Process for the production of refractory metal plates and expanded metal grids platinized on one side

Abstract

A process for the production of refractory metal plates platinized on one side, in which refractory metal plates of predetermined dimensions are tightly, form-fittingly joined together back to back, are coated with platinum on their exposed surfaces by melt electrolysis and the plates are then separated one from the other. These plates may be processed into expanded metal grids platinized on one side. These refractory metal plates platinized on one side and the expanded metal grids platinized on one side produced therefrom may be used highly advantageously as anodes in electrolytic and electroplating processes.

We claim:  
     
         1 . A process for the production of a refractory metal plate platinized on one side, comprising coating a combination of refractory metal plates of predetermined dimensions that are tightly, formfittingly joined together back to back, with platinum on exposed surfaces of said combination by melt electrolysis and then separating said plates one from the other to obtain a refractory metal plate with a coating of platinum on one side thereof.  
     
     
         2 . The process according to  claim 1 , wherein the formfitting, tight joining of the refractory metal plates to be coated with platinum is achieved by screw fastening or welding in an edge area of the plates.  
     
     
         3 . The process according to  claim 2 , wherein the plates are separated by trimming off the edges.  
     
     
         4 . The process according to  claim 1 , wherein the refractory metal is a member selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum, tungsten and alloys of these metals.  
     
     
         5 . The process according to  claim 2 , wherein the refractory metal is a member selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum, tungsten and alloys of these metals.  
     
     
         6 . The process according to  claim 3 , wherein the refractory metal is a member selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum, tungsten and alloys of these metals.  
     
     
         7 . The process according to  claim 1 , wherein the platinum coating is provided in a melt of sodium cyanide and potassium cyanide at temperatures of 500 to 600° C., 
 wherein sheets of pure platinum are provided as the soluble counter-anodes to the refractory metal plates which are to be coated.  
 
     
     
         8 . The process according to  claim 2 , wherein the platinum coating is provided in a melt of sodium cyanide and potassium cyanide at temperatures of 500 to 600° C., 
 wherein sheets of pure platinum are provided as the soluble counter-anodes to the refractory metal plates which are to be coated.  
 
     
     
         9 . The process according to  claim 3 , wherein the platinum coating is provided in a melt of sodium cyanide and potassium cyanide at temperatures of 500 to 600° C., 
 wherein sheets of pure platinum are provided as the soluble counter-anodes to the refractory metal plates which are to be coated.  
 
     
     
         10 . The process according to  claim 4 , wherein the platinum coating is provided in a melt of sodium cyanide and potassium cyanide at temperatures of 500 to 600° C., 
 wherein sheets of pure platinum are provided as the soluble counter-anodes to the refractory metal plates which are to be coated.  
 
     
     
         11 . The process according to  claim 1 , further comprising, once coating is complete, heat treating the separated plates at 500 to 600° C. in an atmosphere containing oxygen in order to oxidize the surface of the sides without the platinum coating.  
     
     
         12 . The process according to  claim 2 , further comprising, once coating is complete, heat treating the separated plates at 500 to 600° C. in an atmosphere containing oxygen in order to oxidize the surface of the sides without the platinum coating.  
     
     
         13 . The process according to  claim 3 , further comprising, once coating is complete, heat treating the separated plates at 500 to 600° C. in an atmosphere containing oxygen in order to oxidize the surface of the sides without the platinum coating.  
     
     
         14 . The process according to  claim 4 , further comprising, once coating is complete, heat treating the separated plates at 500 to 600° C. in an atmosphere containing oxygen in order to oxidize the surface of the sides without the platinum coating.  
     
     
         15 . The process according to  claim 7 , further comprising, once coating is complete, heat treating the separated plates at 500 to 600° C. in an atmosphere containing oxygen in order to oxidize the surface of the sides without the platinum coating.  
     
     
         16 . The process according to  claim 1 , wherein the plates are provided with cuts and drawn out into expanded metal grids platinized on one side.  
     
     
         17 . A refractory metal sheet platinized on one side produced by the method according to  claim 1 .  
     
     
         18 . A refractory metal sheet platinized on one side produced by the method according to  claim 16 .  
     
     
         19 . A process for the production of a set of refractory metal plates each one of which is platinized on one side thereof, comprising coating a set of two identical refractory metal plates of predetermined dimensions that are tightly, form-fittingly joined together back to back, with platinum on an exposed surface of each of said plates by melt electrolysis and separating the plates one from the other to obtain two refractory metal plates having a coating of platinum on one surface thereof.  
     
     
         20 . The process according to  claim 19 , wherein the platinum coating is provided in a melt of sodium cyanide and potassium cyanide at temperatures of between 500 to 600° C., wherein sheets of pure platinum are provided as the soluble counter-anodes to the refractory metal plates which are to be coated.  
     
     
         21 . The process according to  claim 20 , further comprising hearing the separated plates at 500 to 600° C. in an atmosphere containing oxygen in order to oxidize the surface of the plates without the platinum coating to thereby passivate said surface without the platinum coating.