Black doped diamond-like carbon coating structure and preparation method thereof

Abstract

The invention discloses a black doped diamond-like carbon coating structure and a preparation method thereof. According to the black doped diamond-like carbon coating structure, a magnetron sputtering method is adopted for coating deposition, coating equipment is simple in structure and low in cost, the temperature of the magnetron sputtering process is low, and base materials of any shape can be treated; the coating is of a two-layer structure of a black doped diamond-like carbon coating structure, the binding force between the coatings is high, and the coatings are not prone to falling off; a special technology is adopted in the coating deposition process, the blackness and glossiness of the surface of the coating can be effectively improved, the coating is more attractive on the premise that the strength of the coating is guaranteed, and a product has a better decoration effect.

Description

Technical Field

[0001] The invention relates to the technical field of hard film coatings, and in particular to a black doped diamond-like coating and a preparation method thereof. Background Art

[0002] Diamond-Like Carbon (DLC) is a general term for carbon-based thin film coatings that are a mixture of sp2 and sp3 hybrid covalent bonds. The diamond-like carbon film is a unique material of a metastable carbon matrix, which exhibits many important technical properties of diamond, such as high hardness, high chemical stability, electrochemical and wear resistance, high resistivity and high thermal conductivity. The hardness, friction coefficient, conductivity, refractive index of light, etc. of diamond-like can be adjusted by doping with different elements. In addition to meeting the requirements of the above physical properties, the black doped diamond-like coating also has a very good decorative effect. Therefore, it is very popular and has been widely used in cutting tools, molds, automobiles, general industry, aerospace, medical, oil and gas, semiconductors and other fields.

[0003] Existing black doped diamond-like coatings have at least three layers, such as DE3639469 describing a decorative black hard material coating, which also has high wear resistance, and includes a first layer composed of an element in the periodic table Iva or Va, a second layer containing a nitride of the element constituting the first layer, a third layer containing a carbide of the element, and a protective layer composed of a hard carbon layer, wherein small crystal particles of carbide of the element are buried in the protective layer. Patent EP2959032 describes a decorative deep black coating based on a diamond-like coating, prepared by combining magnetron sputtering and plasma-assisted chemical vapor deposition, which also includes a three-layer structure of a metal bonding layer, a metal carbide layer and a diamond-like layer. US20200224318 discloses a two-layer black diamond coating, but its first layer is divided into a bonding layer and a metal carbide or nitride layer, and the second layer is a DLC layer or other mixed coating, which is actually a three-layer structure, similar to patent EP2959032.

[0004] This black doped diamond-like coating has the following defects: 1) It is a multi-layer coating structure, at least three layers, which increases the risk of failure of the bonding force between the coatings and the coating is easy to fall off; 2) Due to the multi-layer structure, the mixing technology has high requirements for the coating equipment, and the equipment cost is high; 3) The formed black coating has poor appearance quality, insufficient blackness, and poor glossiness, and cannot play a better decorative role on the product; 4) The existing processes mostly use chemical vapor deposition or plasma-assisted chemical vapor deposition for preparation, which has high requirements for the substrate. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a black doped diamond-like coating with fewer coating structures and good appearance quality, and a preparation method of the black doped diamond-like coating, in view of the shortcomings of the prior art.

[0006] A black doped diamond-like coating structure comprises a substrate, wherein a metal coating and a metal carbide coating are sequentially deposited on the substrate, and the coating color of the metal carbide coating is L* between 28 and 35, a* between -2 and 2, and b* between -2 and 2.

[0007] Preferably, the coating color of the metal carbide coating is L* between 30 and 32, a* between -1 and 1, and b* between -1 and 1.

[0008] Preferably, the metal coating is one or a mixture of titanium, zirconium, aluminum, vanadium, chromium, molybdenum, tungsten, cobalt, nickel, niobium, ruthenium, rhodium, tantalum, iridium, palladium, platinum, copper, gold or silver, and the metal carbide coating is one or a mixture of titanium carbide, zirconium carbide, aluminum carbide, vanadium carbide, chromium carbide, molybdenum carbide, tungsten carbide, cobalt carbide, nickel carbide, niobium carbide, ruthenium carbide, rhodium carbide, tantalum carbide, iridium carbide, palladium carbide, platinum carbide, copper carbide, gold carbide or silver carbide.

[0009] Preferably, the thickness of the metal coating is 0.01 micrometer to 20 micrometers.

[0010] Preferably, the thickness of the metal coating is 0.01 micrometer to 5 micrometers.

[0011] Preferably, the thickness of the metal carbide coating is 0.01 micrometer to 30 micrometers.

[0012] Preferably, the thickness of the metal carbide is 0.01 micrometer to 10 micrometers.

[0013] The present invention also discloses a method for preparing a black doped diamond-like coating structure. The method uses a magnetron sputtering method to deposit the coating, and specifically comprises the following steps: 1) vacuuming, placing the substrate in a vacuum deposition device, and vacuuming the vacuum deposition device to make the vacuum degree in the vacuum deposition device equal to or less than 1-5x10 -3Pa; 2) Plasma heating, inert gas is introduced, the flow rate is controlled at 100 to 200 sccm, the ion source of the vacuum deposition equipment is turned on to perform plasma heating on the substrate, the current density is 100 to 200A, and the time is 20 to 120 minutes; 3) Plasma etching, the substrate is cleaned by plasma etching process, the H2 gas flow rate is 100 to 200 sccm, the inert gas gas flow rate is 100 to 200 sccm, the plasma current is controlled at 100 to 200A, the bias voltage is 100 to 200 volts, and the time is 10 to 100 minutes; 4) Metal coating deposition, the inert gas Ar flow rate is 100 to 200 sccm, the metal target is turned on, and the sputtering power is 5 to 15kW, bias 100 to 200 volts, time for 5 to 20 minutes; 5) Metal carbide coating deposition, continuously introduce inert gas, flow rate 50 to 200sccm, open the carbide metal target, and introduce acetylene at the same time, with an initial flow rate of 100 to 150sccm, sputtering power of 4 to 5kW, bias starting at 250 to 400 volts, time for 20 to 50 minutes; then keep the Ar gas flow rate unchanged, the acetylene flow rate gradually increases to 250 to 300sccm, the sputtering power is reduced to 2kW, the bias is reduced to 25 to 50 volts, and the deposition is continued for 60 to 90 minutes; 6) After the coating is completed, helium is introduced for cooling, and the product is removed from the equipment after cooling to the specified temperature.

[0014] Preferably, in step 1), the surface of the substrate may be subjected to one or a mixture of various surface treatments such as dry sandblasting, wet sandblasting, glass bead sandblasting, mechanical polishing, electrochemical polishing, anodizing, etc.

[0015] The above technical scheme has the following beneficial effects: the black doped diamond-like coating structure adopts a magnetron sputtering method for coating deposition, the coating equipment has a simple structure, low cost, and the magnetron sputtering process temperature is low, and substrates of any shape can be processed; and the black doped diamond-like coating structure has a two-layer structure, the bonding force between the coatings is strong, the coating hardness can reach 5-25 GPa, and the coating is not easy to fall off; a special process is used in the coating deposition process, which can effectively increase the blackness and glossiness of the coating surface, make the coating more beautiful while ensuring the coating strength, and make the product have a better decorative effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the black doped diamond-like coating structure of the present invention.

[0017] Figure 2 The present invention is a flow chart of the method for preparing a black doped diamond-like coating structure.

[0018] Figure 3 It is a schematic structural diagram of the vacuum deposition equipment of the present invention.

[0019] Figure 4 This is a sample diagram of an embodiment of the present invention.

[0020] Figure 5 This is a graph showing the results of the VDI3198 adhesion test of the sample coating of the embodiment of the present invention.

[0021] Figure 6 This is a graph showing the results of the ASTM-C1624 test on the bonding strength of the coating according to an embodiment of the present invention.

[0022] Figure 7 This is a cross-sectional view of the coating thickness of an embodiment of the present invention.

[0023] Explanation of original component numbers: 1. Substrate; 2. Metal coating; 3. Metal carbide coating; 4. Rotating disk; 5. Substrate; 6. Vacuum system; 7. Magnetic coil; 8. Magnetic coil; 9. Cathode; 10. Plasma chamber; 11. Anode. DETAILED DESCRIPTION

[0024] The following is an explanation of the disclosed embodiments of the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following embodiments will further explain the relevant technical contents of the present invention in detail, but the disclosed contents are not intended to limit the scope of protection of the present invention.

[0025] like Figure 1 As shown, the present invention discloses a black doped diamond-like coating structure, comprising a substrate 1, on which a metal coating 2 and a metal carbide coating 3 are sequentially arranged from bottom to top, and the metal coating 2 and the metal carbide coating 3 are deposited on the substrate 1 by a magnetron sputtering method. Using the Lab* color system, the coating color of the metal carbide coating 3 is L* between 28 and 35, a* between -2 and 2, and b* between -2 and 2.

[0026] As a preferred embodiment of the present invention, the coating color of the metal carbide coating 3 is L* between 30 and 32, a* between -1 and 1, and b* between -1 and 1.

[0027] As another embodiment of the present invention, the metal coating 2 is one or a mixture of titanium, zirconium, aluminum, vanadium, chromium, molybdenum, tungsten, cobalt, nickel, niobium, ruthenium, rhodium, tantalum, iridium, palladium, platinum, copper, gold or silver. The metal carbide coating 3 is one or a mixture of titanium carbide, zirconium carbide, aluminum carbide, vanadium carbide, chromium carbide, molybdenum carbide, tungsten carbide, cobalt carbide, nickel carbide, niobium carbide, ruthenium carbide, rhodium carbide, tantalum carbide, iridium carbide, palladium carbide, platinum carbide, copper carbide, gold carbide or silver carbide.

[0028] As another embodiment of the present invention, the substrate 1 can be a pure metal, titanium (Ti), zirconium (Zr), aluminum (Al), vanadium (V), chromium (Cr), molybdenum (Mo), tungsten (WC), cobalt (Co), nickel (Ni), niobium (Nb), ruthenium (Ru), rhodium (Rh), tantalum (Ta), iridium (Ir), palladium (Pd), platinum (Pt), copper (Cu) gold (Au), silver (Ag), iron (Fe), stainless steel, austenitic chromium-nickel-manganese alloy (200 series stainless steel), austenitic chromium-nickel alloy (300 series stainless steel), ferrite and martensitic chromium alloy (400 series stainless steel), heat-resistant chromium alloy (500 series stainless steel), aluminum alloy, etc., a combination containing at least one or an alloy containing at least one.

[0029] As a specific embodiment of the present invention, the thickness of the metal coating 2 is 0.01 micrometer to 20 micrometers. As a preferred embodiment, the thickness of the metal coating 2 is 0.01 micrometer to 5 micrometers.

[0030] As another embodiment of the present invention, the thickness of the metal carbide coating is 0.01 micrometer to 30 micrometers. As a specific implementation manner, the thickness of the metal carbide is 0.01 micrometer to 10 micrometers.

[0031] like Figure 2 As shown, the present invention also discloses a method for preparing a black doped diamond-like coating structure. As a specific embodiment, the above preparation method is described using metal chromium Cr as the metal coating and tungsten carbide as the metal carbide coating. This method is not intended to limit the scope of protection of the present invention.

[0032] A method for preparing a black doped diamond-like coating structure, wherein the coating is deposited by a magnetron sputtering method, and the equipment used is a vacuum deposition equipment. The schematic diagram of the vacuum deposition equipment is as shown in Figure 3 As shown, it mainly includes a rotating disk 4, a substrate 5, a vacuum system 6, a magnetic coil 7, a magnetic coil 8, a cathode 9, a plasma chamber 10 and an anode 11. The vacuum deposition equipment is a prior art, and its working principle will not be described in detail here.

[0033] The method for preparing the black doped diamond-like coating structure specifically comprises the following steps: 1) Vacuuming: Place the substrate in the vacuum deposition equipment, install the substrate 5 on the rotating disk 4 for rotation inspection, close the equipment chamber door, and perform vacuuming to make the vacuum degree in the vacuum deposition equipment equal to or less than 1~5x10 -3 Pa, the time is 15 to 50 minutes; before the coating, the surface of the substrate 5 can be subjected to one or a mixture of various surface treatments such as dry sandblasting, wet sandblasting, glass bead sandblasting, mechanical polishing, electrochemical polishing, anodizing, etc.

[0034] 2) Plasma heating: rotate the rotating disk 4 at a speed of 2-10 revolutions per minute, introduce inert gas Ar with a flow rate controlled at 100 to 200 sccm, turn on the ion source for plasma heating, the current density is 100 to 200 A, and turn on the upper and lower coils at the same time to ensure uniform heating. This step takes 20 to 120 minutes.

[0035] 3) Plasma etching: The substrate is cleaned with H2 and Ar plasma etching process before deposition. The H2 gas flow rate is 100 to 200 sccm, the Ar gas flow rate is 100 to 200 sccm, the plasma current is controlled at 100 to 200 A, the bias voltage is 100 to 200 volts, and the upper and lower coils are turned on at the same time to make the etching uniform. The duration is 10 to 100 minutes; 4) Metal coating deposition: introduce inert gas Ar flow rate of 100 to 200 sccm, turn on the chromium target, sputtering power of 5 to 15 kW, bias voltage of 100 to 200 volts, turn on the upper and lower coils at the same time to make the coating uniform, the time is 5 to 20 minutes; 5) Deposition of metal carbide coating: continuously introduce inert gas Ar at a flow rate of 50 to 200 sccm, open the tungsten carbide target, and introduce acetylene at the same time, with an initial flow rate of 100 to 150 sccm, a sputtering power of 4 to 5 kW, and a bias voltage starting at 250 to 400 volts. At the same time, open the upper and lower coils to make the coating uniform for 20 to 50 minutes; then keep the Ar gas flow rate unchanged, increase the acetylene flow rate to 250 to 300 sccm, reduce the sputtering power to 2 kW, and reduce the bias voltage to 25 to 50 volts, and continue deposition for 60 to 90 minutes. During this process, the acetylene flow rate increases, but the bias voltage decreases, so that more graphite-type carbon-carbon bonds are produced during the deposition of the metal carbide coating, making the coating appear darker, thereby achieving a better decorative effect without affecting the hardness of the coating.

[0036] 6) After coating, helium is introduced for cooling, and the product is taken out of the equipment after cooling to the specified temperature.

[0037] As a specific implementation, in step 5), the acetylene flow rate is increased from 120 sccm to 280 sccm, the sputtering power is reduced from 5 kW to 2 kW, the bias voltage is reduced from 300 volts to 35 volts, and the time is 70 minutes. The appearance of the prepared sample is as shown in the figure Figure 4 As shown. Its surface is black, and the performance of the sample coating is tested. Figure 5 As shown, the adhesion of the coating is tested. According to the industrial standard VDI3198 for coating adhesion, the substrate hardness is 59HRc, the coating adhesion is HF1, and the adhesion is very good. The following figure is observed under an optical microscope and magnified 100 times. The critical load of the scratch method test is greater than 22 Newtons. Figure 6 This is the result diagram of the coating adhesion test ASTM-C1624. Figure 7 The cross-sectional view of the coating thickness is directly measured by the cross-sectional method combined with a scanning electron microscope. The hardness of the black doped diamond-like coating is 12 GPa, and the color of the metal carbide black coating is L*31, a*0.2, and b*0.1.

[0038] The black doped diamond-like coating structure adopts a magnetron sputtering method for coating deposition. The coating equipment has a simple structure and low cost. The magnetron sputtering process temperature is low and can process substrates of any shape. Moreover, the black doped diamond-like coating structure has a two-layer structure, the bonding force between the coatings is strong, and the coating is not easy to fall off. A special process is used in the coating deposition process to effectively increase the blackness and glossiness of the coating surface, making the coating more beautiful while ensuring the strength of the coating, so that the product has a better decorative effect.

[0039] The contents disclosed above are only preferred feasible embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention's specification and drawings are included in the scope of the present invention.

Claims

1. A black doped diamond-like coating structure, comprising a substrate, characterized in that: A metal coating and a metal carbide coating are sequentially deposited on the substrate, wherein the coating color of the metal carbide coating is L* between 28 and 35, a* between -2 and 2, and b* between -2 and 2.

2. The black doped diamond-like coating structure according to claim 1, characterized in that: The coating color of the metal carbide coating is L* between 30 and 32, a* between -1 and 1, and b* between -1 and 1.

3. The black doped diamond-like coating structure according to claim 1, characterized in that: The metal coating is one or a mixture of titanium, zirconium, aluminum, vanadium, chromium, molybdenum, tungsten, cobalt, nickel, niobium, ruthenium, rhodium, tantalum, iridium, palladium, platinum, copper, gold or silver, and the metal carbide coating is one or a mixture of titanium carbide, zirconium carbide, aluminum carbide, vanadium carbide, chromium carbide, molybdenum carbide, tungsten carbide, cobalt carbide, nickel carbide, niobium carbide, ruthenium carbide, rhodium carbide, tantalum carbide, iridium carbide, palladium carbide, platinum carbide, copper carbide, gold carbide or silver carbide.

4. The black doped diamond-like coating structure according to claim 1, characterized in that: The thickness of the metal coating is 0.01 micrometer to 20 micrometers.

5. The black doped diamond-like coating structure according to claim 4, characterized in that: The thickness of the metal coating is 0.01 micrometer to 5 micrometers.

6. The black doped diamond-like coating structure according to claim 1, characterized in that: The thickness of the metal carbide coating is 0.01 micrometer to 30 micrometers.

7. The black doped diamond-like coating structure according to claim 6, characterized in that: The thickness of the metal carbide coating is 0.01 micrometer to 10 micrometers.

8. A method for preparing a black doped diamond-like coating structure, characterized in that: The preparation method uses a magnetron sputtering method to deposit the coating, and specifically comprises the following steps: Vacuum the substrate into a vacuum deposition device and evacuate the device to make the vacuum degree in the device equal to or less than 1~5x10 -3 Pa; Plasma heating: introducing an inert gas with a flow rate controlled at 100 to 200 sccm, turning on the ion source of the vacuum deposition equipment to perform plasma heating on the substrate with a current density of 100 to 200 A for 20 to 120 minutes; Plasma etching, using a plasma etching process to clean the substrate, H2 gas flow rate of 100 to 200 sccm, inert gas flow rate of 100 to 200 sccm, plasma current controlled at 100 to 200 A, bias voltage applied at 100 to 200 volts, time 10 to 100 minutes; Metal coating deposition, inert gas Ar flow rate 100 to 200 sccm, open the metal target, sputtering power 5 to 15 kW, bias 100 to 200 volts, time 5 to 20 minutes; Metal carbide coating deposition, continuously introduce inert gas at a flow rate of 50 to 200 sccm, open the carbide metal target, and introduce acetylene at the same time, with an initial flow rate of 100 to 150 sccm, a sputtering power of 4 to 5 kW, a bias voltage of 250 to 400 volts, and a time of 20 to 50 minutes; then keep the Ar gas flow rate unchanged, increase the acetylene flow rate by 250 to 300 sccm, reduce the sputtering power to 2 kW, and reduce the bias voltage to 25 to 50 volts to continue deposition for 60 to 90 minutes; After the deposition of the coating is completed, helium is introduced for cooling, and the product is taken out of the equipment after it is cooled to the specified temperature.

9. The method for preparing a black doped diamond-like coating structure according to claim 8, characterized in that: In step 1), the surface of the substrate may be subjected to one or a combination of various surface treatments such as dry sandblasting, wet sandblasting, glass bead sandblasting, mechanical polishing, electrochemical polishing, anodizing, etc.

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