DE10327365A1 - Metal objects with anti-corrosion coating, e.g. vehicle or machine parts, made by coating with a mixture of an aqueous sol containing nano-particles of a silica or metal oxide sol and an aqueous solution of blocked isocyanate - Google Patents

Abstract

A corrosion-proof coating for metals or metal alloys is obtained by coating with an aqueous mixture containing unmodified nano-particles of a silica sol and/or metal oxide sol in colloidal solution together with a blocked isocyanate and then drying, hardening and/or crosslinking the coating. Objects (MO1) made of metal or metal alloy with an anti-corrosion coating obtained by (a) applying an aqueous solution made by mixing (A) an aqueous sol solution containing nano-particles (not surface-modified) of at least one silica sol and/or metal oxide sol in colloidal solution with (B) an aqueous isocyanate solution containing at least one blocked isocyanate, and then (b) pre-drying, drying, hardening and/or crosslinking the coating. Independent claims are also included for (1) metal objects (MO2) with (i) an anti-corrosion coating made by method (a, b) as described above and (ii) a metallic or non-metallic layer on layer (i) (2) metal objects (MO3) with (i) an anti-corrosion coating as above and (ii) metallic or non-metallic layer(s) between the metal substrate and layer (i).

Description

The The present invention relates to an article containing at least a metal or metal alloy whose surface is wholly or partially a Anticorrosive layer has and its use.

Of the Corrosion protection plays an increasingly important role today Role, especially in view of the increasing demands the user to an even higher Fail-safety of mechanical or electrical equipment under extreme mechanical and weather-related influences.

Basically different one between the active corrosion protection, at which the electrochemical Basic reaction of corrosion as such should be suppressed, and the passive Corrosion protection, in which the object to be protected is made of metal and the corrosive agent through a corrosion protection layer mechanically be separated from each other.

Such Corrosion protection layers are well known. Very often, anticorrosive coatings will pass through Applying a metal (chrome plating, nickel plating), a conversion layer (Chromating, phosphating), a polymer layer or a Obtained enamel layer.

meanwhile Beyond the actual corrosion protection also other Requirements placed on the anti-corrosion layer: So should this Layers in particular an ever-increasing mechanical and chemical resistance exhibit.

These steadily growing demands on the part of the processing industry have caused that corrosion protection layers today not only from a homogeneous Material are manufactured, but that more and more hybrid systems or Multi-layer systems are used.

hybrid systems from an organic matrix and anti-corrosive pigments adequately known. In the process, with regard to the anticorrosive pigments distinguish three typical modes of action: On the one hand, pigments used with physical corrosion protection effect. They are chemical inert and are referred to as inactive or passive pigments, their mode of action is that they the diffusion paths for water, oxygen and corrosion-promoting Extend ions considerably and improve the surface adhesion of the paint and the coating. An example for such a passive corrosion inhibiting pigment is iron mica.

A another possibility consists in the use of pigments with chemical corrosion protection, the one certain solubility show and are able to control certain pH levels in the coating to stabilize. Such pigments are referred to as active. Your Mode of action is based on interactions in the interface region between pigment and substrate, pigment and binder as well as pigment and invaded foreign ions. This redox reactions can play, so that new protective Connections can arise. By soaping with the binder or neutralization of Acid degradation products remain in the coating a certain pH largely set. The corrosion-active ions are eliminated. An example is zinc oxide.

Of others are still pigments with electrochemical corrosion protection effect to name a passivating act on the metal surfaces to be protected. These anticorrosive pigments are judged according to whether they are effective in the "anodic region" or the "cathodic region". pigments the the dissolution prevent the metal by protective layer formation, as effectively designated in the anodic region. Pigments due to Their high oxidation potential prevents corrosion as effective in the cathodic area. Examples of anodic Range of effective pigments are phosphates, effective in the cathodic range Pigments are chromates.

Known are also anti-corrosive pigments from combinations of phosphates with borates or silicates (Ruf, J .: Inorganischer Metallschutz, Vincentz-Verlag, Hannover, 1993, in particular pages 248 to 289).

Especially problematic in terms of effective corrosion protection are objects that consist of magnesium or its alloys as well as diecast zinc.

at Magnesium and its alloys, which due to its low specific weight often used in the automotive, aerospace industry, the corrosion is due to various peculiarities.

For example, magnesium is often referred to as the "least precious metal", which indicates its high reactivity with water, and in addition, especially when mixed with steel, aluminum, etc., galvanic corrosion due to contamination of iron, nickel or Copper-induced local elements back is to feed. Furthermore, surfaces of magnesium or its alloys do not have sufficient self-passivation (such as in aluminum) but merely form a mechanically unstable oxide / hydroxide layer. Particularly frequently used, but unfortunately also particularly susceptible to corrosion magnesium alloys are the types Mg AZ 91 (die-cast alloy) and Mg AZ 31 (wrought alloy).

At the Zinc die-cast forms under corrosive conditions the so-called "white rust", which consists of a mixture of zinc oxides and hydroxides.

Especially problematic and vulnerable are zinc die-cast alloys, in particular ZK 410, compared to saline Media. Therefore, the corrosion of zinc die-cast parts is a special one big problem in the automotive industry.

A possibility For corrosion protection, for example, the chromating of objects Magnesium or its alloys. The appropriate procedures especially in the MIL specifications M3171 type I to type III described. Thereby become passivation Chromic acid or their salts used. Also, the use of sodium dichromate in combination with potassium permanganate is described (Dow Chemical Treatment, No. 22). The chemical passivation by means of chromium (VI) -containing aqueous passivation electrolytes is easy to perform. But this has the serious disadvantage that the chromate Substances that also contain in the formed conversion layers are, are carcinogenic.

Furthermore is also the phosphating of objects made of magnesium or its Alloys known (see Dow Chemical Treatment No. 18).

Indeed is the corrosion protection compared to a chromated layer much lower.

One in the most recent Past industrial often applied method for producing a chromate-free corrosion protection on magnesium objects is described in WO 00/56950.

there becomes a conversion layer by passivation of the article by means of an aqueous Passivierungselektrolyten produced, wherein the aqueous passivation electrolyte Potassium permanganate and at least one alkali or ammonium salt of a Anions from the group of vanadate, molybdate and tungstate contains.

Although this conversion layer for objects made of magnesium or magnesium alloy gives excellent corrosion protection, these are the results not on objects cast zinc die-cast, there according to this Procedure at all no conversion coatings can be obtained on zinc diecasting. costly Investigations have shown that the layer formed exclusively from the oxides and hydroxides of the alloying metals zinc, copper and aluminum consists, and does not have elements of the electrolyte used.

Under the term "conversion layer" is used here and in the following understood a layer that is not by order on a Surface, but by chemical conversion (conversion) of the metallic surface and various components of the aqueous passivating electrolyte is formed (see H. Simon, M. Thoma "Applied Surface Technology for metallic Materials ", Carl Hanser Verlag, Munich (1985) p. 4).

Further is known, essentially nanoscale particles in an organic, inorganic or organic / inorganic matrix. On this way you can special property combinations - such as transparency and wear resistance in coatings - by the use of nanoparticles can be achieved.

It is not known nanoscale particles to improve corrosion protection in hybrid systems for surface coating of metals.

One a major problem with the use of nanoscale particles is that these are not discrete by juxtaposition of the primary particles Particles, but predominantly present as agglomerates. Such agglomerates may have diameters of several thousand nanometers, so that the desired, Not achievable with the nanoscale nature of the particles associated properties are.

Therefore There has been no lack of proposals in the past, the agglomeration nanoscale particles by sometimes quite complicated production processes to prevent, so to the desired Property profile of the hybrid systems.

Indeed it is unknown until today, starting from available agglomerate-containing nanoscale Powders with reasonable effort agglomerate-free powder or powder preparations to create.

From the EP 0 637 616 A1 It is known to induce deagglomeration of the particles by milling dry nanoscale materials. The Agglomerates can be reduced in size to one sixth.

disadvantage However, the low space / time yield and the unavoidable contamination by abrasion from the co-used grinding aid.

When Alternative manufacturing processes have developed different methods in which, starting from low-molecular discrete or as z. B. Solen present synthesis blocks via a controlled growth process preparations with at least largely agglomerate-free nanoscale particles or composites can be made.

So can in the sol-gel process starting from Metal alkoxides by controlled molecular weight buildup of particles be produced, whose mean diameter is less than 50 nm. Such For example, systems are used as coating agents or material precursors (e.g., The Polymeric Materials Encyclopedia 1221 Vol 6, 4782-4792).

By high technical effort, usually with such manufacturing processes connected, are the so available Products only very limited use. Also, such methods only a limited selection of chemically different product classes applicable.

Nanoscale metal oxide sols are also known. Here and below, this definition means 30 to 50% strength colloidal solutions of metal oxides (Si, Al, Ti, Zr, Ta, Sn, Zn) in aqueous or organic media having average particle sizes of from 4 to approximately 60 nm. By electrically and / or sterically stabilizing the particle surfaces, it is possible to prevent such metal oxide sols from agglomerating. Particularly noteworthy are aqueous silica sols which can be prepared for example by ion exchange method from alkaline solutions (eg Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, Volume A23, VCH-Verlag, Weinheim, 1993, pp 614-629). Such products are commercially available, for example under trademarks such Levasil® ^® (Messrs. Bayer AG) or Klebosol ^® (Fa. Clariant). These nanoscale metal oxide sols consist of a colloidal solution of non-surface-modified nanoparticles.

"Non-surface modified" under the designation it is understood that the surface is not rendered hydrophobic by contacting it with reactive compounds (for example, by over Si-OH reactive compounds such as octamethylcyclotetrasiloxane, octyltrimethoxysilane, hexamethyldisilazane or dimethyldimethoxysilane). Examples of surface-modified products are Aerosil ^® R 102, R 202, R 805, R 812, R 962 or R 974 from Degussa.

In the EP-A 766 997 a process for the preparation of finely divided solid dispersions is described. By this method it is possible to achieve a comminution of suspended solid particles. A deagglomeration of primary nanoscale particles and their use in paint binders was not considered here. The process is known in principle as Düsendispergierverfahren and is used for other purposes such as. B. for the fine distribution of immiscible liquid phases, such as water in oil, already used industrially. The preparation of improved 2-component aqueous coating emulsions by means of finely divided emulsification can, for. B. according to the method of EP-A 685 544 respectively.

That's how it describes DE 198 11 790 A1 nanoparticle-containing transparent paint binders containing based on the paint solids 0.5 to 25 wt .-% of incorporated as a solid, primarily nanoscale particles prepared by jet jet dispersion of the nanoscale particles in the binder.

The DE 198 11 790 A1 indicates, however, that a particular disadvantage of disperse-dissolved nanoparticles such as silica sols or other metal oxide sols is the strong tendency for agglomeration, so that homogeneous incorporation into a foreign matrix such as a paint formulation is not readily possible. As a solution, it is proposed to allow a homogeneous incorporation into a paint formulation by modifying the surface of the particles and adapting the solvent, as described, for example, in US Pat EP 0 768 351 A1 is disclosed. However, this method is technically very complicated and only limited use.

The resulting layers are due to the addition of nanoscale Particles scratch resistant, one Influence on the corrosion resistance will not be reached.

task The invention is the provision of an article from a Metal or a metal alloy with an effective and chromate-free corrosion protection, the on objects made of aluminum, magnesium, steel and zinc diecasting alloys is. The corrosion protection effect of such a conversion layer should about it Be no worse than those of the known, chromated objects from magnesium or its alloys or known objects Die-cast zinc.

This Corrosion protection should be in thin layers be effective with a thickness of less than 10 microns and the contours of the object does not falsify.

• a) Aufbringen einer wässrigen Korrosionsschutzlösung, hergestellt durch Mischen einer wässrigen Sollösung, enthaltend in wässriger kolloidaler Lösung nicht oberflächenmodifizierte Nanopartikel mindestens eines Kieselsols und/oder Metalloxidsols, mit einer wässrigen Isocyanatlösung, enthaltend mindestens eine Isocycanatverbindung mit mindestens einer blockierten NCO-Gruppe; und
• b) anschließender Vortrocknung, Trocknung, Aushärtung und/oder Vernetzung der in Schritt a) aufgebrachten Schicht.

The object is achieved by an article containing at least one metal or metal alloy, the surface of wholly or partially a corrosion protection layer, the latter obtainable by

• a) applying an aqueous corrosion protection solution prepared by mixing an aqueous sol solution containing nanoparticles not surface-modified in aqueous colloidal solution of at least one silica sol and / or metal oxide sol, with an aqueous isocyanate solution containing at least one Isocycanatverbindung having at least one blocked NCO group; and
• b) subsequent predrying, drying, curing and / or crosslinking of the layer applied in step a).

• i. eine Korrosionsschutzschicht, diese erhältlich durch a) Aufbringen einer wässrigen Korrosionsschutzlösung, hergestellt durch Mischen einer wässrigen Sollösung, enthaltend in wässriger kolloidaler Lösung nicht oberflächenmodifizierte Nanopartikel mindestens eines Kieselsols und/oder Metalloxidsols, mit einer wässrigen Isocyanatlösung, enthaltend mindestens eine Isocycanatverbindung mit mindestens einer blockierten NCO-Gruppe; und b) anschließender Vortrocknung, Trocknung, Aushärtung und/oder Vernetzung der in Schritt a) aufgebrachten Schicht;
• ii. und mindestens eine, auf der Korrosionsschutzschicht befindliche metallische oder nichtmetallische Schicht

aufweist.The object described above is likewise achieved by an article containing at least one metal or metal alloy whose surface is wholly or partially

• i. a corrosion protection layer obtainable by a) applying an aqueous corrosion protection solution prepared by mixing an aqueous sol solution containing nanoparticles not surface-modified in aqueous colloidal solution of at least one silica sol and / or metal oxide sol with an aqueous isocyanate solution containing at least one isocyanate compound having at least one blocked NCO -Group; and b) subsequent predrying, drying, curing and / or crosslinking of the layer applied in step a);
• ii. and at least one metallic or non-metallic layer on the anticorrosion layer

having.

Corresponding of the present invention first objects are obtained, which are industrially widespread and particularly resistant to corrosion. At the same time, the objects according to the invention are mechanically highly loadable and fulfill the salt spray test according to DIN 50 021.

Furthermore is a significant feature of the layer according to the invention, that only very thin Layer thicknesses of the anti-corrosion layer are necessary to the meet these requirements. Are for example for the passive corrosion protection of particularly vulnerable magnesium alloy according to the state the technology still requires layer thicknesses of at least 30 μm, this is the case with the corrosion protection layer according to the invention a better corrosion protection already with a layer thickness of Corrosion protection layer of less than 5 μm achieved.

• i. eine Korrosionsschutzschicht, diese erhältlich durch a) Aufbringen einer wässrigen Korrosionsschutzlösung, hergestellt durch Mischen einer wässrigen Sollösung, enthaltend in wässriger kolloidaler Lösung nicht oberflächenmodifizierte Nanopartikel mindestens eines Kieselsols und/oder Metalloxidsols, mit einer wässrigen Isocyanatlösung, enthaltend mindestens eine Isocycanatverbindung mit mindestens einer blockierten NCO-Gruppe; und b) anschließender Vortrocknung, Trocknung, Aushärtung und/oder Vernetzung der in Schritt a) aufgebrachten Schicht;
• ii. und mindestens eine, zwischen dem Metall oder der Metalllegierung und der Korrosionsschutzschicht befindliche metallische oder nichtmetallische Schicht

aufweist.The object described above is likewise solved by an article comprising at least one metal or metal alloy, the surface of which is wholly or partly

• i. a corrosion protection layer obtainable by a) applying an aqueous corrosion protection solution prepared by mixing an aqueous sol solution containing nanoparticles not surface-modified in aqueous colloidal solution of at least one silica sol and / or metal oxide sol with an aqueous isocyanate solution containing at least one isocyanate compound having at least one blocked NCO -Group; and b) subsequent predrying, drying, curing and / or crosslinking of the layer applied in step a);
• ii. and at least one metallic or non-metallic layer located between the metal or metal alloy and the anticorrosion layer

having.

These embodiment concerns such objects, where the between the metal or the metal alloy and the Corrosion protection layer located metallic or non-metallic Layer alone neither the corrosion protection, nor the mechanical resistance reached.

In addition to the aforementioned advantages, such an article offers for the first time the possibility of producing completely UV-resistant, deep black and abrasion-resistant layers on aluminum. Although UV-resistant and deep black layers are known and are produced, for example, using antimony-containing electrolytes, such as those sold under the name "Black ^Magic® RT-A3" by Hubbard-Hall, the serious disadvantage that these black layers with By a pre-treatment of an object made of aluminum (for example, an optical component for projectors) with the antimony-containing solutions of the prior art, a brief intermediate drying, treatment with the corrosion protection solution described above and subsequent drying at 120 ° C for 30 minutes, an object is obtained, which meets both the mechanical stresses as required by the industry UV resistance.

In the on the corrosion protection layer be According to a particularly preferred embodiment, the sensitive metallic layer is a layer of a metal deposited without external current, in particular of copper, nickel and / or tin, or of its alloys.

Such deposited on the non-metallic corrosion protection layer metal layers are particularly well after that in the German patent application DE 103 17 795 A1 and DE 103 17 196 A1 produced method produced.

The non-metallic layer on the anticorrosion layer is advantageously available by film formation and / or crosslinking of a solution or dispersion containing at least contains a polymer.

According to one particularly preferred embodiment In the present invention, the metal is a barrier layer-forming Metal, in particular a light metal from the group of aluminum, Magnesium and titanium.

ever according to the field of application of the subject invention is this from a metal alloy, the at least one barrier layer-forming Contains metal. In particular, it is a light metal from the group of aluminum, magnesium and titanium, and most preferably around a kneading, casting or die-cast alloy of magnesium or aluminum.

Especially good usable magnesium alloys are AZ91, AZ81, AZ61, AM60, AM50, AM20, AS41, AS21, AE42, QE22, ZE41, ZK61 and AZ31, AZ60, ZK30, ZK60, WE43 and WE54 (designations according to ASTM).

It is according to another embodiment of the invention also possible that between the metal or the metal alloy and the corrosion protection layer a barrier layer containing at least one oxide of the metal.

These Barrier layer available its by a powerless, electrolytic and / or plasma-chemical process.

These Barrier layer has channel-like pores, which again to a improved adhesion of the corrosion protection layer on the metal to lead.

According to one particularly preferred embodiment In the present invention, the metal is selected from the group of Iron, zinc, tin, copper and silver.

Corresponding a likewise particularly preferred embodiment of the present invention Invention is the metal alloy selected from the group of steel alloys and zinc die cast alloys. As steel alloys are special cold rolled steels to name, for example SAE 1010. As Zinkdruckgusslegierung is especially to call ZK 410.

It but it is also possible that between the metal (or the metal alloy) and the Corrosion protection layer an additional Intermediate layer is the at least one oxide and / or phosphate of the Contains metal.

On this way you can already with a commercially widespread corrosion protection pretreated metallic workpieces be treated by applying the corrosion protection solution, without that the commercial one Corrosion protection layer must be removed.

Furthermore can known anticorrosion coatings that are directly on the metal, according to this embodiment cause a synergistic effect: Example meadow shows Object of magnesium, whose metallic surface with a conversion protective layer described in WO 00/56950 after treatment with the corrosion protection solution described above present invention, followed by predrying, drying, curing and / or crosslinking the applied corrosion protection layer best results, the not achieved with or without a conversion layer according to WO 00/56950 could become.

These Interlayer may be available be by an electrolytic and / or electroless method.

When electrolytic processes and as external powerless processes are suitable especially those who worked with chromic acid-containing electrolytes becomes.

According to one particularly preferred embodiment In the present invention, the isocyanate compound has no self-crosslinking Has properties, i. the isocyanate compound is not self-crosslinking.

Under The term "self-crosslinking" is used here and in the following, such isocyanate compounds understood themselves even more, opposite Reactive groups (such as hydroxyl groups) reactive with the isocyanate residues and to form intramolecular polymer networks react without the presence of other components.

In contrast, one distinguishes Iso cyanate compound having crosslinking properties: These are those compounds which react with an additional isocyanate-reactive group-containing component (also known by the term "binder") to form intermolecular polymer networks.

Such embodiments Make sure that the anticorrosive solution produced is an extreme has high processing time (pot life). So can with the corrosion protection solution accordingly Pot life of more than six months (at room temperature) of the invention be achieved. In addition to this advantage is further ensured that no cross-linked particles in the isocyanate solution (and thus in the corrosion protection solution) in a can form such a quantity that the adhesion between metal, barrier layer or interlayer and the corrosion protection layer is impaired.

Especially at objects from barrier-layer forming metals has the presence of crosslinked Particles with isocyanate function have a very negative influence on the Adhesive properties of the resulting corrosion protection layer.

Especially It is advantageous if the isocyanate solution in addition to the isocyanate compound no further film-forming and / or crosslinkable compounds contains.

hereby is effectively preventing cross-linked particles, in particular after a while Leave the corrosion protection solution to be formed.

All more preferably, the isocyanate solution is um a water-dilutable polyurethane dispersion, in particular with an equivalent weight between 900 and 1,200 and a theoretically calculated salary at blocked NCO groups between 3 and 8%.

Such isocyanate solutions are widespread, for example, under the trade name Bayhydur® ^® BL 5140 (Messrs. Bayer AG) as a hardener component in the paint industry.

advantageously, the isocyanate solution has one pH between 8 and 10.

In a further preferred embodiment In the present invention, the isocyanate solution has a non-volatile content Proportion according to DIN EN ISO 3251 (1 g / 1 h 105 ° C) between 15 and 25%. This ensures that by mixing the Sollösung and isocyanate available Corrosion protection solution by simple application methods, e.g. Diving or spraying) applied to the surface to be protected can be, with the resulting anti-corrosion layer - in addition the advantages described above - very uniform is, independent from the geometry of the object.

In a further preferred embodiment In the present invention, the isocyanate compound has no free ones NCO groups on.

By Choosing an appropriate output connection will be very easy It ensures that there is no formation of self-crosslinking or self-crosslinking particles (also known as "microgels" or "microparticles").

According to one also preferred embodiment of the present invention the sol solution and / or the isocyanate solution additionally non-metallic Particles, in particular of a size of less than 100 nm.

These embodiment in particular concerns such anticorrosion coatings, in addition to the corrosion protection yet another range of applications must meet.

The nonmetallic particles can a hardness have more than 1,500 HV and be selected from the group of Silicon carbide, corundum, diamond and tetrabor carbide.

Such non-metallic particles will always be selectable when the corrosion protection layer according to the invention high mechanical stresses, such as Abrasion, are exposed.

The nonmetallic particles can but also have friction-reducing properties and be selected from the group of fluoropolymers and polytetrafluoroethylene, PFA, molybdenum sulfide, cubic boron nitride and tin sulfide.

In In this case, the non-metallic particles impart the corrosion protection layer according to the invention Self-lubricating properties, the early mechanical wear of the subject invention counteract.

The nonmetallic particles can also have a photocatalytic activity and in particular to be from Anatas. Anatas is a tetragonal holohedral Modification of titanium dioxide.

In this case, a corrosion protection layer is obtained which, moreover, also has deodorizing properties. Applications for such items are especially kitchens devices and medical devices.

The sol and / or the isocyanate solution but can According to the invention also additionally metallic Contain particles.

These Metallic particles are in a preferred embodiment the present invention is not made of light metal or a light metal alloy, in particular have a size between 0.5 and 1 μm and are particularly preferably of copper and / or silver.

in the Contrary to the prevailing opinion, therefore the addition of copper particles the formation of local elements and thus the Promotes corrosion, leads the Presence of these metallic particles in the present case, that the corrosion protection is further improved, in particular at objects made of magnesium.

It but it is also possible that the sol solution and / or the isocyanate solution has a pH greater than 8 and that the metallic Particles of a light metal or a light metal alloy are, in particular a size between 0.5 and 10 μm and more preferably magnesium and / or aluminum. In the case of aluminum particles, the pH should not exceed 9 amount.

Also Here is the corrosion protection by these light metal particles improved again. Especially with steel objects this advantage to observe.

According to one also preferred embodiment of the present invention the sol solution and / or the isocyanate solution in addition one water-soluble Dye.

An especially in the context of the present invention to be used water-soluble dye is a metal complex dye, as for example, under the trade name of Neozapon ^® by the company. BASF, Orasol ^® by the company. Ciba-Geigy, Savinyl ^® by the company. Sandoz or Lampronol ^® from the company. ICI is sold.

In a further preferred embodiment of the present invention the sol solution and / or the isocyanate solution additionally a corrosion protection pigment, in particular with a physical corrosion protection effect.

Especially Suitable anti-corrosive pigments are iron mica, carbon black and graphite.

Corresponding a particularly preferred embodiment The present invention is the subject of the invention in the automotive industry, electrical and electronics industry, Mechanical engineering, aerospace used.

To In particular, parts of engines and gearboxes, instrument panels, doors and Parts thereof, steering gear housing, motorcycle wheels, throttle body, receiving devices for cutters, rotors or displacement housing for compressors, Sealing jaws for Packaging machines, parts for Power strips and electrical connectors, lamp holders, lamp housings, rotor housings of Helicopters, and housing for electrical Equipment.

Claims (29)

An article containing at least one metal or Metal alloy, its surface wholly or partly has a corrosion protection layer, the latter available by a) applying an aqueous Corrosion protection solution prepared by mixing an aqueous sol solution containing in water colloidal solution not surface-modified Nanoparticles of at least one silica sol and / or metal oxide sol, with an aqueous isocyanate, containing at least one Isocycanatverbindung with at least one blocked NCO group; and b) subsequent predrying, drying, curing and / or crosslinking the layer applied in step a). An article containing at least one metal or Metal alloy, its surface completely or partially i. a corrosion protection layer, this available through a) Applying an aqueous Corrosion protection solution prepared by mixing an aqueous sol solution containing in water colloidal solution not surface-modified Nanoparticles of at least one silica sol and / or metal oxide sol, with an aqueous isocyanate, containing at least one Isocycanatverbindung with at least one blocked NCO group; and b) followed by Predrying, drying, curing and / or crosslinking the layer applied in step a); ii. and at least one located on the anti-corrosion layer metallic or non-metallic layer having. An article containing at least one metal or metal alloy whose surface is wholly or partly i. a corrosion protection layer obtainable by a) application of an aqueous corrosion protection solution solution prepared by mixing an aqueous sol solution containing in aqueous colloidal solution not surface-modified nanoparticles of at least one silica sol and / or metal oxide sol, with an aqueous isocyanate solution containing at least one Isocycanatverbindung having at least one blocked NCO group; and b) subsequent predrying, drying, curing and / or crosslinking of the layer applied in step a); ii. and at least one metallic or non-metallic layer located between the metal or the metal alloy and the anticorrosion layer. Article according to claim 2 or 3, characterized that on the corrosion protection layer located metallic Layer one without external power deposited layer of a metal, in particular copper, nickel and / or tin, or its alloys. Article according to claim 2 or 3, characterized that on the anti-corrosion layer located non-metallic Layer by film formation and / or crosslinking of a solution or dispersion is that contains at least one polymer. Article according to one of the preceding claims, characterized characterized in that the metal is a barrier layer-forming metal, in particular a light metal from the group of aluminum, magnesium and titanium, is. Article according to one of claims 1 to 6, characterized in that the metal alloy comprises at least one barrier layer-forming metal, in particular a light metal from the group of aluminum, magnesium and titanium, and more preferably a kneading, casting or die-casting alloy Magnesium or aluminum is. Article according to claim 6 or 7, characterized that between the metal or the metal alloy and the anti-corrosion layer Barrier layer containing at least one oxide of the metal. Article according to one of claims 6 to 8, characterized that the barrier is available is by an external power, electrolytic and / or plasma-chemical process. Article according to one of claims 1 to 5, characterized that the metal is selected is from the group of iron, zinc, tin, copper and silver. Article according to one of claims 1 to 5, characterized that the metal alloy is selected is from the group of steel alloys and zinc die-casting alloys. Article according to claim 10 or 11, characterized that is between the metal or the metal alloy and the corrosion protection layer an intermediate layer containing at least one oxide and / or Contains phosphate of the metal. Article according to claim 2, characterized that the interlayer available is by an electrolytic and / or electroless process. Article according to one of the preceding claims, characterized in that the isocyanate compound is not self-crosslinking Features. Article according to one of the preceding claims, characterized characterized in that the isocyanate solution in addition to the isocyanate compound no further film-forming and / or crosslinkable compounds contains. Article according to one of the preceding claims, characterized in that the isocyanate solution is a water-dilutable polyurethane dispersion is, in particular with an equivalent weight between 900 and 1,200 and a theoretically calculated salary at blocked NCO groups between 3 and 8%. Article according to one of the preceding claims, characterized characterized in that the isocyanate solution has a pH between 8 and 10 has. Article according to one of the preceding claims, characterized characterized in that the isocyanate solution is a non-volatile Proportion according to DIN EN ISO 3251 (1 g / 1 h 105 ° C) between 15 and 25%. Article according to one of the preceding claims, characterized characterized in that the isocyanate compound no free NCO groups having. Article according to one of the preceding claims, characterized characterized in that the sol solution and / or the isocyanate solution additionally non-metallic Particles, in particular of a size of less than 100 nm, contains. An article according to claim 20, characterized in that the non-metallic particles have a hardness of more than 1500 HV and in particular are selected from the group of sili ziumcarbid, corundum, diamond and tetraborcarbid. Article according to claim 20, characterized that the non-metallic particles friction reducing properties and in particular are selected from the group of fluoropolymers and polytetrafluoroethylene, PFA, molybdenum sulfide, cubic boron nitride and tin sulfide. Article according to claim 20, characterized that the non-metallic particles have a photocatalytic activity and especially from Anatas. Article according to one of the preceding claims, characterized characterized in that the sol solution and / or the isocyanate solution additionally metallic Contains particles. Article according to claim 24, characterized that the metallic particles are not made of light metal or a Light metal alloy, in particular have a size between 0.5 and 1 micron and particularly preferably copper and / or silver. Article according to claim 24, characterized that the sol solution and / or the isocyanate solution has a pH greater than 8 and that the metallic Particles of a light metal or a light metal alloy are, in particular a size between 0.5 and 10 μm and more preferably magnesium and / or aluminum. Article according to one of the preceding claims, characterized characterized in that the sol solution and / or the isocyanate solution in addition one water-soluble Contains dye. Article according to one of the preceding claims, characterized characterized in that the sol solution and / or the isocyanate solution in addition Anti-corrosive pigment, in particular with a physical anti-corrosive effect, contains. Use of an article according to one of the preceding claims in the automotive industry, electrical and electronics industry, Mechanical engineering, aerospace.