Nickel alloy plating

Abstract

A nickel-boron coating deposited on a substrate which comprises nickel, boron and a material selected from bismuth, tin, tellurium, selenium, indium and gallium.

1 - 14 . (canceled) 
     
     
         15 . A method of depositing a nickel-boron coating comprising at least 75% wt nickel, wherein the method comprises contacting the substrate with a coating solution having a pH of at least 11 comprising:
 a source of nickel ions;   a reducing agent comprising a source of boron ions;   a complexing agent; and   a stabilizer agent comprising a source of ions selected from bismuth ions, tin ions, tellurium ions, selenium ions, indium ions and gallium ions.   
     
     
         16 . The method of  claim 15 , wherein the substrate comprises steel. 
     
     
         17 . The method of  claim 15 , wherein the deposition speed of the nickel-boron coating on the substrate is at least 10 μm/h. 
     
     
         18 . The method of  claim 15 , wherein the coating solution is lead-free and thallium-free. 
     
     
         19 . The method of  claim 15 , wherein the coating solution is phosphorus-free. 
     
     
         20 . The method of  claim 15 , wherein the coating solution has one or more of the following features (a) through (d):
 (a) a concentration of the complexing agent in the range 50 to 70 g/l;   (b) a concentration of the reducing agent in the range 0.25 to 1 g/l;   (c) a concentration of the nickel ions from the source of nickel ions in the range 20 to 30 g/l;   (d) a concentration of the stabilizer agent in the range 10 to 25 mg/l.   
     
     
         21 . The method of  claim 15 , comprising preparing the coating solution by:
 providing an alkaline solution comprising the source of nickel ions, the complexing agent and the stabilizer;   adding the reducing agent to the alkaline solution to form the coating solution.   
     
     
         22 . The method of  claim 15 , further comprising heat treating the nickel-boron coating after its deposition. 
     
     
         23 . The method of  claim 22 , wherein the heat treating comprises a heat treatment which lasts at least 30 minutes at a temperature of at least the crystallisation temperature of the nickel-boron coating. 
     
     
         24 . The method of  claim 22 , wherein the heat treating is carried out at a temperature of at least 280° C. and less than 500° C. 
     
     
         25 . The method of  claim 15 , wherein the nickel-boron coating comprises at least 85% wt of nickel. 
     
     
         26 . The method of  claim 15 , wherein the nickel-boron coating comprises (in % wt):
 at least 85% wt of nickel;   boron in the range 1.0 to 10% wt; and   a material selected from bismuth, tin, tellurium, selenium, indium, gallium and combinations of two or more thereof, in the range 0.1-5% wt.   
     
     
         27 . The method of  claim 15 , wherein the nickel-boron coating is free of at least one of lead, thallium, and phosphorus. 
     
     
         28 . The method of  claim 15 , wherein the nickel-boron coating is free of lead, thallium, and phosphorus. 
     
     
         29 . The method of  claim 26 , wherein the nickel-boron coating has one of the following features (a) through (h):
 (a) a thickness of at least 2 μm;   (b) a wear tracks width of ≤500 μm;   (c) a specific wear rate of ≤4 μm 2 /N;   (d) a friction coefficient of ≤0.35;   (e) a cross section hardness of ≥700 hv 100 ;   (f) a roughness Ra of ≤1 μm;   (g) a roughness Rp of ≤0.7 μm;   (h) a critical load for first damage Lc of at least 15N (scratch test).   
     
     
         30 . The method of  claim 15 , wherein the reducing agent comprises a borohydride. 
     
     
         31 . The method of  claim 15 , wherein the complexing agent comprises ethylene diamine. 
     
     
         32 . The method of  claim 15 , wherein, during the deposition of the nickel-boron coating, the coating solution has a temperature of at least 80° C. and less than 120° C. 
     
     
         33 . A method of depositing a nickel-boron coating on a substrate,
 wherein the nickel-boron coating comprises   at least 85% wt of nickel,   boron in the range 1.0% wt to 10% wt, and   a material selected from bismuth, tin, tellurium, selenium, indium, gallium and combinations of two or more thereof, in the range 0.1-5% wt, and the method comprising contacting the substrate with a coating solution having a pH of at least 11, the coating solution comprising:   a source of nickel ions;   a reducing agent comprising a source comprising a borohydride ;   a complexing agent comprising ethylene diamine; and   a stabilizer agent comprising a source of ions selected from bismuth ions, tin ions, tellurium ions, selenium ions, indium ions and gallium ions; and   wherein the coating solution is lead-free, thallium-free and phosphorus free.   
     
     
         34 . The method of  claim 33 , wherein the coating solution has:
 a concentration of the complexing agent in the range 50 to 70 g/l;   a concentration of the reducing agent in the range 0.25 to 1g/l;   a concentration of the nickel ions from the source of nickel ions in the range 20 to 30 g/l; and   a concentration of the stabilizer agent in the range 10 to 25mg/l.