JP2003505590A - Corrosion protection or post-treatment processes on metal surfaces - Google Patents

Abstract

  (57) [Summary] A method of anticorrosion treatment or post-treatment of a gloss-finished or phosphated steel, galvanized steel, galvanized steel, aluminum, or aluminum alloy, wherein the metal surface is brought into contact with an aqueous solution containing the following components. That is, it contains 0.05 to 10 g / L of a complex fluoride of boron, silicon, titanium and zirconium, and one or more selected from m-nitrobenzenesulfonate ion, N-methylmorpholine N-oxide and hydroxylamine Aqueous solution containing a phosphate formation promoter.

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention relates to anticorrosion treatment of the surface of steel, galvanized steel, galvanized alloy steel, aluminum or its alloys. This method can be used as an alternative to anticorrosion treatment before lacquering, for example iron phosphate treatment. This method is also suitable as a post-treatment of unlayered or layered phosphatized surfaces. Among other things, this method is suitable as a post-corrosion protection treatment for components made of phosphating metal, such as car bodies.

In such parts, the phosphate layer disappears or is damaged at the cut edges and at the rubbed areas. Therefore, the anticorrosion performance is inferior. When such a member is subjected to the anticorrosion treatment of the present invention, it reinforces the anticorrosion performance of the formed phosphate layer on the one hand and, on the other hand, the anticorrosion layer on the part where the phosphate layer is lost or damaged. To form. The parts are then lacquered.

BACKGROUND OF THE INVENTION It is already known to use solutions of complex fluorides as anticorrosion treatments or as post-treatments on metallic glossy surfaces or phosphated surfaces. For example, E
P-B-713540 comprises, as basic components, (a) titanium, zirconium, hafnium, silicon, aluminum, boron fluorometal anions, and (b) cations as selective components, such as copper, and (c). An aqueous treatment liquid for treating a metal surface containing an inorganic oxo anion and / or a phosphonate ion containing phosphorus and (d) a water-soluble or water-dispersible polymer is described.

WO 97/02369 treats aluminum surfaces containing (a) phosphate ions, (b) titanium ions or compounds of titanium, (c) fluorine ions or compounds containing fluorine, and (d) accelerators. The aqueous treatment liquid is described. In this case, the accelerator is an oxidizer selected from nitrite, nitrate, tungstate, molybdate, permanganate and water-soluble organic peroxide.

DISCLOSURE OF THE INVENTION The present invention is directed to bright finish or phosphatized surface steel, galvanized steel,
The present invention provides an anticorrosion treatment method or a post-treatment method applied to the surface of an alloy galvanized steel, aluminum or an alloy thereof, which is a method of bringing a metal surface into contact with an aqueous solution containing the following components.

[0006]   (A) One or more complex fluorides of boron, silicon, titanium and zirconium       0.05 to 10 g / L, and   (B) One or more phosphate formation promoters selected from the following       0.05-2 g / L of m-nitrobenzene sulfonate ion,       0.1-10 g / L free or bound hydroxylamine,       0.05-2 g / L of m-nitrobenzoate ion,       0.05-2 g / L of p-nitrophenol,       1-70 mg / L free or bound hydrogen peroxide,       0.05-10 g / L of organic N-oxide,       0.1-3 g / L nitroguanidine,       1 to 500 mg / L of nitrite ion,       Chlorate ion of 0.5 to 5 g / L.

This method of the present invention can be used, in one embodiment, as a corrosion protection method for glossy metal surfaces and for lacquering immediately after treatment or after extended shipping or inventory. . Although the conventional iron phosphate treatment without forming a layer is simple and exerts an anticorrosion effect, the present invention provides an alternative treatment to this method. On the other hand, the method of the present invention is also suitable as a layer-forming phosphating treatment or a layer-forming phosphating treatment after-treatment.

The present invention thus represents an alternative to the widely practiced post-treatment with liquids containing Cr (IV). The post-treatment method of the present invention is excellent in anticorrosion performance as compared with the conventional post-treatment method of a phosphate-treated metal using hexavalent fluorotitanate or hexavalent fluorozirconate. The present invention is particularly preferred as a post-treatment method for structural members manufactured using phosphinated metals such as car bodies. By the present invention, a portion of such a member where the phosphate layer is lost or a damaged portion is sufficiently protected from corrosion and lacquered.

When the post-treatment of the present invention is performed on the zinc phosphate layer, a zinc phosphate treatment liquid containing almost no nickel can be used. In such a case, as compared with the case where a phosphate treatment liquid containing nickel is used, problems such as poor lacquer adherence or poor corrosion resistance may occur. Such problems can be solved by using the present invention for post-processing. Therefore, when the present invention is used for the post-treatment, a phosphate treatment that does not contain nickel or contains little nickel can be performed. Phosphate treatment without nickel is advantageous in terms of wastewater treatment and sludge treatment, and thus the nickel-free method is advantageous.

In the present invention, a solution containing a complex fluoride of titanium and zirconium is preferably used. When the metal strip is treated by the non-immersion method, the concentration of complex fluoride is 1000 to 10000 mg / L. When the member is dipped after the treatment for a long period of time, the concentration of the complex fluoride is preferably 100 to 1000 mg / L, and particularly preferably 150 to 500 mg / L.

Phosphate promoting components (b) are known in layer-forming phosphate treatments, especially zinc phosphate treatments. These have the property of assisting in the formation of the desired finely crystalline, sealed phosphate layer. In the present invention, the following are particularly preferable as the component (b). That is, 50 to 1000 mg / L of m-nitrobenzene sulfonate ion, 1 to 10 g / L of organic N-oxide, preferably N-methylmorpholine N-oxide, 0.5 to 10 g / L, preferably 0.8. ~ 5 g / L free or conjugated hydroxylamine.

As the hydroxylamine, as it is or as a sulfate or phosphate thereof or a compound releasing hydroxylamine is used, and as it is or a sulfate is preferable. The equilibrium between free hydroxylamine and hydroxylammonium ion is adjusted as a function of the pH of the treatment liquid.

The effect of the anticorrosion treatment obtained by the treatment of the present invention is 0.1 to 50 mg / L in the treatment solution.
It is preferably enhanced by containing 1 to 10 mg / L of copper ion. These are added to the treatment liquid in the form of nitrate, sulfate or acetate.

Further, the addition of 0.2 to 2 g / L of phosphate ions will bring about the following benefits. That is, this type of additive does not prevent Fe (III) ions from becoming iron phosphate and transferring to the solution and precipitating during the treatment of iron-containing surfaces, thus preventing further continuation of the treatment.

Further, in the treatment of the surface containing iron or aluminum, it is 50 to 2000
Addition of mg / L, preferably 100 to 1000 mg / L of fluoride ion has an advantage that a complexing action with a metal occurs.

The treatment liquid may contain other metal ions. In particular, those known as the components of the treatment liquid for performing zinc phosphate and the components of the solution used for post-rinsing after the zinc phosphate treatment are preferable. Zn (II), Mn (II), Ce (III), Ca (II), Ni (
II), Ag (I), Pb (II) and the like are preferable. The concentration of these is preferably 0.3 to 3 g / L.

The pH of the treatment liquid of the present invention is preferably adjusted within the range of 2 to 5.5, and particularly 3
． 5-5 are preferable. If necessary, the pH can be lowered by adding a free acid to the solution, and when the acidity is too strong, it can be raised by adding an alkali metal hydroxide or alkali metal carbonate or ammonia.

The temperature of the processing liquid is 30 to 95 ° C. It is preferably 40 to 85 ° C. The treatment time, that is, the time from the start of contact between the metal surface and the treatment liquid to the time of drying or washing away the treatment liquid varies depending on the operation method. In the so-called no-rinsing treatment of a metal strip, in which the treatment liquid is brought into contact with the surface of the strip by a roller, spray, or immersion, and then the treatment liquid is squeezed, the treatment time is preferably 2 to 10 seconds. After that, the treatment liquid is dried in a drying oven without being washed away. In treating the part, the treatment liquid contacts the metal surface for 1 to 5 minutes. At this time, the metal surface is sprayed with the treatment liquid, or the component to be treated is immersed in the treatment liquid. The parts are then rinsed, preferably with deionized water.

In one embodiment of the present invention, a pre-phosphate-treated member selected from steel, zinc-plated steel, zinc alloy-plated steel, aluminum and aluminum alloy is subjected to anticorrosive post-treatment. Providing a process. At this time, the member is brought into contact with an aqueous solution containing the following.

[0020]   (A) One or more of complex fluorides of boron, silicon, titanium and zirconium       0.05 to 10 g / L, and   (B) One or more phosphate formation promoters selected from the following       0.05-2 g / L of m-nitrobenzene sulfonate ion,       0.1-10 g / L free or bound hydroxylamine,       0.05-2 g / L of m-nitrobenzoate ion,       0.05-2 g / L of p-nitrophenol,       1-70 mg / L free or bound hydrogen peroxide,       0.05-10 g / L of organic N-oxide,       0.1-3 g / L nitroguanidine,       1 to 500 mg / L of nitrite ion,       Chlorate ion of 0.5 to 5 g / L.

The above is also a preferred embodiment in processing the part. This embodiment takes into account the advances in the increased use of phosphate pretreated materials in the construction of cars and household appliances. The manufacturer is supplied with material in the form of strips. The manufacturer cuts the strips into plates, shapes, welds and folds to create the desired shape of the part. If the part is an automobile body, pre-phosphating material is used and re-phosphating is performed.

Household appliances made from pre-phosphated metal are cleaned after processing but are not re-phosphated. In the manufacture of cars, if the car body is made of pre-phosphating material and the necessary anticorrosion treatment before lacquering only requires cleaning and one-step post-treatment, expensive post-treatment phosphorus No need for a salt treatment plant. Heretofore, this type of process has been impossible because the pretreated phosphate layer has a damaged portion or the phosphate layer disappears at the edge or scraped portion during plate cutting. When galvanized steel is not used for car body parts, the anticorrosion performance of these parts is extremely insufficient.

According to this embodiment of the present invention, the existing phosphate layer is further reinforced with anticorrosion performance, and the part where the phosphate layer has disappeared or is damaged is provided with preferable anticorrosion performance. Become.

(Example) The method of the present invention was used for the anticorrosion treatment of a brightly finished and cleaned metal plate. After this treatment, lacquer coating was carried out and subjected to a corrosion test. Cold rolled steel (CRS) and electrogalvanized steel (EG) were used as treatment materials. The following processing was performed. 1. Ridoline 1250i, silicate- and phosphate-free alkaline cleanser (2%, 60 ° C, 5 minutes) 1. Washing with deionized water 3. Anticorrosion treatment shown in Table 1. The pH of the treatment liquid was adjusted to 4.2 with sodium carbonate. 4. Washing with deionized water 5.5 Drying with compressed air in a drying cabinet at 55 ° C 6. Lacker coating with cathodic electrodeposition lacquer Cathogard CG310 (BASF), containing no lead.

The metal plate was subjected to a 10-cycle weather resistance test based on VDA621-415.
The half width of the marking line is expressed in mm, and the creepage for the marking line is shown in Table 1. Furthermore, the VDA621-427 stone impact test was conducted. The adhesion of the lacquer is shown in Table 1 as a K value (1: highest value, 10: worst value). The metal plate of the comparative example was tentatively treated with the usual iron phosphate method (Duridine 7760, Henkel KGaA).

The treatment time was 4 minutes, and the treatment temperature was further tested at 40 ° C., 55 ° C., and 65 ° C., but the higher the treatment temperature was, the smaller the creepage was. The K value did not change.

When the treatment temperature was 55 ° C. and the treatment time was 0.5, 2, 4, 5 minutes, the creepage was small when the treatment time was long. The K value did not change.

Further, cold-rolled steel (CRS) is cleaned and activated by a usual method, subjected to phosphating treatment using a treatment solution for zinc phosphate containing no nickel, and post-passivation is performed by the method of the present invention. Then, the cathodic electrodeposition lacquer was coated as described above. This treated material was subjected to the same corrosion test.

Phosphate treatment was carried out by immersing for 4 minutes in a phosphate treatment liquid of the following components at 40 ° C.

[0030] Zn: 1.3g / L Mn: 0.8g / L H 2 PO 4 -: 13.8g / L SiF 6 2-: 0.7g / L hydroxylamine: 1.1 g / L free acid: 1 0.1 point (titration pH 3.6) Total acid: 24.0 points (titration pH 8.2).

The next cleaning process was carried out by immersing the treatment liquid at different temperatures for 4 minutes. As a result of the investigation, when the treatment time was 1 to 3 minutes, the value was superior to that when it was 4 minutes. For post-passivation, a solution containing hexafluorozirconate containing 100 ppm of Zr was used. The concentration of the accelerator (hydroxylamine) and the concentration of copper at that time are shown in Table 2. Table 2 also shows the results of the corrosion test.

[0032]

[Table 1] Processing parameters and corrosion test results

[0033]

[Table 2] Post passivation after phosphate treatment

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), AU, BG, B R, BY, CA, CN, CZ, HU, ID, IN, JP , KR, MX, NO, NZ, PL, RO, RU, SG, SI, SK, TR, UA, US, UZ, VN, YU, Z A (72) Inventor Combe, Peter             Germany, D-40724 Hilden Kuraray             Nbach Bake 3 F term (reference) 4K026 AA02 AA07 AA09 AA11 AA22                       AA25 BA03 BB08 CA23 CA28                       CA32 CA33 CA34 CA35 CA36                       CA37 CA38 DA03 DA06 DA09

Claims (12)

[Claims] 1. A steel, galvanized steel, bright-finished or phosphated,
A process of anticorrosion treatment or post-treatment in which an aqueous solution containing the following components is brought into contact with the surfaces of alloy galvanized steel, aluminum, and aluminum alloys. (A) 0.05 to 10 g / L of one or more complex fluorides of boron, silicon, titanium and zirconium, and (b) one or more phosphate formation accelerators selected from the following: 0.05 ~ 2 g / L m-nitrobenzene sulfonate ion, 0.1-10 g / L free or bound hydroxylamine, 0.05-2 g / L m-nitrobenzoate ion, 0.05-2 g / L p-nitrophenol, 1-70 mg / L free or bound hydrogen peroxide, 0.05-10 g / L organic N-oxide, 0.1-3 g / L nitroguanidine, 1-500 mg / L nitrite ion, 0.5 to 5 g / L chlorate ion. 2. The process of claim 1 wherein the aqueous solution contains (b) 0.05-1 g / L of m-nitrobenzene sulfonate ion. 3. The process according to claim 1, wherein the aqueous solution contains (b) 1 to 10 g / L of organic N-oxide, preferably N-methylmorpholine N-oxide. 4. The aqueous solution as (b) is 0.5 to 10 g / L, preferably 0.
The process of claim 1 containing 8-5 g / L free or bound hydroxylamine. 5. The aqueous solution is 0.1 to 50 mg / L, preferably 1 to 10 mg / L.
The process according to claim 1, further comprising L copper ions. 6. The aqueous solution further contains 0.2 to 2 g / L of phosphate ions.
The process according to claim 1. 7. An aqueous solution of 50 to 2000 mg / L, preferably 100 to 10
7. The process according to any of claims 1 to 6, further containing 00 mg / L of fluoride ions. 8. An aqueous solution containing Zn (II), Mn (II), Ce (III), Ni (II), Ag (
The process according to claim 1, further comprising a cation selected from I) and Pb (II). 9. The process according to claim 1, wherein the pH of the aqueous solution is 2-5.5, preferably 3.5-5. 10. The process according to claim 1, wherein the temperature of the aqueous solution is 30 to 95 ° C., preferably 40 to 85 ° C. 11. The process according to claim 1, wherein the metal surface is in contact with the treatment liquid for 2 to 10 seconds in the case of a no-rinse strip metal and 1 to 5 seconds in the case of a component. 12. A structural member made of a pre-phosphating material selected from steel, galvanized steel, zinc alloy plated steel, aluminum, and aluminum alloy is contacted with a treatment liquid containing the following components. A post-treatment process for anticorrosion of a structural member, which is characterized by: (A) 0.05 to 10 g / L of one or more complex fluorides of boron, silicon, titanium and zirconium, and (b) one or more phosphate formation accelerators selected from the following: 0.05 ~ 2 g / L m-nitrobenzene sulfonate ion, 0.1-10 g / L free or bound hydroxylamine, 0.05-2 g / L m-nitrobenzoate ion, 0.05-2 g / L p-nitrophenol, 1-70 mg / L free or bound hydrogen peroxide, 0.05-10 g / L organic N-oxide, 0.1-3 g / L nitroguanidine, 1-500 mg / L nitrite ion, 0.5 to 5 g / L chlorate ion.