DD290225A5 - METHOD FOR PREAMBING METAL SURFACES FOR METAL-NON-METAL COMPOUNDS - Google Patents

Abstract

The invention relates to a method for the pretreatment of Metallloberflaechen for edge gap-free metal-non-metal compounds, preferably for metal-plastic compounds, by means of coating technology, in particular for the purpose of corrosion protection of the metal component. According to the invention, the process for the pretreatment of metal surfaces for metal-nonmetal compounds is a combination of the process steps known per se {metal surface pretreatment; Metal-non-metal compound; Metal-plastic compound; electrochemical corrosion; corrosive pretreatment; flame pyrolysis; coating; silane coupling agent; edge gap free connection}

Description

Field of application of the invention

Field of application of the invention is the production of metal-non-metal compounds, preferably for metal-plastic compounds, by means of adhesive and coating technology, in particular for the purpose of corrosion protection of the metal component.

Characteristic of the known technical solutions

There are a large number of technical solutions for the pretreatment of metallic surfaces for the realization of metal-plastic composites.

A proven technology of surface retention is sandblasting. This involves roughening and activating the surface areas.

In extension of this process was z. B. in the dental and implant surgery area, the necessary roughening or enlargement of the surface by metal nets and lattice-like structures, as described in DE-OS3611404. This process for enlarging the surface is labor-intensive and material-consuming. In addition, the microstructures of the metal surface are not taken into account. The adhesive strength of the composite systems to be achieved with the conventional methods is too low.

With the new thin-film technologies CVD, PVD, laser coating, flame pyrolysis, new possibilities of designing a metal-non-metal composite were also considered.

The above-mentioned conventional methods (sandblasting, application of metal meshes and lattice-like structures) serve on the one hand the metal pretreatment for the new thin-film technologies, on the other hand they exist as independent technical solutions for the metal surface pretreatment. There are many patents for the above-mentioned methods, which are currently available.

already used. In particular, reference is made to the flame-pyrolytic coating according to DD-WP0169 522.

Although the metal-plastic composite produced as a result of the silicoate process described in this document has relatively good adhesive strength even under unfavorable thermal and chemical environmental conditions, it is still not optimal due to the poorly matched pretreatment methods for the metal surface.

Object of the invention

The aim of the invention is to increase the strength and the life of the connection between metal and nonmetal and thus to increase the utility of articles with non-Metallic metal compounds.

Explanation of the essence of the invention

The object of the invention is to provide a method for the pretreatment of metal surfaces, by which the production of jointless, marginal gap-free connections to the non-metal is made possible and thus high adhesive strengths can be realized even under unfavorable thermal and chemical conditions. According to the invention, the object is achieved by the combination of the process steps known per se

- Cleaning the metal surface

- corrosive pretreatment

- To wash

flame pyrolytic treatment of the metal surface according to DD-WP0169522 to form a silicon oxide-carbon layer

- Order of Silanhaftvermittler solved on the surface.

The cleaning of the metal surface is preferably carried out by sandblasting, because at the same time an improvement of the specific adhesion between the Meta'loberfläche and the later flame-pyrolytically applied silicon oxide-carbon layer is achieved.

The corrosive pretreatment takes place in an acidic or halogen-containing medium, preferably as an electrochemical treatment.

In the electrochemical surface pretreatment is carried out under the conditions known in the artl, wherein the metal to be treated serves as the anode. The duration of the electrochemical pretreatment depends on the metal to be corroded, the electrolyte and the process parameters. Electrolyte and process parameters are to be determined for each metal by controlling the metal surface. The criteria for the assessment of the metal surface are the degree of raking, the average roughness depth and the factor of the surface enlargement. The parameters mentioned can be determined according to generally known technical solutions.

The corrosive treatment increases the metal surface to be coated and thus improves the mechanical and specific adhesion.

The corrosively treated metals or metal surfaces are washed intensively, wherein ultrasound is preferably used to remove acid or corrosion residues.

The flame-pyrolytic coating of the metal surface with preferably tetraethoxysilane is carried out over a period of time in which a maximum of 5 pm thick silicon oxide-carbon layer is produced, to which a silane coupling agent is applied to the surface in the next step. The flame-pyrolytic coating is carried out according to process parameters according to DD-WP0169522.

The Silanhaftvermittler must be tuned in its functional groups in eggs production of metal-plastic compounds on thisrin. The silane coupling agent is applied by method steps known to the person skilled in the art by brushing or spraying at room temperature. The surface is wetted evenly.

In the process according to the invention, both the flame-pyrolytically applied layer and the silane coupling agent layer follow the corrosion-conditioned metal surface. Both layers bond seamlessly and free of margins to the resulting retentions of the metal surface.

Metal-plastic compounds with a metal surface pretreated according to the invention have the following advantages over metal surfaces pretreated by known processes:

- jointless, marginal gap-free composite material

Increasing the mechanical and specific adhesion of the metal surface pretreated according to the invention

- In a swelling of the plastic due to water absorption is a lesser decrease in the adhesion of the metal-plastic composite in the present invention pretreated metal surface at the same time higher absolute adherence of the metal-plastic composite

- Method according to the invention not only applies to composite technologies, but also to coating technologies application.

In example 1, the surprising effect achieved by the combination according to the invention of the known process steps is demonstrated.

Ausführungsheispiele

The invention will be explained in more detail by way of examples, without limiting it.

example 1

A process for surface pretreatment of a metal-plastic compound to be created by gluing, for example, begins by electrochemically corroding a previously sandblasted metal surface by a 5% HCL solution and at a constant current density of 400mA / cm ² . The metal surface to be prepared for the composite is used as the anode.

The experimentally determined corrosion time for a nickel-chromium-aluminum alloy of the trade name GISADENT NCA is 5 min. After this process step, the flame pyrolytic coating is carried out according to DD-WP0169522 with a Silicoatergerät the Firmal Triebsees. In this case, tetraethoxysilane is used as starting material. The coating duration is 5 min.

The pyrolytic decomposition of this material produces a max. 5 pm thick silicon oxide-carbon layer on the metal surface prepared according to the invention.

After a subsequent cleaning in the ultrasonic bath with distilled water, a methacrylate-containing silane coupling agent is subsequently applied by brushing or spraying. After the air drying of the same can be started with the application of Klubstoffes or plastic. Silane coupling agent and plastic must be coordinated with regard to their functional groups.

The above-mentioned sandblasting was carried out with a commercially available device.

For each metal or its alloy with a non-metal and / or metal, a specific electrolyte must be used for corrosive pretreatment.

Comparison table of the results of the method according to DD-WP169522 with the method according to the invention:

Control method Method according to DD-WP 0169622 according to the invention

Dry adhesion: 10MPa Dry: 15MPa

Unlock. Storage Type Wet: 4 MPa Wet: 10MPa

Relative reduction

the adhesive strength 60% 30%

Necessary sandblasting conditions to achieve equal adhesion Strah! Pressure: 4-5MPa jet pressure: 4-5 MPa

Beamtime ·. 1-3 min beam time ·. 1 min

Shot media:

Siliciumkorundder the silicon or

Particle size aluminum corundum the

50-250mm particle size <40 \ im

Example 2

Procedure as shown in Example 1, but with the following changes:

Metal: cobalt-chromium-molybdenum alloy

Electrolyte of corrosive

Pretreatment: H ₂ SO ₄ in the same concentration as Example 1

Example 3

Procedure as shown in Example 1 but with the following changes:

Metal (alloy): high-alloyed corrosion-resistant steel with the designation X10 CrNiTi 18.10

Example 4

The procedure is as in Example 3. However, the listed technology is not used for the production of an adhesive bond, but the production of coatings for the purpose of multiple corrosion protection with the help of the resulting duplex system: high-alloy steel - coating art? Toff.

Claims (8)

1. A method for the pretreatment of metal surfaces for metal-nonmetal compounds, characterized by the combination of the known process steps - Cleaning the metal surface - corrosive pretreatment - To wash flame pyrolytic treatment of the metal surface to form a silica-carbon layer - Application of silane coupling agent on the surface. 2. The method according to claim 1, characterized in that the cleaning of the metal surface takes place by sandblasting. 3. Process according to claims 1 and 2, characterized in that the corrosive pretreatment of the metal surface in acidic or halogenionhaltigem medium, preferably electrochemically, wherein the metal serves as the anode. 4. Process according to claims 1 to 3, characterized in that the corrosive pretreatment is carried out until the metal surface has a rugged relief shape, wherein the degree of rupture, the roughness and the factor of the surface enlargement serve as a criterion for the assessment, and the middle Roughness is more than 50 μπι. 5. Process according to claims 1 to 4, characterized in that the corrosively pretreated metals or metal surfaces are washed using ultrasound. 6. Process according to claims 1 to 5, characterized in that the flame-pyrolytic coating of the metal surface preferably with tetraethoxysilane, over a period in which a maximum of 5μιη strong silicon-carbon layer is generated takes place. 7. Process according to claims 1 to 6, characterized in that the flame-pyrolytic coating of the metal surface is carried out by a method known per se. 8. Process according to claims 1 to 7, characterized in that the Silanhaftvermittler is tuned in its functional groups in the production of metal-plastic compounds on the respective plastic.