Corrosion resistant coating composition of ni and a phosphate corrosion inhibitor and an electrodeposition method for the manufacture thereof

Patent metadata

Field	Value
Publication number	US-2017190921-A1
Application number	US-201614989430-A
Country	US
Kind code	A1
Filing date	Jan 6, 2016
Priority date	Jan 6, 2016
Publication date	Jul 6, 2017
Grant date	—

Abstract

A corrosion resistant coating composition for a metal substrate is disclosed. The metal substrate, such as carbon steel, is coated with a first layer comprising a phosphate corrosion inhibitor, such as sodium phosphate monobasic (NaH 2 PO 4 ) and a second layer comprising nickel nanoparticles. In addition, an electrodeposition method for the production of the coating composition is disclosed that uses either pulse or direct current electrodeposition to form the coating composition of desired anticorrosive properties. In addition, a coated metal substrate and method for inhibiting corrosion of a metal substrate that apply the corrosion resistant coating composition in any of its embodiments are disclosed.

First claim

1 : A corrosion resistant coating composition for a metal substrate, comprising:
a first coating layer comprising a phosphate corrosion inhibitor; and a second coating layer comprising nickel (Ni) nanoparticles; wherein the first coating layer is disposed between the metal substrate and the second coating layer.

2 : The corrosion resistant coating composition of claim 1 , wherein the phosphate corrosion inhibitor is sodium phosphate monobasic (NaH 2 PO 4 ).

3 : The corrosion resistant coating composition of claim 1 , wherein the metal substrate comprises carbon steel.

4 : The corrosion resistant coating composition of claim 1 , wherein the nickel nanoparticles comprise fine equiaxed grains existing in the form of colonies with an average grain size of less than 100 nm.

5 : The corrosion resistant coating composition of claim 1 , wherein the second coating layer has an average thickness in the range of 1-150 μm.

6 : The corrosion resistant coating composition of claim 1 , wherein the first coating layer covers greater than 75% of the surface of the metal substrate and the second coating layer covers greater than 75% of the surface of the first coating layer.

7 : The corrosion resistant coating composition of claim 1 , wherein the second coating layer comprising Ni nanoparticles has an instrumented nanohardness in the range of 2000-4000 MPa.

8 : The corrosion resistant coating composition of claim 1 , which imparts a corrosion rate in the range of 0.2-5.0 mils penetration per year (mpy) to the metal substrate.

9 : The corrosion resistant coating composition of claim 1 , which imparts a zero current potential (ZCP) in the range of −250 mV to −600 mV to the metal substrate.

10 : A coated metal substrate, comprising:
a metal substrate; a first coating layer comprising a phosphate corrosion inhibitor; and a second coating layer comprising nickel (Ni) nanoparticles; wherein the first coating layer is disposed between the metal substrate and the second coating layer.

11 : A method of forming the corrosion resistant coating composition for a metal substrate of claim 1 , comprising:
applying a phosphate corrosion inhibitor to the metal substrate to form an inhibitor coated metal substrate; and electrodepositing a layer of nickel nanoparticles onto the inhibitor coated metal substrate in an electrolyte solution to form the corrosion resistant coating composition for a metal substrate.

12 : The method of claim 11 , wherein the phosphate corrosion inhibitor is sodium phosphate monobasic (NaH 2 PO 4 ) and the nickel nanoparticles comprise fine equiaxed grains existing in the form of colonies with an average grain size of less than 100 nm.

13 : The method of claim 11 , wherein the electrolyte solution is a Watt's bath, comprising:
an aqueous solution comprising 2-5 wt % NaCl relative to the total weight of the aqueous solution; nickel sulfate; nickel chloride; and boric acid (H 3 BO 3 ).

14 : The method of claim 11 , wherein the electrolyte solution has a pH in the range of 3-5 and the electrodepositing is performed with the electrolyte solution having a temperature in the range of 35-65° C.

15 : The method of claim 11 , wherein the electrodepositing is performed by pulse electrodeposition.

16 : The method of claim 15 , wherein the pulse electrodeposition is performed at a maximum current amplitude of less than 10 A.

17 : The method of claim 15 , wherein the pulse electrodeposition comprises a repeating sequence of current amplitude with a pulse on-time of 1-5 msec and a pulse off-time of 5-15 msec.

18 : The method of claim 17 , wherein the duration of each pulse on-time is the same, the duration of each pulse off-time is the same, and the maximum current amplitude during each pulse on-time is the same in the repeating sequence.

19 : A method for inhibiting corrosion of a metal substrate, comprising:
coating the metal substrate with a phosphate corrosion inhibitor to form an inhibitor coated metal substrate; and electrodepositing a layer of nickel nanoparticles over the inhibitor coated metal substrate in an electrolyte solution to form a corrosion resistant metal substrate; wherein the method reduces the corrosion rate of the metal substrate in mils penetration per year (mpy) by 10-80% relative to the corrosion rate of a substantially similar metal substrate lacking the inhibitor, the layer of nickel nanoparticles, or both.

20 : The method of claim 19 , wherein the phosphate corrosion inhibitor is sodium phosphate monobasic (NaH 2 PO 4 ) and the nickel nanoparticles comprise fine equiaxed grains existing in the form of colonies with an average grain size of less than 100 nm.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Ul Hamid Anwar

Classifications

• C09D5/10 Primary

  containing metal dust · CPC title

• C23C28/322

  only coatings of metal elements only · CPC title

• C23C28/34

  including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates · CPC title

• C25D5/36

  of iron or steel · CPC title

• C09D5/084

  Inorganic compounds · CPC title