DE102012200528A1 - Modifying surface properties e.g. transmissivity of substrate, comprises depositing functional layer on surface of substrate, and treating entire surface of functional layer by laser beam such that property of functional layer is changed - Google Patents

Abstract

The method comprises depositing an open-pore functional layer (5) on a surface of a substrate (2) or on a layer located on the surface of the substrate at a room temperature or at a temperature of 100[deg] C, and treating an entire surface of the functional layer by a laser beam such that a property and/or morphology of the functional layer is changed. The deposition of the functional layer is carried out, under atmospheric pressure, by chemical vapor deposition using a flame or a plasma, by a sol-gel method or by an electrochemical method. The method comprises depositing an open-pore functional layer (5) on a surface of a substrate (2) or on a layer located on the surface of the substrate at a room temperature or at a temperature of 100[deg] C, and treating an entire surface of the functional layer by a laser beam such that a property and/or morphology of the functional layer is changed. The deposition of the functional layer is carried out, under atmospheric pressure, by chemical vapor deposition using a flame or a plasma, by a sol-gel method or by an electrochemical method. The functional layer is deposited by the laser beam treatment into a predetermined depth of up to 1 micrometer over a defined short period of 10 ms, melted and compressed to improve a barrier property of the layer. The barrier property includes a barrier effect against mobile ions and a barrier effect against alkali and alkaline earth metal ions including sodium. An energy input in the laser beam treatment is controlled and/or regulated such that the substrate is heated to a temperature of 100[deg] C. Carbon dioxide laser or yttrium aluminum garnet laser with different wavelengths and different pulse mode is used for the surface treatment.

Description

The invention relates to a method for changing surface properties.

It is known to modify surface properties of substrates by means of coating.

In the coating of surfaces, for example for adhesion promotion or for influencing optical properties such as transmission, the most uniform layer thicknesses in the nanometer range are desired. Common methods for coating surfaces include flame-assisted deposition and flame pyrolysis of metallic oxides. For this purpose, so-called precursors are added to a carrier gas in a burner which is thermally converted during the combustion of the carrier gas and whose resulting reaction products, for example metal oxides, are deposited on the surface as a coating.

The invention is based on the object to provide an improved method for changing surface properties.

The object is achieved by a method having the features of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

In a method according to the invention for modifying surface properties of a substrate, at least one functional layer is deposited on a surface of the substrate or on a surface located on the surface, wherein the functional layer is surface treated in a further step by means of a laser beam such that a property and / or Morphology of the functional layer is changed.

An essential part of the modification of the surface properties takes place during the laser beam treatment.

By this method, it is possible to selectively change or adjust layer morphologies.

The functional layer can be deposited up to a maximum temperature of 600 ° C., preferably at temperatures <100 ° C.

The method has the great advantage that the layers can be applied to the respective substrate material at room temperature and then specifically properties can be generated. It thus eliminates a costly preheating process before the respective coating. In addition, it is possible to thermally not strong resilient materials, for example, to provide plastics with thin layers and then surface treated with a laser without high substrate temperatures (T >> 100 ° C) occur, which lead to destruction of the material would.

The deposition of the functional layer can be carried out by means of chemical vapor deposition using a plasma or a flame or by means of a sol-gel method or electrochemically.

In chemical vapor deposition, a plasma jet or a flame is generated from a working gas. In this case, at least one precursor material is supplied to the working gas and / or the plasma jet or the working gas and / or the flame and reacted in the plasma jet or the flame. This causes a deposition of at least one reaction product of at least one of the precursors on the surface of the substrate.

The coating process may include one or more coating cycles.

In a preferred embodiment, the deposition takes place under atmospheric pressure.

By working at atmospheric pressure, a time-consuming process step of evacuation of a process chamber and apparatus for vacuum generation, such as vacuum pumps and process chamber, is saved in a particularly advantageous manner. Such a type of coating can be realized with a plasma torch with a low power input (for example 100 W to 200 W).

Before the coating process, an activation process may take place in which the plasma jet or the flame sweeps over the surface of the substrate without supplying a precursor material. This cleans and activates the surface, resulting in better adhesion of subsequently applied layers.

The laser beam treatment can be flat, in particular over the entire functional layer, but it can also be partial, geometry-adapted.

In a specific embodiment, an open-pored functional layer is deposited, which is melted and compacted by laser beam treatment at a defined depth of up to one micron (preferably 1 nm to 200 nm) over a defined short period of 1 to 500 ms, for example 10 ms, to improve a barrier property of the layer.

In this case, a barrier effect against mobile ions, especially against alkali and alkaline earth metal ions, preferably sodium, can be improved.

The modified functional layer can also be designed as a diffusion barrier to ions of at least one other alkali element, for example potassium, and / or to at least one alkaline earth element, for example magnesium or calcium.

The modified layer can also be embodied as a diffusion barrier with respect to at least one of the substances oxygen, water, water vapor and / or organic solvents, in particular in the case of plastics.

Preferably, in particular in the treatment of substrates which are not subject to high thermal loads, an energy input in the laser beam treatment is controlled and / or regulated such that the substrate is heated to a maximum of 100 ° C.

With the method, for example, at least one oxide and / or one nitride and / or one oxynitride of at least one of the elements silicon, titanium, aluminum, molybdenum, tungsten, vanadium, zirconium or boron can be deposited in the layer. For the deposition of silicon and / or aluminum oxide layers preferably organosilicon and / or organoaluminum compounds are used as precursors. Such layers are particularly suitable as barrier protective layers.

These precursors may be in solid, liquid and / or gaseous form, with solid and liquid precursors being advantageously converted into a gaseous state or into an aerosol before being introduced into the working gas or the plasma jet.

A throughput of the working gas and / or the precursor is preferably variable and controllable and / or controllable.

By a suitable choice of process parameters and precursors used, for example, the following properties of the substrate are selectively changeable: scratch resistance, self-healing ability, reflection behavior, transmission behavior, refractive index, transparency, light scattering, electrical conductivity, friction, adhesion, hydrophilicity, hydrophobicity, oleophilicity, oleophobia, surface tension, surface energy, anti-corrosive effect, dirt-repellent effect, self-cleaning ability, photocatalytic behavior, anti-stress behavior, wear behavior, chemical resistance, biocidal behavior, biocompatible behavior, antibacterial behavior, electrostatic behavior, electrochromic, photochromic and gasochromic behavior.

In one embodiment of the invention, the functional layer can be applied as a gradient layer. The gradient layer is to be understood as meaning a layer whose composition changes gradually over its thickness. The term is used in contrast to adjacent layers with different properties that have a clear boundary.

As the working gas, a gas, preferably air, oxygen, nitrogen, noble gases, hydrogen, carbon dioxide, gaseous hydrocarbons, ammonia or a mixture of at least two of the aforementioned gases can be used. Ammonia, for example, is suitable for the formation of nitrides and may have a catalytic effect in the reaction of the precursor.

The ignition of the plasma, for example, by means of high frequency excitation inductively or capacitively or by means of microwave radiation.

Embodiments of the invention will be explained in more detail below with reference to a drawing.

1 shows a device for coating a substrate, comprising a conveyor for transporting the substrate, wherein at least one coating device arranged along the conveyor is provided.

2 shows a porous functional layer after deposition.

3 shows a superficially sintered functional layer after the laser beam treatment.

4 shows a completely sintered functional layer after the laser beam treatment.

Corresponding parts are provided in all figures with the same reference numerals.

1 shows a device 1 for coating a substrate 2 , The device 1 includes a conveyor 3 for transporting the substrate 2 , Along the conveyor 3 is at least one attached coating device 4.1 intended. The conveyor 3 can be operated either in a conveying direction or with an alternating conveying direction in order to achieve multiple contact between the substrate 2 and coating device 4.1 to reach.

For example, a layer system consisting of non-metal and / or metal oxides and / or mixtures thereof is deposited thereon.

2 shows a porous functional layer 5 on a substrate 2 after the deposition.

3 shows a superficially sintered functional layer 5 on a substrate 2 after the laser beam treatment.

4 shows a completely sintered functional layer 5 on a substrate 2 after the laser beam treatment.

Example 1 - SiO _x

A silicon oxide layer system (SiO _x ) is deposited. The deposition of this layer system on the substrate can be used as corrosion protection, adhesion promoter and antireflection coating. As precursor substances for the flame pyrolytic deposition of these layers, it is possible to use organosilicon compounds, in particular HMDSO and TEOS. Subsequently, the deposited layer is treated flat with a CO ₂ laser beam.

Example 2 - SiO _x / Al ₂ O ₃

An aluminum oxide (Al ₂ O ₃ ) doped silicon oxide layer system (SiO _x ) is deposited. This layer system mainly serves as a barrier layer. As precursor substances for the flame pyrolytic deposition of these layers, it is possible to use organosilicon compounds with dissolved organoaluminum compounds, for example aluminum acetylacetonate.

For example, the following parameters can be used for the flame pyrolytic deposition of the abovementioned examples: Gas mixture: Fuel gas mixture (propane / air) Volume flow air: <2000 l / min (depending on the substrate size) Ratio propane / air: 1:15 to 1:25 Burner: standard burner Substrate temperature: << 100 ° C Substrate speed: <20 m / min Substrate distance from the burner r: <60 mm Burners: ≥ 1 Brenner Width: <1500 mm precursors: SiO _x HMDSO, TEOS Al ₂ O ₃ aluminum acetyl Laser treatment: CO ₂ laser Wavelength: 10640 nm Power: <100W Scangeschw. <8 m / s Fokusdurchm. <300 μm

As fuel gas, for example, propane, butane, natural gas can be used. Suitable oxidants are, for example, air or oxygen. The distance of the coating device 4.1 from the substrate surface may for example be between 5 mm and 100 mm. There may be a larger number of coating devices 4.1 to 4-n be provided. A width of the coating device 4.1 to 4-n is, for example, according to a width of the substrate 2 selected.

The same precursor can be used in each of the coating devices and the same reaction product can be deposited. It is also possible in different coating facilities 4.1 to 4-n to use different precursors and to deposit correspondingly different reaction products, so that different layers with different properties arise.

In another embodiment, instead of a CO ₂ laser (10640 nm), a YAG (1064 nm), fiber laser (1064 nm) in pulsed or continuous mode or ultrashort pulse laser (wavelengths: 1064 nm, 532 nm, 355 nm) with pulse lengths 100 ps are used.

LIST OF REFERENCE NUMBERS

1

Apparatus for coating a substrate

2

substratum

3

Conveyor

4.1 to 4.n

coater

5

functional layer

Claims (12)

A method for modifying surface properties of a substrate, wherein at least one functional layer is deposited on a surface of the substrate or on a surface located on the surface, wherein the functional layer is surface treated in a further step by means of a laser beam such that a property and / or Morphology of the functional layer is changed. A method according to claim 1, characterized in that the deposition of the functional layer by means of chemical vapor deposition using a flame or a plasma or by means of a sol-gel process or electrochemically. A method according to claim 2, characterized in that the deposition takes place under atmospheric pressure. Method according to one of the preceding claims, characterized in that the laser beam treatment is carried out over the entire surface of the functional layer. Method according to one of the preceding claims, characterized in that an open-pored functional layer is deposited, which by means of the laser beam treatment in a defined depth to to a micrometer over a defined short period of 1 to 500 ms, for example 10 ms, is melted and compacted to improve a barrier property of the layer. A method according to claim 5, characterized in that a barrier effect against mobile ions is improved. A method according to claim 6, characterized in that a barrier effect against alkali and alkaline earth metal ions, preferably sodium, is improved. Method according to one of the preceding claims, characterized in that the functional layer is deposited at a temperature of at most 600 ° C, preferably at most 100 ° C. A method according to claim 8, characterized in that the functional layer is deposited at room temperature. Method according to one of the preceding claims, characterized in that an energy input in the laser beam treatment is controlled and / or regulated so that the substrate is heated to a maximum of 600 ° C. Method according to one of the preceding claims, characterized in that an energy input in the laser beam treatment is controlled and / or regulated so that the substrate is heated to a maximum of 100 ° C. Method according to one of the preceding claims, characterized in that lasers with different wavelengths and different pulse operation, for example CO ₂ laser or YAG laser are used for surface treatment.

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