Film-forming compositions containing molybdate-derived coatings

Abstract

Film-forming composition, comprising particles coated with a chromium-free molybdate-based conversion coating solution to, when combined with a film-forming binder, prevent corrosion on a metallic substrate.

Description

Description Title of the invention: Film-forming compositions containing re- clothing derived from molybdate.

[0001] — This patent application claims the benefit and priority of the application US provisional number 63 / 200,613, filed on March 18, 2021. FIELD OF INVENTION

[0002] = Metallic particles with a coating from a molybdate solution for use with binders and, optionally, corrosion inhibitors to provide a corrosion-inhibiting film-forming composition for use on a metallic substrate. BACKGROUND

[0003] — For decades, uncoated metallic particles have been added to paint to inhibit corrosion, including galvanic corrosion, particles acting as sacrificial electrodes when paint is used for to protect a metallic substrate, which substrate may be exposed to seawater, by Example: Magnesium, zinc, and aluminum (including an aluminum alloy) are three of these metallic particles. More recently, it has been discovered that coating aluminum alloy particles coated with a semi-corrosion-inhibiting coating The conductor provides superior protection when used in paints in turn covered with a metallic surface (see US patent US 8277688 by (example). Such coated aluminum alloy particles act as anodes. sacrificial, but the coating on the particles inhibits the self-corrosion of the particles.

[0004] Effective aluminum-coated powders are available for use in film-forming compositions, such as corrosion-inhibiting coatings trivalent chromium base, see PCT / US2012 / 040371; PCT / US2013 / 046094 and PCT / US2013 / 045190, all incorporated herein by reference. These patent applications di- reveal an aluminum alloy powder coated with a coating solution aqueous trivalent chromium (Cr*+)-based solution, combined with a binder (such as a binder for paint) for use as a film-forming compound applied to aluminum and other metallic substrates to protect them against corrosion. These publications of patents are sometimes referred to as "Navy applications".

[0005] — The aqueous solution from which these single particles were obtained is, ge- Generally, a trivalent chromium compound and a hexafluorozirconate, with fluor- specific hydrocarbons (tetra or hexa) and / or divalent zinc (see US patent) 8277688). The pH is adjusted to 2.5 to 5.5. Water-soluble corrosion inhibitors, inorganic or organic substances can be added. Prior art aluminum alloy particles were treated in a nitrogen / hydrogen atmosphere and supplied in sizes ranging from 2 to 200 microns, the longest dimension being the particle size. The coating on the particles is very thin, on the nanometer scale. It reduces self-corrosion and improves adhesion to binders. The coated aluminum alloy particles, as described in the prior art, were coated with a film-forming binder in a ratio of 20-80 parts to 5-80 parts. Up to 10 parts of an ionic corrosion inhibitor, up to 5 parts of a wetting agent, up to 5 parts of a water-soluble organic corrosion inhibitor, and up to 5 parts of a solvent are optional. In US patent 9243333 (Navy), the aqueous solution is modified to replace fluorocarbons with a fluorometalate, and additional and different corrosion inhibitors are disclosed. Furthermore, various aluminum alloys are disclosed, but the general formula is Al-XY, where X and Y are alloying elements selected from specific groups. The prior art trivalent chromium solution from which the particle coating is derived takes 7 days to equilibrate before being incorporated into the particles. The resulting coated particles, when added to binders with optionally ionic or organic corrosion inhibitors, provide a highly effective corrosion-inhibiting film when applied to metals. Summary of the invention A liquid aqueous solution, capable of reacting with a chromium-free, molybdate-based aluminum alloy, is released, leaving oxidation reaction products on aluminum particles which, in turn, are combined with binders such as those used in paints. Optionally, organic or ionic corrosion inhibitors can also be added. The result is a film-forming composition used to help prevent corrosion of metallic substrates, partly due to the coated alloy particles acting as sacrificial anodes. A molybdate-based coating for metallic particles, including aluminum alloy particles, in certain embodiments, prepared from an aqueous solution comprising molybdate, permanganate, and hexafluorozirionate, adjusted to a pH range of 0-14, and applied to the particles to form an electrically conductive or semiconductive corrosion-preventive coating (approximately 1 nanometer to 5 microns thick) on the particles. The coated particles, in certain embodiments, are intended to be used with a binder to form a paint or other film-forming composition that inhibits the corrosion. In some embodiments, the molybdate in the aqueous solution is potassium molybdate (K,MoO), the permanganate is potassium permanganate (KMnO), and the hexafluorozirconate is potassium hexafluorozirconate (K,ZF4). These components are in the molar range of 0.001–0.50 mol per liter for each. In some embodiments, the pH of the aqueous solution can be adjusted with potassium hydroxide or sulfuric acid to be basic or acidic, with a pH in the range of 0–14. To increase surface growth and reaction yield, an ionic salt of barium or boron can be added to act as a pH buffer.The solution deposits a molybdate oxide-based coating, a corrosion inhibitor and semiconductor, onto the aluminum alloy particles and reduces or eliminates self-corrosion of the particles when the coated particles are added to a binder and applied to an aluminum alloy and exposed to salt spray. In preferred embodiments, potassium permanganate may be used to help provide a colorant and act as a corrosion inhibitor. In some embodiments, the aqueous molybdate / permanganate solution may be acidic, in the range of pH 2 to 5. The pH may be adjusted with sulfuric acid or other suitable acids. In some embodiments, the molybdate-based coating is applied to aluminum alloy particles, including an aluminum alloy of the 2000, 3000, 5000 and 7000 series, to provide, when incorporated into a binder, a film-forming composition offering effective corrosion resistance and electrical conductivity, particularly when applied to a metallic substrate. In accordance with certain aspects of the present invention, an aqueous treatment or coating solution is proposed which contains as ingredients at least potassium molybdate, a fluorozirconate permanganate (such as Potassium hexafluorozirconate) with a pH of 0-14, and preferably without lithium or chromium. In some embodiments, the pH can be adjusted to 2-4 with sulfuric acid or another reagent. In some embodiments, the pH can be adjusted to 9-11 with potassium hydroxide or another reagent. The components are added in powder form to deionized water at room temperature within the indicated molar ranges and mixed for typically 2 to 15 minutes, until dissolved. After mixing, all molybdate solutions are immediately ready to receive the uncoated particles; there is no need to allow them to stand and equilibrate. In some embodiments, particles coated with the molybdate solution described here are used instead of particles coated with a base of trivalent chromium compounds used in the prior art, including the Navy applications incorporated herein by reference. Indeed, molybdate-coated particles can be used as a substitute for any chromium-based coated particles in a film-forming composition. In some embodiments, one or more of the following corrosion inhibitors may be added when the coated particles are added to the binder: Magnesium citrate, Magnesium oxalate, Zinc citrate, Zinc oxalate, Lithium phosphate, or a synergistic combination of these inhibitors and others. According to a first aspect of the invention, coated metallic particles are proposed, characterized by the fact that the coating is derived from a molybdate solution, the molybdate solution being able to react with the metallic particles in an uncoated state. According to preferred features of the first aspect of the invention, taken individually or in combination: - the metal is aluminium or an alloy thereof; - the coating is electrically conductive or semiconductive; - the molybdate solution comprises a molybdate and at least one of a permanganate and a hexafluorozirconate; - molybdate, permanganate and hexafluorozirconate are chosen from the group comprising: potassium molybdate, potassium permanganate and potassium hexafluorozirconate; - molybdate solution is an aqueous solution; - each of the components molybdate, permanganate and hexafluorozirconate present in the molybdate solution is present in the molar range of 0.001 - 0.50 mole per liter of the molybdate solution; - the coating has a thickness of between 1 nanometer and 5 microns; - the individual particles of the particles have a size of between 1 and 200 microns in the longest dimension of the particle; - the individual particles are spherical, granular or flaky in shape: - the coated particles are prepared in an atmosphere chosen from the group including: oxygen, nitrogen / inert gas and nitrogen-hydrogen; - the molybdate solution is an aqueous solution and includes a pH adjusting agent and / or a buffer; - the pH adjusting agent is one of the following: potassium hydroxide or sulfuric acid; - the buffer is an ionic salt of barium or boron; - the pH of the molybdate solution is adjusted to between 2 and 4 or between 9 and 11; - the coating is free from one or more of the following: chromium and lithium; According to a second aspect of the invention, a method for manufacturing coated particles according to the first aspect of the invention is proposed, characterized in that it comprises the steps of: mix the molybdate solution; add the metallic particles to the mixed molybdate solution. According to preferred features of the second aspect of the invention, taken individually or in combination: - the mixed molybdate solution is capable of receiving the metallic particles immediately after the mixing of said molybdate solution; - the process also includes at least one of the following steps: clean the metallic particles before adding said metallic particles to the mixed molybdate solution; agitate or stir the mixture of metallic particles and molybdate solution for a period of time; allow the molybdate solution to decant; Rinse off wet coated particles; and dry the coated particles; - the metallic particles are made of aluminium or an alloy thereof; - The molybdate solution mixing step includes the following steps: provide a quantity of deionized water; add, in powder form, components of the molybdate solution to deionized water; and mix the powdered components of the molybdate solution with deionized water; - the components in powder form are chosen from the group including: potassium molybdate, potassium permanganate and potassium hexafluorozirconate; - the process includes the step of providing an atmosphere selected from the group comprising: oxygen, nitrogen / inert gas and nitrogen-hydrogen, and mixing the metallic particles with the molybdate solution in said atmosphere. According to a third aspect of the invention, a corrosion-resistant composition is proposed for application on metallic substrates comprising: coated metallic particles as defined above according to the first aspect of the invention; and a binder. According to preferred features of the third aspect of the invention, taken individually or in combination: -the binder is a film-forming binder; - the binder includes a hardening agent; - the composition also includes a corrosion inhibitor; - the corrosion inhibitor is ionic or organic; -the film-forming binder is chosen from the group including: paints, oils, greases, polymers, epoxy polymers, polysiloxanes, polyurethanes, lubricants, epoxies, epoxy precursors, isocyanates, acrylics, polymer precursors, polymeric acids, polyfunctional aromatic amines, polyacrylates, a water-soluble acrylic latex emulsion and sealants; - the corrosion-resistant composition comprises at least one corrosion inhibitor selected from the group comprising: a lithium salt, an organic or inorganic lithium salt, lithium phosphate, lithium carbonate, at least one metal polycarboxylate, magnesium-containing materials, metallic magnesium particles, a magnesium alloy, magnesium oxide, magnesium oxy-aminophosphate salts, magnesium carbonate and magnesium hydroxide, magnesium citrate, magnesium oxalate, zinc citrate, zinc oxalate, and a combination thereof: - the corrosion inhibitor is lithium-free; - the corrosion inhibitor comprises lithium-free synergistic combinations of metal oxalates, metal picrates, metal succinates, metal tartrates and metal adipate; - the corrosion-resistant composition comprises, by non-volatile weight, the film-forming composition: 50-95% binder; 10 to 70% coated particles; and 0.0 to 40% corrosion inhibitor. Brief description of the drawings The drawings illustrate preferred embodiments of the invention and are given by way of example: [Fig.1] is a schematic representation of a coated particle; [Fig.2a] is a schematic representation of the film-forming composition; [Fig. 2b] illustrates a reservoir containing molybdate; and [Fig. 3] is a functional diagram illustrating the coating process. DETAILED DESCRIPTION Figure 1 illustrates a coated aluminum alloy particle 10 comprising an aluminum alloy particle 12 which may, in some embodiments, be 1-200 microns in the longest dimension, with a molybdate oxide coating (in the nanometer range) derived from previously disclosed molybdate solutions. The particles can be spherical, granular, or flaky and are prepared in an atmosphere of H, N, Oxygen, or Nitrogen / inert gas. They can be obtained from Valimet, Stockton, CA. Figure 2a illustrates the general composition of a film-forming composition 16 consisting of the coated aluminum alloy particle 10 shown here, mixed with binders comprising, in some embodiments, binders to which a hardening agent is added and, optionally, corrosion inhibitors, including, without limitation, organic and ionic corrosion inhibitors. Figure [Fig. 2b] illustrates a reservoir or container 22 in which the aqueous molybdate coating solution 24 is placed and which can receive the untreated metal particle 12, in certain embodiments of aluminum, aluminum alloy or any other metal particles. Figure 3 illustrates a general process for an aluminum particle, with step A (optional) comprising cleaning, and step B, the application of the molybdate-based coating by soaking the untreated particles 12 in the molybdate solution 24. In some embodiments, the uncoated particles may be added at a rate of 200 grams (range 100-300) per liter of molybdate solution. Step C is the drying of the coated particles. These steps, in general, can be found in US patent 9243333 (Navy). The binders for the film-forming composition may be paints, oils, greases, epoxy polymers, polyurethanes, lubricants, sealants, or similar substances. In some embodiments, the binders may comprise 50–95% of the non-volatile weight of the film-forming composition, 10–70% of coated particles, and 0.0–40% of corrosion inhibitors. The binders may include a film-forming resin and a curing agent for the film-forming resin. The film-forming resin may be selected from the group including: epoxy resins, polyesters, polyacrylates, polyurethanes, polyethers, polyaspartic esters, polysiloxanes, isocyanates, mercaptofunctional resins, amine functional resins, amide functional resins, imide functional resins, silane-containing resins, polysiloxanes, acetoacetate resins, functional fluorinated resins, alkyd resins and mixtures thereof. Binders may include those described in U.S. Patent 9243333 (Navy), including urethane and epoxy binders, and binders with curing agents and binders without curing agents, including those that cure with moisture. Some binders are polymers derived from epoxy, isocyanates, of acrylics and cured polymers or polymer precursors, including polyimides and precursors, i.e., polyamic acids. Various polyfunctional aromatic amines can be used to prepare polyimide precursors or polymers. Other known polymer binders include epoxies or epoxy resins or polymer precursors and binders derived from isocyanates. Binders, including epoxy precursors, include those that are liquid at room temperature. Examples of other binders include polyacrylates and water-soluble acrylic latex emulsion coatings. The physical properties of the film, such as strength, flexibility, chemical resistance, and solvent resistance, can be controlled over a wide range by selecting appropriate polyols and adjusting the NCO to OH ratio. Inorganic binders can also be used; see L.Smith, et al, Generic Coating Types: An Introduction to Industrial Maintenance Coating Materials, Pittsburgh, PA, and US patent US 9243333 (Navy). Lithium salts have been shown to be suitable corrosion inhibitors for binders and include the following, as described in 2012 / 0025142 (Visser, et al.): lithium phosphate and lithium carbonate. Visser discloses, in some embodiments, a coating composition curable below 120°C, comprising a film-forming resin, a curing agent for the film-forming resin, and a lithium salt. The lithium salt is selected from inorganic and organic lithium salts that have a water solubility constant at 25°C in the range of 1 x 10⁻⁷ to 1 x 10⁷. The lithium salt may be selected from the group consisting of lithium carbonate, lithium phosphate, and mixtures thereof. Other combinations of lithium salts, with a synergistic polycarboxylate, can be found in US Patent 10889723 (Navy).These are synergistic, corrosion-resistant inhibitor compositions consisting essentially of combinations of at least one metallic polycarboxylate and 1 to 50 percent by weight of the lithium phosphate composition, the metal of the polycarboxylate being selected from the group consisting of Groups IIa, IIIb, IVb, Vb, VIb, VIII, Ib, and IIIa of the Periodic Table. These inhibitors may be combined with other components of the film-forming composition, in some embodiments in the quantity of 1-40% by volume of the total non-volatile components of the film-forming compound. In some embodiments, the film-forming composition may contain corrosion inhibitors containing magnesium, including: a magnesium-containing material from the group consisting of metallic magnesium particles (size 1-15 microns), a magnesium alloy, magnesium oxide, magnesium oxyaminophosphate salts, magnesium carbonate and magnesium hydroxide. In some embodiments, the film-forming composition is characterized by the absence of lithium. In some embodiments, lithium-free corrosion inhibitors include those described in US Patent 10,351,715 (Navy), comprising polycarboxylate acids and a variety of cations. Certain specific combinations of certain metal polycarboxylate salts have been found to be particularly effective synergistically, in loading ranges from 0.1 to 30% by weight of the non-volatile binder, or from 0.01% to 30% of the total weight of the film-forming composition. This range can be used for any of the corrosion inhibitors disclosed at present. These synergistic, lithium-free corrosion inhibitor combinations may include: at least one metal polycarboxylate obtained from a stoichiometric reaction of metal compounds and polycarboxylic acids to obtain polycarboxylic metal salts, and at least one metal carboxylate obtained from the stoichiometric reaction of metal compounds and polycarboxylic acids to obtain polycarboxylic metal salts, where either the metal or the carboxylic acid in at least one of the carboxylic metal salts is different from the other carboxylic metal salt. Five of these lithium-free synergistic combinations include, in each case, 0.1 to 20 parts by weight of each of the following pairs: magnesium oxalate and zinc oxalate, zinc oxalate and zinc citrate, zinc oxalate and zinc succinate, zinc tartrate and zinc citrate, and zinc adipate and zinc citrate. Note that any of the above combinations may optionally include lithium salts as presented here. For the preparation of Examples LA and 1B, approximately 200 grams (range 100-300 grams) of 10-micron, spherical aluminum alloy particles are added to 1 liter of molybdate solution (with pH adjusted to 3) at room temperature and stirred or agitated for 3-10 minutes. The solution is allowed to settle, and the wet powder is rinsed 3 times with deionized water. The wet brick is air-dried at room temperature for 24-48 hours (alternatively, it can be dried with a polar organic solvent such as acetone, which can then be drawn off under vacuum, or oven-dried at 63°C for 12-36 hours). This results in a metallic oxide coating on the particles, free of lithium and chromium. This semiconducting coating prevents oxidation on the surface of the particles (which would act as an insulator), thus allowing the particles to act as sacrificial anodes when used in a film-forming composition applied to a metal. In Example 1A, 5 pounds of coated particles were added to 3 pounds of epoxy binder, to which 3 pounds of powdered zinc metal carboxylates were added as an additive. Corrosion inhibitors were added and mixed. In Example 1B, 5 pounds of coated particles were added to 3 pounds of polysiloxane binder, to which 3 pounds of powdered zinc metal carboxylates as corrosion inhibitors were added and mixed until complete dispersion. The film-forming compound of Examples LA and IB was applied to test coupons made of aluminum alloy (2024 T-3) and tested by salt spray according to ASTM B117. These corrosion tests and other standard tests show results comparable to the prior art film-forming compositions bearing powdered Cr*. Further examples of combinations of binders, corrosion inhibitors and molybdate-coated particles, such as those presented herein, will improve the corrosion resistance of binder-based compositions only when applied to metallic substrates. In the preceding description, for explanatory purposes, numerous details are presented to allow for a thorough understanding of the embodiments. However, it will be obvious to someone skilled in the art that these specific details are not necessary. In other cases, well-known structures and components are represented as functional diagrams to avoid obscuring understanding. The embodiments described above are considered only as examples. Changes, modifications, and variations may be made to the particular embodiments by those skilled in the art. The scope of the claims should not be limited by the particular embodiments presented in the examples, but should be interpreted as broadly as possible in accordance with the description as a whole.

Claims

Demands

1. Coated metallic particles, characterized in that the re- The garment is made from a molybdate solution, the molybdate solution being able to react with metallic particles in a non- coated.

2. Metallic particles coated with claim 1, characterized by the the fact that the metal is aluminium or an alloy thereof.

3. Particles coated with any one of claims 1 and 2, character- sterilized by the fact that the coating is electrically conductive or semiconductor.

4. Particles coated with any one of claims 1 to 3, character- terrified by the fact that the molybdate solution includes a molybdate and at least one of a permanganate and a hexafluorozirconate.

5. Particles coated with any one of claims 1 to 4, characterized- sterilized by the fact that molybdate, permanganate and The hexafluorozirconate compounds are chosen from the group comprising: potassium molybdate, potassium permanganate and potassium hexafluorozirconate.

6. Particles coated with any one of claims 1 to 5, character- sterilized by the fact that the molybdate solution is a solution aqueous.

7. Particles coated with any one of claims 4 to 6, character- sterilized by the fact that each of the components molybdate, permanganate and hexafluorozirconate present in the molybdate solution is present in the molar range of 0.001 - 0.50 mole per liter of the molybdate solution.

8. Coated particles according to any one of claims 1 to 7, ca- characterized by the fact that the coating has a thickness of between 1 nanometer and 5 microns.

9. Coated particles according to any one of claims 1 to 8, ca- characterized by the fact that the individual particles of the particles have a size of between 1 and 200 microns in the longest dimension of the particle.

10. Coated particles according to any one of claims 1 to 9, ca- characterized by the fact that the individual particles of the particles are spherical, granular or flaky in shape.

11. Coated particles according to any one of claims 1 to 10, ca- characterized by the fact that the coated particles are prepared in a atmosphere chosen from the group including: oxygen, nitrogen / gas inert and nitrogen-hydrogen.

12. Coated particles according to any one of claims | to 11, ca- characterized by the fact that the molybdate solution is a solution aqueous and comprises a pH adjusting agent and / or a buffer.

13. Coated particles according to claim 12, characterized by the fact that the pH adjusting agent is one of the following: hydroxide potassium or sulfuric acid.

14. Coated particles according to any one of claims 12 and 13, characterized by the fact that the buffer is an ionic salt of barium or of boron.

15. Coated particles according to any one of claims 11 to 13, characterized by the fact that the pH of the molybdate solution is adjusted between 2 and 4 or between 9 and 11.

16. Coated particles according to any one of claims 1 to 15, ca- characterized by the fact that the coating is free from one or more among them: chromium and lithium.

17. Method for manufacturing coated particles according to any claims 1 to 16, characterized by the fact that it includes the steps consisting of: mix the molybdate solution; add the metallic particles to the mixed molybdate solution.

18. | Method according to claim 17, characterized in that the solution mixed molybdate is capable of receiving the particles me- tallic acids immediately after mixing said solution of molybdate.

19. A method according to any one of claims 17 and 18, characterized by the fact that it also includes at least one of the following steps: clean the metallic particles before adding said particles tallic acids in the mixed molybdate solution; shake or stir the mixture of metallic particles and solution molybdate for a period of time; allow the molybdate solution to decant; rinse off the damp coated particles; and dry the coated particles.

20. | A method according to any one of claims 17 to 19, characterized by the fact that the metallic particles are aluminum or a alloy of it.

21. A method according to any one of claims 17 to 20, characterized by the fact that the molybdate solution mixing step includes the steps involved in: provide a quantity of deionized water; add, in powder form, components of the solution of molybdate in deionized water; and mix the components in powder form of the solution molybdate with deionized water.

22. A method according to any one of claims 17 to 21, characterized by the fact that the components in powder form are chosen in the group including: potassium molybdate, permanganate of potassium and potassium hexafluorozirconate.

23. A method according to any one of claims 17 and 22, characterized by the fact that it includes the step of providing an atmosphere chosen from the group including: oxygen, nitrogen / inert gas and nitrogen-hydrogen, and to mix the metallic particles with the molybdate solution in said atmosphere.

24. Corrosion-resistant composition for application on metallic substrates including: metallic particles coated with any of the reven- instructions 1 to 16; and a binder.

25. Corrosion-resistant composition according to claim 24, ca- characterized by the fact that the binder is a film-forming binder.

26. Corrosion-resistant composition according to any one of the claims indications 24 and 25, characterized by the fact that the binder comprises an agent hardening.

27. ​​| Corrosion-resistant composition according to any one of the claims indications 24 to 26, characterized by the fact that the composition includes in addition, a corrosion inhibitor.

28. Corrosion-resistant composition according to claim 27, ca- characterized by the fact that the corrosion inhibitor is ionic or organic.

29. Corrosion-resistant composition according to any one of the claims indications 25 to 28, characterized by the fact that the film-forming binder is chosen in the group comprising: paints, oils, greases, polymers, epoxy polymers, polysiloxanes, polyurethanes, lubricants, epoxies, epoxy precursors, isocyanates, acrylics, polymer precursors, polymer acids, the polyfunctional aromatic amines, polyacrylates, an emulsion of water-soluble acrylic latex and sealants.

30. | Corrosion-resistant composition according to any one of the claims indications 27 to 29, characterized by the fact that it includes at least one corrosion inhibitor selected from the group comprising: a salt of lithium, an organic or inorganic lithium salt, lithium phosphate lithium, lithium carbonate, at least one polycarboxylate me- tallic acid, magnesium-containing materials, particles of metallic magnesium, a magnesium alloy, magnesium oxide magnesium, magnesium oxyaminophosphate salts, carbonate magnesium and magnesium hydroxide, magnesium citrate, magnesium oxalate, zinc citrate, zinc oxalate, and a com- combination of these.

31. Corrosion-resistant composition according to any one of the claims indications 27 to 30, characterized by the fact that the corrosion inhibitor is lithium-free.

32. Corrosion-resistant composition according to claim 31, ca- characterized by the fact that the corrosion inhibitor includes com- synergistic combinations free of lithium and metallic oxalates, metallic picrates, metallic succinate, metallic tartrates and metallic adipate.

33. Corrosion-resistant composition according to any one of the claims indications 24 to 32, characterized by the fact that it includes, by weight not volatile of the film-forming composition: 50 to 95% binder; 10 to 70% coated particles; and 0.0 to 40% corrosion inhibitor.

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