Nickel cobalt phosphorous low stress electroplating

Abstract

An electrolytic plating process is provided for electrodepositing a nickel or nickel cobalt alloy which contains at least about 2% to 25% by atomic volume of phosphorous. The process solutions contains nickel and optionally cobalt sulfate, hypophosphorous acid or a salt thereof, boric acid or a salt thereof, a monodentate organic acid or a salt thereof, and a multidentate organic acid or a salt thereof. The pH of the plating bath is from about 3.0 to about 4.5. An electroplating process is also provided which includes electroplating from the bath a nickel or nickel cobalt phosphorous alloy. This process can achieve a deposit with high microyield of at least about 84 kg/mm 2 (120 ksi) and a density lower than pure nickel of about 8.0 gm/cc. This process can be used to plate a deposit of essentially zero stress at plating temperatures from ambient to 70° C.

That which is claimed:  
     
         1 . An electroplated nickel-phosphorous alloy comprising: 
 from about 75% to about 98% by atomic volume of nickel; and    from about 2% to about 25% by atomic volume of phosphorous,    wherein said alloy exhibits an internal stress of less than about 3.5 Mpa and ultimate strength of at least about 1700 Mpa.    
     
     
         2 . A nickel-phosphorous alloy according to  claim 1  wherein said nickel is present in an amount ranging from about 85% to about 89% by atomic volume and said phosphorous is present in an amount ranging from about 11 to about 15% by atomic volume.  
     
     
         3  . A nickel-phosphorous alloy according to  claim 1 , wherein said alloy exhibits an ultimate strength of at least about 1900 Mpa.  
     
     
         4 . A nickel-phosphorous alloy according to  claim 3 , wherein said alloy exhibits a yield of less than 0.2% in response to up to 2000 Mpa stress.  
     
     
         5 . A nickel-phosphorous alloy according to  claim 1 , wherein said alloy exhibits a microyield of at least about 480 Mpa.  
     
     
         6 . A nickel-phosphorous alloy according to  claim 5 , wherein said alloy exhibits a microyield of at least about 850 Mpa.  
     
     
         7 . A nickel-phosphorous alloy according to  claim 1 , wherein said alloy exhibits a hardness value ranging from about 50 to about 54 Rockwell C.  
     
     
         8 . A nickel-phosphorous alloy according to  claim 1 , wherein said alloy defines a freestanding object.  
     
     
         9 . A nickel-phosphorous alloy according to  claim 8 , wherein said object defines about a 2 m 2  area and further has a thickness ranging from about 0.26 to about 1.0 mm.  
     
     
         10 . A nickel-phosphorous alloy according to  claim 8 , wherein said object exhibits a diameter to thickness aspect ratio of greater than 3000:1.  
     
     
         11 . A nickel-phosphorous alloy according to  claim 1 , wherein said alloy deposited in a thickness ranging from about 0.025 mm up to about 7.5 mm remains sound.  
     
     
         12 . A nickel-phosphorous alloy according to  claim 11 , wherein said alloy deposited in a thickness ranging from about 0.15 mm to about 0.25 mm remains sound and allows the formation of complex shapes.  
     
     
         13 . A nickel-phosphorous alloy according to  claim 1 , said alloy comprising: 
 about 89% by atomic volume of nickel; and    about 11% by atomic volume of phosphorous,    wherein said alloy forms a deposit having a thickness of at least about 0.25 mm.    
     
     
         14 . An electroplated nickel-cobalt-phosphorous alloy comprising: 
 from about 30% to about 77% by atomic volume of nickel;    from about 15% to about 50% by atomic volume of cobalt;    from about 8% to about 20% by atomic volume of phosphorous;    wherein said alloy exhibits an internal stress of less than about 0.35 kg/mm 2  and ultimate strength of at least about 1700 Mpa.    
     
     
         15 . A nickel-cobalt-phosphorous alloy according to  claim 14 , wherein said alloy exhibits an ultimate strength of at least about 1900 Mpa.  
     
     
         16 . A nickel-cobalt-phosphorous alloy according to  claim 15 , wherein said alloy exhibits a yield of less than 0.2% in response to up to 2000 Mpa tensile stress.  
     
     
         17 . A nickel-cobalt-phosphorous alloy according to  claim 14 , wherein said alloy exhibits a microyield of at least about 480 Mpa.  
     
     
         18 . A nickel-cobalt-phosphorous alloy according to  claim 17 , wherein said alloy exhibits a microyield of at least about 850 Mpa.  
     
     
         19 . A nickel-cobalt-phosphorous alloy according to  claim 14 , wherein said alloy exhibits a hardness value ranging from about 50 to about 54 Rockwell C.  
     
     
         20 . A nickel-cobalt-phosphorous alloy according to  claim 14 , wherein said alloy defines a freestanding object.  
     
     
         21 . A nickel-cobalt-phosphorous alloy according to  claim 20 , wherein said object defines about a 1m 2  area and further has a thickness ranging from about 0.26 to about 1.0 mm.  
     
     
         22 . A nickel-cobalt-phosphorous alloy according to  claim 20 , wherein said object exhibits a diameter to thickness aspect ratio of greater than 3000:1.  
     
     
         23 . A nickel-cobalt-phosphorous alloy according to  claim 14 , wherein said alloy ranges in thickness from about 0.025 mm up to about 7.5 mm.  
     
     
         24 . A nickel-cobalt-phosphorous alloy according to  claim 23 , wherein said alloy ranges in thickness from about 0.15 mm to about 0.25 mm.  
     
     
         25 . A nickel-cobalt-phosphorous alloy according to  claim 14 , said alloy comprising: 
 about 59% by atomic volume of nickel;    about 30% by atomic volume of cobalt; and    about 11% by atomic volume of phosphorous,    wherein said alloy forms a deposit having a thickness of at least about 0.25 mm.    
     
     
         26 . An optical mirror comprising an electroplated alloy selected from the group consisting of nickel-phosphorous and nickel-cobalt-phosphorous,  
       wherein said alloy exhibits an internal stress of less than about 0.35 kg/mm 2  and ultimate strength of at least about 1700 Mpa.  
     
     
         27 . An optical mirror according to  claim 26 , wherein said alloy exhibits an ultimate strength of at least about 1900 Mpa.  
     
     
         28 . An optical mirror according to  claim 26 , wherein said alloy exhibits a microyield of at least about 850 Mpa.  
     
     
         29 . An optical mirror according to  claim 26 , wherein said alloy exhibits a yield of less than 0.2% in response to up to 2000 Mpa stress.  
     
     
         30 . An optical mirror according to  claim 26 , wherein said alloy exhibits a hardness value ranging from about 50 to about 54 Rockwell C.  
     
     
         31 . An optical mirror according to  claim 26 , wherein said alloy ranges in thickness from about a 0.025 mm up to about 7.5 mm.  
     
     
         32 . An optical mirror according to  claim 26 , wherein said alloy defines a freestanding object.  
     
     
         33 . An optical mirror according to  claim 32 , wherein said alloy defines about a Im 2  area and further has a thickness ranging from about 0.26 to about 1.0 mm.  
     
     
         34 . An optical mirror according to  claim 32 , wherein said mirror defines a diameter to thickness aspect ratio of greater than 3000:1.  
     
     
         35 . An optical mirror according to  claim 26 , wherein said optical mirror comprises an x-ray mirror for detecting galactic and extragalactic energy sources.  
     
     
         36 . An optical mirror according to  claim 35 , wherein said optical mirror comprises a freestanding shape.  
     
     
         37 . An optical mirror according to  claim 36 , wherein said object defines about a 1 m 2  area and further has a thickness ranging from about 0.26 to about 1.0 mm.  
     
     
         38 . An optical mirror according to  claim 26 , wherein said alloy is nickel-phosphorous, 
 said nickel present in an amount ranging from about 75% to about 98% by atomic volume, and    said phosphorous is present in an amount ranging from about 2% to about 25% by atomic volume.    
     
     
         39 . An optical mirror according to  claim 26 , wherein said alloy is nickel-cobalt-phosphorous, 
 said nickel present in an amount ranging from about 30% to about 77% by atomic volume;    said cobalt present in an amount ranging from about 15% to about 50% by atomic volume; and    said phosphorous present in an amount ranging from about 8% to about 20% by atomic volume.