ANTI-CORROSION COATING METHOD

Abstract

A method for applying an anti-corrosion coating to a substrate includes: applying an anti-corrosion composition; and applying a dye which exhibits fluorescence when exposed to ultraviolet radiation.

Claims

1. A method for applying an anti-corrosion coating to a substrate, the method comprising: (a) applying an anti-corrosion composition, and (b) applying a dye which exhibits fluorescence when exposed to ultraviolet radiation.

2. The method according to claim 1 comprising a further step of applying an anti-corrosion composition.

3. The method according to claim 2 further comprising: (a) applying the anti-corrosion composition to the substrate, (b) subsequently applying the dye, and (c) subsequently applying an anti-corrosion composition.

4. The method according to claim 1, wherein the substrate is an aluminium substrate or an aluminium alloy substrate.

5. The method according to claim 1, wherein the anti-corrosion coating is a chromium (III) chemical conversion coating.

6. The method according to claim 1, wherein the dye is a Zyglo dye.

7. The method according to claim 1, wherein the anti-corrosion composition is applied using an applicator pen.

8. The method according to claim 1, further comprising viewing the coated substrate under UV light.

9. A coated substrate on which the method of applying an anti-corrosion coating according to claim 1 has been applied.

10. A substrate which is coated with: at least one coating of anti-corrosion composition; and at least one coating of a dye which exhibits fluorescence when exposed to ultraviolet radiation.

11. The substrate according to claim 10 wherein the substrate is an aluminium substrate or an aluminium alloy substrate.

12. The substrate according to claim 10, wherein the anti-corrosion coating is a chromium (III) chemical conversion coating.

13. The substrate according to claim 10, wherein the dye is a Zyglo dye.

14. A device comprising a coated substrate according to claim 9.

15. The device according to claim 14, wherein the device is a highlift actuator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Certain aspects of the present disclosure will now be described in greater detail, by way of example only and with reference to the accompanying drawings, in which:

[0081] FIG. 1 is a photograph taken under UV light of the part used to test the invention;

[0082] FIGS. 2a-2c shows three possible coated substrates;

[0083] FIGS. 3a-3b shows two possible coated substrates; and

[0084] FIGS. 4a-4c shows possible applications of the dye.

DETAILED DESCRIPTION

[0085] The methods of the disclosure will now be described in relation to the Figures.

[0086] FIG. 1 shows where the applicator pen was applied in the method described in Example 1.

[0087] FIGS. 2a-2c show three separate schematics showing the substrate coated with the UV detectable anti-corrosion coating. FIG. 2a shows substrate 11 coated with a layer of anti-corrosion composition 12, a layer of dye 13 and a further layer of anti-corrosion composition 12. FIG. 2b shows substrate 11 coated with a layer of dye 13, and two further layers of anti-corrosion composition 12. FIG. 2c shows substrate 11 coated with two layers of anti-corrosion composition 12 and a further layer of dye 13.

[0088] FIGS. 3a-3b show two separate schematics showing the substrate coating with the UV detectable anti-corrosion coating. FIG. 3a shows substrate 11 coated with a layer of anti-corrosion composition 12 and a further layer of dye 13. FIG. 3b shows substrate 11 coated with a layer of dye 13 and a further layer of anti-corrosion composition 12.

[0089] FIGS. 4a-4c shows the application of the dye 13. In one aspect, the dye is applied as a random line on the surface as exemplified in FIG. 4a. In an alternative aspect, the dye is applied as multiple stripes across the surface as exemplified in FIG. 4b. As would be appreciated, the stripes can be of varying thicknesses and directions. In an alternative aspect, the dye is applied as spots (or any other marking) over the surface, as exemplified in FIG. 4c. As will be appreciated, the spots can be of varying sizes and in varying positions over the surface.

Example 1

[0090] A part (CH3511-0915) was machined from AMS 4124 aluminium alloy and chromic acid anodised according to 914-032-095. The mating face was abraded in order to remove any residual chemical conversion coating. A single coat of chemical conversion material was applied using an applicator pen (Touch-N-Prep Henkel Bonderite MCR 871 Aero), allowed to dry, and then followed by a layer of Zyglo sensitivity level 2 dye. After the dye was allowed to dry, a second coat was made using the applicator pen (Touch-N-Prep Henkel Bonderite MCR 871 Aero) at right angles to the first coat. This part was exposed to UV radiation and it was found that the coated surface exhibited fluorescence under these conditions. The part was then tested for corrosion performance in accordance with ASTM B117. ASTM B117 is the standard practice for operating salt spray apparatus and provides a controlled corrosive environment.

[0091] FIG. 1 shows where the applicator pen (Touch-N-Prep) has been applied. The lower part of the photograph is where an initial application of chemical conversion coating (Henkel Bonderite MCR 871 Aero) was applied using the applicator pen (Touch-N-Prep) and this was allowed to dry. One drop of dye (Zyglo sensitivity level 2 dye) was applied to a clean cotton bud, which was swabbed across the surface of the part and allowed to dry. A second coat of the chemical conversion coating using the applicator pen (e.g. Touch-N-Prep) was applied. The top part of the photograph shows where the chemical conversion coating has not been applied according to the invention.

[0092] It was found that after 120 hours and 500 hours of corrosion testing there were no signs of corrosion in the target area.