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

Abstract

A metal coated article includes a platinum-group metal region adjacent a refractory metal region, which is adjacent a substrate comprising an inorganic material. A refractory metal carbide layer is adjacent the substrate and the refractory metal layer is adjacent the refractory metal carbide layer. The platinum-group metal region comprises a refractory metal/platinum-group metal layer and a platinum-group metal layer. Related methods are also disclosed.

1 . A method of forming a metal coated article, comprising:
 forming a refractory metal region on a boron-doped diamond substrate, wherein forming the refractory metal region comprises:
 depositing a refractory metal from a functional electrolyte in an alkali halide auxiliary electrolyte bath, onto the boron-doped diamond 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 on the refractory metal carbide layer; 
   forming a platinum-group metal region on the refractory metal region, wherein forming the platinum-group metal region comprises:
 depositing a platinum-group metal from a functional electrolyte in an alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form a platinum-group metal layer; and 
 converting a portion of the platinum-group metal layer to a platinum-group metal, refractory metal transition layer between the platinum-group metal layer and the refractory metal layer, the platinum-group metal layer comprising an exterior coating of the metal coated article. 
   
     
     
         2 . The method of  claim 1 , wherein forming the refractory metal region comprises depositing from a functional electrolyte, a layer of tungsten, molybdenum, titanium, vanadium, or a combination thereof. 
     
     
         3 . The method of  claim 1 , wherein converting a portion of the refractory metal layer to a refractory metal carbide layer comprises annealing the boron-doped diamond 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. 
     
     
         4 . The method of  claim 1 , wherein converting a portion of the refractory metal layer to a refractory metal carbide layer comprises annealing the boron-doped diamond substrate after forming the platinum-group metal region, wherein a platinum-group metal, refractory metal transition layer forms between the platinum-group metal layer and the refractory metal layer. 
     
     
         5 . The method of  claim 1 , 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. 
     
     
         6 . The method of  claim 1 , 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. 
     
     
         7 . A method of forming an alloy, comprising:
 dissolving an ilmenite concentrate (FeO·TiO 2 ) in an electroplating system: comprising:
 a crucible; 
 a metal salt electrolyte in the crucible; 
 a working electrode immersed in the metal salt electrolyte; 
 a reference electrode immersed in the metal salt electrolyte; and 
 a counter electrode immersed in the metal salt electrolyte, the counter electrode comprising:
 a boron-doped diamond substrate; 
 a refractory metal carbide layer on the boron-doped diamond substrate; 
 a refractory metal layer on the refractory metal carbide layer; and 
 a platinum-group layer on a platinum-group metal/refractory metal layer and on the refractory metal carbide layer; and 
 
   applying a voltage and a current between the working electrode and the reference electrode, to co-deposit an iron-titanium alloy on a body connected to the working electrode.   
     
     
         8 . The method of  claim 7 , wherein the metal salt electrolyte is under an inert atmosphere, and wherein dissolving the ilmenite concentrate releases oxygen into the inert atmosphere and further comprises:
 supplying make-up inert gas to the crucible; and   
       bleeding a portion of the inert atmosphere that includes oxygen. 
     
     
         9 . The method of  claim 1 , wherein forming the platinum-group metal region comprises depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form two or more layers of the platinum-group metal. 
     
     
         10 . The method of  claim 1 , wherein forming the platinum-group metal region comprises depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form three or more layers of the platinum-group metal. 
     
     
         11 . The method of  claim 1 , wherein forming the platinum-group metal region comprises depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form three or more layers of the platinum-group metal, wherein one or more of the three or more layers of the platinum group metal comprises a different platinum-group metal. 
     
     
         12 . The method of  claim 1 , wherein forming the platinum-group metal region comprises depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form three or more layers of the platinum-group metal, wherein two layers of the three or more layers of the platinum-group metal comprises the same platinum-group metal. 
     
     
         13 . A method of forming a metal coated article, comprising:
 forming a refractory metal region on a boron-doped diamond substrate, the refractory metal region having a thickness of from about 10 micrometers to about 20 micrometers, wherein forming the refractory metal region comprises:
 depositing a refractory metal from a functional electrolyte in an alkali halide auxiliary electrolyte bath, onto the boron-doped diamond 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 on the refractory metal carbide layer; 
   forming a platinum-group metal region on the refractory metal region, wherein forming the platinum-group metal region comprises:
 depositing a platinum-group metal from a functional electrolyte in an alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form a platinum-group metal layer; and 
 converting a portion of the platinum-group metal layer to a platinum-group metal, refractory metal transition layer between the platinum-group metal layer and the refractory metal layer, the platinum-group metal layer comprising an exterior coating of the metal coated article. 
   
     
     
         14 . The method of  claim 13 , wherein converting the portion of the refractory metal layer to the refractory metal carbide layer, while the portion of the refractory metal layer remains the unreacted refractory metal, comprises:
 converting the portion of the refractory metal layer to the refractory metal carbide layer wherein the refractory metal carbide layer exhibits a relatively greater thickness than a thickness of the refractory metal layer.   
     
     
         15 . The method of  claim 13 , wherein converting the portion of the refractory metal layer to the refractory metal carbide layer, while the portion of the refractory metal layer remains the unreacted refractory metal, comprises:
 converting the portion of the refractory metal layer to the refractory metal carbide layer wherein the refractory metal carbide layer exhibits a greater thickness by a ratio of about 3:1 than a thickness of the refractory metal layer.   
     
     
         16 . The method of  claim 13 , wherein depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form the platinum-group metal layer comprises:
 depositing one or more of platinum, iridium, and ruthenium.   
     
     
         17 . The method of  claim 13 , wherein depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form the platinum-group metal layer comprises:
 depositing one or more of iridium and ruthenium.   
     
     
         18 . The method of  claim 13 , wherein depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form the platinum-group metal layer comprises:
 depositing platinum and one or more of iridium and ruthenium.   
     
     
         19 . The method of  claim 13 , wherein forming the platinum-group metal region comprises:
 depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form two or more layers of the platinum-group metal.   
     
     
         20 . The method of  claim 13 , wherein forming the platinum-group metal region comprises:
 depositing the platinum-group metal from the functional electrolyte in the alkali halide auxiliary electrolyte bath, onto the refractory metal layer to form three or more layers of the platinum-group metal, wherein one or more of the three or more layers of the platinum group metal comprises a different platinum-group metal.