IRON STRIKE PLATING ON CHROMIUM-CONTAINING SURFACES
The present disclosure provides materials that include a stainless steel layer with a consistent or substantially consistent composition diffusion bonded to a carbon steel substrate. The material can have the corrosion resistance associated with the explosively welded stainless steel and the deep diffusion bonding observed typical of chromizing applications. In some embodiments, the disclosure provides materials having metal layers deposited onto a chromium surface and methods for depositing metal layers onto chromium surfaces. The present disclosure recognizes certain advantages to depositing metal layers onto chromium, such as more rapid diffusion of metals when heated to provide a stainless steel layer.
1 . A method for plating iron on a chromium surface, the method comprising:
(a) providing a metal substrate having a surface;
(b) contacting the surface with a solution comprising hydrochloric acid (HCl) and iron, wherein the iron is provided as an iron salt; and
(c) applying a voltage difference between the metal substrate and the solution to deposit a layer of iron from the iron salt onto the surface.
2 . The method of claim 1 , wherein the surface comprises chromium, titanium, or stainless steel.
3 . The method of claim 1 , wherein the surface is a passive surface.
4 . The method of claim 1 , wherein the surface comprises at least about 95% chromium as measured by x-ray photoelectron spectroscopy (XPS).
5 . The method of claim 1 , wherein the metal substrate comprises stainless steel and/or carbon steel.
6 . The method of claim 1 , wherein the layer of iron has a thickness of less than about 1 micrometer (μm).
7 . The method of claim 1 , further comprising depositing an additional layer of metal on the layer of iron.
8 . The method of claim 7 , wherein an additional layer of iron is deposited on the layer of iron, and nickel is deposited on the additional layer of iron.
9 .- 16 . (canceled)
17 . The method of claim 1 , wherein the iron salt comprises ferrous ions (Fe 2+ ).
18 . The method of claim 1 , wherein the iron salt comprises an iron halide.
19 . The method of claim 1 , wherein the iron salt comprises a chloride or sulfate salt.
20 . (canceled)
21 . The method of claim 1 , wherein applying the voltage in (c) produces an electric current between about 50 amperes per square foot (Amp/ft 2 ) and about 200 Amp/ft 2 .
22 . (canceled)
23 . (canceled)
24 . The method of claim 1 , wherein (b) and (c) are performed simultaneously.
25 . A method for making a stainless steel surface diffusion bonded to a metal substrate, the method comprising:
(a) providing a metal substrate;
(b) depositing a layer of chromium adjacent to the metal substrate;
(c) depositing at least one layer of iron adjacent to the layer of chromium;
(d) depositing a layer of nickel adjacent to the layer of iron; and
(e) heating the layers of chromium, iron and nickel to form a layer of stainless steel diffusion bonded to the metal substrate.
26 . The method of claim 25 , wherein the layer of chromium is deposited on the metal substrate.
27 . The method of claim 25 , wherein the layer of iron is deposited on the layer of chromium.
28 . The method of claim 25 , wherein the layer of nickel is deposited on the layer of iron.
29 . The method of claim 25 , wherein the at least one layer of iron comprises at least two layers of iron.
30 . The method of claim 29 , wherein (c) comprises (i) depositing a first layer of iron on the chromium and (ii) depositing an additional layer of iron on the first layer of iron.
31 . The method of claim 30 , wherein the first layer of iron has a thickness of less than about 1 micrometer (μm).
32 . The method of claim 30 , wherein the first layer of iron is deposited by contacting the chromium with a solution comprising hydrochloric acid (HCl) and iron, wherein the iron is an iron salt, and applying a voltage difference between the metal substrate and the solution, whereby the first layer of iron is deposited on the chromium.
33 . The method of claim 25 , wherein (b)-(d) are performed using electro-deposition and/or vapor deposition.
34 .- 36 . (canceled)
37 . The method of claim 25 , wherein the layer of stainless steel is at least about 250 microns (μm) in thickness.
38 . A method for forming a material stack, comprising:
(a) providing a metal substrate, which metal substrate is a carbon or low-carbon steel substrate;
(b) depositing a first metal layer comprising chromium adjacent to the metal substrate; and
(c) depositing a second metal layer comprising iron on the first metal layer to form the material stack,
wherein (a)-(c) are performed without annealing.
39 .- 47 . (canceled)