System and method of plating metal alloys by using galvanic technology

Abstract

The invention relates to a system and a method of plating metal alloys, as well as to the structures thus obtained. The system for plating metal alloys comprises an electrolytic cell containing an electrolytic solution ( 3 ) in which an anode ( 4,4 a ,4 b ), a cathode ( 5 ), and a plurality of metal components to be plated onto the cathode are immersed, the anode ( 4,4 a ,4 b ) and the cathode ( 5 ) being electrically connected to means ( 6 ) adapted to apply a potential difference between said anode ( 4,4 a ,4 b ) and said cathode ( 5 ). The invention is characterized in that the means ( 6 ) adapted to apply a potential difference between said cathode ( 5 ) and said anode ( 4,4 a ,4 b ) impose a potential difference value that changes over time according to a predefined law.

1 . A system of plating metal alloys, comprising:
 an electrolytic cell containing an electrolytic solution ( 3 ) in which an anode ( 4 , 4   a , 4   b ) and a cathode ( 5 ) are immersed, a plurality of metal components of an alloy to be plated onto the cathode, the anode ( 4 , 4   a , 4   b ) and the cathode ( 5 ) being electrically connected to means ( 6 , 60 ) adapted to apply a potential difference between said anode ( 4 , 4   a , 4   b ) and said cathode ( 5 ), characterized in that said means ( 6 , 60 ) adapted to apply a potential difference between said cathode ( 5 ) and said anode ( 4 , 4   a , 4   b ) impose a potential difference having a value that changes over time according to a predefined law.   
     
     
         2 . The system according to  claim 1 , wherein said predefined law comprises at least one stage in which the potential difference value changes over time. 
     
     
         3 . The system according to  claim 2 , wherein said law is a periodic one. 
     
     
         4 . The system according to  claim 3 , wherein said predefined law prescribes that the potential difference stays constant at a first value for a first time interval t 1  and then stays constant at a second value for a second time interval t 2    
     
     
         5 . The system according to  claim 4 , wherein said second value is greater than said first value. 
     
     
         6 . The system according to any one of  claims 1  to  5 , wherein said law prescribes that the potential difference between said cathode ( 5 ) and said anode ( 4 , 4   a , 4   b ) is eliminated as soon as a stationary condition is achieved wherein the concentration ratios of the ions of said metal components in solution no longer change. 
     
     
         7 . The system according to  claim 1 , wherein said predefined law prescribes that the potential difference value stays constant for a time depending on the variation of ions concentrations of said metal components in solution. 
     
     
         8 . The system according  claim 1 , wherein said predefined law depends on one or more parameters selected from a group including: distance between the cathode and the anode, agitation of the solution ( 3 ), pH of the solution ( 3 ), temperature of the solution ( 3 ), concentration in the solution ( 3 ) of the materials to be deposited, charge transfer superpotentials at the interfaces between the liquid of the electrolytic solution and the cathode. 
     
     
         9 . The system according to  claim 1 , wherein said metal components comprise a plurality of metal elements or components which are present in said solution in ionic form. 
     
     
         10 . The system according to  claim 1 , wherein said anode ( 4 ) comprises at least some of said metal components. 
     
     
         11 . The system according to  claim 10 , wherein the anode ( 4 ) is a soluble one. 
     
     
         12 . The system according to  claim 11 , characterized in that the anode ( 4 ) comprises all of the metal components to be deposited onto the cathode. 
     
     
         13 . The system according to  claim 12 , characterized in that the anode ( 4 ) has the same in weight composition as the alloy to be obtained on the cathode. 
     
     
         14 . The system according  claim 1 , further comprising means for agitating the electrolytic solution ( 3 ). 
     
     
         15 . The system according to  claim 1 , wherein said electrolytic solution ( 3 ) contains only acids and complexing agents. 
     
     
         16 . The system according to  claim 1 , further comprising means for purifying said solution ( 3 ), which are adapted to collect and filter any impurities depositing in the electrolytic cell. 
     
     
         17 . The system according to  claim 1 , additionally comprising at least a second anode ( 4   b ) electrically connected in parallel to said anode ( 4   a ). 
     
     
         18 . The system according to  claim 17 , characterized in that said anodes ( 4   a , 4   b ) comprise a plurality of soluble anodes made of any single metals to be plated or alloys thereof. 
     
     
         19 . The system according to  claim 17  or  18 , characterized in that the second anode is a compensating anode for said system. 
     
     
         20 . The system according to  claim 19 , characterized in that said compensating anode has an electric resistance such that, when said potential difference is applied between said cathode and said compensating anode, the compensating anode is crossed by a preset current which is equal to the current used for discharging H+ ions being present in said solution onto the cathode. 
     
     
         21 . The system according to  claim 20 , wherein said compensating anode comprises graphite or coal. 
     
     
         22 . The system according to  claim 21 , wherein said compensating anode is made of graphite or coal. 
     
     
         23 . The system according to  claim 1 , characterized in that said cathode comprises a conductive matrix from which an electroformed coating can be detached. 
     
     
         24 . The system according to  claim 1 , wherein said materials to be deposited comprise at least three different chemical elements. 
     
     
         25 . The system according to  claim 24 , characterized in that said metal components to be plated comprise chemical elements which are suitable to form a Hastelloy alloy. 
     
     
         26 .- 57 . (canceled)