JPS5996945A - Stratiform work material with function layer executed on substrate and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a layered construction material provided with a functional layer made of at least two different materials applied on a support layer, and a method for manufacturing the same. It is applied by plasma exposure of a powder mixture of the constituent substances.

4414 metal or other metal heated to a high temperature for the purpose specified in 11', in most cases 11) and supplementary 11z processing.
A number of methods are known, for example for spraying plastic starting from wire or powder onto supporting materials. This is carried out using known thermal spraying equipment, such as flame spraying, plasma spraying or arc spraying.

It is known from GB 1,083,003 to produce bearing materials, ie layered materials, by spraying the material forming the functional layer onto the support at high temperature. When constructing functional layers from metals with significantly different specific gravities, such as aluminum and lead, these components are sprayed onto the coated areas or at least the intersecting areas of the support surface using separate thermal spraying equipment. In this case, the thermal spraying device is moved by the thermal spraying device (for thermal spraying devices that spray different metals when spraying onto the strip-shaped support, the thermal spraying zone is moved in the direction of composition change so that only metals with low specific gravity, e.g. aluminum, are present in the first planar area). The sprayed area can be arranged to be thermally sprayed.In the intermediate planar area which occupies the main part of the total area, the light material intersects with the sprayed area of heavy weight old material, thus aluminum and lead.The last thin planar area in the direction of composition change. A high weight metal, e.g. lead, is sprayed at the substrate surface, so that the functional layer consists mainly of light metals, e.g. Exists in a certain amount.

(・Regardless of the deviation, a pure lead layer is not formed.

This known method of operation allows only certain composition variations in the end regions of the functional layer. Substantially the same composition will be obtained throughout the entire thickness within the actual functional layer.

From US Pat. No. 2,233,304 a thermal spraying device is known which is capable of spraying mixtures of various materials, for example mixtures of copper or aluminum and molten lead, onto substrates.

However, this device cannot be used to vary the composition of the functional layer over its thickness.

From EP 2 509 109 A1 a layered material is known, in particular for composite plain bearings, in which regions of higher copper content are delimited over the thickness of the functional layer. Such functional layers are applied by electrodeposition. However, the number of metals used in the production of such functional layers is extremely small due to the electrodeposition method. Moreover, such electrodeposition methods cannot be well controlled, so that variations in the layer composition from well-defined areas cannot be achieved with the required reproducibility ().

The object of the invention is to create a layered construction material of the type mentioned at the outset, which allows in virtually any layer structure a well-controlled and precisely reproducible variation of the layer composition from zone to zone over the layer thickness. The purpose is to disclose the manufacturing method of

According to the invention, this problem is solved by temporally performing several plasma spraying steps by varying the composition of a powder mixture of several substances forming the functional layer or of a composite material containing several substances forming the functional layer. The solution is to apply the functional layers in a continuous manner.

Performing several plasma spray steps sequentially in time appears to be expensive. However, it has been found that the industrial outlay required through the multiple plasma spraying steps carried out according to the invention is lower than in the case of known powder metallurgy processes. In particular, the invention avoids the risk of demixing of the powder combination, which is particularly important if the substances to be combined in the functional layer have large differences in their specific gravities.

According to the invention, a layered structure with particularly high homogeneity is achieved with continuous transitions between zones of different composition.

The method of the invention can be applied to almost all combinations of materials. For example, a 100% adhesive base coat can be sprayed with a certain substance, and after a certain number of thermal spraying steps, the proportion of the adhesive base coat is such that the proportion of the functional layer becomes, for example, a functional layer consisting of an oxide ceramic 10θ group. can be changed in multiple steps. The transition from the adhesive basecoat to the functional layer can take place continuously or in stages or in a single step. Particularly advantageous in the process of the invention are coatings carried out by thermodynamic coating methods, which make it possible to spray on layers that are virtually non-porous or to process materials requiring temperatures >3500.degree.

Achievement of such temperatures can be achieved with plasma spraying performed in accordance with the present invention. Due to the high temperature of the plasma flame, almost all metallic and non-metallic materials can be processed in powder form.

The selected thermal spray parameters, such as the spray distance, together with the selection of the plasma gas, allow the layer quality to vary widely and be precisely matched to the desired application. The method and amount of powder feeding into the plasma flame can have an additional influence on the subsequent layer quality.

A wide range of variations are possible in the method of the invention. For example, one substance or one group of substances forming the functional layer can be supplied in a high starting proportion, possibly 100%, and in a subsequent plasma spraying step in a lower proportion, while the second substance or The two material groups are supplied in low starting proportions and in subsequent plasma spraying steps in high proportions, possibly up to 100 parts. At this time, the third material or third material group among the materials forming the functional layer is supplied at substantially the same mixing ratio in all plasma spraying steps. In one or more final plasma spraying steps, the proportion of one substance or one group of substances is reduced to zero in the mixture. On the other hand, the second material or the second group of materials can be provided with a starting proportion of zero in the first plasma spraying step or steps.

In the method of the present invention, substances with a low evaporation temperature are
It is advantageous to introduce it into the powder mixture with a particle size larger than that of the substance with the vaporization temperature.

An embodiment of the invention which is particularly suitable for the production of layered materials used for the production of sliding elements or friction elements having sliding elements or friction layers from aluminum/lead suspension alloys is:
Powdered lead is supplied in the powder mixture to be applied through the plasma spraying process in a starting proportion of zero and a final proportion of 15 to 40% by weight, in particular 20% by weight. At that time, the particle size of aluminum powder is 100 μm, especially K is 50 to 100 μm.
m and the lead powder has a particle size > 4 oIm, in particular 80 to 100 m.
Can be supplied in μm. The choice of plasma spraying instead of thermodynamic coating methods such as flame spraying or arc spraying in the processing of low melting materials aluminum and lead resulting in structures according to the present invention makes it possible to This is evidenced by the fact that when processing molten metal by plasma spraying, an extremely tight and almost pore-free layer is obtained, which has an advantageous effect on the strength of the sprayed layer.

Temperature >15000° with an evaporation temperature of about 2060°C for aluminum and 1740°C for lead
The feeding of aluminum and lead powder into the flame, which may be C, has a short residence time and therefore these powder particles are not accelerated, but can be deposited in the melt or in the slurry state at high energy depending on the choice of spray distance. Significant only when impinging on the substrate.

On the substrate, in addition to mechanical adhesion, rapid cooling occurs in the tensile spray particles, which can largely explain the adhesion mechanism.

The layer structure for the purpose of the invention is achieved by applying the actual layer structure after preheating the substrate surface by means of a plasma flame. This is the first time that one substance or one
This is carried out in such a way that a substance group, for example aluminum, is supplied to the flame in a constant amount per unit time. After several thermal spraying steps and the achievement of the desired layer thickness, the proportion or powder amount of the first substance can be reduced or kept constant, while at the same time the second substance, for example lead, is applied at a constant rate per unit time. feed the plasma flame in quantity. In this case, after an arbitrary number of thermal spraying steps, the bearing piece is coated with 80 parts by weight of aluminum and 2 parts by weight of lead.
It can be repeated by supplementing or adding the first substance portion with a second substance portion until the layer structure or the final layer reaches a total thickness containing 0 parts by weight. Similar layered structures with a continuous transition to higher proportions of other materials components are advantageous for use under lubrication conditions and cannot be produced by conventionally known methods.

Furthermore, the present invention relates to a layered construction material produced by the method of the present invention, comprising a metal support layer and a functional layer made of a metal alloy. In the layered material according to the present invention, the ratio of at least one alloy component in the functional layer is the same as that of the adjacent part of the support layer, and as the distance from the support layer increases, It is characterized by a substantially continuous increase up to a maximum percentage.

In this case, the proportion of the alloy component, which increases with distance from the support layer, passes to a maximum proportion of essentially 100% on the side of the functional layer remote from the support layer. In the example of a suspension alloy containing aluminum and lead, this means that the composition is initially 100% aluminum and finally 100% lead present as a coating. Such a structure would be unsuitable for use as a structural member, such as a plain bearing, for example. For this purpose, the functional layer should mainly be made of aluminum/
As a sliding layer consisting of a lead-suspended alloy, which layer is made of pure aluminum in the vicinity of the support layer and on the side of the functional layer remote from the support layer, it contains 15 to 40% by weight of lead, in particular 2% by weight.
It is advantageous to configure the structure so that it contains the following.

However, the functional layer transitioning to a coating from Pb 100 on the free surface is of great importance when it is a question of making structural components corrosion resistant, a technical problem that often occurs in chemical plants. .

Particularly advantageous for achieving the layered structure according to the invention are powder feeding devices that operate as follows: the powder is fed mechanically, for example by an impeller, through a connection to the plasma flame, the mechanical actuation being controlled by the carrier gas. Supported by This carrier gas carries the powder particles together into the flame under a predetermined gas pressure and gas flow rate. Regarding the powder to be processed, equipment is required such that the amount of powder to be simultaneously processed by plasma spraying depends on the number of feed devices used;
An alternative to the process according to the invention is to mix the powder or all the powders to be processed with the others before processing, that is to say before charging the feed device. Furthermore, it is clearly possible to process not only powder mixtures but also alloy powders. For example, aluminum can be supplied with alloying components typical of aluminum. The same applies to lead, which may be similarly alloyed.

The shape of the particles of the mixture or alloy or powder used for the thermodynamic coating within the scope of the invention is preferably spherical. Such spherical particles are advantageous over irregularly shaped or seed rod-shaped particles.

Nitrogen and argon can be used as plasma gases in the thermal spraying process, with hydrogen in each case being used as secondary gas.

The spraying distance between the nozzle and the substrate to be coated is 1
00 to 150 + nm, in particular 125 ± 5 mm.

Even a small difference in distance - even with an otherwise constant ξ parameter - can significantly affect the quality.

By means of the method of the invention, an optimum bonding of the thermally sprayed layer at 0.degree.

The continuous coating process is carried out by feeding a plasma gas with a predetermined amount of the respective powder and coating the preheated substrate to be coated with a plasma flame moving across it.

Additionally, it can be similarly carried out by stopping the plasma spray machine and moving the substrate relative to the plasma flame.

The plasma flame is moved across the entire substrate surface to be coated at a constant vertical and horizontal speed of 500 mm/S. Thermal spraying steps or cycles can then be carried out until the desired sprayed layer thickness is achieved. After each step, the composition of the sprayed layer can be varied by varying the amount of powder fed into the plasma flame.

Layered materials produced in this way do not require additional compaction after the coating process. This is because the sprayed layer obtained by plasma flame spraying is almost non-porous (porosity <5).

A modification of the process according to the invention is carried out in that the powder to be introduced into the plasma flame is compression-molded into a solid after its mixing and introduced into the plasma flame in the form of a compression-molded solid, for example a composite material in a linear shaped body. be able to.

Next, one embodiment of the layered material manufactured according to the present invention will be described in detail with reference to the accompanying drawings.

The accompanying drawing shows an enlarged sectional view of a layered material according to the invention with a support layer made of steel and a functional layer made of an Al-Pb suspension alloy, with the desired composition of aluminum to Al-Pb suspension alloys.
The transition to suspension alloy is continuous.

The surface of the copper strip 1 to be coated is pretreated by irradiation to provide the functional layer to be applied with a dirt-free surface which promotes mechanical adhesion in parts due to its shape.

A coating 3 mainly consisting of an aluminum component 4 and a lead component 5 was applied by multiple plasma spraying steps. Steel with a thickness of 1.5 mm according to DIN 1623 was used as the support material. The ground sprayed layer 6 is made of A199.5. Furthermore, the sprayed layer 7 applied thereon contains a proportion of lead that increases continuously up to a proportion of 80 parts by weight aluminum and 20 parts by weight lead.

Example 1 Mainly, the aluminum powder used has a particle size of 100>4
It had a spherical shape of 0 μm. The particle size range of the lead used was similarly excellent spherical particles with a factor of 100>50 μm.

-Nitrogen as the next gas at a pressure of 35 x 1 and a gas flow rate of 1
50A! /min. Hydrogen as a secondary gas at a pressure of 3
It was used at 5 pars and a flow rate of 10. The output of the plasma device was kept constant at 30 kW. The thermal spray process was started at 40 g/min of aluminum.

After the conclusion of the third thermal spraying step, the lead is placed separately into the plasma flame together with the aluminum, and when the desired thickness is reached, the proportion of lead is 2.
It was fed until it reached zero weight.

Example 2 The procedure was as in Example 1, but using argon as the plasma gas, i.e. as the gas. -The gas pressure was 69 par. The gas flow rate was 150. Hydrogen was used as the secondary gas at a pressure of 35 par and a gas flow rate of 51/min.

[Brief explanation of the drawing]

The accompanying drawing is an enlarged sectional view of a layered construction material according to the present invention. DESCRIPTION OF SYMBOLS 1... Steel strip material, 2... Steel surface, 3... Film, 4...
...Aluminum component, 5...Lead component, 6...Ground sprayed layer, 7...Thermal sprayed layer

Claims (1)

[Claims] 1. In a layered material comprising a metal support layer and a functional layer made of a metal/alloy, a proportion of at least one alloy component in the functional layer (3) is equal to that of the support layer (1). zero in the adjacent part,
Layered construction material with a functional layer applied on a support layer, characterized in that the functional layer increases substantially continuously away from the support layer (3) up to a predetermined maximum proportion. 2. Claim 1, in which the proportion of the alloy component increasing with distance from the support layer (1) shifts to a maximum proportion of substantially 100 on the side of the functional layer (3) remote from the support layer. The ball fee. 3. The functional layer (3) consists of pure aluminum in the vicinity of the support layer (1) and, on the side remote from the support layer (1), mainly contains 15 to 40% by weight, in particular 20% by weight, of lead. The material according to claim 1, which is a sliding layer made of an aluminum/lead suspension alloy. 4. The functional layer (3) is formed only of pure aluminum adjacent to the support layer (1) and transitions to a surface layer formed only of lead on the side remote from the support layer (1). The workpiece according to claim 1 or 2, which is a corrosion protection layer. 5. Consisting of at least two different substances, in the form of a powder mixture of several substances forming the functional layer or a composite material containing several substances forming the functional layer applied onto the support layer by plasma spraying. In a method for producing a layered material having a functional layer, the composition of a powder mixture of several substances forming the functional layer or a composite material containing several substances forming the functional layer is varied. 1. A method for manufacturing a layered material having a functional layer applied on a support layer, characterized in that the functional layer is applied by sequentially performing plasma spraying processes over time. 6. Supplying one substance or one group of substances forming the functional layer in a high starting proportion and in a subsequent plasma spraying step in a low proportion, while the second substance or second group of substances is supplied in a low starting proportion. 6. The method according to claim 5, wherein the plasma is supplied at a high rate in a subsequent plasma step. 7 Third substance or third substance among the substances forming the functional layer
7. A method according to claim 6, wherein said group of substances are supplied in substantially the same mixing ratio in all plasma spraying steps. 8. The method according to claim 6 or 7, wherein in the final plasma spraying step or steps, the proportion of one substance or one group of substances is reduced to zero in the mixture. 9 In the first plasma spraying step or steps, the second
A method according to any one of claims 6 to 8, characterized in that the substance or the second group of substances is supplied at a starting rate of zero. JO: Substances with a low evaporation temperature are
11. A process according to any one of claims 5 to 9. The layered material used in the production of friction elements or materials with a friction layer is coated with powdered lead in a powder mixture to be applied through a plasma spraying process with a starting proportion of 0 and a final proportion of 1.
Claim 5: Supplied and manufactured in a weight range of 5 to 40
The method according to any one of Items 1 to 10. 12 Aluminum powder with particle size > 100 μm, especially 50 to 100 μm and particle size > 40 μm, especially 80 to 100 μm
12. A method according to claim 10 or claim 11 for supplying lead powder of .mu.m.