SURFACE ALLOYED METALS AND METHODS FOR ALLOYING SURFACES
The disclosure provides a material that includes a stainless steel layer with a 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.
1 . A material that comprises an alloyed metal layer having an alloying agent, the alloyed metal layer being coupled to a substrate with the aid of a diffusion layer between the alloyed metal layer and the substrate, wherein the amount of alloying agent in the diffusion layer changes with depth at a rate between about −0.01% per micrometer and −5.0% per micrometer as measured by x-ray photoelectron spectroscopy.
2 . (canceled)
3 . The material of claim 1 , wherein the diffusion layer provides a metallurgical bond between the alloyed metal layer and the substrate.
4 . The material of claim 1 , wherein the alloyed metal layer comprises stainless steel.
5 . The material of claim 1 , wherein the alloying agent comprises chromium.
6 . The material of claim 1 , wherein the alloying agent comprises nickel.
7 . The material of claim 1 , wherein the alloying agent comprises iron.
8 . The material of claim 1 , wherein the substrate comprises a steel substrate.
9 . (canceled)
10 . The material of claim 8 , wherein the substrate comprises carbon steel.
11 . The material of claim 1 , wherein the thickness of the alloyed metal layer is less than 200 micrometers.
12 . (canceled)
13 . (canceled)
14 . The material of claim 1 , wherein the depth is measured from an exterior surface of the alloyed metal layer.
15 . (canceled)
16 . The material of claim 1 , wherein the alloyed metal layer has a composition that varies by about 20 wt. % or less over a depth of about 50 micrometers or less.
17 . A material that comprises an outer metal layer metallurgically bonded to a steel substrate, wherein the material has a composition that varies by about 20 wt. % or less over a depth of about 50 micrometers or less and corrodes at a rate of at most about 1 nanometer per hour when exposed to an oxidizing or corrosive environment.
18 . The material of claim 17 , wherein the outer metal layer comprises steel.
19 . The material of claim 17 , wherein the outer metal layer comprises stainless steel.
20 . The material of claim 17 , wherein the outer metal layer comprises chromium.
21 . The material of claim 17 , wherein the outer metal layer comprises nickel.
22 . (canceled)
23 . The material of claim 17 , wherein the steel substrate comprises carbon steel.
24 . The material of claim 17 , wherein the thickness of the outer metal layer is less than 200 micrometers.
25 - 28 . (canceled)
29 . The material of claim 17 , wherein the surface of the material corrodes at a rate of at most 10 micrometers per year.
30 . (canceled)
31 . The material of claim 17 , wherein the material has no material discontinuity between the outer metal layer and the steel substrate.
32 . (canceled)
33 . A material that comprises a stainless steel layer metallurgically bonded to a steel substrate, wherein the material has a composition that varies by about 20 wt. % or less over a depth of about 50 micrometers or less and has a corrosion resistance of at least about 1 year under the copper acetic acid spray (CASS) test.
34 - 39 . (canceled)
40 . A metal-containing object that comprises a steel core at least partially coated with an alloyed metal layer having an alloying agent, wherein the alloyed metal layer has a thickness of less than 500 micrometers, and wherein the concentration of the alloying agent is at a maximum concentration in the metal-containing object and decreases by no more than 20 wt. % in the alloyed metal layer over a depth of about 50 micrometers or less as measured with x-ray photoelectron spectroscopy.
41 - 53 . (canceled)
54 . A metal-containing object that comprises an alloying agent, wherein the alloying agent has a concentration of at least 10 wt. % at a depth of less than or equal to 30 micrometers from the surface of the metal-containing object, and wherein the alloying agent has a concentration of at most 6 wt. % at a depth of greater than 150 micrometers from the surface of the metal-containing object.
55 - 57 . (canceled)
58 . The metal-containing object of claim 54 , wherein the alloying agent comprises chromium.
59 . The metal-containing object of claim 54 , wherein the alloying agent comprises nickel.
60 . The metal-containing object of claim 54 , wherein the alloying agent comprises iron.
61 . The metal-containing object of claim 54 , wherein the alloying agent has a concentration of at least 15 wt. % at a depth of less than or equal to 50 micrometers from the surface of the metal-containing object.
62 . (canceled)
63 . (canceled)
64 . The metal-containing object of claim 54 , wherein the metal-containing object is metal roofing material.