DE19800035A1 - Joining of magnesium and plastic components especially of an automobile body - Google Patents

Abstract

A component (2) with a magnesium surface is joined to a component (1) with a plastic surface by a forge joining process and/or an adhesive bonding process. Independent claims are also included for the following: (i) a method of pretreating the joint region of one or more components prior to the above joining process; and (ii) a joined assembly produced by the above joining process. Preferred Features: The forge jointing process comprises clinching; riveting, especially with a galvanized steel rivet or a semi-hollow and/or plastic coated aluminum rivet; or screwing, especially with a self-tapping screw. A sealant may be used between the magnesium surface and the rivet or screw to prevent corrosion and an adhesive (4) may be provided around the rivet or screw perforation point. The components are pretreated by surface activation and/or cleaning using an organic solvent (especially acetone or MEK), an alkaline cleaner and/or a detergent/surfactant solution. The component (2) with a magnesium surface may be (a) pre-heat treated at 150-200 deg C; (b) mechanically cleaned by brushing (especially with fibers on which resin-bonded Al2O3 is applied), lapping, grinding, polishing or corundum grit blasting; (c) provided with an adhesion promoter which may be a phosphonic acid derivative and/or which is formed by anodizing in a solution of 8-hydroxyquinoline, a 8-hydroxyquinoline derivative containing a spacer to the polymer adhesive, caustic soda, phosphoric acid and/or sulfuric acid; and/or (d) subjected to a fluorozirconate and/or chromating pretreatment. The component (1) with a plastic surface may be pretreated by fluorination and/or low pressure plasma treatment.

Description

The present invention relates to methods for joining at least one joining partner, which has a surface made of a magnesium material at least in the joining area, and at least one other joining partner, who at least in the joining area Has surface made of a plastic, a method for pretreating at least the Joining area of at least one joining partner and a composite component from two or more joined partners, with at least one joining partner at least in Joining area a surface made of a magnesium material and at least one Joining partner has a surface made of plastic at least in the joining area. The In particular, the invention relates to joining methods for use in vehicle construction, especially in motor vehicle body construction.

Vehicles, in particular bodies of motor vehicles, have so far been predominant made of steel materials, especially sheet steel. For joining partners from Steel materials are therefore available in a wide range of well-tried varieties Joining processes, especially thermal joining processes such as welding etc.

More recently, in vehicle construction, particularly in vehicle body construction, also other materials and material combinations - such as aluminum or Plastics - used. Magnesium materials have also recently been found - d. H. Magnesium or magnesium alloys - increased use in vehicle construction.

As for joining partners with magnesium surfaces on the one hand and plastic surfaces on the other hand, there are hardly any joining methods known and little tested, so there is Task, improved method for joining at least one joining partner, the has a surface made of a magnesium material at least in the joining area, and at least one other joining partner, which has a surface at least in the joining area has to propose from a plastic. Under "Joining partner, who at least in Joining area has a surface made of a magnesium material "is both understood a joining partner who only made a surface from one in the joining area Magnesium material, as well as a joining partner, which also in other Areas or completely has a surface made of a magnesium material as  also and in particular a joining partner which consists of a magnesium material. Under "Joining partner who has a plastic surface at least in the joining area" is understood to mean both a joining partner who only has a surface in the joining area has a plastic, as well as a joining partner, which is also in other Areas or completely has a surface made of a plastic, as well and especially a joining partner, which consists of a plastic material.

The object is achieved by a joining process according to claim 1, by a joining process according to claim 2, by a joining method according to claim 14, by a Pretreatment method according to claim 49 and by a composite component according to Claim 51 solved. Developments of the invention are the subject of dependent claims.

The forming technology joining method according to claim 1, the combined forming-adhesive Joining method according to claim 2 and the adhesive bonding method according to claim 14 allow a secure, firm and long-term stable connection to be established, which also high requirements in motor vehicle body construction are sufficient.

Push-through joining (also pressure joining) is preferred as the forming technology joining process or called clinching), rivets and screwing, both individually and also in combination with each other.

Steel rivets and rivets made of an aluminum material are particularly suitable as rivets Question. In order to avoid problems due to contact corrosion when riveting, the choice is yours Pay special attention to the material of the rivets used. For steel rivets have proven their worth in zinc-coated steel rivets. With rivets plastic-coated aluminum rivets and / or rivets are made of an aluminum material made of aluminum alloys, their copper, iron and other content Magnesium alloys trace corrosion-promoting trace elements each below 1% lies. Aluminum rivets are generally preferable to steel rivets because they are lighter show less contact corrosion with magnesium alloys and later Recycling of the composite component produced according to the invention is less disruptive when further use of the magnesium recyclate obtained act. With regard to the Strength of the rivet against mechanical stress during or after However, rivets are inferior to steel rivets. To reduce or avoid Crevice corrosion can seal on all types of rivets or screws, for example glue can also be provided.  

In particular, solid rivets and / or semi-hollow rivets as well as come as rivet shapes Blind rivets in question. Blind rivets can also be used if the joining zone is only accessible from one side are used, while punch rivets provide double-sided accessibility to the joining area presuppose.

The at least two joining partners can also advantageously be screwed together get connected. In particular, self-tapping screws can be used here come that allow a particularly quick and economical processing. Regarding Similar considerations apply to the material selection of the screws as they did before the rivets were set out.

In tests by the applicant, it has proven particularly useful in terms of forming technology Joining processes such as clinching, riveting and / or screwing with an additional one Combine bonding of the joining areas of the joining partners. It showed up that at a z. B. strip-shaped, provided with adhesive joining area two Joining partners produce particularly strong connections if the enforcement joining points and / or rivets and / or screws not or at least not exclusively in the middle the z. B. strip-shaped adhesive application zone are arranged, but in the longitudinal side the edge areas of the z. B. strip-shaped adhesive application are arranged.

In principle, the at least two joining partners can also be made by pure Adhesive connections are joined together. Generally, however, have combined Push-through / rivet / screw / adhesive connections in attempts by the applicant highest static and dynamic strength values achieved.

The adhesive comes both for pure adhesive connections and for combined forming Adhesive connections prefer both adhesive based on polyurethane and adhesive Epoxy resin base in question. Epoxy-based adhesives enable high-strength bonds; they are therefore preferred e.g. B. used for structural parts of a motor vehicle body, where high strength is important. This can e.g. B. bonds with or with Body pillars or profiles.

Adhesives based on polyurethane, on the other hand, also enable elastic bonds larger joint gaps, since they have a better gap filling capacity. you will be therefore preferred for gluing to the body shell of a motor vehicle used, e.g. B. on the body roof. In addition, there are also adhesive tapes for an adhesive joint in question.  

In general, it has proven useful to have at least one joining partner with one surface at least in the joining area made of a magnesium material before joining one To undergo heat pretreatment at least in the joining area. The thermal Pretreatment typically takes place at 150 to 200 ° C. Through this Heat pretreatment is especially cracks and cracks when pressed or Penetration of the magnesium material through the clinching tool or through the rivets or reduced or avoided by the screws. Generally occur when riveting or screws cracks and cracks in the material to a lesser extent than with Assert.

Especially when using adhesives, both with pure Adhesive connections as well as combined forming-adhesive connections, it has proven that the joining partners at least in the joining area of a surface pretreatment subject. This surface pretreatment can serve the surface of the To clean joining partners at least in the joining area and thus better adhesion of the To enable adhesive on the joining partners in the joining area. Alternatively or additionally it can also serve to impart adhesion-promoting substances to the joining partners at least in the Apply the joining area in order to create favorable technical conditions on the joining surfaces to accomplish.

Various surface pretreatments were used in the applicant's experiments applied methods that are used individually or in combination can.

In general, pretreatment of at least the joining surfaces using solutions of cleaning-active substances - e.g. B. detergents and / or surfactants and / or an alkaline cleaning bath - and / or by means of organic solvents. In this way, greases, oils, dirt, dust and other surface contaminations that hinder optimal wetting of the surfaces to be joined by the adhesive can be reduced or removed. In tests by the applicant, acetone CH ₃ COCH ₃ and / or methyl ethyl ketone CH ₃ COC ₂ H ₅ have proven particularly useful as organic solvents. The cleaning effect of the preferably aqueous solution of cleaning-active substances or of the organic solvents can be significantly improved by an ultrasound treatment. Of course, the solutions of cleaning-active substances used and / or the organic solvents used are to be selected appropriately with regard to their compatibility with magnesium and in particular plastic surfaces.

Alternatively or in addition to the pretreatment of at least the joining surfaces by means of a Solution of cleaning-active substances and / or for surface pretreatment with organic solvents can be at least one joining partner with a surface at least in the joining area made of a magnesium material, in particular a mechanical one abrasive surface pretreatment is carried out at least at a later joining surface.

One possibility for this is brushing, rubbing, grinding, lapping or polishing at least the joining area of the at least one joining partner with a surface made of a magnesium material at least in the joining area. In tests by the applicant, brushing by means of a nonwoven made of synthetic Nylon® fibers, to which phenolic resin-bound aluminum oxide Al ₂ O _{3 is} applied, has proven particularly useful. Such brushes are commercially available from 3M under the name Scotch-Brite®. Because of the resilient mounting of the aluminum oxide abrasive grains on the Nylon® fibers, the roughness depths achieved are comparable in comparison with e.g. B. for grinding the joining surfaces much lower. The magnesium surface to be treated is cleaned thoroughly, but particularly gently, and roughened before joining, so that even thin parts can be processed with this method without changing the geometry of the joining surfaces and without excessively increasing the roughness of the joining surfaces. By varying the brushes used, different roughness depths can be easily set. By inserting components of the synthetic resin bond into the magnesium surface to be pretreated during brushing, a surface that is favorable in terms of adhesive technology is additionally generated. This effect can be exploited even better by using fibers instead of the conventional phenolic resin bond of the abrasive grains on the fibers of the commercially available Scotch-Brite® brushes, which have a synthetic resin system corresponding or similar to the adhesive used later - e.g. B. based on epoxy or polyurethane - to bind the abrasive grains.

As an alternative or in addition to brushing, grinding, polishing, rubbing or lapping, another mechanical abrasive pretreatment method can also be particle blasting of at least the area of a later joining surface of the at least one joining partner with a surface made of a magnesium material at least in the joining area. Compressed air blasting with high-grade corundum (GBEK) as the blasting medium has proven itself in tests by the applicant. The fine corundum specified as a blasting agent according to DIN 8201 consists mainly of aluminum oxide granules (Al ₂ O ₃ ). By influencing the blasting parameters, such as used blasting air pressure, blasting angle, blasting distance, composition of the blasting medium, grain shape and grain size of the blasting medium etc., the blasting process can be easily adjusted to the existing magnesium material joining partner and the desired blasting results.

Alternatively or in addition to the previously described surface pretreatment The joining partner can also move a chemical one, at least in the later joining area Activation pretreatment can be carried out.

In tests by the applicant, anodizing of the at least one joining partner who, at least in the joining area, has a magnesium Has surface, at least in the joining area. Anodizing is a process understood, by applying a voltage to the part to be pretreated a new surface layer on the part to be joined or at least on the area to be joined is formed. These layers are in aqueous electrolyte solutions with the help generated from an external power source, the workpiece being connected as an anode. Thereby the base material is converted and is due to the reaction of its metal material ions involved in the layer build-up with the electrolyte partner. By anodizing the Adhesion between the joining surface and the adhesive improved and the tendency to corrode of the metal material can be reduced.

In tests by the applicant, 8-hydrnoyquinoline solutions and / or 8-hydroxyquinoline derivative solutions, which contain a spacer for the polymeric adhesive or lacquer, and / or sodium hydroxide solutions NaOH / L and / or phosphoric acid solutions H ₃ PO ₄ / L have been used as anodizing agents and / or sulfuric acid solutions H ₂ SO ₄ / L.

Alternatively or additionally, as another chemical activation pretreatment also apply a solution of a phosphonic acid derivative as an adhesion promoter on at least one of the joining surfaces of the at least one to be connected a joining partner with a magnesium material surface at least in the joining area be performed.

As another chemical surface activation pretreatment process for the at least one joining partner with a magnesium material surface at least in A fluorozirconate pretreatment, at least its later, comes in the joining area Joining area in question. Fluorozirconate pretreatments are for other materials, especially steels, already known.

As an alternative or in addition, there is another chemical surface pretreatment Activation method also chromating at least the joining surface of the at least a joining partner with a magnesium material surface at least in the joining area in Question. Chromating is also already known for steel materials.  

All of these surface pretreatment processes can be used individually or in combination can be used together. For all surface Pretreatment procedures offer support either simultaneously or alternately ultrasound treatment.

Through the described surface pretreatment processes, at least the later ones Joining zone of the at least one joining partner with a magnesium material surface At least in the joining area, the main objectives are: the surface at least of the later joining area should in particular be compared to polymers (e.g. Adhesives and paints) can be activated. (This includes, for example, the removal of oils, Greases and dust as well as the removal of existing oxide layers on corroded Magnesium surfaces.) Contact corrosion should be reduced or avoided. On surface layers generated on the surfaces of at least the joining area and possibly Adhesives used should be formable, in particular thermoformable, and also temperature stable in the temperature range of paint and / or KTL immersion baths or drying ovens (i.e. to at a maximum of about 200 ° C), well adherent and storable even when weathered.

As a preferred chemical pretreatment process, at least later Joining area of the at least one joining partner with a plastic surface pretreatment by fluorination is used at least in the joining area. The Fluorination of plastic surfaces is described in detail in Articles G. Kranz, R. Lüschen, A. Pahl, O.-D. Hennemann; Surface activation of PE and PP with fluorine; Kleben & Dichten, 38 (1994) 6, pages 21-24 and O.-D. Hennemann, G. Kruger; Gas phase fluorination of plastics; Kunststoffberater 37 (1993) 3, pages 25-27 shown.

Alternatively or additionally, at least the joining area of the at least one Joining partner with a plastic surface at least in the joining area of a plasma Pretreatment process, especially a low pressure plasma Pretreatment procedures.

The surface treatment processes described at least one later Joining zone of the at least one joining partner with a plastic surface at least in the Joining areas essentially serve to activate the surface, at least later Joining area compared to adhesives and varnishes as well as the removal of oils and greases and dust.  

When using at least one joining partner with a surface made of one Magnesium material, at least in the joining area, can be castings, especially die-cast parts, but also around sheet metal parts, especially rolled sheet metal parts, or act on pressed parts, in particular extruded parts. Under "Magnesium Materials" both magnesium and magnesium alloys are understood.

When using at least one joining partner with a surface at least in Joining area made of a plastic material can be, for example act plate-shaped plastic part. There are both pure polymers as well Mixed polymers as well as fiber-reinforced polymers as plastics in question.

The joining processes are advantageous in vehicle construction, especially in automotive Body construction for joining body components. E.g. can they described method for joining a vehicle pillar or vehicle pillar component with a vehicle sill or a vehicle sill component, with a Vehicle side member or a vehicle side member component or with a Serve vehicle roof or a vehicle roof component. You can also for example for joining an internal vehicle side part or one internal vehicle side component with an external vehicle Serve side part or an external vehicle side part component.

The invention is described below using several exemplary embodiments, the with reference to the accompanying drawings.

In the accompanying drawings:

Figure 1 is a plan view of an overlap joint connection of two joining partners (in the breakout), a combined rivet-adhesive connection of the one joining partner made of a magnesium alloy with the other joining partner made of a plastic material being shown;

Fig. 2 is a cross section along line II of FIG. 1 by the joint connection of FIG. 1.

The joining tests were preferably carried out on plate-shaped samples made of plastic 1 or magnesium materials 2 with a thickness of 1.5 mm to 2.5 mm.

The standardized, commercially available magnesium material was predominantly used Magnesium die casting alloy AM 50 (MgAl5Mn) used. The composition of the According to the manufacturer, magnesium alloy is 4.50 to 5.30% aluminum Al, 0.28 to 0.50% manganese Mn, ≦ 0.20% zinc Zn, ≦ 0.05% silicon Si, ≦ 0.08% copper Cu, ≦ 0.001% Nickel Ni ≦ 0.004% iron and ≦ 0.01% other components per chemical element; of the The main ingredient is Magnesium Mg. In addition, the commercially available, standardized magnesium alloys AM 60, AZ 91 and AZ 31 are used.

The magnesium test plates were initially degreased in one Subjected to acetone bath at room temperature, while ultrasound (frequency 20 kHz to 40 kHz) to increase the cleaning effect of the acetone bath has been.

Some of the magnesium test specimens were then subjected to a mechanical abrasive surface pretreatment of the joining zones by brushing using standard Scotch-Brite® brushes. The brushes used consist of a fleece of Nylon® fibers, to which aluminum oxide Al ₂ O ₃ bonded by means of a phenolic resin is applied. Scotch-Brite® brushing was used to remove thin oxide layers (typically a maximum of 100 µm thick) with an almost constant roughness of the machining surface.

Another part of the magnesium material test specimens was blasted with compressed air using high-grade corundum grains in a dry blasting system. The fine corundum used as the blasting agent consisted of more than 95% aluminum oxide (Al ₂ O ₃ ) grains, had an average mohs hardness of 9, an angular grain shape and a grain size of 0.12 to 1.5 mm. The jet pressure was 8 bar, the distance 10 cm and the jet angle 90 °. The sample plates were then blown off with compressed air and again subjected to acetone immersion degreasing in an ultrasonic bath in order to remove loose adhering abrasive residues on the surfaces of the parts to be joined.

Part of the magnesium sample plates was subjected to a chemical activation pretreatment by means of a phosphonic acid derivative which has the ability to to form existing hydroxide groups with magnesium stable chelate complexes and can serve as an adhesion promoter. A 0.5- of the phosphonic acid derivative was % by weight aqueous solution with a pH value equal to 3. The previously with Magnesium samples degreased in the ultrasonic bath were then placed in the for 10 minutes Solution dipped, then rinsed with water and dried.  

Other magnesium material samples were subjected to chemical pretreatment by anodizing. For this purpose, the samples were first degreased in the acetone ultrasonic bath and then subjected to an alkaline cleaning in an alkaline aqueous solution of 50 grams per liter of sodium hydroxide NaOH and 10 grams per liter of trisodium orthophosphate dodecahydrate. The samples subsequently rinsed with water were then placed in the respective anodizing bath for 15 minutes at an anodizing current of 12 mA / cm ² . A stainless steel cathode was used as the cathode.

One of the anodizing baths was composed of an aqueous solution of 25 grams per liter of potassium dichromate K ₂ Cr ₂ O ₇ and 25 grams per liter of ammonium sulfate (NH ₄ ) ₂ SO ₄ . Other anodizing baths contained aqueous solutions of sodium hydroxide solution NaOH / L, phosphoric acid H ₃ PO ₄ / L, sulfuric acid H ₂ SO ₄ / L, 8-hydroxyquinoline and an 8-hydroxyquinoline derivative, which contained a spacer for the polymeric adhesive or varnish.

Following the treatment in the anodizing bath, the magnesium samples were taken with each Rinsed water and dried.

Other magnesium samples were subjected to fluorozirconate treatment in the joint area subject. The fluorozirconate process is a coating process from Chemetall using an NP bonder (the NP bonder C4740 was used). This chrome-free treatment product forms a conversion layer that increases adhesion and Infiltration resistance of paints (especially powder paints) improved.

Other magnesium material test specimens were subjected to chromating. As The chromating process was carried out using the NH 35 process from Norsk Hydro. The NH 35 process gives good passivation against corrosion as well as good Adhesion to organic coatings (e.g. adhesives and paints). Of the Treatment process was carried out as follows: first, the test specimens in an organic solvent bath and / or in an aqueous alkaline bath, optionally under Ultrasound support, cleaned. Then - if alkaline cleaning baths were used - rinsed with water and then 20 to Perform the chromate process for 30 seconds. In conclusion, the Test specimen again rinsed with water and dried.

Among other things, the plastic Tepex 201 from Du Pont was used as the plastic material (a carbon fiber reinforced thermoplastic polyamide plastic) used. Besides  thermosetting carbon fiber reinforced polyester and epoxy resin plastics Prototec company used.

Some of the plastic test specimens were subjected to chemical pretreatment Subject to fluorination. Another part of the plastic test grains became one Low pressure plasma pretreatment process.

The parts pretreated in this way were then added using various adhesives Glued together at room temperature.

A thermosetting, one-component epoxy adhesive based on Bisphenol-A and Bisphenol-F are used. Epoxy adhesives of this type are available under the Designation XW 1185 and under the designation XD 4600 from the company Ciba-Geigy, Basel offered commercially. The epoxy adhesive can e.g. B. in KTL immersion baths or Drying ovens of the automotive industry are cured.

As another adhesive, a one-component polyurethane adhesive was used, the commercially available under the name Tivo 9551/43 from Tivoli, Hamburg becomes.

The adhesive tests were partly immediately after the described Surface pretreatment process, sometimes even after several hours or Waiting for several days - sometimes with outside ventilation.

In some of the adhesive bonds produced, an additional forming joining by means of solid rivets, half rivets, Blind rivets and / or tapping screws performed. The used Rivets or screws consisted of either a particularly low-copper or low-iron content Aluminum alloy with a plastic coating, or with an ALMAC zinc Coated steel. Such ALMAC zinc coatings are in H. Kaesche, Die Korrosion der Metalle, Springer-Verlag 1990 described in more detail.

The clinching points, rivets 3 and / or screws has proved particularly suitable, not to be arranged in the middle of the adhesive agent application in the strip-shaped joining zone, but to attach the longitudinal side in the edge regions of the adhesive application zone (comp. Fig. 1 and Fig. 2). With regard to the adhesive portion of a rivet-adhesive connection or push-through adhesive connection or screw-adhesive connection of the two joining partners 1 , 2 , the strength of the adhesive connection by means of the adhesive 4 in the central region C of the strip-shaped joining zone 5 is optimal, while it is significantly lower in the edge areas A, B of the joining zone 5 . If one now arranges the rivets 3 , clinching joints and / or screws in these edge areas A, B of the strip-shaped joining zone 5 , they give the combined rivet-adhesive connection or clinching-joint connection or screw-gluing connection exactly in this by the adhesive 4 only weakly connected edge areas A, B a high bond strength.

This is the case in riveting tests carried out with the polyurethane adhesive Rivet element the "main joining process". That (compared to epoxy resin adhesives) with the Lower stiffness, well deformable polyurethane is predominantly used as Sealant, corrosion protection and damping material used. When using the stiffer Epoxy glue, on the other hand, acts as the "main joining process". The riveting here serves as Fixing aid and as relief for certain types of mechanical stress, especially with peeling loads.

In the experiments of the applicant, both pure forming joining methods and pure adhesive methods for joining at least one joining partner 2 , which has a surface made of a magnesium material at least in the joining area, and at least one joining partner 1 , which has a surface made of a plastic at least in the joining area, were found , proved to be suitable. The combined forming-glue-joining processes have proven to be particularly suitable because they are particularly strong, long-term stable and safe.

Claims (52)

1. A method for joining at least one joining partner ( 2 ), which has a surface made of a magnesium material at least in the joining region, and at least one further joining partner ( 1 ), which has a surface made of a plastic at least in the joining region, characterized in that the joining partners ( 1 , 2 ) are connected to one another by one or more forming joining processes. 2. The method according to claim 1, characterized in that the forming Joining process is combined with an adhesive joining process. 3. The method according to claim 1 or 2, characterized in that as forming joining method clinching is used. 4. The method according to any one of the preceding claims, characterized in that riveting is used as the forming technique. 5. The method according to claim 4, characterized in that a rivet for riveting a steel material, in particular a zinc-coated steel rivet, is used. 6. The method according to claim 4 or 5, characterized in that a rivet for riveting made of an aluminum material, in particular an aluminum semi-tubular rivet and / or a plastic-coated aluminum rivet is used. 7. The method according to claim 6, characterized in that the aluminum material Aluminum or an aluminum alloy is at most one percent by weight Contains copper Cu and / or iron Fe. 8. The method according to any one of claims 4 to 7, characterized in that for Rivets a punch rivet, in particular a punch rivet and / or a punch semi-rivet is used.   9. The method according to any one of claims 4 to 8, characterized in that for Rivets a blind rivet is used. 10. The method according to any one of the preceding claims, characterized in that Screwing as a forming technique, especially by means of tapping screws. 11. The method according to any one of claims 4 to 10, characterized in that between Rivet or screw and magnesium material to reduce or avoid Corrosion a sealant is used. 12. The method according to any one of claims 2 to 11, characterized in that clinching points or rivets ( 3 ) or screws are arranged in the edge regions of the adhesive arrangement ( 4 ). 13. The method according to claim 12, characterized in that the adhesive ( 4 ) is arranged in a strip shape and the clinching points or the rivets ( 3 ) or the screws are arranged longitudinally in the edge regions (A, B) of the strip-shaped adhesive application ( 4 ) . 14. A method for joining at least one joining partner ( 2 ), which has a surface made of a magnesium material at least in the joining region, and at least one further joining partner ( 1 ), which has a surface made of a plastic at least in the joining region, characterized in that the joining partners ( 1 , 2 ) are connected to each other by an adhesive joining process. 15. The method according to any one of claims 2 to 14, characterized in that as Adhesive an adhesive based on polyurethane is used. 16. The method according to any one of claims 2 to 15, characterized in that as An epoxy-based adhesive is used. 17. The method according to any one of the preceding claims, characterized in that at least one of the joining partners ( 1 , 2 ) is subjected to a pretreatment, in particular a cleaning pretreatment and / or a surface activation pretreatment, before the joining, at least in the joining area. 18. The method according to claim 17, characterized in that the at least one Joining partners with a surface at least in the joining area from one Magnesium material before joining a heat pretreatment at least in Joining area is subjected. 19. The method according to claim 18, characterized in that the heat pretreatment takes place at about 150 to 200 ° C. 20. The method according to any one of claims 17 to 19, characterized in that at least one of the joining partners before joining, at least in the joining area a liquid detergent is cleaned. 21. The method according to claim 20, characterized in that the liquid Detergent an organic solvent and / or an alkaline Detergent and / or a detergent / surfactant solution. 22. The method according to claim 21, characterized in that the organic solvent is acetone CH ₃ COCH ₃ and / or methyl ethyl ketone CH ₃ COC ₂ H ₅ . 23. The method according to any one of claims 17 to 22, characterized in that the at least one joining partner with a surface at least in the joining area a magnesium material before joining, at least in the joining area mechanical cleaning process, especially a mechanical abrasive Cleaning process. 24. The method according to claim 23, characterized in that the mechanical Cleaning process a brushing, rubbing, lapping, grinding and / or polishing in Joining area includes. 25. The method according to claim 24, characterized in that the brushing takes place by means of fibers to which synthetic resin-bonded aluminum oxide Al ₂ O _{3 is} applied. 26. The method according to any one of claims 23 to 25, characterized in that the mechanical abrasive cleaning method includes particle beams. 27. The method according to claim 26, characterized in that as the blasting agent Corundum from a compressed air jet is used.   28. The method according to any one of claims 17 to 27, characterized in that at least one of the joining partners before joining, at least in the joining area undergoes chemical pretreatment. 29. The method according to any one of claims 17 to 28, characterized in that before joining at least to the later joining area of the at least one Joining partner with a surface at least in the joining area from one Magnesium material an adhesion promoter is applied. 30. The method according to claim 29, characterized in that the adhesion promoter Phosphonic acid derivative is. A method according to claim 29 or 30, characterized in that the application of the bonding agent is done by anodizing. 32. The method according to claim 31, characterized in that with an 8-hydroxyquinoline solution and / or with an 8-hydroxyquinoline diene solution which contains a spacer to the polymer, and / or with a sodium hydroxide solution NaOH / L and / or with a phosphoric acid solution H ₃ PO ₄ / L and / or anodized with a sulfuric acid solution H ₂ SO ₄ / L. 33. The method according to any one of claims 28 to 32, characterized in that the at least one joining partner with a surface at least in the joining area a magnesium material before joining, at least in the joining area Fluorozirconate pretreatment is subjected. 34. The method according to any one of claims 28 to 33, characterized in that the at least one joining partner with a surface at least in the joining area a magnesium material before joining, at least in the joining area Pretreatment is subjected to chromating. 35. The method according to any one of claims 17 to 34, characterized in that the Cleaning or pretreatment before joining at least the joining area at least one of the joining partners is supported by an ultrasound treatment. 36. The method according to any one of claims 17 to 35, characterized in that the at least one joining partner with a surface at least in the joining area  a plastic before joining, at least in the joining area of a pretreatment is subjected to fluorination. 37. The method according to any one of claims 17 to 36, characterized in that the at least one joining partner with a surface at least in the joining area a plastic before joining at least in the joining area Plasma pretreatment, especially low pressure plasma pretreatment, is subjected. 38. The method according to any one of the preceding claims, characterized in that the at least one joining partner with a surface at least in the joining area a magnesium part is a casting, in particular a die-cast part. 39. The method according to any one of claims 1 to 37, characterized in that the at least one joining partner with a surface at least in the joining area a magnesium material is a pressed part, in particular an extruded part. 40. The method according to any one of claims 1 to 37, characterized in that the at least one joining partner with a surface at least in the joining area a sheet metal part, in particular a rolled sheet metal part, is a magnesium material. 41. The method according to any one of the preceding claims, characterized in that the at least one joining partner, the surface at least in the joining area has a magnesium material, consists of a magnesium material. 42. The method according to any one of the preceding claims, characterized in that the at least one joining partner with a surface at least in the joining area Plastic is a plate-shaped plastic part. 43. The method according to any one of the preceding claims, characterized in that the at least one joining partner, the surface at least in the joining area has a plastic, consists of a plastic. 44. The method according to any one of the preceding claims, characterized in that the process in vehicle construction, especially in motor vehicle body construction, is used.   45. The method according to claim 44, characterized in that the method for joining a vehicle pillar or vehicle pillar component with a vehicle sill or a vehicle sill component. 46. The method according to claim 44, characterized in that the method for joining a vehicle pillar or vehicle pillar component with a vehicle side member or a vehicle side member component. 47. The method according to claim 44, characterized in that the method for joining a vehicle pillar or vehicle pillar component with a vehicle roof or a vehicle roof component. 48. The method according to claim 44, characterized in that the method for joining an internal vehicle side part or an internal vehicle Side panel component with an external vehicle side panel or one external vehicle side part component is used. 49. A method for pretreating at least the joining region of at least one joining partner to prepare a joining at least one further join partner, wherein at least one joining partner (2) at least in the joining region, a surface of a magnesium material and at least one joining partner (1) at least in the joining area has a surface made of plastic having. 50. The method according to claim 49, characterized in that the method according to a of claims 18 to 48 is developed. 51. Composite component made of two or more joining partners ( 1 , 2 ) joined together, at least one joining partner ( 2 ) having a surface made of a magnesium material at least in the joining area and at least one joining partner ( 1 ) having a surface made of plastic at least in the joining area, characterized in that that at least two joining partners ( 1 , 2 ) are joined together by a joining method according to one of claims 1 to 48. 52. Composite component according to claim 51, characterized in that the composite component Is part of a vehicle, in particular a motor vehicle body.