Nickel-Chromium Nanolaminate Coating or Cladding Having High Hardness
Electrodeposited nanolaminate materials having layers comprised of nickel and/or chromium with high hardness and processes for making them are disclosed. The uniform or substantially uniform appearance, chemical resistance, and high hardness of embodiments of the nanolaminate NiCr materials described herein render them useful for a variety of purposes including wear (abrasion) resistant barrier coatings or claddings for use in decorative as well as demanding physical, structural and chemical environments.
1 . A process for forming a multilayered coating or cladding on a surface of a substrate or mandrel by electrodeposition, comprising:
(a) providing an electrolyte solution comprising a nickel salt and/or a chromium salt;
(b) providing a conductive substrate or mandrel for electrodeposition;
(c) contacting at least a portion of the surface of the substrate or mandrel with the electrolyte solution;
(d) passing a seed layer plating current through the substrate or mandrel to deposit a nickel and chromium containing seed layer on the substrate or mandrel, where the seed layer comprises greater than about 90% nickel by weight;
(e) passing a first electric current through the substrate or mandrel to deposit a nickel-chromium alloy first layer comprising from about 5 to about 35% chromium by weight;
(f) passing a second electric current through the substrate to deposit a nickel and chromium containing second layer comprising greater than about 90% nickel by weight;
(g) repeating steps (e) and (f) four or more times, thereby producing a multilayered coating or cladding having a seed layer and alternating first layers and second layers on the surface of the substrate or mandrel; and
(h) optionally separating the substrate or mandrel from the coating or cladding.
2 . The process of claim 1 , wherein the seed layer plating current has a density from about 20 to about 60 mA/cm 2 .
3 . The process of claim 1 , wherein the seed layer plating current has a density selected from the group consisting of about 20 mA/cm 2 , about 25 mA/cm 2 , about 30 mA/cm 2 , about 35 mA/cm 2 , about 40 mA/cm 2 , about 45 mA/cm 2 , about 50 mA/cm 2 , about 55 mA/cm 2 , and about 60 mA/cm 2 .
4 . The process of claim 1 wherein the seed layer plating current is applied to the substrate or mandrel for a time period about 1 minute to about 10 minutes.
5 . The process of claim 1 wherein the seed layer comprises nickel in a weight percent (Ni wt. %) range selected from about 90.00 up to about 100 percent.
6 . The process of claim 1 , wherein the first electric current has a density in a range selected from about 100 to about 300 mA/cm 2 .
7 . The process of claim 1 , wherein the first electric current has a density selected from the group consisting of about 160 mA/cm 2 , about 180 mA/cm 2 , about 200 mA/cm 2 , about 220 mA/cm 2 , about 240 mA/cm 2 , and about 260 mA/cm 2 .
8 . The process of claim 1 , wherein the first current is applied for a time period selected from about 50 milliseconds to about 500 milliseconds.
9 . The process of claim 1 , wherein the second electric current has a density in a range selected from the group consisting of from about 20 to about 60 mA/cm 2 , from about 20 to about 50 mA/cm 2 , from about 30 to about 60 mA/cm 2 , from about 30 to about 50 mA/cm 2 , from about 25 to about 55 mA/cm 2 , from about 20 to about 45 mA/cm 2 , from about 20 to about 35 mA/cm 2 , from about 30 to about 45 mA/cm 2 , from about 30 to about 40 mA/cm 2 , and from about 40 to about 50 mA/cm 2 .
10 . The process of claim 1 , wherein the second electric current has a density selected from the group consisting of about 20 mA/cm 2 , about 25 mA/cm 2 , about 30 mA/cm 2 , about 35 mA/cm 2 , about 40 mA/cm 2 , about 45 mA/cm 2 , about 50 mA/cm 2 , about 55 mA/cm 2 , and about 60 mA/cm 2 .
11 . The process of claim 1 , wherein the second electric current is applied for a time period selected from about 50 milliseconds to about 500 milliseconds.
12 . The process of claim 1 , where steps (e) and (f) are repeated greater than 50 times.
13 . The process of any claim 1 , where steps (e) and (f) are repeated from about 4 to 10,000 times.
14 . The process of claim 1 , wherein two or more of the first layers comprise chromium in a weight percent (Cr wt. %) from about 7 to about 32 percent.
15 . The process of claim 1 , wherein each of the first layers comprises chromium in a weight percent (Cr wt. %) from about 5 to about 35 percent.
16 . The process of claim 1 , wherein two, or more of the second layers comprise nickel in a weight percent (Ni wt. %) from about 90.00 to about 100 percent.
17 . The process of claim 1 , wherein each of the second layers comprises nickel in a weight percent (Ni wt. %) from about 90.00 to about 100 percent.
18 . A process for forming a multilayered coating or cladding on a surface of a substrate or mandrel by electrodeposition, comprising:
(a) providing an electrolyte solution comprising a nickel salt and/or a chromium salt from which nickel and/or chromium can be electrodeposited;
(b) providing a conductive substrate or mandrel for electrodeposition;
(c) contacting at least a portion of the surface of the substrate or mandrel with the electrolyte solution;
(d) passing a seed layer plating current having a density of about 30 to about 50 mA/cm 2 for a time period of about 1 minute to about 5 minutes through the substrate or mandrel to deposit a nickel and chromium containing seed layer on the substrate or mandrel, where the seed layer comprises greater than about 90% nickel by weight;
(e) passing a first electric current having a density of about 100 to about 300 mA/cm 2 for a time period of about 200 milliseconds to about 400 milliseconds through the substrate or mandrel to deposit a nickel-chromium alloy first layer comprising from about 5 to about 35% chromium by weight;
(f) passing a second electric current having a density of about 30 to about 50 mA/cm 2 for a time period of about 200 milliseconds to about 400 milliseconds through the substrate to deposit a nickel and chromium containing second layer comprising greater than about 90% nickel by weight;
(g) repeating steps (e) and (f) 10 or more times, thereby producing a multilayered coating or cladding having a seed layer and alternating first layers and second layers on the surface of the substrate or mandrel; and
(h) optionally separating the substrate or mandrel from the coating or cladding.
19 . A process for forming a multilayered coating or cladding on a surface of a substrate or mandrel by electrodeposition, comprising:
(a) providing an electrolyte solution comprising a nickel salt and/or a chromium salt from which nickel and/or chromium can be electrodeposited;
(b) providing a conductive substrate or mandrel for electrodeposition;
(c) contacting at least a portion of the surface of the substrate or mandrel with the electrolyte solution;
(d) passing a seed layer plating current having a density of about 35 to about 45 mA/cm 2 for a time period of about 1 minute to about 3 minutes through the substrate or mandrel to deposit a nickel and chromium containing seed layer on the substrate or mandrel, where the seed layer comprises greater than about 90% nickel by weight;
(e) passing a first electric current having a density of about 150 to about 260 mA/cm 2 for a time period of about 250 milliseconds to about 350 milliseconds through the substrate or mandrel to deposit a nickel-chromium alloy first layer comprising from about 5 to about 35% chromium by weight;
(f) passing a second electric current having a density of about 35 to about 45 mA/cm 2 for a time period of about 250 milliseconds to about 350 milliseconds through the substrate to deposit a nickel and chromium containing second layer comprising greater than about 90% nickel by weight;
(g) repeating steps (e) and (f) 10 or more times, thereby producing a multilayered coating or cladding having a seed layer and alternating first layers and second layers on the surface of the substrate or mandrel; and
(h) optionally separating the substrate or mandrel from the coating or cladding.
20 . A process according to claim 18 , wherein two, or more of the first layers comprise chromium in a weight percent (Cr wt. %) range of from about 12 to 26 percent and wherein two or more second layers comprise about 95% nickel by weight.
21 . (canceled)