WO2015070130A1

WO2015070130A1 - Anti-fouling stainless steel compositions

Info

Publication number: WO2015070130A1
Application number: PCT/US2014/064770
Authority: WO
Inventors: Daniel E. Bullard; Adam G. THOMAS; Joseph E. MCDERMOTT; Ersan Ilgar
Original assignee: Arcanum Alloy Design Inc.
Priority date: 2013-11-11
Filing date: 2014-11-10
Publication date: 2015-05-14

Abstract

Structure, composition, and process of manufacturing copper coated steel wires for the marine environment, where the structure and composition can include a core material metallurgical bonded, by a bonding layer, to a surface layer which carries the single continuous surface; the core material comprising about 50 wt.% to about 90 wt.% iron and about 10 wt.% to about 30 wt.% chromium, wherein the core material is substantially free of copper; the surface layer comprising about 60 wt.% to about 95 wt.% copper, about 5 wt.% to about 35 wt.% of a first element selected from the group consisting of nickel, zinc, tin, aluminum and a mixture thereof, and 0 wt.% to about 10 wt.% of a second element selected from the group consisting of iron, molybdenum, manganese, and a mixture thereof; the bonding layer comprising the first element in a concentration greater than in the surface layer.

Description

ANTI-FOULING STAINLESS STEEL COMPOSITIONS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This disclosure claims the benefit of priority to US Provisional Patent Application

No. 61/902,361 , filed 1 1 November 2013, and US Provisional Patent Application No.

61/913,492, filed 09 December 2013, the disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] This disclosure relates to the composition, manufacturing method, and use of stainless steel wires that have copper based surface compositions.

BACKGROUND

[0003] Aquaculture nets or fish-farming nets are used to raise aquatic life such as fish.

The aquaculture net keeps the aquatic life controlled and contained and protects the aquatic life inside the net against predators such as shark, squid, and whales.

[0004] To survive the marine environment, the aquaculture nets need to meet at least three functional characteristics: strength, corrosion resistance, and bio-fouling resistance. As the dimensions of an aquaculture net can be very large (e.g., the dimensions of a single net can be 30 m x 30 m x 15 m), nets can routinely weight more than 4 metric tons. Examples of aquaculture net can be found, for example, in US 4,615,301 and 8,336,499. Additionally, the marine environment creates special galvanic corrosion issues, especially at the air-water interface. Accordingly, portions of nets potentially exposed to the atmosphere require galvanic protection (e.g., are made from galvanized steel wires). Furthermore, the bio-fouling of a net both increases the weight of the net (e.g., causing the net to sink or the wiring to break) and decreases the suitability of the net for aquaculture (e.g., reducing the exchange of water through the netting). Fouling material generally refers to organisms such as barnacles, algae or mollusks, which may attach and grow to the wire material of the mesh structure. As such, aquaculture net ideally incorporate high-tensile strength high-gauge wire that is both corrosion and bio-fouling resistant.

[0005] JP/A/2004/261023 discloses a steel wire for aquaculture nets. The steel wire has a stainless steel core and a metal coating of cupronickel: a copper nickel alloy with nickel content ranging between 10% and 30% by weight. The metal coating can be applied either by hot dipping the stainless steel core in a copper nickel bath or by plating the stainless steel core with copper, thereafter with nickel and finally applying a thermal diffusion treatment.

[0006] US 2010/0294201 overcomes the problem of controlling the composition of the copper nickel coating by adhesion bonding copper nickel foils to the surface of the steel wire. These welded structures have inconsistencies in the surface which facilitate the failure, through corrosion, of the underlying steel substrate.

[0007] Upon review of known aquaculture nets with anti-fouling and anti-corrosion properties, it is clear that there is a need for new wire materials and processes for their manufacture.

SUMMARY

[0008] A first embodiment is, an anti-fouling steel wire having a single continuous surface that includes a core material metallurgically bonded, by a bonding layer, to a surface layer which carries the single continuous surface; the core material comprising about 50 wt.% to about 90 wt.% iron and about 10 wt.% to about 30 wt.% chromium, wherein the core material is substantially free of copper; the surface layer comprising about 60 wt.% to about 95 wt.% copper, about 5 wt.% to about 35 wt.% of a first element selected from the group consisting of nickel, zinc, tin, aluminum and a mixture thereof, and 0 wt.% to about 10 wt.% of a second element selected from the group consisting of iron, molybdenum, manganese, and a mixture thereof; the bonding layer comprising the first element in a concentration greater than in the surface layer.

[0009] Another embodiment is a process of manufacturing an anti-fouling steel wire that includes providing a "core wire" made of a core material, the core material comprising about 50 wt.% to about 90 wt.% iron and about 10 wt.% to about 30 wt.% chromium, wherein the core material is substantially free of copper, the core wire including a primary surface; depositing an intermediate layer onto the primary surface, the intermediate layer including Ni, Zn, Sn, Al, Mo, Mn, or a mixture thereof, the intermediate layer carrying an intermediate surface; depositing a copper layer onto the intermediate surface; heating the core wire and deposited layers to a temperature in the range of about 500 to about 800 °C; forming a surface layer having a composition that comprises about 50 wt.% to about 95 wt.% copper about 5 wt.% to about 35 wt.% of a first element selected from the group consisting of nickel, zinc, tin, aluminum and a mixture thereof, and 0 wt.% to about 10 wt.% of a second element selected from the group consisting of iron, molybdenum, manganese, and a mixture thereof.

[0010] Yet another embodiment is an aquaculture net comprising steel wires; the steel wires having a stainless steel core metallurgically bonded to a surface layer by a bonding layer, the stainless steel core having anti-corrosion properties; the surface layer having anti-corrosion and anti-fouling properties; the surface layer free of a weld interface; the surface layer having a surface composition that comprises at least 50 wt.% copper and about 5 wt.% to about 50 wt.% nickel and/or zinc.

BRIEF DESCRIPTION OF THE FIGURES

[0011] For a more complete understanding of the disclosure, reference should be made to the following detailed description and accompanying drawing figures wherein:

[0012] Figure 1 is an plot of compositional data by EDS for a product carried by annealed stainless steel;

[0013] Figure 2 is an plot of compositional data by EDS for a product carried by full hard stainless steel;

[0014] Figure 3 is an plot of compositional data by EDS for a product carried by annealed stainless steel which was annealed for twice as long as the product of Figure 1 ;

[0015] Figure 4 is an plot of compositional data by EDS for a product carried by full hard stainless steel which was annealed for twice as long as the product of Figure 2;

[0016] Figure 5 is a SEM image of a cross section of the same product in Figure 2;

[0017] Figure 6 is a SEM image of a cross section of the same product in Figure 3; and

[0018] Figure 7 is a plot of the compositional data by EDS of a product where a copper strike was applied prior to the deposition of an intermediate layer.

[0019] While specific embodiments are illustrated in the figures, with the understanding that the disclosure is intended to be illustrative, these embodiments are not intended to limit the invention described and illustrated herein.

DETAILED DESCRIPTION

[0020] A first embodiment is a steel form carrying, as a surface layer, an antimicrobial and/or antifouling composition. The antimicrobial and/or antifouling properties of the composition can be provided by the surface layer including, for example, copper, aluminum, silver, lead, zinc, gold, or alloys thereof. In one preferable instance, the antimicrobial and/or antifouling properties are provided by the surface layer including copper, silver, aluminum or an alloy thereof. More preferably, the surface layer includes a majority of copper, silver, aluminum, or an alloy thereof. In a preferable instance, the surface layer includes about 60 wt.% to about 95 wt.% copper.

[0021] In a first example, the steel form is an anti-fouling steel wire having a single continuous surface. That is, the steel wire has a cross section that includes a core, a bonding layer, and a surface layer where the surface layer covers the exterior portion (e.g., the circumference) of the steel wire. Herein, the steel wire will have a continuous surface if the surface layer has an unbroken composition about the exterior portion of the steel wire. A surface that includes welds, lap bonding, brazed joints are not continuous as the composition of the surface layer would have discontinuities.

[0022] In one instance, the anti-fouling steel wire has a core material that is

metallurgically bonded, by a bonding layer, to a surface layer which carries the single continuous surface.

[0023] The core material, preferably, includes about 50 wt.% to about 90 wt.% iron and about 10 wt.% to about 30 wt.% chromium, and is substantially free of copper. That is, the core material includes less that about 2 wt.%, 1 wt.%, or 0.5 wt.% copper. Preferably, the core material is a stainless steel, more preferably a marine compatible stainless steel.

[0024] Preferably, the core material includes about 15 wt.% to about 25 wt.% Cr, or about 16 wt.% to about 22 wt.% Cr. The core material can include about 50 wt.% to about 90 wt.% iron and about 10 wt.% to about 30 wt.% chromium and further includes about 5 wt.% to about 25 wt.% nickel. Preferably, about 6 wt.% to about 20 wt.% Ni, about 10 wt.% to about 20 wt.% Ni, about 15 wt.% to about 25 wt.% Ni, or about 12 wt.% to about 25 wt.% Ni. The core material can further include about 2 wt.% to about 7 wt.% molybdenum, about 2 wt.% to about 3 wt.% Mo, about 3 wt.% about 4 wt.% Mo, or about 6 wt.% Mo. Nominal compositions of the core material can include, for example, the following stainless steel grades: 316, 317, 6 Moly, Al- 6XN, 254 SMO, 904L, Alloy 20, 302, 303, 304, 321 , and 347.

[0025] In one example, the surface layer includes about 60 wt.% to about 95 wt.% copper. For example, the surface layer can include about 60 wt.% to about 70 wt.% Cu, about 70 wt.% to about 80 wt.% Cu, about 80 wt.% to about 90 wt.% Cu, or about 90 wt.% to about 95 wt.% Cu. Preferably, the surface layer includes about 70 wt.% to about 90 wt.% Cu. [0026] The surface layer, preferably, further includes about 5 wt.% to about 35 wt.% of a first element selected from the group consisting of nickel, zinc, tin, aluminum and a mixture thereof. In one example, the first element is nickel, preferably, where the surface layer includes about 5 wt.% to about 10 wt.% more nickel than the core material. In alternate example, the first element is selected from the group consisting of zinc, tin, aluminum and a mixture thereof, preferably, wherein the first element is zinc. More preferably, wherein the surface layer is substantially free of or completely free of nickel. In this example, the surface layer composition can include, for example, about 5 wt.% to about 15 wt.% Zn, about 15 wt.% to about 30 wt.% Zn, or about 30 wt.% to about 35 wt.% Zn; about 5 wt.% to about 15 wt.% Sn, about 15 wt.% to about 30 wt.% Sn, or about 30 wt.% to about 35 wt.% Sn; and/or about 5 wt.% to about 15 wt.% Al, about 15 wt.% to about 30 wt.% Al, or about 30 wt.% to about 35 wt.% Al.

[0027] The surface layer can further includes about 0 wt.% to about 10 wt.% of a second element selected from the group consisting of iron, molybdenum, manganese, and a mixture thereof. In one example, the surface layer includes about 1 wt.% to about 10 wt.% iron, about 1 wt.% to about 5 wt.% Mo, and/or about 1 wt.% to about 5 wt.% Mn.

[0028] The surface layer of the anti-fouling steel wire, preferably, has a (radial) thickness in the range of about 100 to 300 microns, or in the range of about 150 to 250 microns. The surface layer can have a thickness in the range of about 10 to about 100 microns but preferably has a thickness of about 100, 125, 150, 175, 200, 225, 250, 275, or 300 microns.

[0029] Preferably, the surface layer has a consistent composition. That is, the radial

(from core outward) and circumferential (around the entire steel wire) composition of the surface layer varies by less than 5, 4, 3, 2, or 1 % in each element of the surface layer composition. For example, the radial composition can be determined by cross-sectional EDS analysis whereas the circumferential composition can be determined by EDS or auger spectroscopy of the surface. More preferably, steel wire has a plurality of identical radial compositions; that is the radial composition profile (e.g., the composition along the radius from the core to the surface) is independent on the angle selection of the radius. In another example, the wire has a non- circular surface (e.g., oval, square, hexagonal, octagonal); in such examples the radial composition profile may vary by thickness of the core, bonding and surface layers but, preferably, do not vary by the weight percentage of the individual elements in the respective layers.

[0030] The anti-fouling steel wire further includes a bonding layer disposed between the surface layer and the core material. In one example, the bonding layer, preferably, has a composition that includes the first element in a concentration that is greater than in the surface layer and greater than in the core composition. For example, the bonding layer can include a Gaussian distribution of the first element, where the maximum of the Gaussian distribution is greater than the concentration in the surface layer or in the core material. In another example, the bonding layer has a composition that includes the first element in a decreasing

concentration from the surface layer to the core composition. For example, the bonding layer can include a linear or sigmoidal decrease of the concentration of the first element from the surface layer to the core material. In particularly preferable example, the bonding layer comprises a series of iron-copper alloys. Notably, iron and copper can be immiscible and the bonding layer may include a heterogeneous mixture of iron and copper alloys.

[0031] In a particularly preferable embodiment, the anti-fouling steel wire is formed into an aquaculture net. The aquaculture net is manufactured, primarily, from steel wires where the steel wires have a stainless steel core metallurgically bonded to a surface layer by a bonding layer, for example, as described above. The stainless steel core, preferably, has anti-corrosion properties, whereas, the surface layer has anti-corrosion and anti-fouling properties.

Furthermore, the surface layer is free of a weld interface, a braze interface, a solder interface, or any other metal to metal junction about the circumference of the wire. Preferably, the surface layer has a surface composition that comprises at least 50 wt.% copper and about 5 wt.% to about 50 wt.% nickel and/or zinc. In a preferable example, the surface layer has a higher weight percentage of nickel and/or zinc than the stainless steel core.

[0032] In another embodiment, an anti-fouling steel wire can be manufactured by a process that includes providing a "core wire" made of a core material and having a primary surface. Depositing an intermediate layer onto the primary surface, the intermediate layer carrying an intermediate surface. Depositing a copper layer onto the intermediate surface.

Heating the core wire and deposited layers and thereby forming a surface layer.

[0033] In this embodiment the core material, preferably, includes about 50 wt.% to about

90 wt.% iron and about 10 wt.% to about 30 wt.% chromium, wherein the core material is substantially free of copper. That is, the core material includes less that about 2 wt.%, 1 wt.%, or 0.5 wt.% copper. Preferably, the core material is a stainless steel, more preferably a marine compatible stainless steel. In one instance, the core wire is annealed wire, in another instance the core wire is full hard wire.

[0034] Preferably, the core material includes about 15 wt.% to about 25 wt.% Cr, or about 16 wt.% to about 22 wt.% Cr. The core material can include about 50 wt.% to about 90 wt.% iron and about 10 wt.% to about 30 wt.% chromium and further includes about 5 wt.% to about 25 wt.% nickel. Preferably, about 6 wt.% to about 20 wt.% Ni, about 10 wt.% to about 20 wt.% Ni, about 15 wt.% to about 25 wt.% Ni, or about 12 wt.% to about 25 wt.% Ni. The core material can further include about 2 wt.% to about 7 wt.% molybdenum, about 2 wt.% to about 3 wt.% Mo, about 3 wt.% about 4 wt.% Mo, or about 6 wt.% Mo. Nominal compositions of the core material can include, for example, the following stainless steel grades: 316, 317, 6 Moly, Al- 6XN, 254 SMO, 904L, Alloy 20, 302, 303, 304, 321 , and 347.

[0035] The intermediate layer can be deposited onto the primary surface by a process selected from electrodeposition, electroless deposition, hot dip coating, physical vapor deposition, and chemical vapor deposition. In one instance, the intermediate layer is provided by electrodeposition or electroless deposition. The intermediate layer can include a metal or alloy, where the metal or alloy is selected from the group consisting of Ni, Zn, Sn, Al, Mo, Mn, and a mixture thereof. The intermediate layer (e.g., the metal or alloy) can further include sulfur, phosphorous, carbon, or arsenic in an amount less than 25, 20, 15, 10, or 5 wt.%. In another instance, the intermediately layer can consists essentially of a metal or alloy selected from the group consisting of Ni, Zn, Sn, Al, Mo, Mn, and a mixture thereof. Preferably, the intermediate layer includes nickel or consists essentially of nickel. In an alternate preferable example, the intermediate layer includes zinc or consists essentially of zinc. The metal or alloy of the intermediate layer can be deposited to a thickness of less than about 125 microns, preferably a thickness of about 10 to about 125 microns, or about 25 to about 100 microns. That is, the intermediate layer can have a thickness that is less than about 125 microns, preferably a thickness of about 10 to about 125 microns, or about 25 to about 100 microns.

[0036] In a particularly preferable instance, the primary surface is modified by the application of a strike layer prior to the disposition of the intermediate layer. The strike (or flash) layer is very thin, preferably less than 1 micron, 0.5 microns, or 0.1 microns thick. The intermediate layer is therefore preferably deposited onto the strike layer. In one example, the strike layer is a copper strike, preferably, the copper strike has a thickness of about 0.5, 0.4, 0.3 0.2, 0.1 or 0.05 microns. In another example, the strike layer is a zinc strike. In still another example, the strike layer includes a nickel strike and a copper strike, where the nickel strike modifies the surface of the core material and the copper strike modifies the surface of the nickel strike. More preferably, the nickel strike is thinner than the copper strike (e.g., the nickel strike can have a thickness that is 75%, 50%, 25%, or 10% of the copper strike thickness). [0037] The copper layer can be deposited onto the intermediate surface by a process selected from electrodeposition, electroless deposition, hot dip coating, physical vapor deposition, and chemical vapor deposition. In one example, the copper layer is provided by hot dip coating of the wire in a melt of relatively pure copper; in another example the copper layer is provided by hot dip coating in a melt of a eutectic copper alloy (e.g., copper/silicon).

[0038] In one example, the copper layer consists essentially of copper (Cu). In one example, the copper layer has a composition that includes at least 95, 97.5, or 99% copper. The copper layer can be deposited to a thickness of about 1 to about 500 microns, preferably a thickness of about 5 to about 400 microns, or about 10 to about 300 microns. That is, the copper layer can have a thickness in the range of about 10 to about 300 microns, preferably, the thickness that is less than about 250 microns. More preferably, the copper layer has a thickness of about 50 to about 200 microns, about 75 to about 175 microns, or about 100 to about 150 microns.

[0039] In another example, the copper layer includes copper and less than 50 wt.% of a co-deposited metal. Preferably, the copper layer includes less than 40, 30, 20, or 10 wt.% of the co-deposited metal. In one instance, the copper layer can include silicon, for example, about 5 wt.% to about 20 wt.% silicon, preferably about 7 wt.% to about 15 wt.% silicon.

[0040] Following the deposition of the copper layer, the core wire and the deposited layers are heated to a temperature sufficient to form the intermediate layer and the copper layer (e.g., sufficient to alloy the intermediate layer and the copper layer and/or sufficient to alloy the intermediate layer and the core material). For example, the core wire and the deposited layers can be heated to a temperature in the range of about 400 to about 1000 °C, about 500 to about 800 °C, about 600 to about 800 °C, or about 650 to about 750 °C. In preferable examples, the core wire and the deposited layers can be heated under a controlled atmosphere. The controlled atmosphere can be, for example, nitrogen, argon, helium, or another "inert" gas and, optionally, hydrogen, carbon monoxide, carbon dioxide, or oxygen. In one preferable example, the controlled atmosphere is a mixture of nitrogen and hydrogen. In one instance, the intermediate layer and the copper layer are deposited onto the core wire and then the deposited layers and the core wire are heated to the described temperature. In another instance, the intermediate layer is deposited onto the core wire, this structure is heated to alloy or partially alloy the intermediate layer with the core wire, then the copper layer is deposited onto the alloyed or partially alloyed wire surface, and then heated to alloy the copper layer with the remainder of the intermediate layer. [0041] In one instance, the surface layer is formed by alloying the intermediate layer with the copper layer at the temperature sufficient to alloy the intermediate layer and the copper layer, as described above. While heating the deposited layers to the described temperature will facilitate the alloying (that is the interdiffusion of the elements) of the layers, the deposited layers, preferably, are held at the described temperature for a sufficient time to interdiffuse the intermediate layer and the copper layer and interdiffuse the intermediate layer and the core. Examples of sufficient times include 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, and 20 hours. During the formation of the surface layer by the alloying of the intermediate layer with the copper layer, a bonding layer can be formed by alloying a portion of the core material with the intermediate layer and, preferably, the copper layer such that the bonding layer has a composition that includes copper, the intermediate layer elements, and iron.

[0042] The surface layer formed, preferably, has a composition that includes about 50 wt.% to about 95 wt.% copper, about 5 wt.% to about 35 wt.% of the intermediate layer metal or alloy. In one example, the intermediate layer metal or alloy is selected from the group consisting of nickel, zinc, tin, aluminum and a mixture thereof, and 0 to about 10% of a second element selected from the group consisting of iron, molybdenum, manganese, and a mixture thereof. Preferably, when the second element is iron, the iron is derived from the core wire. Furthermore, the surface layer, preferably, has a thickness of about 100 to about 300 microns.

[0043] The process of forming the anti-fouling steel wire can further include depositing an outer layer onto the copper layer before or after forming the surface layer (e.g., before heating the deposited copper layer to the temperature sufficient to alloy the copper layer and the intermediate layer). This outer layer can include an element selected from the group consisting of Ni, Zn, Sn, Al, Mo, Mn, and a mixture thereof and can be provided by a method selected from electrodeposition, electroless deposition, hot dip coating, physical vapor deposition, and chemical vapor deposition, preferably, electrodeposition or electroless deposition.

Claims

WHAT IS CLAIMED:

1. An anti-fouling steel wire having a single continuous surface comprising:

a core material metallurgically bonded, by a bonding layer, to a surface layer which carries the single continuous surface;

the core material comprising about 50 wt.% to about 90 wt.% iron and about 10 wt.% to about 30 wt.% chromium, wherein the core material is substantially free of copper;

the surface layer comprising about 60 wt.% to about 95 wt.% copper, about 5 wt.% to about 35 wt.% of a first element selected from the group consisting of nickel, zinc, tin, aluminum and a mixture thereof, and 0 wt.% to about 10 wt.% of a second element selected from the group consisting of iron, molybdenum, manganese, and a mixture thereof;

the bonding layer comprising the first element in a concentration greater than in the surface layer.

2. The anti-fouling steel wire of claim 1 , wherein the core material further includes about 5 wt.% to about 25 wt.% nickel.

3. The anti-fouling steel wire of claim 2, wherein the core material further includes about 2 wt.% to about 7 wt.% molybdenum.

4. The anti-fouling steel wire of claim 2, wherein the first element is nickel and the surface layer includes about 5 to about 10% more nickel than the core material.

5. The anti-fouling steel wire of claim 1 , wherein the first element is selected from the group consisting of zinc, tin, aluminum and a mixture thereof.

6. The anti-fouling steel wire of claim 5, wherein the first element is zinc.

7. The anti-fouling steel wire of claim 1 , wherein the surface layer includes about 1 wt.% to about 10 wt.% iron.

8. The anti-fouling steel wire of claim 1 , wherein the bonding layer comprises iron- copper alloys.

9. The anti-fouling steel wire of claim 1 , wherein the surface layer has a (radial) thickness in the range of about 100 to 300 microns, preferably in the range of about 150 to 250 microns.

10. The anti-fouling steel wire of claim 1 , wherein the surface layer has a consistent composition.

1 1 . A process of manufacturing an anti-fouling steel wire comprising:

providing a "core wire" made of a core material, the core material comprising about 50 wt.% to about 90 wt.% iron and about 10 wt.% to about 30 wt.% chromium, wherein the core material is substantially free of copper, the core wire including a primary surface;

depositing an intermediate layer onto the primary surface, the intermediate layer including Ni, Zn, Sn, Al, Mo, Mn, or a mixture thereof, the intermediate layer carrying an intermediate surface;

depositing a copper layer onto the intermediate surface;

heating the core wire and deposited layers to a temperature in the range of about 500 to about 800 °C;

forming a surface layer having a composition that comprises about 50 wt.% to about 95 wt.% copper about 5 wt.% to about 35 wt.% of a first element selected from the group consisting of nickel, zinc, tin, aluminum and a mixture thereof, and 0 wt.% to about 10 wt.% of a second element selected from the group consisting of iron, molybdenum, manganese, and a mixture thereof.

12. The process of claim 1 1 further comprising providing a strike layer to the primary surface prior to depositing the intermediate layer.

13. The process of claim 1 1 further comprising forming a bonding layer by alloying a portion of the core material with the intermediate layer and the copper layer.

14. The process of claim 1 1 , wherein the intermediate layer has a thickness of about 10 to about 125 microns; and the copper layer has a thickness of about 50 to about 200 microns.

15. The process of claim 1 1 , wherein the surface layer has a thickness of about 100 to about 300 microns.

16. The process of claim 1 1 , wherein the intermediate layer includes nickel.

17. The process of claim 1 1 , wherein the intermediate layer includes zinc.

18. The process of claim 1 1 further comprising annealing an element, selected from the group consisting of Ni, Zn, Sn, Al, Mo, Mn, and a mixture thereof, with copper to form the surface layer.

19. An aquaculture net comprising steel wires;

the steel wires having a stainless steel core metallurgically bonded to a surface layer by a bonding layer,

the stainless steel core having anti-corrosion properties;

the surface layer having anti-corrosion and anti-fouling properties; the surface layer free of a weld interface;

the surface layer having a surface composition that comprises at least 50 wt.% copper and about 5 wt.% to about 50 wt.% nickel and/or zinc.

20. The aquaculture net comprising of claim 19, wherein the surface layer has a higher weight percentage of nickel and/or zinc than the stainless steel core.