Corrosion resistant and low embrittlement aluminum alloy coatings on steel by magnetron sputtering

Patent metadata

Field	Value
Publication number	US-2018355470-A1
Application number	US-201715678757-A
Country	US
Kind code	A1
Filing date	Aug 16, 2017
Priority date	Jun 9, 2017
Publication date	Dec 13, 2018
Grant date	—

Abstract

The present disclosure provides alloys for coating a steel substrate, the alloys comprising aluminum and one or more of zinc, magnesium, and zirconium. The alloy coatings have a percent total pore volume of about 5% or less and an average pore diameter about 10 microns or less. The present disclosure further provides methods of depositing aluminum alloy onto a substrate, magnetron sputtering targets, and methods for making coated steel.

First claim

1 . An alloy coating for coating a substrate, the alloy comprising:
aluminum; and one or more of:
about 1 wt % to about 15 wt % zinc based on the total weight of the alloy,
about 1 wt % to about 10 wt % magnesium based on the total weight of the alloy, and
about 0.1 wt % to about 5 wt % zirconium based on the total weight of the alloy,
the alloy coating having a percent total pore volume of about 5% or less and an average pore diameter about 10 microns or less.

2 . The alloy coating of claim 1 , wherein the alloy comprises zinc from about 5 wt % to about 12 wt %.

3 . The alloy coating of claim 1 , wherein the alloy comprises magnesium from about 1 wt % to about 5 wt % based on the total weight of the alloy.

4 . The alloy coating of claim 3 , wherein the alloy comprises about 5 wt % magnesium based on the total weight of the alloy.

5 . The alloy coating of claim 4 , wherein the alloy comprises about 9 wt % zinc based on the total weight of the alloy.

6 . The alloy coating of claim 5 , wherein the alloy comprises about 1 wt % Zr based on the total weight of the alloy.

7 . The alloy coating of claim 1 , wherein the alloy is:
an alloy comprising 5 wt % Mg and 95 wt % Al, an alloy comprising 5 wt % Zn, 5 wt % Mg, and 90 wt % Al, an alloy comprising 9 wt % Zn, 5 wt % Mg, and 86 wt % Al, or an alloy comprising 9 wt % Zn, 5 wt % Mg, 1 wt % Zr and 85 wt % Al.

8 . The alloy coating of claim 7 , wherein the alloy comprises 9 wt % Zn, 5 wt % Mg, 1 wt % Zr and 85 wt % Al.

9 . The alloy coating of claim 1 , wherein 10% or less of the total pores of the alloy have a pore diameter greater than 0.5 microns.

10 . A substrate comprising a coating according to claim 1 disposed thereon.

11 . The steel substrate of claim 10 , wherein the coating has a thickness from about 1 μm to about 50 μm.

12 . The steel substrate of claim 11 , wherein the coating has a thickness from about 2 μm to about 30 μm.

13 . The steel substrate of claim 10 , wherein the alloy coating has an open circuit potential that is less than an aluminum coating of the same porosity in both distilled water and 3.5% sodium chloride solution according to ASTM G 82 at 30° C.

14 . The steel substrate of claim 10 , wherein the alloy coating does not fracture at about 2,965 Kg load for 200 hours according to ASTM F 519.

15 . The steel substrate of claim 10 , further comprising a second layer disposed between the steel substrate and the alloy, the second layer comprising a metal oxide, nitride, carbide, or metal-oxynitride.

16 . A method of magnetron sputtering an aluminum alloy onto a substrate, the method comprising:
flowing a sputter gas to a processing region of a process chamber, the process chamber having an aluminum alloy sputter target comprising one or more of about 1 wt % to about 15 wt % zinc based on the total weight of the alloy, about 1 wt % to about 10 wt % magnesium based on the total weight of the alloy, and about 0.1 wt % to about 5 wt % zirconium based on the total weight of the alloy; delivering an energy pulse to the sputter gas; and depositing the aluminum alloy onto a steel substrate

17 . The method of claim 16 , wherein the sputter gas is argon.

18 . The method of claim 16 , wherein delivering an energy pulse to the sputter gas comprises delivering an average power from 2 W/cm 2 to 12 W/cm 2 .

19 . The method of claim 16 , wherein delivering an energy pulse to the sputter gas comprises delivering a maximum sputter current from about 0.1 A to about 2 A and a maximum power from about 0.3 kW to about 5 kW.

20 . The method of claim 16 , wherein depositing is performed at a deposition rate from about 2 micrometers per hour to about 3 micrometers per hour at a DC power of 300 Watts.

21 . The method of claim 16 , further comprising evacuating the chamber with a high vacuum pump to a pressure below 5×10 −4 Torr before providing the sputter gas.

22 . The method of claim 16 , wherein depositing comprises applying a magnetic field of less than 300 Gauss to the chamber.

23 . The method of claim 16 , wherein the substrate is rotated between about 20 revolutions per minute and about 200 revolutions per minute during deposition and the distance between a surface of the target and a surface of the substrate is between about 6 cm and about 10 cm.

Assignees

• Boeing Co

Inventors

• Gaydos Stephen P
• Ijeri Vijaykumar S
• Prakash Om
• Mishra Suman K
• Singh Raghuvir
• Paswan Sharma
• Pathak Lokesh C

Classifications

• C23C14/165 Primary

  by cathodic sputtering · CPC title

• C22C21/10

  with zinc as the next major constituent · CPC title

• C23C14/3407

  Cathode assembly for sputtering apparatus, e.g. Target · CPC title

• C22C21/06

  with magnesium as the next major constituent · CPC title

• H01J37/3467

  Pulsed operation, e.g. HIPIMS · CPC title