Metal coated articles comprising a refractory metal region and a platinum-group metal region, and related methods

1. A metal coated article, comprising:

a substrate comprising an inorganic material;

a refractory metal region adjacent the substrate, the refractory metal region comprising:

a refractory metal carbide layer adjacent the substrate; and

a refractory metal layer adjacent the refractory metal carbide layer; and

a platinum-group metal region adjacent the refractory metal region, the platinum-group metal region comprising:

a refractory metal/platinum-group metal layer adjacent the refractory metal layer; and

a platinum-group metal layer adjacent the refractory metal/platinum-group metal layer, the platinum-group metal layer comprising:

one or more of iridium and ruthenium; or

platinum and one or more of iridium and ruthenium.

2. The metal coated article of claim 1 , wherein the substrate comprises a boron-doped diamond material.

3. The metal coated article of claim 1 , wherein the refractory metal carbide layer directly contacts the substrate and the refractory metal layer.

4. The metal coated article of claim 1 , wherein the refractory metal/platinum-group metal layer directly contacts the refractory metal layer and the platinum-group metal layer.

5. The metal coated article of claim 1 , wherein the substrate comprises a boron-doped diamond material, a molybdenum disilicide material, a graphite material, a lanthanum chromite-based material, a perovskite material, or a titanium oxide material.

6. The metal coated article of claim 1 , wherein the refractory metal layer comprises tungsten, molybdenum, vanadium, titanium, or a combination thereof.

7. The metal coated article of claim 1 , wherein the refractory metal carbide layer comprises tungsten carbide, molybdenum carbide, vanadium carbide, titanium carbide, or a combination thereof.

8. The metal coated article of claim 1 , wherein the platinum-group metal layer comprises two or more layers of platinum-group metals.

9. The metal coated article of claim 1 , wherein the platinum-group metal layer comprises three or more layers of platinum-group metals.

10. The metal coated article of claim 9 , wherein one or more layers of the three or more layers of platinum-group metals comprises a different platinum-group metal.

11. The metal coated article of claim 8 , wherein two layers of the three or more layers of platinum-group metals comprise the same platinum-group metal.

12. The metal coated article of claim 1 , wherein the platinum-group metal region is bonded to the refractory metal region.

13. A method of forming a metal coated article, comprising:

forming a refractory metal region adjacent a substrate comprising an inorganic material, wherein forming the refractory metal region comprises:

depositing a refractory metal from a functional electrolyte in an alkali halide auxiliary electrolyte bath, onto the substrate to form a refractory metal layer; and

converting a portion of the refractory metal layer to a refractory metal carbide layer, while a portion of the refractory metal layer remains an unreacted refractory metal, the refractory metal layer adjacent the refractory metal carbide layer and the refractory metal carbide layer adjacent the substrate;

forming a platinum-group metal region adjacent the refractory metal region, wherein forming the platinum-group metal region comprises:

depositing a platinum-group metal from the functional electrolyte in an alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form a platinum-group metal layer comprising:

one or more of iridium and ruthenium; or

platinum and one or more of iridium and ruthenium; and

converting a portion of the platinum-group metal layer to a refractory metal/platinum-group metal layer adjacent the refractory metal layer, the platinum-group metal layer adjacent the refractory metal/platinum-group metal layer and comprising an exterior coating of the metal coated article.

14. The method of claim 13 , wherein forming the refractory metal region comprises depositing from a functional electrolyte, a layer of tungsten, molybdenum, titanium, vanadium, or a combination thereof.

15. The method of claim 13 , wherein converting a portion of the refractory metal layer to a refractory metal carbide layer comprises annealing the substrate and the refractory metal layer at a temperature from about 500° C. to about 600° C., for a time period range from about 1 hour to about 12 hours, and in an inert-gas environment.

16. The method of claim 13 , wherein converting a portion of the refractory metal layer to a refractory metal carbide layer comprises annealing the substrate after forming the platinum-group metal region, wherein the refractory metal/platinum-group metal layer forms adjacent the refractory metal layer.

17. The method of claim 13 , wherein forming the refractory metal region comprises depositing the refractory metal layer from the functional electrolyte at a temperature in a range of about 350° C. to about 500° C.

18. The method of claim 17 , wherein forming the platinum-group metal region comprises depositing the refractory metal layer from the functional electrolyte at a temperature in a range of about 350° C. to about 500° C.

19. The metal coated article of claim 1 , wherein the refractory metal region exhibits a thickness in a range of from about 10 micrometers to about 20 micrometers.

20. The metal coated article of claim 1 , wherein the refractory metal carbide layer exhibits a greater thickness than a thickness of the refractory metal layer by a ratio of about 3:1.