Anode containing lead dioxide deposit and process of production

1. An anode comprising a substrate having a continuous adherent deposit of lead dioxide containing bismuth in an amount sufficient to provide a ratio of bismuth to lead in the deposit of at least about 1:10.sup.2 and being sufficient to increase the current efficiency of the anode at temperature of use below 25.degree. C., and/or to decrease lead loss from the anode surface.

2. The anode of claim 1 wherein the ratio of bismuth to lead in the coating is between about 1:20 and about 1:8.

3. The anode of claim 1 wherein the ratio of bismuth to lead at the surface is greater than the ratio at the substrate interface.

4. The anode of claim 1 which further includes a lead dioxide deposit between said substrate and said deposit of lead dioxide containing bismuth.

5. The anode of claim 1 wherein said substrate is graphite or a metal selected from titanium, tantalum, zirconium, niobium, tungsten, hafnium, mixtures thereof, and alloys thereof.

6. The anode of claim 1 wherein the thickness of the coating is about 0.01" to about 0.5".

7. The anode of claim 1 wherein the thickness of the coating is about 0.02 to about 0.2.

8. The anode of claim 1 wherein said substrate includes a precoating of an electroreactive metal-containing coating.

9. The anode of claim 8 wherein said metal-containing coating is selected from the group consisting of a metal of the platinum group, oxides thereof, nitrides thereof, borides thereof, and mixtures thereof.