-noble metal, wherein the other noble metal of which the outer layer is comprised is platinum.
Dependencies are inferred from the claim text.