DE3730862C2 - - Google Patents

Description

The invention relates to a layer material for the production of sliding elements with at least one Carrier layer and a functional layer metallic dispersion alloy in which the dispersed metal portion globular, sub microscopically distributed in the metallic matrix. Further The invention relates to a method for producing such a layered material.

The known layer materials of this type show in the Functional layer a more or less inhomogeneous structure on in some applications of such a layer material, especially with sliding elements, disadvantages be things. This inhomogeneity occurs with functional layers made of real metallic alloys by crystallization phenomena or recrystallization phenomena. Even more powerful and correspondingly more disadvantageous such inhomogeneity in functional layers made of dispersions alloy on. Because such dispersion alloys usually from metallic components with very different The heavier parts tend to be formed with weights for example lead in aluminum / lead dispersion alloys, strongly to segregation. So there have been many ways struck to use such dispersion alloys as possible fine and even distribution of the dispersed metal share in the metallic matrix. The for this attempts have largely failed, so that the functional layers known to date Dispersion alloy still far from a uniform fine Distribution of the dispersed metal components and first are quite far from a homogeneous structure. For dispersion alloys, the components of which are mixed these gaps will become significant larger because of the tempera in this mixture gap door of the melt mixture already separate the melt  Phases of the different mixture components disintegrate and - due to large difference in density or Weights of the individual components - in the melted Alloy a very rapid segregation and coagulation occur.

For the production of functional layers from such Dispersion alloys is for example from DE-OS 31 37 745 the formation of metal powders by atomization of a melt mixture and sintering this metal together powder on the carrier layer. This ver However, driving leads to a strongly inhomogeneous structure of the Functional layer.

From DE-AS 21 30 421 it is already a method for Manufacture of a composite metal strip known in which molten aluminum through an opening in the bottom of the Crucible passes through and molten lead in a thin, threadlike stream through the melted Aluminum also into the bottom opening of the enamel crucible is led. That in the bottom opening of the enamel crucible melt mixture of aluminum and lead is then whirled and mixed using gas jets and on the top surface of the substrate being passed blown. A functional layer formed in this way is still highly inhomogeneous, with the lead particles tend to be due to their much greater density Impingement of the swirling stream of melt mixture on the surface of the substrate to a large extent and to coagulate.

In a method known from DE-AS 22 63 268 a Melt mixture of lead and aluminum using an in Kind of a suction cup trained rotor in the form of fine Particles thrown off to the side and on a baffle quenched and solidified into scaly material.  

This scale-like material cannot be done without Apply heat and pressure to form a closed layer unite, again, segregation to a large extent occurs and excessive inhomogeneity of a so educated Functional layer leads.

PCT WO 87/04 377 is a layer material for the production of sliding elements with a Carrier layer and a functional layer known, however, the metal alloy of the Functional layer is not in the amorphous state located. The alloy band becomes medium Roll cladding applied, which is the disadvantage has that the fine when applying the tape Lead distribution is adversely changed. The Roll cladding leads to a line Arrangement of the lead in the aluminum, whereby the Plain bearing properties of the Aluminum-lead sliding layer essential is deteriorating.

From "Neue Werkstoffe" at METAV 86, 1986, p. 32, it is known to use metallic glasses such. B. Fe-B, Pt-Zr, Cu-Ti or Mg-Zn with cooling rates in the range from 10² to 10⁶ degrees per second.

In contrast, the object of the invention is a layered work fabric of the type mentioned in a simple, safe and easy-to-implement process while doing it the fine distribution of the dispersed metal component close to a homogeneous structure of the functional layer to improve.

This object is achieved in that the metal alloy of the functional layer in amorphous Condition is, or at least the metallic Matrix component of the dispersion alloy is amorphous and that the functional layer by ultrasonic welding, explosion welding, gluing or Soldering is attached to the carrier layer.

The functional layer is due to the invention amorphous state of their material with significantly ver better features. For example the strength of the functional layer is significantly increased. The Shear modulus is significantly lower than that of the corresponding ones crystalline alloys. The elasticity of the functional layer is increased significantly. Likewise, despite being extremely high Strength also the ductility and toughness of the functional layer improved. All of these improved properties come into their own when the functional layer is as Sliding layer is used. In such a case come under many possibilities, especially sliding layers made of aluminum / Lead dispersion alloys, for example those with lead proportion between 8% and 40% mass proportions, or also Lead bronze sliding layers into consideration. In any case then the lead portion is globular in the respective aluminum  matrix or copper matrix distributed.

For the production of the layered material according to the invention, a method is considered in which the melt mixture of a dispersion alloy with the desired alloy composition is poured out under high pressure to form a film strip and at a cooling rate of between about 10 ⁶ and about 10 ⁹ K / s while maintaining the amorphous state - at least the matrix component of the dispersion alloy - is quenched and in which the film strip thus formed is attached to the carrier layer by means of ultrasound welding, explosion welding, soldering or gluing while maintaining the amorphous state of its material. The implementation of this method can be carried out, for example, by spraying a fine jet of the melt mixture onto a rotating, forcibly cooled cylinder for the continuous formation of a film, the outer surface of this cylinder not being bound to the alloy melt or a component of the melt mixture. With this procedure, however, only the side of the film strip lying on the cylinder surface is cooled. However, if desired, the exposed surface of the film strip can also be cooled, for example by means of cold gas jets or cooled rollers. Another Her in the context of the method according to the invention provides that the film strip is formed by injecting one or more parallel fine jets of the melt mixture into a nip, the rollers being cooled and no binding to the alloy melt or a component of the melt mixture on their outer surfaces should come in.

It has been found that foil strips in this way several centimeters wide and about 0.5 mm thick and can be manufactured continuously, preferably  in a finished thickness of the intended functional layer. The method according to the invention can still be essentially improve if you look at that Melt mixture one or more crystallization inhibitors (Glass formers) in a total amount between about 0.2 to 2.0 wt .-% admixed. In the case of the formation of a functional layer come with aluminum or copper as the main ingredient for example silicon, boron, phosphorus, iron, cobalt, Titanium individually or as a mixture as a crystallization inhibitor (Glass former) into consideration.

The connection of the during the inventive method formed film tape with the backing is on in any case while maintaining the amorphous state in the material of the film strip. To do this comes a Plate the foil tape onto the backing with the help of ultrasonic welding or explosion welding in Consider. This is so with the backing layer Foil tape to be connected essentially made of aluminum, so can be an intermediate film made of pure aluminum between the Foil tape and the backing layer are bound to the Improve bond strength. The same can be done at the application of foil tape with the main component copper using an intermediate foil made of pure copper be considered. The foil tape can also can be attached to the carrier layer by soft soldering. The film tape can be well bonded to the backing layer can also be achieved by gluing, although to ensure this the heat conduction between the functional layer and the carrier layer of the adhesive more thermally conductive, especially metallic Filler, for example fine silver powder or copper powder, should be mixed. If necessary, one can Roll cladding to apply the film strip to the Carrier layer can be considered. In that case but there will be some crystallization process during do not avoid roll cladding in the foil strip.  

If on the one hand high bond strength between the Functional layer and the backing layer and on the other hand safe maintenance of the amorphous state in the material the functional layer are desired, it will Roll cladding is generally not recommended.

Embodiments of the invention are as follows explained in more detail with reference to the drawing. It shows

FIG. 1 is a greatly enlarged fragmentary sectional view of an inventive coating material to an embodiment;

Fig. 2 is a greatly enlarged fragmentary section through an inventive coating material to a second embodiment;

Fig. 3 is a schematic for a method of production of a foil strip of amorphous metallic material; and

Fig. 4 is a diagram for a modified manufacturing way for a film strip made of amorphous metallic cal material.

In the example of FIG. 1 is a layer of material 10 with backing layer 11 made of steel and functional layer 13 as a sliding layer of aluminum / lead dispersion alloy with a lead content of 8% by mass of 1% by mass of silicon as a crystallization inhibitor, balance aluminum. As can be seen from FIG. 1, lead particles 14 are dispersed in the amorphous aluminum matrix of the functional layer 13 in a globular, submicroscopically fine distribution. The silicon is dissolved as a "glass former" in the amorphous aluminum matrix.

In the example in FIG. 1, the functional layer 13 is attached to the carrier layer 11 by ultrasound welding.

In this example, a binding agent layer 12 made of pure aluminum is provided between the functional layer 13 and the carrier layer 11 .

In the example in FIG. 2, there is a layer of material 10 , the carrier layer 11 of which is made of steel and which carries a functional layer 13 of lead bronze. In this example, the functional layer 13 contains an amorphous copper matrix and in this globular, submicroscopically finely distributed lead particles 15 , of which only the larger lead particles appear in the illustration in FIG. 2, while the large amount of the lead particles in the one shown in FIG . 2 selected magnification not appear. Above all, Fig. 2 shows that in the amorphous copper matrix, the crystallization of copper that has been typical for lead bronze has been avoided.

In the example in FIG. 2, the functional layer 13 is glued onto the carrier layer 11 . In this example, the adhesive layer 16 which can be seen in FIG. 2 contains heat-conducting copper particles 17 which have been added to the adhesive in the form of a fine copper powder.

For the production of the layer material 10 , a film strip 20 is first formed from the metallic material selected for the respective functional layer 13 . Depending on the purpose of the functional layer, this metallic material can be a more or less pure metal. In general, however, a real metallic alloy or a metallic dispersion alloy will be chosen as the material for the functional layer. For functional layers 13 , which are to serve as sliding layers on sliding elements, lead / tin alloys, lead / tin / copper alloys, lead / tin-antimony alloys, etc., come into consideration, for example, on real metallic alloys. Dispersion alloys based on aluminum / lead, aluminum / tin, aluminum / bismuth, aluminum / antimony, copper / lead, copper / iron, lead / iron and others are also suitable. The respective genuine metallic alloy or metallic dispersion alloy can preferably also be mixed with a crystallization inhibitor or "glass former" in a total amount of between about 0.2 to 2.0% by weight. Depending on the type of metallic alloy or metallic dispersion alloy, silicon, boron, phosphor, iron, cobalt, titanium and others are suitable for this. The alloy or the dispersion alloy is melted and placed in a crucible 21 which has an outlet 22 at its lower end for a fine jet 23 of the melt. As indicated by arrow 24 , the crucible 21 is supplied with a pressurized gas from the top, which is inert to the melt and also dissolves as little as possible in the melt. The crucible 21 is surrounded in the examples shown by an induction coil 25 , with which the melt is kept at a predetermined temperature at which it is sufficiently liquid to be pressed through the outlet 22 and form a fine jet 23 . If a dispersion alloy is to be processed, the crucible 21 can additionally have stirring devices or vibrating devices which continuously mix the melt mixture of the dispersion alloy intensively and keep it in a fine distribution of its mixture components. These mixing devices or vibrating devices are not shown in FIGS. 3 and 4 for the sake of simplicity.

In the example of FIG. 3, the thin jet 23 of molten alloy or melt mixture of a dispersion alloy pressed out of the crucible strikes the surface of a strongly forced-cooled cylinder 26 . The angle ϑ is chosen so that the jet 23 is immediately distributed in the manner of a narrow band without lateral spraying or splashing back on the surface of the cylinder 26 . This band becomes thin like a film and very quickly cools to the film band 20 on the surface of the cooled cylinder 26 . The cooling takes place primarily from the cylinder 26 . However, in order to also intensively cool the exposed side of the film strip 20 , the example in FIG. 3 provides that 27 jets 28 of cold gas or cold liquid are directed onto the film strip 20 by means of a nozzle arrangement. After the film strip 20 has been taken along by the cylinder 26 for a predetermined distance, it is lifted off the latter by means of a knife-like strip pickup. The cooling speed of the film strip 20 on the cooled roller 26 under the action of the cooling jets 28 is above 10 ⁶ K / s up to about 10 ⁹ K / s. Accordingly, a real alloy, which forms the foil strip 20, is kept in an amorphous state. If a dispersion alloy with a mixture gap of its constituents is processed, the result is a film strip 20 in which the constituent part of the dispersion alloy is in the amorphous state, while the constituent dispersed in this matrix is globally, submicroscopically finely distributed in the matrix is.

In the operation according to Fig. 4, the melt of the functional layer 13 (Fig. 1 and 2) provided metallic alloy or the melt mixture is added a dispersion alloy in a crucible 21 and set in this corresponding to the arrow 24 by means of a gaseous medium under pressure. The crucible 21 allows the melt or the melt mixture to enter the roll gap 30 between two rolls 31 and 32 in a jet at its lower end 22 . Both rollers 31 and 32 are strongly forced cooled. The width of the nip 30 is set accordingly the desired thickness of the film tape 20 to be produced. As indicated in FIG. 4, a small accumulation of melt or melt mixture is formed in front of the roller gap 30 without any significant delay in the transfer of the melt or the melt mixture from the outlet 22 of the crucible 21 into the roller gap 30 . The two rollers 31 and 32 thus do not exert any appreciable pressure effect on the film strip to be formed, but only a certain smoothing effect on the surface of the film strip 20 that is created . Furthermore, due to the small accumulation of material at the nip 30, the melt or the melt mixture is distributed in the axial direction of the rollers 31 and 32 , so that film strips of greater width than in the example according to FIG. 3 can also be produced. In order to facilitate this axial distribution of the melt or the melt mixture along the roller gap 30 , the crucible 21 is arranged in an inclined position at an angle R in order in this way to directly pressurize the melt or the melt mixture in the crucible 21 into the roller gap 30 to inject.

The surfaces of the rollers 31 and 32 are designed so that they enter into virtually no bond with the molten alloy or one of the alloy components or one of the constituents of a dispersion alloy to be processed. In order to keep the film strip formed in the nip 30 on the surface of the roller 31 , the upper roller 32 is equipped with a tape remover 33 . In order to cool the film strip remaining on the surface of the roller 31 at the outlet of the roller nip 30 on the surface that is now exposed, a cooling nozzle 34 is first provided which directs a jet of cold gaseous or liquid medium against the outlet of the roller nip 30 . The remaining on the surface of the roll 31 side of the film tape 20 is further cooled by the cooling roll 31st

The cooling roller 31 is a third cooling roller 35 , which is strongly forced-cooled and to further cool the film strip 20 on the side quenched by the roller 32 and the coolant jet from the nozzle 34 . A fourth cooling roller 36 is provided behind the third cooling roller 35 and takes over the film strip from the roller 31 . To this end, the roller 31 is associated with a belt pickup 37 . In order to force an effective support of the film strip 20 on the upper surface of the fourth cooling roller 36 , a likewise cooled pressure roller 38 is juxtaposed with the fourth cooling roller 36 . The film strip 20 is then removed from the fourth cooling roller 36 by means of a strip remover 39 .

Compared to the operation of Fig. 3 is a further intensification of the cooling is in the example of FIG. 4 process made so that s s can be achieved on the foil strip cooling rates in size between 10 ⁸ K / to 10 ⁹ K / s. This results in the possibility of also producing foil strips of greater thickness, for example 0.5 mm thick, and so intensively quenching over their entire thickness that the amorphous state of the metallic material is frozen during the cooling process. Finally, the method of operation according to FIG. 4 also offers the possibility of producing wider foil strips, in particular if several crucibles 21 are arranged next to one another along the nip 30 .

The according to one of the procedures shown in FIG. 3 or FIG. 4 foil strip produced is then laminated to a support layer, either by ultrasonic welding, or explosion welding, wherein a corresponding pure metal film 12 between the respective carrier layer 11 and the functional layer 13 (Fig. 1) insert is, for example, a foil made of pure aluminum or a foil made of pure copper. It is also possible, in particular in the case of functional layers 13 based on copper, to fasten the film web produced in the manner described above by soft soldering to a carrier, for example a steel strip previously copper-coated on the side receiving the functional layer. There are also adhesive connections into consideration, as explained above in connection with FIG. 2. If it is contemplated to apply a functional layer 13 ( FIGS. 1 and 2) forming film strip 20 by roll cladding on a carrier, such a connection method is to be carried out with great care, so that recrystallization does not occur due to the effect of elevated temperature and increased pressure Foil tape 20 or the functional layer 13 occurs.

Reference symbol list

10 layer material
11 backing layer
12 bonding agent layer
13 functional layer
14 lead particles
15 lead particles
16 adhesive layer
17 copper particles
20 foil tape
21 crucibles
22 outlet
23 jet (molten alloy / melt mixture)
24 arrow
25 induction coil
26 cylinders
27 nozzle arrangement
28 jets (cold gas / cold liquid)
30 nip
31 roller
32 roller
33 tape takers
34 cooling nozzle
35 chill roll
36 cooling roller
37 tape takers
38 pressure roller
39 tape takers

Claims (16)

1. Layer material for the production of sliding elements with at least one carrier layer and a functional layer made of metallic dispersion alloy, in which the dispersed metal portion is globular, submicroscopically finely distributed in the metallic matrix, characterized in that the functional layer ( 13 ) is in an amorphous state or at least the metallic matrix portion of the dispersion alloy is amorphous and that the functional layer ( 13 ) is attached to the carrier layer ( 11 ) by ultrasound welding, explosion welding, gluing or soldering. 2. Layer material according to claim 1, characterized in that the functional layer ( 13 ) is formed as a sliding layer made of aluminum / lead dispersion alloy, the lead content is between 8% and 40% by weight and is globularly distributed in the amorphous aluminum matrix. 3. Layered material according to claim 1, characterized in that the functional layer ( 13 ) is formed as a sliding layer of lead bronze, the lead portion is distributed globularly in the amorphous copper matrix. 4. Layer material according to one of claims 1 to 3, characterized in that the matrix of the functional layer ( 13 ) one or more of the alloy components silicon, boron, phosphorus, iron, cobalt, titanium in a total amount between 0.2 and 2.0 wt .-% contains as a crystallization inhibitor (glass former). 5. Layered material according to claim 1, characterized in that the functional layer ( 13 ) contains aluminum as an essential metallic component and between the functional layer ( 13 ) and the carrier layer ( 11 ) a bonding agent layer ( 12 ) made of pure aluminum is provided. 6. Layer material according to claim 1, characterized in that the adhesive layer ( 14 ) located between the functional layer ( 13 ) and the carrier layer ( 11 ) contains heat-conducting filler ( 17 ), for example fine silver powder or fine copper powder. 7. A method for producing layered material according to one of claims 1 to 6, characterized in that the melt mixture of a dispersion alloy with the desired alloy composition is poured out under increased pressure to form a film strip and at a cooling rate between about 10 ⁶ and about 10 ⁹ K / s while maintaining the amorphous state - at least the matrix component of the dispersion alloy - is quenched, and that the film strip thus formed is attached to the carrier layer by means of ultrasound welding, explosion welding, soldering or gluing while maintaining the amorphous state of its material. 8. The method according to claim 7, characterized in that the functional layer from one  Dispersion alloy with miscibility gap, for example a dispersion alloy on the Basis Al-Pb, Al-Sn, Al-Bi, Al-Sb, Cu-Pb, Cu-Fe, Pb-Fe, formed and the melt mixture of these Dispersion alloy for pouring out under increased pressure to above the mixture gap of the components temperature of the dispersion alloy is heated or through continuous intensive mixing in fine Ver division of their mixture components is kept. 9. The method according to claim 7 or 8, characterized in that the melt mixture of Dispersion alloy one or more Crystallization inhibitor (glass former) in one Total amount between about 0.2 to 2.0% by weight is admixed. 10. The method according to claim 9, characterized in that one or more of the substances silicon, boron, Phosphorus, iron, cobalt, titanium as Crystallization inhibitor (glass former) used will or will. 11. The method according to claim 7, characterized in that the Foil tape by spraying a fine jet of the melt mixture onto one rotating, forced-cooled cylinders continuously formed is, the outer wall of which with the Melt mixture and one of its components non-binding material with high thermal conductivity. 12. The method according to claim 11, characterized in that the film tape during its formation on the cooled cylinder also on its free  Surface is cooled, for example by means of cold gas jets or chilled rollers. 13. The method according to claim 7 or 8, characterized characterized in that the film strip by Inject one or more parallel fine rays of the melt mixture in a nip is formed, the rollers chilled, not with the melt mixture and one its component binding surface is equipped and a jacket wall Has material with high thermal conductivity. 14. The method according to any one of claims 7 to 13, characterized in that the film strip already in its manufacture in the finished thickness of the Functional layer, for example of 0.05 mm, is produced. 15. The method according to claim 7 to 14, characterized in that a foil tape Alloy with aluminum as main component, for example aluminum / tin dispersion alloy for the formation of the functional layer is used and a Pure aluminum intermediate film between the Carrier layer and the functional layer forming film tape is integrated. 16. The method according to any one of claims 7 to 15, characterized in that the adhesive more thermally conductive, especially metallic Filler, for example fine silver powder or fine copper powder is added.