阅读说明：本技术 防腐蚀处理液及用途 (Corrosion-proof treatment liquid and its use ) 是由 杰罗姆·弗雷雷特 马修·波瑞洛 桑德拉·佐卡利 让-查尔斯·杜平 阿诺·乌哈特 于 2019-12-19 设计创作，主要内容包括：本发明涉及一种不含任何氧化态铬的溶液,所述溶液包含：至少一种氧化性化合物,至少一种铝络合剂,至少一种缓蚀剂化合物,以及可能需要的填充化合物,所述溶液的pH值为1至5。本发明还涉及一种金属表面处理方法,包括将如上定义的溶液喷涂到所述表面上。本发明的还涉及一种可以通过如上定义的表面处理方法获得的金属表面涂层、一种包含所述涂层的金属表面以及所述溶液在金属表面防腐蚀处理方面的用途。(The invention relates to a solution free of chromium in any oxidation state, comprising: at least one oxidizing compound, at least one aluminum complexing agent, at least one corrosion inhibitor compound, and optionally a filler compound, the solution having a pH of 1 to 5. The invention also relates to a metal surface treatment method comprising spraying the solution as defined above onto said surface. The invention also relates to a metal surface coating obtainable by the surface treatment method as defined above, a metal surface comprising said coating and the use of said solution for the anti-corrosion treatment of metal surfaces.)

1. A solution free of chromium in any oxidation state comprising:

-at least one oxidizing compound,

-at least one aluminium complexing agent,

at least one corrosion inhibitor compound, and

-a filling compound that may be required,

the pH of the solution is 1 to 5.

2. The solution of claim 1, wherein the oxidizing compound is selected from the group consisting of permanganate, molybdate, persulfate, and hydrogen peroxide.

3. The solution of claim 1, wherein the complexing agent is selected from the group consisting of fluoride-containing salts and mixtures thereof, organic compounds selected from the group consisting of gluconate, citrate, oxalate, acetate and formate, and mixtures of at least one fluoride-containing salt and at least one of the organic compounds.

4. The solution of claim 3 wherein the complexing agent is a fluoride-containing salt selected from the group consisting of hexafluorozirconates, hexafluorotitanates, hexafluorosilicates, and mixtures thereof.

5. A solution according to any one of the preceding claims, wherein the corrosion inhibitor is selected from rare earth salts, tungstates, vanadates, phosphates and cerium III salts, zirconium salts, titanium salts or silicon salts.

6. Solution according to any one of the preceding claims, further comprising a bulking agent compound based on phosphate, phosphonate or polyphosphate ions or iron ions.

7. The solution of claim 6, wherein:

-the concentration of permanganate ions is between 0.01 and 0.45mol/L,

-the concentration of said phosphate ions is between 0.001 and 0.20mol/L,

-the concentration of the complexing agent is between 0.001 and 0.15 mol/l.

8. The solution of claim 6, wherein:

-the compound comprising permanganate ions is potassium permanganate,

-the compound comprising phosphate ions is selected from potassium hydrogen phosphate, phosphoric acid or iron salts,

-the complexing agent is a mixture of hexafluorozirconic acid, hexafluorotitanic acid and hexafluorosilicic acid.

9. A metal surface treatment process comprising spraying a solution as defined in any one of claims 1 to 8 on said surface.

10. The method of claim 9, further comprising the step of pretreating the metal surface.

11. The method of claim 10, wherein the pre-processing step comprises the steps of, in order:

-alkali degreasing of said surface, then nitric descaling of said surface, and then hydrofluoric descaling of said surface, or

-alkali degreasing of the surface and derusting of the surface with sulphonitroiron, or

-alkaline degreasing of the surface followed by sodium alkaline etching of the surface under an optional ultrasonic field.

12. The method of any one of claims 9 to 11, wherein the metal surface is comprised of aluminum or an aluminum alloy.

13. A metal surface coating obtainable by a metal surface treatment process as defined in any one of claims 9 to 11.

14. A metal surface comprising a coating as defined in claim 13.

15. Use of a solution as defined in any one of claims 1 to 8 for the corrosion-inhibiting treatment of metal surfaces.

Technical Field

The present invention relates to a solution free of chromium in any oxidation state, a method for treating a metal surface comprising spraying the solution on such a surface, and a metal surface coating obtainable by said treatment method.

In the following description, reference numerals in square brackets ([ ]) refer to the list of references listed at the end of this document.

Background

Reducing the fuel consumption of aerospace products is an important issue for equipment manufacturers and aircraft manufacturers, as well as for engine manufacturers.

During the development of emerging materials, new aluminum-based alloys have been developed that are lighter.

However, aluminum and its alloys are susceptible to corrosion. For this reason, objects based on aluminium or alloys thereof must be protected from the external environment, which may lead to corrosion. It must be sprayed with a protective coating to protect the aluminum.

Most of the existing methods of corrosion protection employ compositions based on hexavalent chromium. Such compositions include, for example, chromium trioxide (CrO)₃) Potassium dichromate (K)₂Cr₂O₇) Sodium dichromate (Na)₂CrO₇) Or strontium chromate (SrCrO)₄) Hexavalent chromium, however, is classified as a prohibited hazardous substance by REACH (chemical registration, assessment, approval, and restriction) regulations, which aim to protect human health and the environment from chemical-related risks while promoting the competitiveness of the european union chemical industry. And therefore use has been prohibited after 2017.

Various treatments exist to protect aluminum alloys from corrosion and depend on the composition of the alloy: electrochemical deposition, anodic oxidation, chemical conversion, vapor deposition, sol-gel coating, or laser deposited coating. These different treatment processes are utilized on an industrial scale and the best processes are found to be anodic oxidation and chemical conversion processes. In particular, surface treatment by chemical conversion has several advantages, such as low cost, ease of use and compliance of the resulting protective layer with, for example, aviation regulations. In fact, in the aeronautical environment, the metal parts subjected to an anti-corrosion treatment should exhibit adhesion, colouring, electrical conductivity and fastness to the paints or varnishes subsequently used. In fact, paints or varnishes are often sprayed after conversion coating to improve corrosion protection. Tinting may enable visual inspection of the quality of the corrosion protection coating and represents a common component in certain customer specifications. Furthermore, adhesion between the coating and the metal surface is necessary.

Various types of treatment processes have been used for chemical conversion using solutions free of hexavalent chromium and are currently marketed. Typically, these are solutions based on trivalent chromium, also denoted by Cr (III) (J.T. Qi et al: "trivalent chromium conversion coating formation on aluminum, surface and coating techniques", 280(2015)317-329([1]) (ii) a W. -k. chen et al: "influence of chromium sulfate concentration and immersion time on the texture and corrosion protection of Cr (III) conversion coatings on aluminum alloys", surface science, 256(2010)4924-]) Such as sold by seideck corporation650, or Lanthanum 613.3 solution sold by the company Kevinya, or TCS sold by the company SOCOMORE.

Another alternative method of using hexavalent chromium-based compositions is to use solutions based on phosphate compounds (F. Andreatta et al: "addition of phosphate or copper nitrate in fluorotitanate conversion coatings containing silane coupling agents for AA6014 aluminum alloys", organic coating development, 77(2014)2107-, molybdenum or manganese (6), or rare earths, such as cerium (B. Valdez et al: "cerium-based conversion coatings improve corrosion resistance of 6061-T6 aluminum alloys", Corrosion science, 87(2014) 141-.

The advantages and disadvantages of the above solutions are listed in table 1. These advantages and disadvantages allow for the case where hexavalent chromium is not used.

TABLE 1 various types of coatings

The current solutions do not satisfactorily replace hexavalent chromium-based compositions. In fact, these solutions are not as effective in terms of corrosion resistance. On the other hand, for parts with complex geometries, i.e. parts containing inaccessible recesses and/or internal areas, such as internal pipes or containers, or for parts with size limitations, these solutions can cause dimensional changes or an increase in the side length of 1 or 2 microns. Such a variation is unacceptable in the field of aviation and the like.

The solution used for the chemical conversion uses a trivalent (III) chromium-based solution so that the coating has sufficient adhesion. However, the protection against corrosion achieved by these solutions does not meet the requirements of, in particular, aeronautical specifications. On the other hand, these trivalent (III) chromium-based solutions do not have corrosion resistance equivalent to hexavalent chromium-based solutions. Corrosion resistance can be evaluated by a test consisting in exposing a standard size sample to a salt spray for 168 hours. The results of this test for hexavalent chromium-based compositions, such as Alodine 1200, are approximately less than 2.5 pits per sample. By using650, the results vary depending on the grade of aluminum alloy being treated. For example, for 5000 and 6000 series aluminum alloys, a salt spray resistance of more than 168 hours is obtained, and therefore the corrosion resistance is satisfactory. For 2000 series aluminum alloys, by spraying650 can achieve satisfactory protection in a short time, i.e. a salt spray resistance of less than 168 hours. For 7000-series aluminum alloys, the corrosion protection was not qualified (salt spray resistance less than 100 hours) (C.Jambon: Light Metal Surface Finishing, A3TS, 12 months 3-4 days 2013, France Boolean ([11]]) (ii) a Frou, background of aviation productivity improvementIn particular, to meet REACH requirements, support GIFAS development in the surface treatment industry, aerospace valley surface treatment/DAS AMP, 2016, 3 months, 18 days, french totez ([ 12)])。

Only one permanganate ion-based solution is listed, but has not yet been identified ([11 ]). In addition, although solutions have been used for treating objects based on magnesium or magnesium alloys, it is noted that these solutions are not suitable for treating objects made of aluminum alloys or aluminum.

Accordingly, there is a real need for corrosion protection coatings that are free of hexavalent chromium to overcome these drawbacks, disadvantages and obstacles of the prior art.

Disclosure of Invention

Through extensive research, the applicant has developed a chromium-free corrosion protection, in particular in the form of a treatment bath for aluminium alloys, and a related treatment method.

The present invention therefore relates to a chemical conversion solution free of chromium and advantageously having good properties, namely:

good corrosion resistance, in particular a corrosion potential variation of the protected alloy with respect to the untreated aluminum alloy (Δ E) equal to +0.3V, Δ E +0,45V with an annual corrosion rate of less than 5 μm/year with respect to the coating obtained with Alodine 1200, whereas the annual corrosion rate can only be limited to around 15 μm/year when the protection is carried out with a liquid bath of Alodine 1200,

good fastness of the varnish and/or paint,

-no size limitation: the layer thicknesses obtained are between 1 and 2 μm, even less than 1 μm,

-obtaining a coloured and electrically conductive deposit: the color of the mixture is yellow-orange,

-self-healing properties.

The treatment of aluminium or aluminium alloy parts with the solution according to the invention advantageously makes it possible to:

oxidation of the surface of the aluminium alloy to form a thick protective layer,

formation of a material that may contain manganese oxide (MnO)₂(s), MnO (s)),

dealing with porosity problems encountered, e.g. with manganese dioxide (MnO) alone₂(s)) a layer of a polymer,

limiting the concentration of aluminium in the deposit due to the action of the aluminium complexing agent/agents,

-adding corrosion inhibitors to improve corrosion resistance.

-capturing potassium permanganate to give the deposit self-regenerating properties.

The invention is beneficial in the field of aviation (civil and military) affected by REACH regulations, in particular equipment manufacturers, aircraft manufacturers and engine manufacturers, and in the field where chemical transformation of hexavalent chromium is used, such as in the automotive, construction, municipal facilities industries.

Accordingly, a first object of the present invention relates to a solution free of chromium in any oxidation state, comprising:

-at least one oxidizing compound,

-at least one aluminium complexing agent,

at least one corrosion inhibitor compound, and

-a filling compound that may be required,

the pH of the solution is 1 to 5.

In the present invention, "solution" means a liquid composition into which a part containing aluminum or an aluminum alloy can be impregnated. The solutions of the invention are advantageously chemical conversion solutions, that is to say suitable for use in chemical conversion treatments, or can be used for the chemical conversion of aluminium and its alloys.

In the present invention, "aluminum alloy" means an alloy whose main component is aluminum. The alloy may also contain at least one other component selected from the group consisting of copper, silicon, magnesium, titanium and zinc. The mass percent of the at least one other component in the alloy may be between about 0.10% and about 21.00% by weight of the alloy. The aluminum alloy may be, for example, a 2000 series alloy (aluminum association, washington, d.c. 2006), such as a 6000 series or 7000 series alloy No. 2024 or 2618, such as alloy No. 7075 or 7175.

The solution of the invention may "comprise" or "consist of" the above-mentioned ingredients. If it "comprises" the listed components, it may comprise these components as well as other components, except chromium. If it is "composed" of these ingredients, it contains only the ingredients listed above, and no other ingredients.

In the context of the present invention, "free of any chromium in the oxidation state" means that chromium is completely absent in the solution according to the invention. In other words, it means that the solution according to the invention is completely free of detectable chromium in the oxidation state from-II to VI, in particular hexavalent chromium. The chromium ions may be in particular chromates or dichromates. Chromium-free may be due to the absence of added chromium-containing components, particularly hexavalent chromium, during the preparation of the solutions of the present invention.

The pH of the solution may be 1.0 to 5.0, border values included. It may be, for example, 1.2 to 4.8, or 1.5 to 4.5, or 2.0 to 5.0, or 2.2 to 4.8, or 2.5 to 4.5, or 3.0 to 4.0, or 3.2 to 3.8, inclusive. In one embodiment, if the pH of the solution changes beyond these values, the pH may be adjusted back to the indicated value, for example by adding a strong acid such as sulfuric acid (H)₂SO₄) To lower the pH, or a strong base such as potassium hydroxide (KOH) is added to raise the pH. Advantageously, a pH of around 4.0 allows to obtain optimum protection against corrosion, in particular Δ E ═ 0,3V with respect to the untreated alloy, that is to say without the coating formed by the solution of the invention.

In the present invention, "oxidizing compound" refers to any compound capable of obtaining at least one electron from another chemical substance during a redox reaction. The oxidizing compound in the solution according to the invention may be chosen from the group comprising permanganates, molybdates, persulfates and hydrogen peroxide, and mixtures thereof. Advantageously, the concentration of the oxidizing compound in the solution may be between 0.01 and 0.45mol/L, including the border values, for example between 0.05 and 0.40mol/L, or between 0.1 and 0.4mol/L, or between 0.2 and 0.3mol/L, including the border values.

In the case of permanganates or molybdates, the permanganate or molybdate ions contained in the solutions of the invention can be combined with any type of suitable counter ion, for example potassium permanganate (KMnO)₄) Or sodium permanganate (NaMnO)₄) And sodium molybdate (Na)₂MoO₄) Potassium molybdate (K)₂MoO₄) Or ammonium molybdate ((NH)₄)₂MoO₄). Advantageously, the first and/or second electrode means,permanganate ion is used because it is the manganese source, while molybdate ion is used as the molybdenum source.

In the case of persulfate salts, the persulfate ion can be peroxymonosulfate (SO)₅ ^2-) Or peroxodisulfate (S)₂O₈ ^2-). The persulfate may be selected, for example, from all known persulfate salts, and may be selected, for example, from the triple salts of ammonium persulfate, sodium persulfate, potassium persulfate, oxone and potassium monopersulfate.

In the present invention, "complexing agent" means any compound capable of reacting with metals, in particular aluminium and its alloys, and thus forming a soluble complexing compound. Advantageously, the aluminum complexing agent also acts as a corrosion inhibitor. It can therefore advantageously prevent or limit corrosion of metal parts, in particular aluminium and its alloys, with the exception of chromium ions. Corrosion can be evaluated by measuring the number of pits on the surface of the metal part at a given time and under given conditions. The desired property is that no craters are present after 168 hours when the salt spray test is carried out according to the ASTM B117 standard.

The aluminium complexing agent contained in the solution according to the invention may be a fluoride-containing salt or a mixture of fluoride-containing salts, an organic compound selected from gluconate, citrate, oxalate, acetate and formate, or any mixture thereof. The fluoride containing salt may for example be selected from hexafluorozirconates, hexafluorotitanates, hexafluorosilicates and any mixtures thereof. Among the gluconates, mention may be made, for example, of sodium gluconate, potassium gluconate, calcium gluconate or ammonium gluconate. Among the citrates, there may be mentioned, for example, sodium citrate, potassium citrate or ammonium citrate. Among the oxalates, sodium oxalate, potassium oxalate or ammonium oxalate may be mentioned. Among the acetates, sodium acetate, potassium acetate or ammonium acetate may be mentioned. Among the formates, there may be sodium formate, potassium formate or ammonium formate.

In the present invention, "corrosion inhibitor compound" refers to any compound that is capable of reducing the corrosion rate of a metal surface under normal use conditions. The corrosion inhibitor compound may be selected from the group consisting of rare earth salts, tungstates, vanadates, phosphates and salts of cerium, zirconium, titanium or silicon in valence III. These compounds may be added in small amounts, for example in a mass percentage of 0.1% to 5%, especially 0.5% to 4.0%, or 1.0% to 3.0%. A single corrosion inhibitor or a mixture of corrosion inhibitors may be used to improve the corrosion resistance of the coating.

In the present invention, "filler" means any compound that can avoid pore formation or thickness unevenness of the precipitate layer. The filler contained in the solution according to the invention may be a compound based on phosphate, phosphonate or polyphosphate ions or iron ions. Thus, the phosphate ions may be combined with any type of suitable counter ion. This may be, for example, potassium hydrogen phosphate or sodium hydrogen phosphate (KH)₂PO₄、K₂HPO₄、NaH₂PO₄Or Na₂HPO₄) Or phosphoric acid (H)₃PO₄). Advantageously, phosphate ions can be used as filler, that is to say, their function is to standardize the thickness and chemical composition distribution of the manganese and aluminium oxide layers formed, so as to make them more passive. The filler may also be iron (Fe) sulfate₂(SO₄)₃) Iron chloride (FeCl)₃) Potassium ferricyanide (K)₃Fe (CN)6), iron salts of the type of ferric gluconate or ferric oxalate. In the solution of the invention, the concentration of the filler may be between 0.001 and 0.20mol/L, including the boundary values, in particular 0.010 to 0.18mol/L, or 0.050 to 0.18mol/L, or 0.08 to 0.18mol/L, or 0.10 to 0.15mol/L, including the boundary values.

For example, the chemical conversion solution of the present invention may be a solution having the following composition:

-the oxidizing compound is potassium permanganate,

-fillers, if any, being compounds selected from potassium hydrogen phosphate, phosphoric acid or iron salts, and

the complexing agent is a mixture of hexafluorozirconic acid, hexafluorotitanic acid and hexafluorosilicic acid.

In the solution according to the invention, the concentration of permanganate ions can be between 0.01 and 0.45mol/L, including the boundary values. The concentration may be, for example, between 0.05 and 0.40mol/L, or 0.1 to 0.4mol/L, or 0.2 to 0.3mol/L, inclusive.

In the solutions of the invention, the concentration of phosphate ions may be between 0.001 and 0.20mol/L, border values included. The concentration may be, for example, between 0.010 and 0.18mol/L, or 0.050 and 0.18mol/L, or 0.08 and 0.18mol/L, or 0.10 and 0.15mol/L, border values included.

In the solutions according to the invention, the concentration of the complexing agent may be between 0.001 and 0.15mol/l, including the border values. The concentration may be, for example, between 0.005 and 0.15mol/L, or 0.010 and 0.15mol/L, or 0.05 and 0.15mol/L, or 0.08 and 0.12mol/L, inclusive.

Another object of the invention relates to a metal surface treatment method or a metal surface coating comprising spraying the solution as defined above onto said surface. The treatment may be, for example, an anti-corrosion treatment.

The method may further comprise at least one step of pre-treating the surface. Thus, the method of the invention may consist of a single or a series of pre-treatment steps followed by a step of treatment with the solution of the invention.

The pretreatment step may be of the following type (1), (2) or (3), comprising the following steps in sequence:

(1) alkali degreasing the surface, then nitric acid derusting the surface, hydrofluoric acid derusting the surface,

(2) alkali degreasing the surface and derusting the surface with iron sulphonitrode, or

(3) The surface is alkali degreased and then sodium alkali etched under an ultrasonic field or without an ultrasonic field.

Each type of pretreatment (1), (2), or (3) may include or consist of: immersion was carried out in a liquid bath maintained at a stable temperature for a prescribed time, followed by two successive rinses with deionized water.

The surface treatment may comprise or consist of: in a bath maintained at a stable temperature, comprising or consisting of the solution according to the invention, immersion is carried out for a defined time and then two successive rinses with deionized water.

The concentrations of the various substances during the preparation of the bath of the conversion solution may be as specified in the definition of the solution according to the invention as described above. For example, the ion concentration may be as follows:

-MnO₄ ^-the concentration of ions may be equal to 0.01-0.45mol/L,

-H₂PO₄ ^-the concentration of ions may be equal to 0.05-0.2mol/L,

-H₂ZrF₆the concentration of ions may be equal to 0.005-0.1mol/L,

the concentration of Ce (III) ions may be equal to 0.003-0.3mol/L,

this may correspond, for example, to the initially added mass, which is approximately:

potassium permanganate (KMnO) at 1.5 to 75g/L₄)，

-5 to 30g/L of potassium hydrogen phosphate (KH)₂PO₄)，

1.4 to 27ml/L of 50% hexafluorozirconic acid,

1 to 10g/L of cerium III nitrate.

In the method of the present invention, the object to be treated may have a metal surface made of aluminum or an aluminum alloy.

Advantageously, a coating can be formed on a metal surface by the method of the present invention.

Therefore, another object of the present invention relates to a metallic surface coating, obtainable by a surface treatment process as defined above. Advantageously, the coating of the invention may be a compact layer, less than 1 μm thick and having adhesion for spraying of varnish or paint. Advantageously, other characteristics of the coating may be all or part of the following:

-is visibly, uniformly colored, free of defects,

continuous, uniform, adherent, uninterrupted (cracks, holes, etc.), free of flying powder, smooth and recognizable (i.e. coloured or easily marked),

has a perfect temperature resistance up to 80 ℃ without deterioration,

salt spray resistance of at least 168 hours, 1.5 pits/dm²No pits with the diameter larger than 0.8mm exist after 168 hours,

layer weight of 0.42g/m²To 1.2g/m²In the above-mentioned manner,

good dry and wet adhesion to any corrosion resistant primer,

insoluble in alcohol, water and solvent, but soluble in alkaline products and strong acids,

-electrical continuity of less than 5000 μ Ohms/inch2 in the initial state and not more than 10000 μ Ohms/cm2 after 168 hours of exposure in salt spray.

Another object of the invention relates to a metal surface, in particular an aluminium or aluminium alloy surface, comprising a coating as defined above.

Another object of the invention relates to the use of a solution as defined above for treating metal surfaces, in particular surfaces of aluminium or aluminium alloys.

The treatment may be selected from:

a- (preventive) anti-corrosion treatment,

-a pre-treatment of the paint spraying,

-local repair of the coating of the treated part,

-filling of the anodized part.

Other advantages will be better understood by those skilled in the art from the following examples.

Detailed Description

Example 1: preparation of the chemical conversion solution of the present invention

The chemical conversion solution is prepared by dissolving several kinds of potassium permanganate salt, potassium hydrogen phosphate salt, cerium nitrate salt and hexafluorozirconate in water in the following proportions:

potassium permanganate (KMnO) at 1.5 to 75g/L₄)，

-5 to 30g/L of potassium hydrogen phosphate (KH)₂PO₄)，

1.4 to 27ml/L of 50% hexafluorozirconic acid,

1 to 10g/L of cerium III nitrate.

The preparation was carried out at 60 ℃ and the total dissolution time of the salt was about 1 hour.

Example 2: treatment of aluminum or aluminum alloy metal surfaces with the chemical conversion solution of the present invention

The method for processing the aluminum or aluminum alloy part comprises the following steps:

-immersing the piece for a few minutes (2-6 minutes) in an alkaline degreasing bath selected from the various solutions available in surface treatment plants,

rinsing in a neutral bath and then in a bath of deionized water,

-dipping the parts in an acidic rust-removing bath available in a surface Treatment (TS) plant for a few minutes (2-6 minutes),

rinsing in a neutral bath and then in a bath of deionized water,

immersion in the bath of chemical conversion solution according to the invention for a period of 2 to 10 minutes, depending on the alloy to be treated,

rinsing in a neutral bath and then in a bath of deionized water.

List of references

1. J.t.qi et al: "formation of trivalent chromium conversion coating on aluminum, surface and coating techniques", 280(2015) 317-.

2. W. -k. chen et al: "influence of chromium sulfate concentration and immersion time on the structure and corrosion protection properties of Cr (III) conversion coatings on aluminum alloys", surface science, 256(2010) 4924-.

3. Andreatta et al: "addition of phosphate or copper nitrate in fluorotitanate conversion coatings containing silane coupling agents for AA6014 aluminum alloys", organic coating development, 77(2014) 2107-2115.

4. B. valdez et al: "cerium-based conversion coatings improve the corrosion resistance of 6061-T6 aluminum alloy," science of corrosion, 87(2014) 141-149.

5. H.r.asemni et al: "zirconium conversion coating effect: adhesion and corrosion protection characteristics "of epoxy organic coatings containing zinc aluminum polyphosphate (ZAPP) pigments on mild steel organic coatings, organic coating development, 94(2016) 18-27.

6. Santa Coloma et al: "inorganic salt (Zr/Ti/Mn/Mo) based chromium-free conversion coatings for aircraft aluminum alloys", applied surface science, 345(2015) 24-35.

7. F.o.george et al: "formation of zirconium-based conversion coatings on aluminum and aluminum-copper alloys," science of corrosion, 65(2012) 231-.

8. Campastrini et al: "formation of a cerium-based conversion coating on AA 2024: microstructure-related, surface and coating techniques ", 176(2004) 365-.

9. P.d.deck et al: "investigation of fluoride acid-based conversion coating on aluminum surface, organic coating development", 34(1998) 39-48.

10. Nordlien et al. : "formation of zirconium-titanium based conversion layers on AA 6060 aluminum", surface and coating technique, 153(2002) 72-78.

11. C, jambon: light Metal Surface Finishing (Light Metal surfacing), A3TS, 12 months, 3-4 days 2013, boolean, france.

12. Frou, in the context of the improvement of aeronautical productivity, in particular to meet REACH requirements, supports the GIFAS development of the surface treatment industry, aerospace valley surface treatment/DAS AMP, 2016, 3 months and 18 days, france totez.