U.S. patent application number 16/679542 was filed with the patent office on 2020-06-25 for anti-corrosion coating method.
The applicant listed for this patent is Goodrich Actuation Systems Limited. Invention is credited to Jasbir Singh AUJLA.
Application Number | 20200199757 16/679542 |
Document ID | / |
Family ID | 64755477 |
Filed Date | 2020-06-25 |
United States Patent
Application |
20200199757 |
Kind Code |
A1 |
AUJLA; Jasbir Singh |
June 25, 2020 |
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.
Inventors: |
AUJLA; Jasbir Singh;
(Wolverhampton, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Goodrich Actuation Systems Limited |
Shirley |
|
GB |
|
|
Family ID: |
64755477 |
Appl. No.: |
16/679542 |
Filed: |
November 11, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 22/84 20130101;
B05D 2202/25 20130101; C23C 2222/10 20130101; B05D 7/54 20130101;
B05D 1/26 20130101; B05D 7/58 20130101; B05D 5/061 20130101; B05D
1/34 20130101; C23C 22/42 20130101; C23C 22/06 20130101; B05D 1/36
20130101; C09D 5/08 20130101 |
International
Class: |
C23C 22/06 20060101
C23C022/06; C23C 22/84 20060101 C23C022/84 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2018 |
EP |
18275189.1 |
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
FOREIGN PRIORITY
[0001] This application claims priority to European Patent
Application No. 18275189.1 filed Dec. 20, 2018, the entire contents
of which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a method of applying an
anti-corrosion coating to substrates to form an anti-corrosion
coating which is UV detectable. The method is particularly well
adapted to coating aluminium and aluminium alloy substrates.
BACKGROUND
[0003] Anti-corrosion coatings, such as chemical conversion
materials and the resulting coatings, are used to treat, salvage or
repair surfaces that require corrosion protection. They are widely
used with metals including aluminium and aluminium alloys,
magnesium and magnesium alloys and zinc and zinc alloys. For
example, chemical conversion materials are examples of
anti-corrosion coatings which are applied to a metal substrate
whereupon the metal can react with the chemical conversion material
to produce a corrosion protective film, i.e. a chemical conversion
coating.
[0004] Anti-corrosion coatings (e.g. chemical conversion materials
and coatings) which are suitable for use in aerospace engineering
ideally comply with certain requirements, e.g. may be REACH
compliant.
[0005] Certain anti-corrosion coatings are discernible after
application by colour (for example, some chemical conversion
materials such as Alocrom/Alodine 1200), whereas in others, there
is no way of detecting their presence visually (e.g. Bonderite MCR
871 Aero). For those materials that are not visually detectable, it
is not immediately apparent whether they have been applied or not.
This can lead to substrates being recoated unnecessarily in an
attempt to ensure that they have corrosion protection.
[0006] In an attempt to address this issue, certain anti-corrosion
coatings have been produced which contain a pigment or indicator in
order for the end user to detect whether a part has been coated
with the material. These are compositions which contain both the
anti-corrosion coating (e.g. chemical conversion material) and an
indicator compound in mixture. The resulting mixtures can have a
limited shelf life, e.g. due to interaction between the
ingredients, and often have reduced corrosion protection
performance. For example, manufacturers of some anti-corrosion
coatings have developed products which contain an ultraviolet
fluorescing dye, but have discovered that the dye degrades the
corrosion protection performance of the product.
[0007] There is therefore a need for a method of applying an
anti-corrosion coating (e.g. a chemical conversion coating) which
allows the coating to be detected once applied, while retaining
good corrosion protection performance.
SUMMARY
[0008] Viewed from a first aspect, the present disclosure provides
a method for coating a substrate, e.g. for applying an
anti-corrosion coating (e.g. a chemical conversion coating) to a
substrate, the method comprising (in any order): applying an
anti-corrosion composition (e.g. a chemical conversion material),
and applying a dye which exhibits fluorescence when exposed to
ultraviolet radiation.
[0009] In one aspect, the anti-corrosion composition and the dye
are applied individually, i.e. they are not mixed prior to
application. In one aspect, steps (a) and (b) are performed
separately, e.g. sequentially. The application steps of the method
disclosed herein may be performed at different times and/or via
different means.
[0010] In one aspect, steps (a) and (b) are performed
simultaneously. If steps (a) and (b) are performed simultaneously,
the materials may be applied individually, but simultaneously, e.g.
by co-spraying or co-spreading.
[0011] In one aspect, the method comprises applying the
anti-corrosion composition to the substrate and subsequently
applying the dye, e.g. onto said anti-corrosion composition and/or
to the substrate. Alternatively, the method may comprise applying
the dye to the substrate and subsequently applying the
anti-corrosion composition (e.g. chemical conversion material),
e.g. on top of the dye and/or onto the substrate.
[0012] The method as described herein can further comprise a second
(or further) step of applying an anti-corrosion composition (e.g. a
chemical conversion material). The further applications of
anti-corrosion composition can be of the same or different
composition or material to the first.
[0013] In some aspects the anti-corrosion coating consists of, or
consists essentially of, the anti-corrosion composition and the dye
as herein described.
[0014] In one aspect, the method comprises applying the dye to the
substrate, followed by applying the anti-corrosion composition at
least twice, e.g. as two or more separate coats or layers. In a
further aspect, the method comprises applying the anti-corrosion
composition at least twice, e.g. as two or more separate coats or
layers, followed by applying the dye. The method may also comprise
applying the anti-corrosion composition and the dye in an
alternating fashion.
[0015] In one aspect, the method comprises: applying an
anti-corrosion composition to the substrate, subsequently applying
a dye which exhibits fluorescence when exposed to ultraviolet
radiation onto the anti-corrosion composition and/or substrate, and
subsequently applying an anti-corrosion composition.
[0016] Typically, in the method and products disclosed herein, the
anti-corrosion composition and/or the dye will be applied or
deposited as a coating or a layer. The anti-corrosion composition
may be a chemical conversion material, e.g. which forms a chemical
conversion coating on the substrate.
[0017] The substrate can be metallic, e.g. it may be or comprise
aluminium, an aluminium alloy, zinc, a zinc alloy, magnesium or a
magnesium alloy. In one aspect, the substrate is or comprises
aluminium or an aluminium alloy.
[0018] The substrate may also consist of or comprise aluminium
plated steel.
[0019] Aluminium alloys are those in which aluminium is the
predominant metal. Typical alloying elements are scandium, copper,
magnesium, manganese, silicon, iron, titanium, chromium, tin and
zinc. Particular aluminium alloys include 1420, 2004, 2014, 2017,
2020, 2023, 2080, 2090, 2091, 2095, 2219, 2224, 2324, 2519, 2524,
4047, 6013, 6061, 6063, 6113, 6951, 7010, 7049, 7050, 7055, 7068,
7075, 7079, 7093, 7150, 7178, 7475 and 8009. Examples of aluminium
alloys are the 7000 series and 2000 series aluminium alloys.
[0020] Other exemplary substrates include high copper aluminium
substrates (i.e. substrates including an alloy containing both
aluminium and copper, in which the amount of copper is relatively
high, e.g. an amount of copper in the alloy of 3 to 4%).
[0021] The substrates onto which the method is applied can be part
of a larger component or article (e.g. the substrate can be a
veneer or layer on a component or article), or the substrate can be
a whole component or article, i.e. the component or article is
formed from the substrate material. Thus, the disclosure
encompasses devices, components or articles comprising the
substrates mentioned herein, e.g. where the substrate is a surface
of a device, component or article. The substrate has a surface upon
which the materials of the method are applied.
[0022] Anti-corrosion compositions are well known in the art.
Typically, they comprise substances which inhibit corrosion of the
substrate to be protected, or which react with the substrate to
form a protective coating which inhibits corrosion. The resulting
anti-corrosion coatings (e.g. chemical conversion coatings) may
result in increased corrosion resistance and may also be used as a
decorative finish.
[0023] The anti-corrosion compositions and coatings described may
also be viewed as corrosion inhibition compositions and coatings.
The anti-corrosion composition described herein may be a chemical
conversion material. Similarly the, anti-corrosion coating
described herein may be a chemical conversion coating. Chemical
conversion coatings are used on metals and involve application of a
material (chemical conversion material or coating) which may
convert the substrate surface into a decorative or protective
substance. Typically this conversion takes place via chemical
processes between the surface of the substrate and the chemical
conversion material. The resulting chemical conversion coating can
be an oxide layer, e.g. a very thin oxide layer.
[0024] The anti-corrosion coating (e.g. chemical conversion
coating) can be formed from or comprise any anti-corrosion
composition (e.g. chemical conversion material) which is suitable
for applying to the substrates described herein, e.g. an aluminium,
aluminium alloy, zinc, zinc alloy, magnesium or magnesium alloy
substrate. The term "anti-corrosion coating" may refer to the
coating formed by application of the anti-corrosion composition
and/or the coating resulting from all steps of the method herein
disclosed, i.e. including the dye. The anti-corrosion composition
may comprise a corrosion inhibiting cation, e.g. one or more
cations of rare earth elements (such as cations of cerium, yttrium,
praseodymium, neodymium), Group 1 (IA) metal cations (such as
cations of lithium, sodium, potassium, rubidium, cesium, francium),
Group 2 (IIA) metal cations (such as cations of beryllium,
magnesium, calcium, strontium, barium, radium), Group 12 (2B) metal
cations (such as cations of zinc), Group 4 (IVB) metal cations
(such as cations of titanium or zirconium) and/or Group 6 (VIB)
metal cations (such as cations of chromium, e.g. trivalent
chromium).
[0025] Coatings and compositions suitable for applying to an
aluminium or aluminium alloy substrate may be used. In one aspect,
the anti-corrosion composition of the present disclosure can comply
with industrial standards, such as being selected from the military
specification referred to as MIL-DTL-5541.
[0026] The anti-corrosion coating which results from applying the
anti-corrosion composition (e.g. chemical conversion coating) may
be a combination of both metal(s) of the anti-corrosion composition
and metal(s) of the substrate's surface. Anti-corrosion coatings
such as chemical conversion coatings may involve a treatment for a
metal surface where a metal substrate is contacted at least in part
with a solution (e.g. an aqueous solution) comprising a different
metal, where the substrate dissolves, leading to precipitation of a
coating (optionally using an external driving force to deposit the
coating on the metal substrate).
[0027] Examples of anti-corrosion coatings and chemical conversion
materials include materials known as chemical film, yellow iridite
and coatings from brand names such as Iridite, Bonderite and
Alocrom/Alodine. Specific examples include Alochrom 1200, Iridite
NCP, Surtec 650 and Bonderite MCR 871 Aero. In a certain aspect of
the present disclosure, the chemical conversion material is
Bonderite M-CR 871 Aero (also known as Alodine.RTM. 871), available
from Henkel.
[0028] In some aspects, the anti-corrosion composition of the
present disclosure may comprise a metal silicate (e.g. magnesium
metasilicate), a metal molybdate (e.g. zinc molybdate, sodium
molybdate, magnesium molybate and/or copper molybdate) and/or a
metal phosphate silicate. In some aspects, the anti-corrosion
composition of the present disclosure may comprise
trimethylbenzene, sodium perborate, thiourea, zinc stearate, zinc
nitrate, zinc oxide, calcium carbonate, dihydric phosphate and/or
sodium phosphates such as sodium hexametaphosphate.
[0029] In some aspects, the anti-corrosion composition comprises
the following by weight: 8-10 parts of sodium molybdate, 4-5 parts
of magnesium molybdate, 2-4 parts of copper molybdate, 12-14 parts
of dihydric phosphate, 5-8 parts of sodium hexametaphosphate, 2-5
parts of zinc oxide, 1.5-2.5 parts of trimethylbenzene, 2.5-3.5
parts of sodium perborates, 2.2-3.8 parts of thiourea, 4.5-5.5
parts of zinc stearate, 0.8-1.2 parts of calcium carbonate (e.g.
ground calcium carbonate) and 0.5-0.8 parts of zinc nitrite.
[0030] In some aspects, the anti-corrosion coating of the present
disclosure can be an oxide coating, a phosphate coating or a
chromate coating. Chemical conversion coatings of these types are
well known.
[0031] Oxide coatings can be black oxide. Black oxide for ferrous
materials can be magnetite (Fe.sub.3O.sub.4). Black oxide for
ferrous materials can be applied by using a bath of sodium
hydroxide, nitrates and nitrites to convert the surface of the
substrate to be coated into magnetite. Black oxide for copper is
known as Ebonol C. This converts the copper surface to cupric
oxide. Black oxide for zinc can be known as Ebonol Z or Ultra-Blak
460. Oxide coatings can also be formed by anodizing. In some
aspects, the anti-corrosion composition of the present disclosure
may comprise zinc oxide.
[0032] Phosphate coatings can include manganese, zinc and/or iron,
e.g. manganese phosphate, zinc phosphate and/or iron phosphate.
Phosphate coatings may comprise dihydric phosphate and/or sodium
phosphates such as sodium hexametaphosphate. Examples of phosphate
coatings include Parkerize and Lubrite. Phosphate coatings may be
used on aluminium, zinc, cadmium, silver and tin. Manganese, zinc
and/or iron phosphate salts can be dissolved in a solution of
phosphoric acid and the surface of the substrate to be coated can
be placed into the solution. Alternatively, the solution (i.e. the
anti-corrosion coating (e.g. chemical conversion material) as
herein described) can be applied to the surface of the substrate to
be coated.
[0033] In one aspect, the anti-corrosion coating is a chromate
coating, e.g. a chromate chemical conversion coating. Suitable
chromate coatings can be formed through the interaction of chromium
salts or chromium acid with water solutions. Examples of chromate
coatings include Alodine or Iridite. Suitable chromate coatings can
comprise hexavalent chromium and/or trivalent chromium, e.g.
Bonderite MCR 871 Aero or Bonderite MCR 1132 Aero (also known as
Alodine.RTM. 1132). Chromate coatings according to the present
disclosure can include one or more of chromium (IV) oxide, barium
nitrate, sodium silicofluoride and ferricyanide. Chromate coatings
according to the present disclosure can form a chemical film on
aluminium or can be used to passivate steel, aluminum, zinc,
cadmium, copper, silver, magnesium and tin alloys. In an aspect,
the anti-corrosion composition of the present disclosure comprises
trivalent chromium. The anti-corrosion coating may be a chromium
(III) chemical conversion coating.
[0034] The dye according to the present disclosure exhibits
fluorescence when exposed to electromagnetic radiation in the
ultraviolet (UV) range, e.g. with a wavelength from 10 nm to 400
nm.
[0035] The dye may be selected from those which are approved to
Aerospace Material Specification (AMS) 2644. For example, suitable
dyes include those approved to AMS 2644 type 1, method A,
sensitivity levels 2, 3 or 4. Type 1 is a fluorescent dye and
method A is water washable. QPL-AMS-2644 (Qualified Products List
of Products Qualified Under SAE Aerospace Material Specification
AMS 2644) provides a list of products approved to the various
types, methods and sensitivity levels.
[0036] Suitable dyes for use as described herein include those that
meet the criteria of AMS 2644 or are listed in the Qualified
Products List QPL-AMS-2644.
[0037] In some aspects, the dye is one that absorbs light in the
ultraviolet range, e.g. 275 to 400 nm and emits light in the
ultraviolet blue spectrum, e.g. 400-500 nm.
[0038] In some aspects, when the dye is applied, no obvious colour
change occurs. The dye can appear colourless or substantially
colourless in the visible light spectrum.
[0039] Examples of suitable dyes include ARDROX 970P23, ARDROX
970P23E, ARDROX 970P24, ARDROX 970P24E, P133D, P133E, P134E, 9732,
BRITEMOR 4455, BRITEMOR 4455A, ZL-60C and ZL-60D. In a certain
aspect, the dye is a Zyglo dye.
[0040] Further examples of suitable dyes include those marketed as
Zyglo ZL-30, Fluorol 7GA, Calcofluor Yellow, Azsol Brilliant Yellow
6GF, Rhodamine B, Calcolfuor White RW, Blancophor White AW,
Auramine, and Eosine G.
[0041] In one aspect, the dye according to the present disclosure
can be a water soluble dye. The dye may comprise one or more of the
following: 4,4'-bis-(2-sulfostyryl)-biphenyl disodium salt,
bistriazinyl derivatives of 4,4'-diaminostilbene-2-2'-disulfonic
acid, sulfonated 2-(stilbene-4-yl) naptholtriazoles,
bis(azol-2-yl)stilbenes, bisstyrylbiphenyl sodium salt and
sulfonated pyrazolines. The dye can contain a luminescence pigment
selected from oxides, sulphides, or oxide sulphides or a metal or
semimetal. The metal or semimetal can be chosen from aluminium,
germanium, silicon, scandium, yttrium, lanthanum, cerium,
praseodymium, neodymium, samarium, europium, gadolinium, terbium,
dysprosium, holmium, erbium, thulium, ytterbium or lutetium.
[0042] The anti-corrosion composition can be applied using any
conventional technique, such as dip immersion, spraying or
spreading, e.g. spreading using a brush, roller, applicator pen
(e.g. Touch-N-Prep.RTM., available from Henkel) or the like. For
application by spraying, automatic or manual spray techniques can
be used. In a certain aspect, the anti-corrosion composition is
applied using an applicator pen (e.g. Touch-N-Prep.RTM.).
[0043] In one aspect, the anti-corrosion composition is applied in
a uniform layer, e.g. to form a uniform coating. It may be useful
for more than one, e.g. two, applications of anti-corrosion
composition to be made in order to achieve a uniform layer, e.g. in
terms of thickness, or degree of surface coverage. A uniform layer
can help to ensure consistent corrosion protection.
[0044] In a certain aspect, the anti-corrosion composition is
applied in one direction (e.g. left to right or up to down), and
the second coat is applied in another, e.g. substantially
perpendicular, direction (e.g. up to down or left to right). The
method of applying anti-corrosion composition in one direction and
then applying anti-corrosion composition in the other direction can
be used in a variety of application techniques as described herein,
e.g. with an applicator pen (e.g. Touch-N-Prep.RTM.).
[0045] The amount of anti-corrosion composition applied depends on
the surface and substrate to be covered. In a certain aspect, the
anti-corrosion composition is applied such that it covers the
entire surface of the substrate to be covered (e.g. the area to be
protected against corrosion). The thickness of the anti-corrosion
coating applied can be less than or equal to 10 .mu.m, less than or
equal to 5 .mu.m, less than or equal to 1 .mu.m. In certain
aspects, the thickness of the anti-corrosion coating (e.g. chemical
conversion coatings) can be 0.001 to 10 .mu.m, 0.001 to 5 .mu.m,
0.001 to 1 .mu.m, 0.01 to 10 .mu.m, 0.01 to 5 .mu.m, 0.01 to 1
.mu.m, 0.1 to 10 .mu.m, 0.1 to 5 .mu.m, or 0.1 to 1 .mu.m.
[0046] The dye can be applied using any conventional technique,
such as dip immersion, spraying or spreading, e.g. spreading using
a brush, roller, applicator pen, cotton bud or the like. For
application by spraying, automatic or manual spray techniques can
be used. In a certain aspect, the dye is applied using a cotton
bud.
[0047] The dye can be applied as a complete layer, i.e. the dye
layer can cover or substantially cover the entire area of the
substrate for which protection is required, or the area upon which
the anti-corrosion composition is applied. In an alternative
aspect, the layer of dye does not completely cover the entire area,
e.g. covers up to 10% of the area (e.g. 0.1 to 5%), 10% to 90% of
the area, 20% to 75% of the area, 30% to 60% of the area, greater
than or equal to 50% of the area or greater than or equal to 90% of
the area.
[0048] The way in which the surface is covered with the dye can be
varied. The dye can be applied in any way and in any style. In one
aspect, the dye is applied to cover the surface sufficiently so
that the dye's presence is detectable under UV light.
[0049] The dye can be applied as a line on the surface, e.g. as
shown in FIG. 4a. The dye can be applied as multiple stripes across
the surface, e.g. as shown in FIG. 4b. The stripes can be of
varying thickness and directions. The dye can be applied as spots
on the surface, e.g. as shown in FIG. 4c. The spots can be of
varying sizes and in varying positions and amounts over the
surface. Any pattern can be made using the dye on the surface, e.g.
it can be used to make a distinguishing mark.
[0050] The dye can be applied before the application of the
anti-corrosion composition, between applications of anti-corrosion
composition and/or after the anti-corrosion composition has been
applied. In a certain aspect, one coat of the anti-corrosion
composition is applied, the dye is applied and then a second coat
of anti-corrosion composition is applied.
[0051] The anti-corrosion composition and the dye may be applied
independently as continuous layers, or as a discontinuous
application. If the first material (i.e. anti-corrosion composition
or dye) to be applied to the substrate does not fully cover the
area to be protected, then the following material can be applied on
top of the first material, on top of the substrate (i.e. on parts
of the substrate which the first material is not), or both.
Similarly, subsequent materials may, or may not, be applied
directly on top of the material that was applied previously.
[0052] In some aspects, the anti-corrosion composition is applied
such that it covers all, or substantially all, of the area of the
substrate for which protection is required. This may be achieved by
a single, uniform layer of material, or by subsequent applications
of the material ensuring uniform coverage across the area to be
protected.
[0053] The amount of dye applied should be enough to provide a
visible marking when exposed to UV, e.g. for a part surface of
around 0.0013 m.sup.2, one drop of dye may be sufficient.
[0054] Before applying the materials according to the method as
herein described, the surface of the substrate can be cleaned using
any conventional technique in the art such as using conventional
cleaners or solvents to remove grease, dirt or other extraneous
matter. Inclusion of such a cleaning step forms a further aspect of
the present disclosure. Conventional cleaners include acetone and
ProClean. Solvents suitable for cleaning the surface include
acetone, hexanes, pentanes, propanes, isopropanol, ethanol,
methanol and water. Alternative methods of cleaning the surface of
the substrate before applying the anti-corrosion composition
include using a moistened abrasive pad (to remove oxides from the
surface of the metal) and wiping the substrate, e.g. with a damp
lint-free cloth (to ensure complete removal of soils and dislodged
oxides generated from the previous step).
[0055] The cleaning step can be followed by or preceded by a water
rinse.
[0056] Between applications of the anti-corrosion composition
and/or dye, the previously applied material is typically allowed to
dry before the next material is applied. This minimizes mixing of
the two materials.
[0057] In some aspects, 0.5, 1, 2, 3, 5 or 10 min is allowed
between the application of each material. In some aspects, an
applied material is dried completely before a further material is
applied. In some aspects, an applied material can be air dried
and/or force-dried with hot air.
[0058] In some aspects, the anti-corrosion composition or coating
and the dye are present on the substrate as distinct entities, i.e.
they do not mix with one another.
[0059] If an applicator pen is used to apply the anti-corrosion
composition, the method of application can be as follows: press the
pen down on the surface until the solution fills the pen tip; apply
the anti-corrosion composition with firm, smooth, even strokes,
covering all edges; overlap each stroke and allow to dry; within 5
min of applying the first coat, apply the dye; within 5 min of
applying the dye, apply a second coat at a 90.degree. angle to the
first coat with the same, smooth, firm stroke; and allow the
coating to air dry thoroughly.
[0060] In a further aspect, the present disclosure comprises a
substrate on which an anti-corrosion coating and a dye as herein
described has been applied, e.g. a substrate (or a component or
article comprising the substrate) coated with the materials
described herein. The present disclosure also provides components,
articles or devices comprising the substrate as herein described.
The substrate may be a surface of the component, article or device,
or may be a layer on the component, article or device.
[0061] In one aspect, the present disclosure comprises a substrate
on which the method of applying the anti-corrosion coating (e.g.
chemical conversion coating) as discussed herein has been
applied.
[0062] The substrate can be in the form of, or be the surface of, a
metal sheet or fabricated part. Such parts include parts for
aircraft, aerospace, missiles, vehicles, trains, electronic
devices, apparatuses, construction equipment, military equipment,
sport equipment, among others.
[0063] The substrate or component may be selected from aircraft
components such as gas turbine engine components, turbine vanes and
blades, propeller-blades, -shanks, -hubs, -barrels and -tulips,
landing gear components, engine gears, engine discs, shafts, struts
and counterweights.
[0064] In one aspect, the present disclosure comprises a device
(e.g. a gas turbine engine, a highlift actuator, a highlift system,
or component thereof) comprising a substrate, or component
comprising a substrate, on which the method as discussed herein has
been applied.
[0065] In one aspect, the present disclosure provides a coated
substrate (e.g. a substrate as herein described) which comprises at
least one coating of anti-corrosion coating as herein described and
at least one coating of a dye as herein described, which can be
present any order.
[0066] In a further aspect, the present disclosure provides a
coated substrate (e.g. a substrate as herein described) which
comprises a coating of anti-corrosion coating as herein described
and a coating of dye as herein described on top of the layer of
anti-corrosion coating. A further layer of anti-corrosion coating
may be present on top of the dye and/or on top of the first coating
or substrate.
[0067] In a further aspect, the present disclosure provides a
component comprising a coating on a surface of said component, said
coating comprising a layer of anti-corrosion composition (as herein
described) and a layer of a dye which exhibits fluorescence when
exposed to ultraviolet radiation (as herein described).
[0068] The component may be a coated substrate, a device or an
article as described herein. The surface of the component may be
the substrate as described herein. As described above, the
materials (i.e. the anti-corrosion composition and the dye) may be
present as continuous or discontinuous layers of coatings. The
materials may be present in the coating any of the configurations
described herein in relation to the method.
[0069] In some aspects, the anti-corrosion composition and the dye
are substantially separate from one another i.e. there is minimal
mixing of the two materials.
[0070] In one aspect, the anti-corrosion composition does not
contain the dye.
[0071] In one aspect, the dye does not contain the anti-corrosion
composition.
[0072] In one aspect, the present disclosure provides a kit
comprising the anti-corrosion composition as herein described (e.g.
in the form of an applicator pen such as Touch-N-Prep.RTM.), a dye
as herein described, and instructions outlining the method for
application as herein described.
[0073] The method can be easily integrated into existing coating
procedures, whenever convenient. The method of the present
disclosure could therefore be mandated by a process specification
(e.g. the instructions mentioned herein) which could specify the
method which must be used in order to apply (and optionally detect)
the anti-corrosion coating as herein disclosed.
[0074] The method of the present disclosure provides a simple but
effective way of applying an anti-corrosion coating which is easily
detectable. The method can utilise commercially available
anti-corrosion compositions (e.g. chemical conversion materials)
and dyes, e.g. those which have a long shelf life. A further aspect
of the disclosure therefore includes the step of viewing the coated
substrate (described herein) under UV light, e.g. in a dark room.
This allows identification of the substrates that have been coated
according to the coating method disclosed herein.
[0075] A further aspect of the present disclosure therefore relates
to a method of detecting coated parts or detecting the presence of
an anti-corrosion coating, e.g. identifying whether a substrate has
been coated by the method as herein described. The method of
detecting coated parts comprises providing a part (e.g. a substrate
coated as herein described or any of the devices, components and
articles described herein) and viewing it under UV light. Parts
which have been coated as described therein will be identified by
the fluorescence of the dye. A further aspect of the present
disclosure thus involves viewing the coated substrate (as described
herein in relation to products and methods) under UV light.
Detecting the presence of an anti-corrosion coating may be useful
in quality control procedures.
[0076] In one aspect, the present disclosure provides a method of
detecting the presence of an anti-corrosion coating, said method
comprising: applying an anti-corrosion coating as described herein
and viewing the coated substrate under UV light.
[0077] The UV light can be provided by a UV device. Examples of UV
devices include UV-LED products, e.g. UV-LED products at
wavelengths of 265, 280, 285 or 300 nm. The UV devices can be
mounted on carrier.
[0078] The UV light can be provided by an artificial UV device.
Examples of artificial UV lights include black lights (e.g. devices
which emit long-wave UVA radiation), short-wave ultraviolet lamps
(e.g. devices which emit UV light with two peaks in the UVC band,
e.g. at 253.7 nm and 185 nm), incandescent lamps (e.g. devices
which emit UV light in the near UV range, from 400-300 nm),
gas-discharge lamps (e.g. argon and deuterium arc lamps, xenon arc
lamps, deuterium arc lamps, mercury-xenon arc lamps, metal-halide
arc lamps and excimer lamps), ultraviolet LEDs and ultraviolet
lasers.
[0079] References to "comprises" and/or "comprising," should be
understood to also encompass "consist(s) of", "consisting of",
"consist(s) essentially of" and "consisting essentially of".
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.RTM. 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.RTM. 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.RTM.)
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.RTM.) 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.RTM.) 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.
* * * * *