Electrode and method of preparing same

Claim 2

In an electrode having a titanium substrate with a ruthenium containing coating thereon, the improvement wherein said coating is substantially free of deposited titanium and comprises: (1) a first oxide layer, deposited on said substrate and comprising a major portion of ruthenium and a minor portion of tin; and (2) a second oxide layer, atop said first layer, comprising a major portion of ruthenium and minor portions of tin and palladium.

Claim 3

The electrode of claim 1 wherein the substrate contains from about 0.0002 to about 0.01 weight percent yttrium.

Claim 4

The electrode of claim 1 wherein the first oxide layer contains from about 75 to about 90 weight percent ruthenium, basis elemental metal.

Claim 5

The electrode of claim 1 wherein the first oxide layer has a coating density of from about 1 to about 10 grams per square meter.

Claim 6

The electrode of claim 1 wherein the second oxide layer contains from about 80 to about 85 weight percent ruthenium, from about 7 to about 10 weight percent palladium, and from about 6 to about 10 weight percent tin, basis elemental metal.

Claim 7

The electrode of claim 1 wherein the second oxide layer has a coating density of from about 1 to about 10 grams per square meter.

Claim 8

In a bipolar electrolyzer having a plurality of bipolar electrodes, parallel to and spaced from each other, each of said bipolar electrodes comprising a titanium plate having an anodic portion and a coated cathodic portion whereby the cathodic portion of one bipolar electrode faces the anodic portion of a prior bipolar electrode and the anodic portion of the bipolar electrode faces the cathodic portion of a subsequent bipolar electrode, the improvement wherein said cathodic coating is substantially free of deposited titanium and comprises: (1) a first oxide layer, deposited on said plate and comprising a major portion of ruthenium and a minor portion of tin; and (2) a second oxide layer, atop said first layer, comprising a major portion of ruthenium and minor portions of tin and palladium.

Claim 9

In a bipolar electrolyzer having a plurality of bipolar electrodes, parallel to and spaced from each other, each of said bipolar electrodes comprising a titanium plate having an anodic portion and a coated cathodic portion whereby the cathodic portion of one bipolar electrode faces the anodic portion of a prior bipolar electrode and the anodic portion of the bipolar electrode faces the cathodic portion of a subsequent bipolar electrode, the improvement wherein said cathodic coating is substantially free of deposited titanium and comprises: (1) a first oxide layer, deposited on said plate and comprising a major portion of ruthenium and a minor portion of tin; and (2) a second oxide layer, atop said first layer, comprising a major portion of ruthenium and minor portions of tin and palladium.

Claim 10

The bipolar electrolyzer of claim 7 wherein the substrate is a titanium-yttrium alloy containing from about 0.0002 to about 0.01 weight percent yttrium.

Claim 11

The bipolar electrolyzer of claim 7 wherein the first oxide layer contains from about 75 to about 90 weight percent ruthenium basis elemental metal.

Claim 12

The bipolar electrolyzer of claim 7 wherein the first oxide layer has a coating density of from about 1 to about 10 grams per square meter.

Claim 13

The bipolar electrolyzer of claim 7 wherein the second oxide layer contains from about 80 to about 85 weight percent ruthenium, from about 7 to about 10 weight percent palladium, and from about 6 to about 10 weight percent tin, basis elemental metal.

Claim 14

The bipolar electrolyzer of claim 7 wherein the second oxide layer has a coating density of from about 1 to about 10 grams per square meter.

Claim 15

In a bipolar electrolyzer having a plurality of anodes extending into the electrolyzer from one end thereof, a plurality of cathodes extending into the electrolyzer from an opposite end thereof, and a plurality of bipolar electrode blades, each of said bipolar electrode blades having a cathodic portion, and an anodic portion, said anodes, cathodes and bipolar electrode blades being mutually parallel, the first group of bipolar electrode blades being arrayed between and parallel to the anodes and having the cathodic portions thereof opposed to the anodes and the anodic portions thereof remote from the anodes, the last group of bipolar electrode blades being arrayed between and parallel to the cathodes and having the anodic portions thereof opposed to the cathodes and the cathodic portions thereof remote from the cathodes, the improvement wherein said bipolar electrode blades comprise: (a) a titanium substrate, and (b) a coating thereon substantially free of deposited titanium and comprising: (1) a first oxide layer, deposited on said substrate and comprising a major portion of ruthenium and a minor portion of tin; and (2) a second oxide layer, atop said first oxide layer, comprising a major portion of ruthenium and minor portions of tin and palladium.

Claim 16

In a bipolar electrolyzer having a plurality of anodes extending into the electrolyzer from one end thereof, a plurality of cathodes extending into the electrolyzer from an opposite end thereof, and a plurality of bipolar electrode blades, each of said bipolar electrode blades having a cathodic portion, and an anodic portion, said anodes, cathodes and bipolar electrode blades being mutually parallel, the first group of bipolar electrode blades being arrayed between and parallel to the anodes and having the cathodic portions thereof opposed to the anodes and the anodic portions thereof remote from the anodes, the last group of bipolar electrode blades being arrayed between and parallel to the cathodes and having the anodic portions thereof opposed to the cathodes and the cathodic portions thereof remote from the cathodes, the improvement wherein said bipolar electrode blades comprise: (a) a titanium substrate, and (b) a coating thereon substantially free of deposited titanium and comprising: (1) a first oxide layer, deposited on said substrate and comprising a major portion of ruthenium and a minor portion of tin; and (2) a second oxide layer, atop said first oxide layer, comprising a major portion of ruthenium and minor portions of tin and palladium.

Claim 17

The bipolar electrolyzer of claim 13 wherein the substrate contains from about 0.0002 to about 0.01 weight percent yttrium.

Claim 18

The bipolar electrolyzer of claim 13 wherein the first layer contains from about 75 to about 90 weight percent ruthenium basis elemental metal.

Claim 19

The bipolar electrolyzer of claim 13 wherein the first oxide layer has a coating density of from about 1 to about 10 grams per square meter.

Claim 20

The bipolar electrolyzer of claim 13 wherein the second oxide layer contains from about 80 to about 85 weight percent ruthenium, from about 7 to about 10 weight percent palladium, and from about 6 to about 10 weight percent tin, basis elemental metal.

Claim 21

The bipolar electrolyzer of claim 13 wherein the second oxide layer has a coating density of from about 1 to 10 grams per square meter.

Claim 22

In a method of electrolyzing alkali metal chloride brine comprising passing electrical current from an anode to a cathode in a common electrolyte, evolving anodic and cathodic products and forming chlorate ion, the improvement wherein said cathode comprises: (a) a titanium substrate; and (b) a coating thereon, substantially free of deposited titanium, comprising: (1) a first oxide layer, deposited on said substrate and comprising a major portion of ruthenium and a minor portion of tin; and (2) a second oxide layer, atop said first oxide layer, comprising a major portion of ruthenium and minor portions of tin and palladium.

Claim 23

In a method of electrolyzing alkali metal chloride brine comprising passing electrical current from an anode to a cathode in a common electrolyte, evolving anodic and cathodic products and forming chlorate ion, the improvement wherein said cathode comprises: (a) a titanium substrate; and (b) a coating thereon, substantially free of deposited titanium, comprising: (1) a first oxide layer, deposited on said substrate and comprising a major portion of ruthenium and a minor portion of tin; and (2) a second oxide layer, atop said first oxide layer, comprising a major portion of ruthenium and minor portions of tin and palladium.

Claim 24

The method of claim 19 wherein the substrate contains from about 0.0002 to about 0.01 weight percent yttrium.

Claim 25

The method of claim 19 wherein the first oxide layer contains from about 75 to about 90 weight percent ruthenium, basis elemental metal.

Claim 26

The method of claim 19 wherein the first oxide layer has a coating density of from about 1 to about 10 grams per square meter.

Claim 27

The method of claim 19 wherein the second oxide layer contains from about 80 to about 85 weight percent ruthenium, from about 7 to about 10 weight percent palladium, and from about 6 to about 10 weight percent tin, basis elemental metal.

Claim 28

The method of claim 19 wherein the second oxide layer has a coating density of from about 1 to 10 grams per square meter.

Claim 31

The method of claim 25 wherein the titanium substrate comprises a hydride formation inhibiting amount of yttrium.

Claim 32

The method of claim 26 wherein the titanium substrate contains from about 0.0002 to about 0.01 weight percent yttrium.

Claim 33

The method of claim 25 wherein the first oxide layer contains from about 75 to about 90 weight percent ruthenium, basis elemental metal.

Claim 34

The method of claim 25 wherein the first oxide layer has a coating density of from about 1 to about 10 grams per square meter.

Claim 35

The method of claim 25 wherein the second oxide layer contains from about 80 to about 85 weight percent ruthenium, from about 7 to about 10 weight percent palladium, and from about 6 to about 10 weight percent tin, basis elemental metal basis.

Claim 36

The method of claim 25 wherein the second oxide layer has a coating density of from about 1 to about 10 grams per square meter.

Claim 37

An electrode for an electrolytic cell comprising: (a) a substrate selected from the group consisting of titanium, copper, and silver, and (b) a coating substantially free of deposited titanium and comprised of a first oxide layer on said substrate of a major amount of ruthenium and a minor amount of tin, and a second oxide layer atop said first layer of a major amount of ruthenium and minor amounts of tin and palladium.

Claim 38

An electrode for an electrolytic cell comprising: (a) a substrate selected from the group consisting of titanium, copper, and silver, and (b) a coating substantially free of deposited titanium and comprised of a first oxide layer on said substrate of a major amount of ruthenium and a minor amount of tin, and a second oxide layer atop said first layer of a major amount of ruthenium and minor amounts of tin and palladium.

Claim 39

The electrode of claim 32 wherein the substrate is titanium or titanium alloy containing minor amounts of at least one metal from Group III or Group VIII.

Claim 40

The electrode of claim 33 wherein the substrate is a titanium-yttrium alloy.