Surface treatment method on Micro-arc Oxidation treated Mg alloys

Patent metadata

Field	Value
Publication number	US-2017137945-A1
Application number	US-201715406789-A
Country	US
Kind code	A1
Filing date	Jan 16, 2017
Priority date	Nov 21, 2013
Publication date	May 18, 2017
Grant date	—

Abstract

Chemically and mechanically protective oxide film was formed on Mg alloys using micro-arc oxidation (MAO) methods. Further modification of the obtained MAO surfaces was made in various aspects and the processes thereof were described. Firstly, the protection is enhanced by forming super-hydrophobic surfaces, with water contact angle higher than 140°, attributed to hierarchical nano-micro structures. Secondly, the electrical property of the MAO surfaces is modified. A film with sheet resistance as low as 0.05 Ω/sq is achieved by electro-less Ni deposition on MAO surfaces. Thirdly, black colors are achieved by the sol-gel process on MAO samples.

First claim

What is claimed is:

1 . A method of treating the surface of micro-arc oxidation treated magnesium alloy, comprising
a) providing a micro-arc oxidation treated magnesium alloy sample; b) pre-treating said sample with nickel acetate solution in ethanol solution; c) activating said pre-treated sample with a solution of reducing agent; and d) forming electro-less Ni on the surface of said activated sample with a deposition solution,
wherein, said treated sample obtained from step (d) is electrically conductive.

2 . The method of claim 1 , wherein said solution of reducing agent is an ethanol solution of NaBH 4 .

3 . The method of claim 1 , wherein said deposition solution comprises NiSO 4 .6H 2 O, NaH 2 PO 2 .H 2 O, Na-citrate, H 3 BO 3 , C 3 H 6 O 3 and thiourea.

4 . The method of claim 1 , wherein said magnesium alloy has a sheet resistance of said treated sample obtained from step (d) is less than 0.05 Ω/sq.

5 . A magnesium alloy comprising a layer of nickel of 10-30 μm thickness on said alloy with a micro-arc oxidation treated layer of 5-40 μm thickness therebetween; said layer of nickel forming a uniform surface on said micro-arc oxidation treated layer to provide improved conductivity such that said alloy has a sheet resistance of less than 0.05 Ω/sq.

6 . The magnesium alloy of claim 5 wherein said micro-arc oxidation treated layer has pores with an average pore size of 1-3 μm that are filled by nickel.

7 . The magnesium alloy of claim 5 manufactured by the process of claim 1 .

Assignees

• Nano & Advanced Materials Inst Ltd

Inventors

• Tao Hong
• So King Ho
• Li Siyue
• Zhang Xuezhu
• Lai Kwok Cheong

Classifications

• C23C28/345

  with at least one oxide layer · CPC title

• C25D11/026

  Anodisation with spark discharge · CPC title

• B05D2202/20

  based on light metals · CPC title

• C23C18/1225

  Deposition of multilayers of inorganic material · CPC title

• Y10T428/266

  of base or substrate · CPC title