JP2000054105A - Method for pretreatment and coating of surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method treatment and coating of a substrate surface in which the layer of pollutants produced on the surface of the substrate is effectively removed, and the formation of a coating layer is executed, and to provide a device therefor. SOLUTION: This is the method and device for the pretreatment and forming coating by thermal spraying of the surface of a substrate 1, in which the surface of the substrate is progressively exposed to laser irradiation 2, there by, a thin film by pollutants on the surface of the substrate is at least partially removed. Moreover, directly after this pretreatment, a depositing material is deposited on the pretreated substrate surface by thermal spraying. The substrate surface is continuously exposed to the laser irradiation and thermal spraying, there by, many layers of the depositing material are laminated on the substrate surface. The substrate can be made to have a cylindrical shape, and furthermore, in the process of the continuous laser irradiation and thermal spraying, it can be rotated around the axis. The substrate is rotated in the direction in which the substrate surface is first subjected to laser irradiation and is next subjected to thermal spraying. As the laser, a pulse laser is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of surface treatment, and more particularly to the field of surface treatment by deposition on a surface, and a method of pretreating and coating a surface and an apparatus for realizing the method. It is assumed that.

[0002]

2. Description of the Related Art In coating a substrate with a deposit, the surface characteristics of the substrate and the quality of the interface between the substrate surface and the deposition material are essential to the mechanical strength and adhesion of the deposit. Role.

[0003] This is particularly noticeable when the deposition is performed, for example, by thermal spraying with a plasma arc or a torch.

At present, there are mainly two types of pretreatment of the surface to be deposited. A continuous pretreatment step and a step of improving the surface geometry. These two types of pretreatment are used in the framework of thermal spray coatings.

[0005] The usual range of surface pretreatments is generally, firstly, removal of surface roughness and secondly,
Mechanical pretreatment with a tool or suspended (oscillating, oscillating) supported abrasive material (polisher) or projection (sandblasting, shotblasting) and finally a second complementary The removal is performed.

[0006] Nevertheless, these different operations require special equipment corresponding to each, and each equipment has to be adjusted to the conditions of the substrate to remove surface roughness and obtain desired surface characteristics. Adaptation must be possible.

[0007] Also, the mechanical work of surface pretreatment results in the penetration of certain materials into the surface, which is detrimental to the ultimate properties of the deposit on the substrate. Also, when the substrate is thin, it also causes its deformation.

In addition, certain materials, such as titanium, aluminum or their alloys, have a very high affinity for oxygen and are reoxidized very quickly after mechanical pretreatment. Therefore, the time required to install the preprocessed substrate can be reduced in the surrounding atmosphere without considering the time required to remove the substrate from the mechanical pretreatment device and the time required to transfer the substrate to the thermal spraying device. It takes a sufficient time for the layer to be formed. This oxide layer, even though thin, is nevertheless detrimental to the mechanical strength and adhesion of the subsequently formed deposited layer.

[0009]

SUMMARY OF THE INVENTION The present invention aims, inter alia, to overcome the above-mentioned problems, and furthermore allows to carry out such an approach in the coating process.

[0010]

SUMMARY OF THE INVENTION To this end, the present invention is directed to a pretreatment and coating process for a substrate surface, wherein the coating process is performed under normal or controlled atmosphere by thermal spraying. Exposing the substrate surface to laser radiation to treat the surface, thereby removing, in whole or in part, a thin film of contaminants on the surface and improving the morphology of the underlying layer; Spraying the deposited material on the surface area immediately after the pretreatment by the thermal spraying device, performing the pretreatment and the spraying in synchronization, thereby performing a continuous laser operation during the spraying of the deposited layer, and It is characterized in that it is possible to improve the properties of the sediment by continuous pretreatment of the surface.

The present invention also implements the above-described invention.
It is also directed to an apparatus for surface pretreatment and coating.
This device is basically, first, a spraying device, for example, a plasma torch, second, a pulse laser beam generator,
Thirdly, the apparatus comprises a device for controlled support and movement of the substrate to be processed, and the laser beam irradiation area on the substrate overlaps with the area where the injection flow of the material to be deposited collides or is opposite to the direction of movement of the substrate. In the direction, adjacent to the collision area.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the invention may be had from the following description of a preferred embodiment, given by way of non-limiting example and with reference to the accompanying schematic drawings, in which: FIG.

According to the invention, the surface pre-treatment and coating step essentially consists in progressively exposing the substrate surface to laser radiation 2 to treat it, thereby causing a thin film 3 of surface contaminants to cover the entire substrate. Or partially removing and improving the morphology of the lower surface 4 of the substrate 1, after the pre-treatment operation and in synchronism with the pre-treatment,
rmal projection device 9, pre-treated surface 6
And a coating step of directly injecting the deposited material 5 thereon.

The action of the laser beam 2 irradiating the contaminant thin film 3 covering the surface of the substrate 1 is to cause three different phenomena. The first is a simple thermal effect, the second is that at least partial evaporation of the contaminant thin film 3 generates a plasma of the evaporating substance that jumps out at a high speed, and the third is a plasma. The shock wave is induced by the partial expansion of.

Further, the plasma of the substance vapor induces a compression shock wave from the remaining portion of the contaminant thin film toward the inside of the substrate 1, and this compression wave is generated at the interface between the contaminant thin film and the surface 4 of the substrate 1. The reflection causes the remaining portion of the thin film of the contaminant to be decomposed, destroyed and removed (see FIG. 2).

As a result, the surface of the substrate is perfectly adapted to accept deposits in a single processing operation.

Furthermore, the deposition of the deposition material 5 takes place immediately after the pretreatment with the laser beam 2, whereby any formation of a new contaminant, in particular a thin film of the contaminant by oxidation or condensation of the substrate material on the surface of the substrate 1. Can also be avoided.

The pretreatment of the surface according to the invention is preferably carried out by means of a continuous laser pulse, which will remove contaminants in the adjacent area 8. Each region 8 is adapted to be subjected to a plurality of successive impacts.

According to a feature of the invention, the value of the period of the impact and the value of the surface of the laser irradiation area 8 are preferably optimally adapted to the speed of displacement of the thermal spraying device 9 relative to the surface of the substrate 1. The laser beam 2 and the device 9
Allows precise synchronization of the operations of the two, so that they are as close as possible to a given area of the substrate surface, so that the surface pre-treatment and the deposition of the deposition material 5 by thermal spraying can be performed immediately. .

Furthermore, the output of the laser pulse is preferably adapted to achieve not only the removal of the contaminant thin film 3 but also the fusion and / or deformation of the material of the substrate 1 in the irradiation area 8 of said laser beam. be able to. The value of the output is necessary to obtain such a result, which depends on the thickness of the contaminant thin film and the nature of the material of the substrate 1 to be treated. As a result, after laser irradiation, the substrate,
In particular, an irregular surface 4 is formed at the center of the laser-irradiated area 8, which has an increased surface roughness, which promotes the adhesion and firm anchoring of the deposited material 5 deposited by continuous spraying. It is.

According to the present invention, the projected area of the laser beam irradiation area and the coating material (deposition material) are used.
The collision areas of the stream of coating material) are located adjacent to each other (see FIG. 3). This means that after the action of the laser beam, the jet of material is deposited immediately. It is desirable that these areas overlap (see FIG. 4). That is, the deposition of the injection flow of the material is performed in parallel with the action by the laser beam.

In practice, when the laser beam and the material jet flow cover the same area, the action of the laser beam precedes the coating material jet flow. This is because photons move at the speed of light, at which speed particles of the coating material do not move.

Such an arrangement will prevent any surface oxidation between the path of the laser beam and the injection stream of the coating material to be deposited, even if the substrate material is easily oxidized in a few milliseconds. An atmosphere that protects against particles will be avoided without the need.

In addition, the laser beam can be applied during or immediately after the deposition of the coating material on the substrate due to at least partially overlapping the overlap or the collision region of the coating material with the laser irradiation area. It can act on the particles.

As a result, the laser beam can extract some of the particles that are not firmly fixed to the substrate, or remove oxide thin films that may be formed while these particles are being emitted. As a result, the adhesive properties of the coating are improved and the porosity of the deposited material is appropriately reduced.

Furthermore, bringing the laser beam and the injection flow of the coating material into spatial proximity involves placing the thermal spraying device and the laser beam generating device on the same workbench or attaching them to the same robot arm.

According to another feature of the invention, the pretreatment and coating of the surface is effected by applying the deposited material 5 to a plurality of overlapping layers 7 (see FIGS. 3 and 4) by successive depositions, It consists of a pretreatment and an improvement of the planarized deposited layer 7 with the laser beam 2 in providing a predetermined area directly before the deposition of the new layer 7.

According to the invention, the object of the invention by means of a laser beam is not only to remove dirt on the substrate surface, but also to obtain an irregular and rough surface in order to achieve a firm anchoring of the coating. And depositing a thick coating in multiple successive steps. In fact, after each step, the plasma torch deposits a discontinuous underlayer of coating material after cleaning and compacting the previous underlayer with a laser beam.

Thus, for a given area of the substrate 1, the contaminant 3, the coating material 5 deposited by previous injection from the device 9, by the continuous action of the pulsed laser beam 2
The solidified and low-adhesive particles on the immediate layer 7 are removed and at the same time the previous layer compaction is effected, whereby the porosity is substantially reduced and likewise the assembly to which the coating has been applied The mechanical strength of the whole, that is, the substrate and the coating layer thereon is enhanced.

The present invention is also directed to an apparatus for pre-treating and coating a surface, the apparatus comprising firstly a thermal spraying device 9 and secondly a device for generating a pulsed laser beam 2.
Eleventh and third are devices that support and controllably displace the substrate 1 to be processed. The irradiation area 8 of the laser beam 2 on the substrate 1 overlaps with the collision area of the ejection flow 12 from the apparatus 9.
Alternatively, it is adjacent to a collision area in a direction opposite to the moving direction of the substrate 1.

A special embodiment of the invention and the accompanying FIG.
As shown, the device for supporting and displacing the substrate 1 for processing has an axis of symmetry around which the substrate rotates. The thermal spraying device 9 and the generator 11 for the laser beam 2 are arranged so that the direction of transmission of the laser beam 2
Are arranged on the substrate 1 such that the direction of the injection flow 12 is nearly perpendicular to the surface of the substrate 1. It is desirable that the angle between the laser beam 2 and the emission stream 12 be as small as possible in accordance with the shape and size of the substrate.

An actual example of the present apparatus will be described below using an actual configuration example. Adjustment of the parameters for surface preparation and coating is similar to the result obtained by deposition of the deposition material 5. The coating material is composed of 60% Al2 O3 and 40% by weight TiO2, and the substrate is composed of an aluminum alloy, for example, AU4G.

The laser pulse generator 11 is triggered by a YAG-Nd laser, and is a known device called 502 DNS manufactured by BMI Company. The laser has a wavelength of 1.06 μm, a pulse width of 12 ns, a pulse output of 700 mJ or more, and a spot diameter of 8 mm. For example, a thin film of a contaminant (titanium oxide) having a thickness of 0.25 μm or more can be removed.

The thermal spraying device 9 can be composed of a conventional atmospheric pressure plasma spraying device. The optimum relative displacement speed of the torch 10 with respect to the substrate 1 is 75 m / mm, and the average injection distance is 0.
13 m, thickness of deposited layer 7 of deposited material 5 for each process is about 10 μm
It is.

A comparative test is shown after depositing a plurality of layers 7 of the deposition material 5 with a continuous laser on the surface before thermal spraying. In the actual case, the porosity of the deposited layer is substantially reduced (on the order of 70%) and the adhesion of the deposited layer to the substrate 1 compared to a deposited layer deposited without the action of the laser beam 2 Significant improvements in quality (on the order of 400%) were seen.

Of course, the invention is not limited to the embodiments described above and shown in the accompanying drawings. In particular, there is room for improvement without departing from the scope of protection of the present invention, by means of various components and replacement with equivalent technology.

[Brief description of the drawings]

FIG. 1 is a schematic view of a surface pretreatment and coating apparatus according to the present invention.

FIG. 2 is a cross-sectional view of a substrate that has been subjected to a pretreatment according to the present invention.

FIG. 3 is a view similar to FIG. 2 showing a surface coating step according to the present invention, and shows that a laser beam irradiation area is adjacent to an area where a material jet flows.

FIG. 4 is a view showing a surface coating step according to another embodiment of the present invention, similarly to FIG. 2, showing that a laser beam irradiation area overlaps with an area where a material jet flows.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Laser beam 3 Contaminant 4 Irregular surface of substrate 1 5 Deposition material 6 Treated surface of substrate 1 7 Deposition layer of deposition material 5 8 Irradiation area of laser beam 2 9 Thermal spray device 10 Plasma torch 11 Laser beam generator 12 Deposition material injection flow

Continued on the front page F term (reference) 4K031 AA01 AB03 AB04 AB05 BA01 BA04 CB42 CB43 DA04 EA01 EA02 EA09 EA11 FA02 FA13

Claims (12)

[Claims] A method for pre-treating and spray coating a substrate surface, wherein the substrate surface is progressively exposed to laser radiation, thereby at least partially removing a thin film of contaminants on the substrate surface. And a pretreatment step of increasing the surface roughness, and a step of spraying the deposited material on the substrate surface by a spraying device, in order to overlap the laser beam irradiation area and the sprayed area, immediately after the pretreatment. Thermal spraying step of performing thermal spraying, comprising continuously performing laser irradiation and thermal spraying on the substrate surface so as to form a similar number of deposited layers of the deposited material, thereby reducing the porosity of the deposited layer. And improve the adhesion between the previously formed layer and the layer formed thereon,
Surface pretreatment and coating methods. 2. The method according to claim 1, wherein the substrate is cylindrical, and the substrate is rotated around its axis when continuously performing laser beam irradiation and thermal spraying on the substrate, and rotating the substrate. The substrate is first irradiated with a laser beam,
A pretreatment and coating method for the surface, which is followed by thermal spraying. 3. The method according to claim 2, wherein the laser beam irradiation and the thermal spraying are performed substantially perpendicular to the substrate surface, and the angle between the laser beam direction and the thermal spray direction is reduced. Pretreatment and coating method. 4. The method of claim 1, wherein the deposition material is a metal oxide. 5. The method according to claim 4, wherein the metal oxide is aluminum oxide and titanium oxide. 6. The method of claim 1, wherein the substrate is an aluminum alloy. 7. A method for pretreating and spray coating a substrate surface, wherein the substrate surface is progressively exposed to laser radiation comprising a laser pulse, whereby at least a contaminant thin film on the substrate surface is exposed. A pre-treatment step of partially removing and increasing the surface roughness of the substrate surface under the contaminant thin film and improving the surface morphology; and A step of spraying the deposited material on the surface, wherein the spraying step is performed in synchronization with the pretreatment so that the irradiation area of the laser beam and the sprayed area are overlapped with each other. In obtaining a coating layer coated with a layer of the deposited material, before each new coating layer is deposited, the pre-treatment and the laser beam are applied to the coating layer previously formed for a predetermined region. The coating layer is obtained by making improvements and by continuously applying a laser during thermal spraying to improve the deposit on each of the coating layers surface and to compress the previously formed coating layer. Processing and coating methods. 8. The method according to claim 7, wherein the substrate is cylindrical, and rotating the substrate around its axis when continuously performing laser beam irradiation and thermal spraying on the substrate; The substrate to be rotated is first irradiated with a laser beam,
A pretreatment and coating method for the surface, which is followed by thermal spraying. 9. The method according to claim 8, wherein the laser beam irradiation and the thermal spraying are performed substantially perpendicular to the substrate surface, and the angle between the laser beam direction and the thermal spray direction is reduced. Pretreatment and coating method. 10. The method according to claim 9, wherein the deposition material is a metal oxide. 11. The method according to claim 10, wherein the metal oxide is aluminum oxide and titanium oxide. 12. The method of claim 7, wherein the substrate is an aluminum alloy.