Black PVD (Physical Vapor Deposition) film, low-temperature preparation method thereof and composite material structural member

Abstract

The invention discloses a black PVD (Physical Vapor Deposition) film, a low-temperature preparation method of the black PVD film and a composite material structural member comprising the black PVD film. Wherein the color layer of the black PVD thin film is deposited by adopting an ion source assisted intermediate-frequency magnetron sputtering process. The ion source can increase the ionization rate so as to increase the deposition speed and shorten the deposition time, the temperature rise in the deposition process can be reduced by adopting low current and bias voltage in the deposition process, the production efficiency can be greatly improved, the requirement for the temperature resistance of the base material is reduced, and the method can be applied to the base material with poor temperature resistance, such as a plastic base material and the like. And the problem of plastic deformation caused by long-time or high-temperature deposition is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of vacuum coating, and in particular relates to a black PVD film and a low-temperature preparation method thereof, and a composite material structural part. Background Art

[0002] In recent years, with the improvement of people's living standards, the aesthetic requirements for the appearance of daily necessities have become higher and higher, and consumers are no longer satisfied with a single color. In order to meet this demand of consumers, many manufacturers have begun to coat the outer surface of products to give the products rich colors. Common coating methods include chemical electroplating, spraying, anodizing, physical vapor deposition, etc. Among them, the physical vapor deposition (PVD) method has gained the attention of more and more manufacturers due to its low pollution, wide range of substrate selection, strong bonding force of black PVD film, and strong texture. At present, PVD films of various colors have been mass-produced on the market, such as: gray, gold, rose gold, black, etc. Among these colors, black, as a popular color that never fades, has continued to be favored by users recently.

[0003] The traditional black film preparation process has the problems of long deposition time, heating or some parameters being too harsh, resulting in high furnace temperature. Therefore, most of them can only be used for metal materials with good temperature resistance, which greatly limits the application scope of black PVD film. Recently, some patents have been devoted to the black film deposition process for plastic substrates, but there are problems of long deposition time and large color difference. The deposition time of the color layer ranges from 35min to 60min. For some products with thin wall thickness (less than 3mm), such a long coating time will inevitably lead to problems such as product shrinkage and deformation. Patent CN208121182B provides a black conductive PVD film that can be used for plastic substrates, but its process requires heating the vacuum chamber to 80-300℃ and the system will gradually heat up during its deposition process, resulting in a high system temperature. This process still cannot be applied to some plastic substrates with poor temperature resistance. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a black PVD film and a low-temperature preparation method thereof, and a composite material structural part. The prepared black PVD film has a color close to pure black and can be prepared on a substrate with poor temperature resistance.

[0005] The technical solution of the present invention is as follows:

[0006] A black PVD film is deposited on the surface of a substrate, and its PVD film layer structure includes, from inside to outside:

[0007] Base layer, the base layer is a single metal base layer;

[0008] Transition layer, the above transition layer is a CrSi mixed coating;

[0009] Color layer, the color layer is a CrSiC mixed coating;

[0010] The above-mentioned color layer is prepared by an ion source assisted medium frequency magnetron sputtering process, and its process parameters are as follows: the temperature of the vacuum chamber is not higher than 55°C, the pressure of the vacuum chamber is 0.1Pa~0.5Pa, the gas volume of the protective gas is 200sccm~500sccm, the gas volume of acetylene is gradually increased from 30sccm to 150-250sccm, the bias voltage is -30V~-70V, the duty cycle is 30%~60%, the target materials are sputtered chromium target and sputtered silicon target, the target current of the above-mentioned sputtered chromium target is 10A~25A, the target current of the above-mentioned sputtered silicon target is 10A~25A, the ion source working current is 0.5-2A, and the sputtering time is 10min~16min.

[0011] In the above technical solution, the color layer is mainly silicon carbide and chromium carbide obtained by reacting a sputtered silicon target, a sputtered chromium target and acetylene. In addition, there are also some silicon elements, chromium elements and amorphous carbon.

[0012] In some possible implementations, the ion source is an anode layer linear ion source, a radio frequency ion source, or a Hall ion source.

[0013] In some possible implementations, the single metal bottom layer is a zirconium metal coating.

[0014] In some possible implementations, the substrate is composed of at least one of metal, alloy and plastic. For example, the substrate can be acrylonitrile-butadiene-styrene copolymer (ABS), zinc alloy, copper and stainless steel.

[0015] In some possible implementations, the substrate is an electroplated substrate plated with a copper layer, a nickel layer and a chromium layer. In some other possible implementations, when the substrate is stainless steel, its surface may not be electroplated.

[0016] A low-temperature preparation method for a black PVD film, wherein the temperature of a vacuum chamber is not higher than 55° C., and the low-temperature preparation method comprises the following steps:

[0017] (1) Plasma cleaning of a substrate in a vacuum chamber;

[0018] (2) depositing a primer layer on the substrate using a multi-arc ion plating process;

[0019] (3) depositing a transition layer on the above-mentioned base layer by a magnetron sputtering process;

[0020] (4) depositing a color layer on the surface of the transition layer by using an ion source assisted medium frequency magnetron sputtering process;

[0021] The process parameters of the above-mentioned ion source assisted medium frequency magnetron sputtering process are as follows: the vacuum chamber pressure is 0.1Pa~0.5Pa, the gas volume of the protective gas is 200sccm~500sccm, the gas volume of acetylene gradually increases from 30sccm to 150-250sccm, the bias voltage is -30V~-70V, the duty cycle is 30%~60%, the target materials are sputtered chromium target and sputtered silicon target, the target current of the above-mentioned sputtered chromium target is 10A~25A, the target current of the above-mentioned sputtered silicon target is 10A~25A, the ion source working current is 0.5-2A, and the sputtering time is 10min~16min.

[0022] Compared with the traditional deposition process, the above technical solution does not need to heat up the vacuum chamber, but can complete the deposition at a lower temperature. Based on the above process, further, this solution controls the temperature of the vacuum chamber to be no higher than 55°C, effectively preventing the plastic substrate from shrinking and deforming.

[0023] In some possible implementations, the vacuum condition of the vacuum equipment used in steps (2) to (4) is 6*10 -3 Pa~5*10 -1 Pa.

[0024] In some possible implementations, the ion source is an anode layer linear ion source, a radio frequency ion source, or a Hall ion source.

[0025] In some possible implementations, the process parameters of the magnetron sputtering process in step (3) are as follows: the gas volume of the protective gas is 200 sccm to 500 sccm, the vacuum chamber pressure is 0.1 Pa to 0.5 Pa, the bias voltage is -50 V to -130 V, the duty cycle is 30 to 60%, the target materials used are sputtered chromium target and sputtered silicon target, the target current is 10 to 30 A, and the sputtering time is 3 min to 6 min.

[0026] In some possible implementations, the process parameters of the multi-arc ion plating process in step (2) are as follows: the gas volume of argon is 200sccm~500sccm, the vacuum chamber pressure is 0.1Pa~0.5Pa, the bias voltage is -80V~-450V, the duty cycle is 30~60%, the target material is a multi-arc zirconium target, the target current is 60~90A, and the plating time is 20s-60s.

[0027] In some possible implementations, the process parameters of plasma cleaning in step (1) are as follows: the gas volume of argon is 200 sccm to 600 sccm, the vacuum chamber pressure is 0.6 Pa to 1.5 Pa, the bias voltage is -300 V to -600 V, the duty cycle is 30 to 60%, and the cleaning time is 2 min to 6 min.

[0028] A composite material structural part, the surface of which is at least partially covered with the above-mentioned black PVD film.

[0029] In some possible implementations, the composite material structural component is a bathroom product, an electronic product, or an ornament.

[0030] The present invention has at least the following beneficial effects:

[0031] 1. The color layer of the black PVD film provided by the present invention is deposited by using an ion source assisted medium frequency magnetron sputtering process. The ion source can increase the ionization rate, thereby increasing the deposition speed and shortening the deposition time. The use of a lower current and bias voltage during the deposition process can reduce the temperature rise during the deposition process, which can not only greatly improve the production efficiency but also reduce the requirements for the heat resistance of the substrate. It can be applied to substrates with poor heat resistance, such as plastic substrates, and avoid the problem of plastic deformation caused by long-term or high-temperature deposition.

[0032] 2. The color layer of the black PVD film provided by the present invention is obtained by reacting a chromium target and a silicon target with acetylene. During the preparation process, the gas ratio, bias voltage and target current are adjusted so that the L value corresponding to the color in the Lab color space is 30 to 43, the a value is -1 to 1, and the b value is -1 to 1. The black PVD film has a bright color and no color difference visible to the naked eye. In addition, the introduction of the ion source makes the black PVD film have a higher color stability.

[0033] 3. The color layer adopts a gradual gas addition method to increase the acetylene gas volume in stages, which greatly improves the density of the color layer and significantly reduces the color difference of products in the same furnace.

[0034] 4. The black PVD film provided by the present invention has a transition layer between the base layer and the color layer, which can reduce the residual stress between the layers, increase the bonding strength and greatly improve the salt spray corrosion resistance and hydrolysis resistance of the black PVD film.

[0035] 5. In some possible implementations, the black PVD film provided by the present invention uses a zirconium metal coating as a base layer, and the use of a zirconium metal stripping solution will not cause the substrate water-plated chrome coating to be damaged, thereby avoiding the problem of difficulty in reworking the film layer of the traditional chrome-based structure. At the same time, the base layer prepared by the high bias multi-arc process can improve the bonding strength between the substrate and the black PVD film.

[0036] 6. The black PVD film prepared by the low-temperature preparation method provided by the present invention has uniform color and a small thickness, and its thickness is 0.1μm to 0.35μm. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0038] In the following examples, unless otherwise specified, the detection methods in the following examples are conventional detection methods; the reagents in the following examples are purchased from commercial channels unless otherwise specified.

[0039] Example 1

[0040] This embodiment provides a black PVD film, which is deposited on the surface of a substrate, and the PVD film layer structure includes a base layer, a transition layer and a color layer from the inside to the outside. The base layer is a zirconium metal coating, the transition layer is a mixed coating of chromium and silicon, the color layer is a mixed coating of silicon carbide and chromium carbide, and the substrate is an electroplated ABS plastic substrate with a copper layer, a nickel layer and a chromium layer prepared by water electroplating from the inside to the outside.

[0041] The preparation method of black PVD film is as follows:

[0042] (1) Plasma cleaning of the substrate in the vacuum chamber

[0043] The specific operation is: open the argon valve, introduce 400sccm of argon into the vacuum coating furnace, the vacuum chamber pressure is 0.6Pa~1.5Pa, the bias voltage used is -300V~-600V, the duty cycle is 30~60%, and the argon bombardment time is 3min.

[0044] (2) Using multi-arc ion plating process to deposit a base layer on the above substrate

[0045] The specific operation is: open the argon valve, introduce 200sccm of argon into the vacuum coating furnace, turn on the multi-arc zirconium target, the multi-arc zirconium target current is 70A, and use the multi-arc ion plating method to deposit a zirconium layer on the surface of the substrate. During the deposition process, the vacuum chamber pressure is 0.1Pa~0.5Pa, the bias voltage used is -150V~-350V, the duty cycle is 50%, and the time is 40s.

[0046] (3) Depositing a transition layer on the above-mentioned base layer using a magnetron sputtering process

[0047] Open the argon valve and introduce 200 sccm of argon into the vacuum coating furnace. Start sputtering chromium target and sputtering silicon target. The current of sputtering chromium target and sputtering silicon target are both 15A. Use medium frequency magnetron sputtering method to sputter chromium silicon layer on the surface of the base layer. During the sputtering process, the pressure of the vacuum chamber is 0.1Pa~0.5Pa, the bias voltage used is -80V, the duty cycle is 50%, and the sputtering is divided into 2 times. The total sputtering time is 200s.

[0048] (4) Using an ion source assisted medium frequency magnetron sputtering process to deposit a color layer on the surface of the above transition layer

[0049] Open the argon and acetylene valves, and introduce the protective gas argon and the reactive gas acetylene into the vacuum coating furnace at the same time. The gas volume of argon is constant at 200sccm and the initial gas volume of acetylene is 30sccm. During the color layer deposition process, the gas volume is gradually increased until it reaches 170sccm. The current of the sputtering chromium target and the sputtering silicon target is the same, 15A. The ion source assisted medium frequency magnetron sputtering method is used to sputter the silicon carbide and chromium carbide composite layer on the surface of the transition layer. During the sputtering process, the vacuum chamber pressure is 0.1Pa~0.5Pa, the bias voltage used is -60V, the duty cycle is 50%, the ion source working current is 1.5A, and the sputtering time is 12min.

[0050] Example 2

[0051] The difference between this embodiment and embodiment 1 is that the maximum gas volume of acetylene in step (4) is 210 sccm, the sputtering time in step (4) is 20 min, and other conditions remain unchanged.

[0052] Comparative Example 1

[0053] The difference between Comparative Example 1 and Example 1 is that the bias voltage in step (4) is -90 V, and other conditions remain unchanged.

[0054] Comparative Example 2

[0055] The difference between Comparative Example 2 and Example 1 is that the ion source is not turned on in step (4), and other conditions remain unchanged.

[0056] Comparative Example 3

[0057] The difference between Comparative Example 3 and Example 1 is that in step (4), the target currents of the sputtering chromium target and the sputtering silicon target are both 22 A, and other conditions remain unchanged.

[0058] Comparative Example 4

[0059] The difference between Comparative Example 3 and Example 1 is that the PVD film structure of the black PVD film prepared in Comparative Example 4 only has a primer layer and a transition layer, that is, its preparation method does not include step (3), and other conditions remain unchanged.

[0060] Comparative Example 5

[0061] The difference between Comparative Example 5 and Example 1 is that the bias voltage in step (2) is 70 V, and other conditions remain unchanged.

[0062] Performance Testing

[0063] 1. The Lab values ​​of the black PVD films (hereinafter referred to as samples) prepared in Example 1, Example 2 and Comparative Examples 1-5 were tested using a spectrophotometer, wherein the L value represents lightness, the a value represents the red-green color index, and the b value represents the yellow-blue color index. The specific results are shown in Table 1:

[0064] Table 1 Lab values ​​of black PVD films

[0065]

[0066] As can be seen from Table 1, when a higher bias voltage is selected during the color layer deposition process, the plastic sample obtained in Example 1 is deformed, indicating that under the same conditions, the selection of too high a bias voltage will lead to excessive energy of the bombarding ions, causing the sample to overheat and deform.

[0067] In Comparative Example 2, the ion source was turned off so that the obtained sample met the LAB range of black, but the subsequent water immersion experiment showed obvious discoloration of the black PVD film, indicating that the use of the ion source can improve the color stability of the black PVD film.

[0068] After the target current of Comparative Example 3 was changed, although L met the requirement, b* exceeded the limit. The overall color was yellowish when observed with the naked eye, which did not meet the set LAB requirement of the black PVD film and had slight shrinkage.

[0069] The sample obtained in Comparative Example 4 meets the LAB range of the black film, but fails to pass further tests such as corrosion resistance and bonding strength, indicating that the present invention introduces a transition layer between the metal base layer and the color layer, which can greatly improve the salt spray corrosion resistance and hydrolysis resistance of the black film.

[0070] Comparative Example 5 reduces the deposition bias of the pure metal bottom layer, resulting in the color of the obtained product being within the range, but film peeling occurs after the bonding strength test, indicating that short-term high bias can promote the bonding strength between the black PVD film and the substrate, giving the black PVD film excellent bonding strength and adhesion.

[0071] 2. The hydrolysis resistance, bonding strength and corrosion resistance of the black PVD films prepared in Example 1 and Example 2 were tested. The reference standards and test results are shown in Table 2.

[0072] Table 2 Hydrolysis resistance, bonding strength and corrosion resistance of black PVD films

[0073]

[0074] It can be seen from Table 2 that the black PVD film of the present invention has excellent hydrolysis resistance. After being immersed in water at 60°C for 24 hours, there is no visible discoloration, cracking, bubbles and other undesirable conditions on the surface, and the film layer has good stability. From the results of the bonding test, i.e., the hot and cold cycle test, it can be seen that there is no visually observable blistering or peeling on the surface of the sample, indicating that the black PVD film has high bonding strength, good adhesion and excellent resistance to hot and cold shocks. The black PVD film can meet the requirements of the ASME A112.18.1 standard, indicating that it has excellent corrosion resistance and can meet the corrosion resistance requirements of the sanitary ware industry.

[0075] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A black PVD film, deposited on a substrate surface, characterized in that: The PVD film structure includes: Base layer, the base layer is a single metal base layer; Transition layer, the above transition layer is a CrSi mixed coating; Color layer, the color layer is a CrSiC mixed coating; The above-mentioned color layer is prepared by an ion source assisted medium frequency magnetron sputtering process, and its process parameters are as follows: the temperature of the vacuum chamber is not higher than 55°C, the pressure of the vacuum chamber is 0.1Pa~0.5Pa, the gas volume of the protective gas is 200sccm~500sccm, the gas volume of acetylene is gradually increased from 30sccm to 150-250sccm, the bias voltage is -30V~-70V, the duty cycle is 30%~60%, the target materials are sputtered chromium target and sputtered silicon target, the target current of the above-mentioned sputtered chromium target is 10A~25A, the target current of the above-mentioned sputtered silicon target is 10A~25A, the ion source working current is 0.5-2A, and the sputtering time is 10min~16min.

2. The black PVD film according to claim 1, characterized in that: The single metal bottom layer is a zirconium metal plating layer.

3. The black PVD film according to claim 1 or 2, characterized in that: The substrate is composed of at least one of metal, alloy and plastic.

4. The black PVD film according to claim 3, characterized in that: The substrate is an electroplated substrate plated with a copper layer, a nickel layer and a chromium layer.

5. A low-temperature preparation method for a black PVD film, characterized in that: The temperature of the vacuum chamber is not higher than 55°C. The low-temperature preparation method comprises the following steps: (1) Plasma cleaning of a substrate in a vacuum chamber; (2) depositing a primer layer on the substrate using a multi-arc ion plating process; (3) depositing a transition layer on the above-mentioned base layer by a magnetron sputtering process; (4) depositing a color layer on the surface of the transition layer by using an ion source assisted medium frequency magnetron sputtering process; The process parameters of the above-mentioned ion source assisted medium frequency magnetron sputtering process are as follows: the vacuum chamber pressure is 0.1Pa~0.5Pa, the gas volume of the protective gas is 200sccm~500sccm, the gas volume of acetylene gradually increases from 30sccm to 150-250sccm, the bias voltage is -30V~-70V, the duty cycle is 30%~60%, the target materials are sputtered chromium target and sputtered silicon target, the target current of the above-mentioned sputtered chromium target is 10A~25A, the target current of the above-mentioned sputtered silicon target is 10A~25A, the ion source working current is 0.5-2A, and the sputtering time is 10min~16min.

6. The low temperature preparation method according to claim 5, characterized in that: The process parameters of the magnetron sputtering process described in step (3) are as follows: the gas volume of the protective gas is 200sccm~500sccm, the vacuum chamber pressure is 0.1Pa~0.5Pa, the bias voltage is -50V~-130V, the duty cycle is 30~60%, the target material is a sputtered chromium target and a sputtered silicon target, the target current is 10~30A, and the sputtering time is 3min~6min.

7. The low temperature preparation method according to claim 5 or 6, characterized in that: The process parameters of the multi-arc ion plating process in step (2) are as follows: the gas volume of the protective gas is 200sccm~500sccm, the vacuum chamber pressure is 0.1Pa~0.5Pa, the bias voltage is -80V~-4450V, the duty cycle is 30~60%, the target material is a multi-arc zirconium target, the target current is 60~90A, and the plating time is 20s-60s.

8. The low temperature preparation method according to claim 5, characterized in that: The process parameters of the plasma cleaning in step (1) are as follows: the gas volume of argon is 200 sccm to 600 sccm, the vacuum chamber pressure is 0.6 Pa to 1.5 Pa, the bias voltage is -300 V to -600 V, the duty cycle is 30 to 60%, and the cleaning time is 2 min to 6 min.

9. A composite material structural part, characterized in that: The surface is at least partially covered with the black PVD film according to any one of claims 1 to 4.

10. The composite material structural member according to claim 9, characterized in that: It is a bathroom product, an electronic product or an ornament.

Images