Assembly for detecting corrosion or the possibility of corrosion of a metallic substrate
The corrosion detection system uses colloidosomes to amplify fluorescence signals from metal cations, addressing the sensitivity issues of existing methods and enabling effective corrosion detection in inaccessible areas.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- SAFRAN SA
- Filing Date
- 2024-12-19
- Publication Date
- 2026-06-26
AI Technical Summary
Existing methods for detecting corrosion on metallic substrates, particularly in inaccessible areas, lack sensitivity and effectiveness.
A corrosion detection system comprising a corrosion detection coating with colloidosomes that release a metal cation upon pH change, forming a fluorescence signal through a ligand complex, amplified by a chain reaction, allowing sensitive detection of corrosion.
Facilitates the detection of corrosion with enhanced sensitivity, particularly in inaccessible areas, by amplifying the fluorescence signal through a chain reaction of colloidosomes.
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Title of the invention: Corrosion detection system for a metallic substrate. Technical field
[0001] The present invention relates to an assembly for detecting corrosion or the possibility of corrosion of a metallic substrate, and an associated method. Prior art
[0002] Various methods have been described in the state of the art for detecting corrosion of a part, particularly in the aeronautical or aerospace field.
[0003] In this regard, we can cite application WO 2018 / 193220 which discloses a coating containing nanocapsules capable of producing a fluorescence signal in the presence of a corrosion product of a part, in this case a metal ion.
[0004] We can also cite US patent 7790225 which discloses a coating comprising capsules having a wall capable of disintegrating in the presence of a pH greater than 7 resulting from a corrosion phenomenon.
[0005] It remains desirable, however, to propose new methods for detecting corrosion or the possibility of corrosion of a metallic substrate which have good sensitivity, and which are, in particular, adapted to the detection of corrosion in inaccessible areas. Description of the invention
[0006] According to a first aspect, the invention proposes an assembly comprising: - a metallic substrate, and - a corrosion detection coating, comprising: • a first layer comprising colloidosomes including (i) a core formed by a liquid medium comprising a metal cation and an H+ or OH ion, (ii) a first envelope, located around the core, formed by polymer particles, and (iii) a second envelope, located around the first envelope and ensuring its cohesion, formed by a pH-sensitive gel that is configured to eliminate itself when in the presence of a pH change associated with substrate corrosion so as to cause the release of the core contents, and • a second layer covering at least part of the first layer and in contact with the latter, the second layer comprising a ligand configured to form, with the metal cation, a complex capable of producing a fluorescence signal under predetermined light irradiation.
[0007] The invention is based on the detection of corrosion or the possibility of corrosion of the metallic substrate by detecting the fluorescence signal produced by the complex formed between the metal cation and the ligand in the second layer. This complex is formed following the release of the contents of the colloidosomes from the first layer, which is triggered by the removal of the gel from the second layer when the latter is subjected to a change in pH, i.e. when it is placed in the presence of H+ or OH ions.
[0008] The H+ or OH ion released from a first colloidosome causes the elimination of the second layer of a second colloidosome, which in turn releases its contents to trigger the release of the contents of a third colloidosome, and so on. The quantity of species released by the colloidosomes is thus amplified by a chain reaction. The metal cation diffuses to the second layer to form a complex with the ligand, resulting in a strong fluorescence signal even in cases of low corrosion. The invention thus provides a particularly sensitive corrosion detection technique.
[0009] Such a characteristic advantageously facilitates the removal of the gel from the second envelope of colloidosomes during the pH change associated with corrosion.
[0010] According to a particular feature, the gel forming the second envelope is an electrolytic copolymer (“polyelectrolyte copolymer”).
[0011] According to a particular feature, the gel forming the second envelope can be a gel comprising at least one chemical group selected from an amine function (-NH2), a carboxylic acid function (-COOH), a sulfonic acid function (-SO3H), or a combination of these functions.
[0012] Such a characteristic makes it possible to improve the sensitivity of the second envelope to pH.
[0013] According to a particular characteristic, the gel forming the second envelope can be chosen from: Poly(N-isopropylacrylamide-co-acrylic) known in English as "Poly(N-isopropylacrylamide-co-acrylic acid)", the co-polymer n-alkyl methacrylate esters-co-(dimethylamino)ethyl methacrylate.
[0014] Such a characteristic advantageously improves the pH sensitivity of the second envelope even further, since this compound comprises an amine group and a carboxylic acid group, both of which are sensitive to pH changes. The same applies to the n-alkyl methacrylate copolymer esters-co-(dimethylamino)ethyl methacrylate, which comprises an amine group and several carboxylic acid groups.
[0015] According to a particular feature, colloidosomes may further comprise (iv) a third envelope, situated around the second envelope, and formed by a second pH-sensitive gel, identical or different from the gel forming the second envelope, which is configured to eliminate itself when in the presence of a pH change associated with substrate corrosion.
[0016] Such a characteristic advantageously makes it possible to strengthen the durability and stability of the colloidosomes present in the first layer of the corrosion detection coating.
[0017] According to a particular feature, the second gel forming the third envelope can be an electrolytic copolymer.
[0018] According to a particular feature, the second gel forming the third envelope can be a gel of at least one chemical group chosen from an amine function (-NH2), a carboxylic acid function (-COOH), a sulfonic acid function (-SO3H), or a combination of these functions.
[0019] Such a characteristic makes it possible to improve the sensitivity of the third envelope to pH.
[0020] According to a particular characteristic, the second gel forming the third envelope can be chosen from: Poly(N-isopropylacrylamide-co-acrylic) known in English as "Poly(N-isopropylacrylamide-co-acrylic acid)", n-alkyl methacrylate copolymer esters-co-(dimethylamino)ethyl methacrylate.
[0021] The presence of Poly(N-isopropylacrylamide-co-acrylic) advantageously further improves the pH sensitivity of the second envelope because this compound comprises an amine group and a carboxylic acid group, both of which are sensitive to pH changes. The same is true for the copolymer n-alkyl methacrylate esters-co-(dimethylamino)ethyl methacrylate, which comprises an amine group and several carboxylic acid groups.
[0022] According to a particular characteristic, the metal cation may comprise at least one of: Li+, Na+, K+ or a mixture of these cations.
[0023] Li+, Na+, and K+ ions have the advantage of being highly mobile due to their small size, which facilitates their diffusion into the second layer. This makes it possible to further increase the signal intensity and thus further facilitate corrosion detection.
[0024] According to a particular feature, the first layer may comprise an epoxy matrix in which the colloidosomes are dispersed.
[0025] Such a matrix facilitates the diffusion of the metallic cation from the first layer of the coating to the second layer of the corrosion detection coating.
[0026] According to a particular characteristic, the second layer can have a thickness of at most 80 pm.
[0027] A second layer with a reduced thickness makes it easier to detect the signal.
[0028] According to a particular characteristic, the second layer can have a thickness of at most 10 pm.
[0029] According to a particular feature, the metallic substrate may be a female part intended to cooperate with a male part, the first layer of the corrosion detection coating covering a first cooperation surface of the female part which is intended to be covered by the male part, and a second surface, distinct from the first surface, intended not to be covered by the male part, and the second layer of the corrosion detection coating extending over the second surface.
[0030] Such a feature advantageously allows the detection of corrosion in a cooperation surface between a female part and a male part which constitutes an inaccessible area.
[0031] According to another aspect, the invention proposes a method for detecting corrosion or the possibility of corrosion, implementing an assembly according to the invention, comprising at least: - the detection of any fluorescence signal by subjecting the second layer to predetermined light irradiation, and - the determination of a state of corrosion or possible corrosion of the substrate from the detection carried out.
[0032] Thus, it is possible to detect corrosion or the beginning of corrosion of the metallic substrate of the assembly in a simple and rapid manner. Brief description of the drawings
[0033] [Fig-1] Fig. 1 represents, schematically, an example of the assembly according to the invention.
[0034] [Fig.2] Figure [Fig.2] schematically represents an example of a colloidosome according to the invention,
[0035] [Fig.3] Figure [Fig.3] schematically represents another example of a colloidosome according to the invention,
[0036] [Fig.4] Fig.4 represents, schematically, another example of the assembly according to the invention.
[0037] [Fig.5] The [Fig.5] represents, schematically, the flowchart of the steps of an embodiment of a process according to the invention for detecting corrosion or the possibility of corrosion of the whole of the [Fig.4]. Description of the implementation methods
[0038] Fig. 1 illustrates an example of assembly 1 according to the invention, useful for detecting corrosion or the possibility of corrosion of a part.
[0039] In the example illustrated in [Fig.1], assembly 1 comprises a metallic substrate 2 and a corrosion detection coating 3. The corrosion detection coating 3 comprises a first layer 4 and a second layer 5.
[0040] In the example illustrated in [Fig.1], the first layer 4 completely covers the metallic substrate 2 and is in contact with the latter.
[0041] The second layer 5 completely covers the first layer 4 and is in contact with the latter.
[0042] Alternatively, the second layer 5 partially covers the first layer 4 of the corrosion detection coating 3.
[0043] Alternatively, the first layer 4 partially covers the metallic substrate 2.
[0044] The first layer 4 can constitute a primer or a wet primer.
[0045] The metallic substrate 2 may comprise steel with or without a sacrificial metallic coating, for example of the zinc-nickel or aluminium type.
[0046] The first layer 4 of the corrosion detection coating 3 comprises a plurality of colloidosomes 41 dispersed in a first medium 42. The first medium 42 may be an epoxy matrix.
[0047] There are documents in the prior art that describe colloidosomes and their methods of manufacture. In the article "Colloidosomes: synthesis, properties and applications" of the "Journal of Colloid and Interface Science" published in 2014, a "colloidosome" is defined as a microcapsule comprising a wall formed by colloidal particles.
[0048] There are many processes for manufacturing colloidosomes such as thermal annealing, polyelectrolyte complexation and layer-by-layer deposition, gel trapping, droplet polymerization, and formation via covalent cross linking.
[0049] The second layer 5 of the corrosion detection coating 3 comprises a plurality of ligands 51 dispersed in a second medium 52. The second medium may be a polyurethane matrix.
[0050] In the example illustrated in [Fig. 1], the second layer 5 of the corrosion detection coating 3 has a thickness less than or equal to 1 Opm. Such a thickness advantageously facilitates the detection of the fluorescence signal.
[0051] Each colloidosome 41 comprises a core 410, a first envelope 411 and a second envelope 412, as illustrated in Figures 1 and 2.
[0052] The core 410 is formed by a liquid medium 4100. In the example illustrated in figures 1 and 2, the liquid medium 4100 of the core 410 is an aqueous liquid.
[0053] Alternatively, the core 410 is an organic medium such as toluene, or an n-alkane. Such an organic solvent has the advantage of exhibiting some miscibility with water.
[0054] In the example illustrated in [Fig. 1], the core 410 further comprises a metallic cation M+ having reference 4101 and a corrosion-associated ion H+ having reference 4102.
[0055] The presence of the H+ ion associated with corrosion is not limiting to the invention. Alternatively, the ion associated with corrosion may be the OH ion.
[0056] The core 410 is coated by the first envelope 411. The first envelope 411 is coated by the second envelope 412.
[0057] The first envelope 411 comprises a plurality of polymeric particles 4110. The presence of the first envelope 411 creates a barrier between the contents of the core 410 of the colloidosome 41 and the second envelope 412.
[0058] Alternatively, the polymeric particles 4110 can be formed by an ionic polymer.
[0059] In the example illustrated in Figures 1 and 2, the first envelope 411 comprises a plurality of polystyrene particles.
[0060] The second envelope 412 ensures the cohesion of the first envelope 411. The second envelope 412 is formed by a first pH-sensitive gel associated with corrosion.
[0061] A "corrosion-sensitive gel" is understood to mean a gel which decomposes or is eliminated in the presence of an acidic or basic pH resulting from the presence of corrosion-associated ions.
[0062] The first gel forming the second envelope can be an electrolytic copolymer.
[0063] In the example illustrated in [Fig. 1], the first gel forming the second envelope 412 comprises Poly(N-isopropylacrylamide-co-acrylic).
[0064] Alternatively, the first gel forming the second envelope 412 is a microgel. A "microgel" is understood to be a gel that covers a particle whose size is between 0.1 pm and 100 pm.
[0065] Alternatively, the first gel forming the second envelope 412 is a microgel whose size is between 0.1 pm and 5 pm.
[0066] As illustrated in [Fig. 1], when a colloidosome 41 is in the presence of H+ ions associated with corrosion of the metallic substrate 2, the second envelope 412 disintegrates, which produces the disintegration of the first envelope 411 and, the H+ ion and the metal cation M+ contained in the core 410 of the colloidosome 41 are released.
[0067] The H+ ion released by colloidosome 41 interacts in turn with the second envelope 412 of another colloidosome 41 and causes the release of the latter's contents. A chain reaction is therefore triggered as soon as one of the H+ ions associated with the corrosion of the metallic substrate 2 is present.
[0068] The metal cations M+ released during the chain reaction diffuse from the first layer 4 to the second layer 5, as illustrated in [Fig. 1]. Each of the metal cations M+ present in the second layer 5 interacts with a ligand 51 contained in the second layer 5 to form a complex 53. When the second layer 5 of the corrosion detection coating 3 is irradiated by radiation of a predetermined wavelength, the complexes 53 formed in the second layer 5 produce a fluorescence signal. The presence of such a fluorescence signal indicates the presence of corrosion or the possibility of corrosion of the metal substrate 2.
[0069] The metal cation M+ comprises at least one cation selected from Li+, Na+, K+ or a mixture of these cations. Alternatively or in combination, the metal cation M+ may comprise at least one cation selected from Be 2+, Mg2+, Ca2+, transition metal cations, or a mixture of these cations.
[0070] The ligand 51 can be selected from calixarene, crown ethers, pyridine, Schiff base, triazole, N,N-di-(2-picolyl)ethylenediamine, or a mixture thereof. Such ligands have the advantage of facilitating corrosion detection during irradiation. Indeed, these ligands exhibit intense fluorescence in the visible and near-infrared spectral regions. Furthermore, these ligands have high photo- and thermal stability.
[0071] Alternatively or in combination, the ligand 51 may further comprise a dye selected from anthracene, pyrene, quinoline, quinazoline, naphthalimide, rhodamine, fluorescein or a mixture thereof.
[0072] According to one example, the metal cation M+ comprises the metal cation Na+ and the ligand 51 comprises sodium-bonded benzofuran isophthalate in the form of acetoxymethyl esters, the acronym for which is "SBFLAM".
[0073] According to one example, the metal cation M+ comprises the metal cation Na+ and the ligand 51 comprises the crown ether CoroNa Green in the form of an acetoxymethyl ester having the molecular formula C30H29F2NO3 OR C30H29F2NO9, whose acronym is "CoroNa-AM". Preferably, the ligand 51 comprises the crown ether CoroNa-AM of the CoroNa™ Green brand.
[0074] According to one example, the metal cation M+ comprises the metal cation Na+ and the ligand 51 comprises 1' acetyloxymethyl 3-[3-(acetyloxymethoxy)-7-[3-(acetyloxymethoxy)-3-oxopropyl]-4,5-dichloro-9-[3-methoxy-4-[13-(2-methoxy-4-methylphenyl)-1,4,10-trioxa-7,13-diazacyclopentadec-7-yl]phenyl]-6-oxoxanthen-2-yl]propanoate, whose acronym is "ANG-2-AM".
[0075] According to one example, the metal cation M+ comprises the metal cation K+ and the ligand 51 comprises potassium-bonded benzofuran isophthalate in the form of acetoxymethyl ester whose formula is 4-[6-[16-[2-(2,4-dicarboxyphenyl)-5-methoxy-l-benzofuran-6-yl]-l,4,10,13-tetraoxa-7,16-diazacyclooctadec-7-yl]-5-methoxy-l-benzofuran-2-yl]benzene-l,3-dicarboxylic acid, whose acronym is "PBFI-AM".
[0076] According to one example, the metal cation M+ includes the metal cation K+ and the ligand 51 includes an azacouronne squarylium dye having the molecular formula C20H20N2O2 whose acronym is "ACSQ".
[0077] The radiation may be ultraviolet radiation. The wavelength of the radiation may be between 200 and 500 nm.
[0078] Figure 3 illustrates another example of a colloidosome according to the invention. In Figure 3, the elements bearing numerical references identical to those in Figures 1 and 2 are identical to the elements of the embodiments in Figures 1 and 2.
[0079] In the example illustrated in [Fig. 3], the colloidosome 43 further comprises a liquid medium 413 intercalated and a third envelope 414. The liquid medium 413 intercalated separates the second envelope 412 from the third envelope 414.
[0080] In the example illustrated in [Fig. 3], the intercalated liquid medium 413 is a liquid aqueous. The presence of the intercalated liquid medium 413 creates a barrier between the contents of the second envelope 412 and the third envelope 414 of the colloidosome 43.
[0081] The third layer 414 is formed by a second pH-sensitive gel associated with corrosion. Similar to the first gel, the second gel decomposes or is eliminated in the presence of an acidic or basic pH resulting from the presence of corrosion-associated ions.
[0082] The second gel forming the third envelope can be an electrolytic copolymer.
[0083] Alternatively, the second gel forming the third envelope 414 is a microgel. A “microgel” is understood to be a gel that covers a particle whose size is between 0.1 pm and 100 pm.
[0084] Alternatively, the second gel forming the third envelope 414 is a microgel whose size is between 0.1 pm and 5 pm.
[0085] In the example illustrated in [Fig.3], the second gel forming the third envelope 414 comprises poly(N-isopropylacrylamide-co-acrylic).
[0086] Figure 4 represents, schematically, another example of the assembly according to the invention.
[0087] In [Fig.4] the elements bearing numerical references identical to those of [Fig.1] to 3 are identical to the elements of the embodiments of figures 1 to 3.
[0088] In the example illustrated in [Fig.4], the assembly 10 comprises a metallic substrate 20 and a corrosion detection coating 30. The corrosion detection coating 30 comprises a first layer 40 and a second layer 50.
[0089] The metallic substrate 20 of the assembly 10 is a female part and cooperates with a male part 60.
[0090] The female part 20 comprises a first cooperation surface SI and a second surface S2. The first cooperation surface SI cooperates with the male part 60. The second surface S2 does not cooperate with the male part 60.
[0091] The shapes of the female part 20 and the male part are not limiting of the invention.
[0092] The first layer 40 of the corrosion detection coating 30 covers the first SI cooperation surface and the second S2.
[0093] The second corrosion detection layer 50 30 covers the second surface S2.
[0094] As illustrated in [Fig.4], the metal cations M+ released during the chain release produced by the interaction of colloidosomes 41 with H+ diffuse from the first layer 40 to the second layer 50.
[0095] In the second layer 50, each of the metal cations M+ forms the complex 53 with a ligand 51. The complex 53 produces a fluorescence signal 55 when the second layer 50 is irradiated by radiation 54 having a predefined wavelength. Thus, it is possible to detect corrosion or the possibility of corrosion of the first SI surface, which is not accessible.
[0096] Figure 5 illustrates an example of an embodiment of the process according to the invention for detecting corrosion or the possibility of corrosion of the assembly 10. During a first detection step El, the second layer 50 of the corrosion detection coating 30 is irradiated by radiation 54 having a predefined wavelength.
[0097] Next, the first irradiation step El is followed by a determination step E2 during which the state of corrosion or possible corrosion of the metallic substrate 20 is determined. Indeed, the absence of a fluorescence signal detected during the first detection step El indicates the absence of corrosion or the possibility of corrosion. of corrosion. Conversely, a high fluorescence signal indicates the presence of corrosion or the possibility of corrosion.
Claims
Demands
1. An assembly (1,10) comprising: - a metallic substrate (2,20), and - a corrosion-detecting coating (3,30), comprising: • a first layer comprising colloidosomes (41, 43) including (i) a core (410) formed by a liquid medium (4100) comprising a metallic cation (4101), and an H+ or OH ion (4102), (ii) a first envelope (411), located around the core (410), formed by polymeric particles (4110), and (iii) a second envelope (412), located around the first envelope (411) and ensuring its cohesion, formed by a pH-sensitive gel configured to evaporate when exposed to a pH change associated with corrosion of the substrate (2,20) so as to cause the release of the contents of the core (410), and • a second layer (5, 50) covering at least a portion of the first layer (4, 40) and in contact with the latter (5,50), the second layer (5,50) comprising a ligand (51) configured to form,with the metal cation (4101), a complex (53) capable of producing a fluorescence signal under predetermined light irradiation.
2. Assembly according to claim 1, wherein the gel forming the second shell (412) is an electrolytic copolymer.
3. Assembly according to claim 2, wherein the gel forming the second shell (412) is selected from: Poly(N-isopropylacrylamide-co-acrylic), n-alkyl methacrylate copolymer esters-co-(dimethylamino)ethyl methacrylate.
4. Together according to any one of claims 1 to 3, wherein the colloidosomes further comprise (iv) a third envelope (414), situated around the second envelope (412), and formed by a second pH-sensitive gel, identical or different from the gel forming the second envelope (412), which is configured to eliminate itself when in the presence of a pH change associated with substrate corrosion (2,20).
5. Assembly according to claim 4, wherein the second gel forming the third shell (414) is an electrolytic copolymer.
6. Assembly according to any one of claims 4 or 5, wherein the second gel forming the third envelope (414) is selected from: Poly(N-isopropylacrylamide-co-acrylic), n-alkyl methacrylate copolymer esters-co-(dimethylamino)ethyl methacrylate.
7. Assembly according to any one of claims 1 to 6, wherein the metal cation (4101) comprises at least one of: Li+, Na+, K+ or a mixture of these cations.
8. Assembly according to any one of claims 1 to 7, wherein the first layer (4, 40) comprises an epoxy matrix in which the colloidosomes are dispersed.
9. Assembly according to any one of claims 1 to 8, wherein the second layer (5, 50) has a thickness (e5) of at most 80 pm.
10. Assembly according to any one of claims 1 to 9, wherein the metallic substrate (20) is a female part intended to cooperate with a male part (60), the first layer of the corrosion-sensing coating covering a first cooperation surface (S1) of the female part which is intended to be covered by the male part, and a second surface (S2), distinct from the first surface, intended not to be covered by the male part (60), and the second layer (50) of the corrosion-sensing coating (30) extending over the second surface (S2).
11. A method for detecting corrosion or the possibility of corrosion implementing an assembly (1, 10) according to any one of claims 1 to 10, comprising at least: - the detection of a possible fluorescence signal by subjecting the second layer (5, 50) to predetermined light irradiation, and - the determination of a state of corrosion or possible corrosion of the substrate (2, 20) from the detection carried out.