A high-bonding high-light-absorption AlN-based composite coating, a preparation method and application thereof
By depositing an AlN-based composite coating on a metal substrate, the problems of easy oxidation and weak adhesion of existing materials under harsh working conditions are solved, achieving high light absorption and oxidation resistance, which is suitable for equipment in fields such as solar photovoltaic and deep space radio wave detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGBO INST OF MATERIALS TECH & ENG CHINESE ACAD OF SCI
- Filing Date
- 2023-10-20
- Publication Date
- 2026-06-12
Smart Images
Figure CN117626178B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of light-absorbing materials technology, specifically relating to a strongly bonded, high-light-absorbing AlN-based composite coating, its preparation method, and its application. Background Technology
[0002] Equipment and devices used in energy, astronomy, and military fields, such as solar photovoltaics, ground-based and deep-space radio wave detection, advanced space optoelectronic measurement and sensing, and optical remote sensing, require their photosensitive components to have high absorbance in specific wavelength bands. This reduces reflection from non-target wavelengths, thereby improving the signal-to-noise ratio and achieving efficient photothermal energy conversion or the ability to absorb a large proportion of stray light. By selecting inherently high-absorbing materials or through microstructure design and control, the reflection of incident light on the material's surface can be reduced, achieving light absorption. Currently, existing high-absorbing materials are mostly carbon black, carbon nanotubes, black silicon, and metal dichalcogenides, primarily relying on their porous micro / nanostructures to achieve light absorption through long-distance, multiple internal reflections of incident light.
[0003] However, solar energy collection and military optical detection equipment often need to operate in desert environments or at high speeds, posing a significant challenge to the surface light-absorbing coating's ability to withstand high-speed particle erosion and high-temperature oxidation. Current nanoporous materials are fragile, have large specific surface areas, and are easily oxidized, especially exhibiting weak bonding with the substrate. Their bonding strength often falls below the lower limit of the micron-level scratch test, making them unsuitable for operation under harsh conditions of high-speed particle erosion and high temperatures. Therefore, avoiding the inherent contradiction between the loose porous structure designed for high light absorption and the requirements for strong bonding and oxidation resistance, and developing a light-absorbing coating that combines excellent light absorption performance with high structural and chemical stability, maintaining good bonding with the substrate for extended periods under harsh conditions, and being resistant to damage and oxidation, is of great significance for further improving light-to-heat conversion efficiency and developing high-resolution optical detection technology for military applications. Summary of the Invention
[0004] The main objective of this invention is to provide a strongly bonded, high-absorption AlN-based composite coating, its preparation method, and its application. The composite coating combines excellent light absorption performance with high structural and chemical stability. Even under harsh operating conditions, it can maintain good bonding with the substrate for a long time, is not easily damaged, and is not easily oxidized, thereby overcoming the shortcomings of the prior art.
[0005] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:
[0006] One aspect of the present invention provides a strongly bonded, high-absorption AlN-based composite coating, the AlN-based composite coating comprising a bottom dense support layer and a top loose light-absorbing layer, the top loose light-absorbing layer being deposited on the bottom dense support layer;
[0007] The bottom dense support layer is composed of either TiAlN or CrAlN, and the top loose light-absorbing layer is composed of either TiAlN or CrAlN.
[0008] In one embodiment, the bottom dense support layer is deposited on the surface of the metal substrate by arc ion plating.
[0009] Furthermore, the top loose light-absorbing layer is deposited on the bottom dense support layer by high-power pulsed magnetron sputtering.
[0010] Furthermore, the bottom dense support layer has a thickness of 0.3μm-1.0μm and exhibits a dense columnar crystalline structure.
[0011] Furthermore, the material of the metal matrix includes an alloy containing at least one of iron and titanium.
[0012] Furthermore, the bonding strength between the AlN-based composite coating and the metal substrate is 25N-28N.
[0013] Furthermore, the strongly bonded, high-absorption AlN-based composite coating has an average absorbance of 95% in the 200-2500nm range and an average absorbance of more than 98% in the 300nm-800nm band.
[0014] Furthermore, after the strongly bonded, high-absorption AlN-based composite coating is oxidized in air at 400°C and 500°C for 20 hours, the absorbance in the 300-800nm wavelength band is greater than 97%.
[0015] Furthermore, the top loose light-absorbing layer has a thickness of 1μm-5μm, exhibits a slender fibrous crystal structure, has a triangular pyramidal shape at the top, a grain diameter of 50nm-120nm, and a spacing of 9-70nm between adjacent grains.
[0016] Another aspect of the present invention provides a method for preparing the above-mentioned strongly bonded, high-absorption AlN-based composite coating, comprising depositing a TiAlN or CrAlN layer on a metal substrate as a bottom dense support layer using arc ion plating technology, and depositing a TiAlN or CrAlN layer on the bottom dense support layer as a top loose light-absorbing layer using high-power pulsed magnetron sputtering technology.
[0017] Furthermore, the above-mentioned method for preparing a strong-bonded, high-absorption AlN-based composite coating involves first removing the oxide layer and impurities on the surface of the metal substrate by ion etching to activate the surface, then depositing a TiAlN or CrAlN layer on the metal substrate as a bottom dense support layer using arc ion plating technology, and finally depositing a TiAlN or CrAlN layer on the bottom dense support layer as a top loose light-absorbing layer using high-power pulsed magnetron sputtering technology.
[0018] Furthermore, in the above-mentioned method for preparing a strongly bonded, high-absorption AlN-based composite coating, when depositing a dense support layer on the metal substrate, a pure TiAl or CrAl alloy target is used as the cathode, and the target current density is 0.54-0.77 A / cm². 2 The negative bias voltage is 70V-200V, the working gas is nitrogen, the gas pressure is 25mTorr-55mTorr, and the deposition time is 10-20 minutes.
[0019] Furthermore, in the above-mentioned method for preparing the strongly bonded, high-absorption AlN-based composite coating, when depositing the top loose light-absorbing layer on the bottom dense support layer using high-power pulsed magnetron sputtering technology, a pure TiAl or CrAl alloy target is used as the cathode, and the target current density is 0.005-0.01 A / cm². 2 The frequency is 100Hz-500Hz, the duty cycle is 5%-15%, the working gas is argon and nitrogen, the total gas pressure is 3mTorr-10mTorr, the negative bias voltage is 70V-150V, the deposition time is 120-240 minutes, the vertical magnetic field strength at the center of the target is 48-106mT, the vertical magnetic field strength at 10mm from the center of the target is 2-20mT, and the vertical magnetic field strength at 19mm from the center of the target is 40-60mT.
[0020] Furthermore, it also includes first cleaning the metal substrate and then placing it under a vacuum of 3×10⁻⁶. 5 Torr-5×10 5 Inside the sealed chamber of Torr, the sealed chamber is heated to 200℃-300℃, and the oxide layer and impurities on the surface of the metal substrate are removed by ion etching to perform surface activation. Then, the bottom dense support layer is deposited on the surface of the metal substrate.
[0021] In this invention, firstly, Al and N elements combine to form strong covalent bonds. AlN is a wide-bandgap semiconductor with strong intrinsic light absorption and a dark appearance. After combining with Ti and Cr elements, a TiAlN and CrAlN ternary solid solution system is formed. The crystal structure changes from hexagonal to face-centered cubic, significantly improving mechanical properties. It possesses ultra-high hardness and excellent oxidation resistance, and bonds well with the metal substrate. It has been widely used in wear-resistant protection fields such as tool coatings. By selecting the TiAlN and CrAlN ternary system, the coating exhibits wear resistance and oxidation resistance far exceeding those of existing light-absorbing coatings. By controlling the deposition atomic energy through physical vapor deposition process parameters, the microstructure of the coating is altered, thereby improving its light absorption performance.
[0022] Another aspect of the present invention provides an optoelectronic device, including a photosensitive component, wherein at least a strongly bonded, high-absorption AlN-based composite coating is disposed on a partial surface of the photosensitive component. The optoelectronic device includes, but is not limited to, equipment and devices in the energy, astronomical, and military fields such as solar photovoltaic, ground-based and deep-space radio wave detection, advanced space optoelectronic measurement and sensing, and optical remote sensing.
[0023] Compared with the prior art, the beneficial effects of the present invention are at least as follows:
[0024] 1. TiAlN itself has good bonding performance with the metal substrate. Through the homogeneous heterogeneous design of the bottom dense layer and the top loose layer, the composite coating has good light absorption and good bonding performance with the substrate. The bonding force by scratch test reaches 25-28N, which is far higher than that of existing light-absorbing coatings such as carbon black, carbon nanotubes, black silicon, and dichalcogenides.
[0025] 2. The AlN-based composite coating provided by the present invention has excellent light absorption performance in a wide wavelength range, with an average light absorption rate of over 94% in the 200-2500nm wavelength range and an average light absorption rate of over 97% in the 300nm-800nm wavelength range.
[0026] 3. The AlN-based composite coating provided by the present invention has excellent high-temperature oxidation resistance. After oxidation at 400℃ and 500℃ for 20 hours, it still maintains an absorbance of more than 97% in the 300-800nm wavelength range, which is significantly better than carbon-based, sulfur-based, resin-based and other light-absorbing coating materials. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a scanning electron microscope image of the surface morphology of the composite coating prepared in Example 1 of the present invention.
[0029] Figure 2 This is a cross-sectional scanning electron microscope image of the composite coating prepared in Example 1 of the present invention.
[0030] Figure 3 This is the X-ray diffraction pattern of the composite coating prepared in Example 1 of this invention.
[0031] Figure 4 These are the micron-sized scratch morphology and acoustic emission curves of the composite coating prepared in Example 1 of this invention.
[0032] Figure 5 This is a comparison of the absorption curves of the coatings prepared in Examples 1 and 2 and Comparative Examples 2, 3 and 5 of the present invention in the 200-2500nm wavelength range.
[0033] Figure 6 This is a comparison of the absorption curves of the coatings prepared in Examples 1 and 2 of this invention and Comparative Examples 2, 3 and 5 in the 300-800nm wavelength range.
[0034] Figure 7 This is an absorption rate curve of the composite coating prepared in Example 1 of the present invention in the 300-800nm band after oxidation at 400℃ and 500℃ for 20 hours. Detailed Implementation
[0035] The invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as intended to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.
[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This application specification and embodiments are merely exemplary.
[0037] Example 1
[0038] This embodiment provides a strongly bonded, high-absorption AlN-based composite coating, with a TC4 titanium alloy as the substrate. The preparation method includes:
[0039] (1) Place the TC4 titanium alloy substrate in a sealed cavity and evacuate the sealed cavity to a background vacuum of 5×10⁻⁶. - 5 Torr, while the cavity is heated to 300℃ and kept at that temperature; argon is used as the working gas with a pressure of 1.5mTorr, the linear ion source is turned on with an ion source current of 0.2A, a bias voltage of 1200V, a substrate negative bias voltage of 200V, and an ion etching time of 20 minutes. Ion etching removes the oxide layer and impurities on the surface of the metal substrate and activates the surface.
[0040] (2) Using nitrogen as the working gas at a pressure of 55 mTorr, and high-purity TiAl alloy as the cathode target, the cathode arc target is ignited at a target current density of 0.77 A / cm². 2 A dense TiAlN layer was deposited under a negative bias of 200V for 10 minutes.
[0041] (3) Using nitrogen and argon as working gases, with a total pressure of 10 mTorr, and high-purity TiAl alloy as the cathode target, magnetron sputtering was performed using a high-power pulse method to deposit a loose TiAlN layer; the target current density was 0.007 A / cm². 2 The frequency was 500Hz, the duty cycle was 15%, the negative bias was 100V, and the deposition time was 150 minutes.
[0042] The vertical magnetic field strength at the center of the target is 48 mT, the vertical magnetic field strength at 10 mm from the center of the target is 2 mT, and the vertical magnetic field strength at 17 mm from the center of the target is 40 mT.
[0043] See Figure 1 , Figure 1 This is a scanning electron microscope image of the surface morphology of the strongly bonded, high-absorption AlN-based composite coating prepared in Example 1 of the present invention. It can be seen that the top of the loose light-absorbing layer on the surface of the obtained strongly bonded, high-absorption AlN-based composite coating is triangular pyramidal, and there are gaps of 9-70 nm between adjacent grains.
[0044] See Figure 2 , Figure 2 This is a cross-sectional morphology diagram of the strongly bonded, high-absorption AlN-based composite coating prepared in Example 1 of the present invention. The obtained TiAlN composite coating has a bottom dense bonding layer thickness of 0.3 μm and a top loose layer thickness of 2.85 μm. The cross-sectional morphology of the loose layer shows slender fibrous columnar crystals with a grain size of 50-120 nm. The grain gaps are large, the grain boundary bonding is weak, and the coating breaks along the grain boundaries, retaining a complete polyhedral columnar crystal morphology.
[0045] See Figure 3 The X-ray diffraction pattern of the strongly bonded, high-absorption AlN-based composite coating prepared in Example 1 of this invention shows the presence of TiAlN characteristic diffraction peaks, confirming the formation of the TiAlN phase.
[0046] The adhesion of the coating was characterized using a scratch test. A diamond indenter was applied continuously at a rate of 0-80 N to scratch the coating surface for 3 mm. The adhesion was determined based on the presence of cracks and peeling within the scratches. (See reference...) Figure 4The image shows the micron-sized scratch morphology and acoustic emission curve of the strongly bonded, high-absorption AlN-based composite coating prepared in Example 1 of this invention. From the scratch morphology, the first localized peeling phenomenon appears at a load of 7 N, and continuous peeling begins at 28 N. The acoustic emission curve also shows signals at the corresponding positions, thus determining that the coating adhesion is 28 N.
[0047] See Figure 5 and Figure 6 The prepared coating exhibited an average absorbance of 95.5 ± 2.3% in the 200-2500 nm wavelength range and an average absorbance of 98.5 ± 0.4% in the 300-800 nm wavelength range. (See reference...) Figure 7 The strongly bonded, high-absorption AlN-based composite coating prepared in Example 1 of this invention, after being oxidized at 400℃ and 500℃ for 20 hours, still has an average absorbance of 98.1±0.59% and 97.9±0.99% in the 300-800nm wavelength band, respectively, which is much higher than that of conventional carbon-based, sulfur-based, and resin-based light-absorbing coating materials, and can ensure long-term service in a high-temperature environment of 500℃.
[0048] Example 2
[0049] This embodiment provides a strongly bonded, high-absorption AlN-based composite coating, with 316 stainless steel as the metal substrate. The preparation method includes:
[0050] (1) Place the 316 stainless steel substrate in a closed cavity and evacuate the closed cavity to a background vacuum of 3×10⁻⁶. - 5 Torr, while the cavity is heated to 200℃ and held at that temperature; argon is used as the working gas at a pressure of 1.8 mTorr, the linear ion source is turned on with an ion source current of 0.2A, a bias voltage of 1100V, a substrate negative bias voltage of 300V, and an ion etching time of 20 minutes.
[0051] (2) Using nitrogen as the working gas at a pressure of 45 mTorr, and high-purity TiAl alloy as the cathode target, the cathode arc target is ignited at a current density of 0.65 A / cm². 2 A dense TiAlN layer was deposited under a negative bias of 80V for 15 minutes.
[0052] (3) Using nitrogen and argon as working gases, with a total pressure of 3 mTorr, and high-purity TiAl alloy as the cathode target, magnetron sputtering was performed using a high-power pulse method to deposit a loose TiAlN layer; the target current density was 0.01 A / cm². 2 The frequency was 300Hz, the duty cycle was 10%, the negative bias was 70V, and the deposition time was 240 minutes.
[0053] The vertical magnetic field strength is 106 mT at 7 mm from the center of the target, 20 mT at 15 mm from the center of the target, and 60 mT at 20 mm from the center of the target.
[0054] The resulting composite coating consists of a single-phase TiAlN layer. The bottom dense bonding layer is 0.5 μm thick, and the top loose light-absorbing layer is 5 μm thick. The grain size of the loose layer ranges from 50 to 120 nm, with intergranular spacing varying from 9 to 70 nm. The composite coating exhibits an adhesion strength of 30 N. (See reference...) Figure 5 and Figure 6 The prepared coating exhibited an average absorbance of 95.4 ± 2.5% in the 200-2500 nm wavelength range and 98.4 ± 0.4% in the 300-800 nm wavelength range. After oxidation at 400℃ and 500℃ for 20 hours, the average absorbances in the 300-800 nm wavelength range were 98.2 ± 0.03% and 98.1 ± 0.95%, respectively.
[0055] Example 3
[0056] This embodiment provides a strongly bonded, high-absorption AlN-based composite coating with M2 high-speed steel as the metal substrate. The difference between Example 3 and Example 1 is that in step (2) of Example 3, the nitrogen pressure is 25 mTorr and the target current is 0.54 A / cm². 2 The negative bias voltage was 70V, and the deposition time was 20 minutes; in step (3), the total gas pressure was 8 mTorr, and the target current density was 0.005 A / cm². 2 The frequency was 100Hz, the duty cycle was 5%, the negative bias was 150V, and the deposition time was 120 minutes.
[0057] The resulting composite coating consists of a TiAlN single phase, with a dense bottom bonding layer of 1 μm thickness and a loose top light-absorbing layer of 1 μm thickness. The grain size ranges from 50 to 120 nm, and the intergranular spacing varies from 9 to 70 nm. The composite coating exhibits an adhesion strength of 25 N. The prepared coating has an average absorbance of 95.2 ± 2.4 nm in the 200–2500 nm wavelength range and 98.1 ± 0.6% in the 300–800 nm wavelength range. After oxidation at 400 °C and 500 °C for 20 hours, the average absorbances in the 300–800 nm wavelength range are 97.3 ± 0.7% and 97.1 ± 0.9%, respectively.
[0058] Example 4
[0059] The difference between Example 4 and Example 1 is that the metal substrate used in Example 4 is a cemented carbide, while the other conditions are the same as in Example 1.
[0060] The resulting composite coating consists of a TiAlN single phase, with a dense bottom bonding layer of 0.31 μm thickness and a loose top light-absorbing layer of 2.8 μm thickness. The grain size ranges from 50 to 120 nm, with intergranular spacing varying from 9 to 70 nm. The composite coating exhibits an adhesion strength of 28 N. The prepared coating shows an average absorbance of 95.6 ± 2.4% in the 200-2500 nm wavelength range and 98.3 ± 0.4% in the 300-800 nm wavelength range. After oxidation at 400℃ and 500℃ for 20 hours, the average absorbances in the 300-800 nm wavelength range are 97.4 ± 0.6% and 97.3 ± 1.1%, respectively.
[0061] Comparative Example 1
[0062] The only difference between Comparative Example 1 and Example 1 is that in Comparative Example 2, the target current density is 0.92 A / cm² during step 2 when preparing the densely bonded support layer. 2 The remaining conditions are the same as in Example 1.
[0063] The resulting composite coating consists of a TiAlN single phase, with a dense support layer at the bottom (0.42 μm thick) and a loose light-absorbing layer at the top (2.85 μm thick). The grain size ranges from 50 to 120 nm, with intergranular spacing varying from 9 to 70 nm. The composite coating exhibits a bonding strength of 32 N. Due to the significant increase in the arc target current density, the number and size of "large particle" defects increased significantly, exacerbating surface morphology fluctuations. Consequently, the absorption capacity and stability of the resulting coating decreased significantly in the infrared band, with the average absorbance decreasing to 90.5 ± 3.2% in the 200-2500 nm band and 92.8 ± 1.3% in the 300-800 nm band.
[0064] Comparative Example 2
[0065] The only difference between Comparative Example 2 and Example 2 is that the deposition time in Comparative Example 1 in step (3) is 30 minutes. All other conditions are the same as in Example 2.
[0066] The resulting composite coating consists of a single-phase TiAlN layer. The bottom dense bonding layer is 0.5 μm thick, while the top loose light-absorbing layer is only 0.6 μm thick. The grain size of the loose layer ranges from 40 to 100 nm, with intergranular spacing varying from 5 to 50 nm. The composite coating exhibits an adhesion strength of 20 N. (See also...) Figure 5 and Figure 6 The average absorbance decreased to 92.8±4.9% in the 200-2500nm band and to 96.9±0.7% in the 300-800nm band, indicating that a sufficiently thick porous layer is required to maintain excellent light absorption performance.
[0067] Comparative Example 3
[0068] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, after ion etching of TC4 titanium alloy, a dense TiAlN layer was deposited for 60 minutes using arc ion plating under the same conditions as in Example 1, and the loose TiAlN light-absorbing layer on top was not deposited.
[0069] The resulting composite coating consists of a single-phase TiAlN layer with a thickness of 1.8 μm. The coating is densely grown with no intergranular gaps and exhibits a high bonding strength of 80 N. For light absorption properties, please refer to [reference needed]. Figure 5 and Figure 6 Due to the loss of the loose structure, the average absorbance of the resulting coating is 94.8±1.3% in the 300-800nm wavelength range, while the average absorbance is only 84.6±7.4% in the 200-2500nm wavelength range. The absorption performance in the infrared band drops significantly, indicating that the intrinsic color absorption performance of TiAlN is insufficient.
[0070] Comparative Example 4
[0071] The difference between Comparative Example 4 and Example 1 is that, in Comparative Example 4, after ion etching of TC4 titanium alloy, a dense TiAlN support layer was deposited at the bottom without arc ion plating. Instead, a loose TiAlN light-absorbing layer at the top was deposited using high-power pulsed magnetron sputtering under the same conditions as in Example 1.
[0072] The resulting composite coating consists of a single-phase TiAlN layer with a top loose absorbing layer thickness of 2.85 μm. The grain size of the loose layer is 50-120 nm, and the grain spacing varies from 9-70 nm. The average absorbance is 95.5 ± 1.9% in the 200-2500 nm wavelength range and 98.5 ± 0.4% in the 300-800 nm wavelength range, consistent with Example 1. However, due to the lack of a bottom dense bonding support layer, its bonding strength is only 5.8 N, and the coating is easily worn off due to scratches. This indicates that the top loose TiAlN layer is indispensable for high light absorption performance, while the dense bonding layer is indispensable for maintaining a strong bond between the light-absorbing coating and the substrate.
[0073] Comparative Example 5
[0074] The difference between Comparative Example 5 and Example 1 is that the order of steps (2) and (3) is reversed in Comparative Example 5. A loose TiAlN layer is deposited first, and then a dense TiAlN layer is deposited on the loose TiAlN layer by arc ion plating. The resulting composite coating is composed of a single phase of TiAlN. The thickness of the bottom loose light-absorbing layer is 2.85 μm, the thickness of the bottom dense layer is 0.3 μm, and the bonding force reaches 40 N. However, the top is a dense layer, and the light absorption capacity is significantly reduced. The average light absorption rate in the 200-2500 nm wavelength band is 83%, and the average light absorption rate in the 300-800 nm wavelength band is 83%.
[0075] The obtained TiAlN composite coating has a bottom porous layer thickness of 2.85 μm and a top dense layer thickness of 0.3 μm. For light absorption properties, please refer to [reference needed]. Figure 5 and Figure 6 Because the surface layer is a dense layer, the average absorbance of the composite coating is 87.8±2.6% in the 200-2500nm wavelength range and 89.9±1.2% in the 300-800nm wavelength range.
[0076] Comparative Example 6
[0077] The difference between Comparative Example 6 and Example 1 is that Comparative Example 6 did not use etching to activate the surface of the metal substrate, while the other conditions were the same as in Example 1.
[0078] The average absorbance of the obtained TiAlN composite coating in the 200-2500nm range was 95.1±1.3%. Due to the fact that contaminants and impurities such as oxide scale on the sample surface were not removed, the bonding force between the coating and the substrate decreased significantly, to only 8N.
[0079] In summary, this invention provides a strongly bonded, high-absorption AlN-based composite coating. This AlN-based composite coating comprises a bottom dense support layer and a top loose light-absorbing layer, with the top loose light-absorbing layer deposited on the bottom dense support layer. Both the bottom dense support layer and the top loose light-absorbing layer are composed of either TiAlN or CrAlN, with the two layers having identical or similar compositions. This composite coating exhibits high light absorption and anti-reflection performance over a wide wavelength range, with an average absorbance exceeding 95% in the 200-2500 nm wavelength range and an average absorbance exceeding 98% in the 300-800 nm wavelength range. Simultaneously, it demonstrates a bonding strength exceeding 20 N with the metal substrate, is scratch-resistant, and possesses excellent chemical stability. After oxidation at 500°C for 20 hours, the absorbance in the 300-800 nm wavelength range still exceeds 97%, ensuring long-term service under harsh conditions. The preparation method of the composite coating provided by this invention is simple to operate.
[0080] Although this application discloses the information as described above, the scope of protection of this disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this application, and all such changes and modifications will fall within the protection scope of this invention.
Claims
1. A method for preparing a strongly bonded, high-absorption AlN-based composite coating, characterized in that, include: An AlN-based material is deposited on a metal substrate using an arc ion plating technique to form a dense bottom support layer. Then, a high-power pulsed magnetron sputtering technique is used to deposit an AlN-based material on the dense bottom support layer to form a loose top light-absorbing layer. The metal substrate was placed under a vacuum of 3 × 10⁻⁶. -5 ~-5×10 -5 Inside the sealed chamber of Torr, the sealed chamber is heated to 200~300°C, and the oxide layer and impurities on the surface of the metal substrate are removed by ion etching to perform surface activation. Then, the bottom dense support layer is deposited on the surface of the metal substrate. The arc ion plating technology includes using a pure TiAl or CrAl alloy target as the cathode, with a target current density of 0.54~0.77 A / cm². 2 The negative bias voltage is 70~200 V, the working gas is nitrogen, the gas pressure is 25~55 mTorr, and the deposition time is 10~20 minutes; The high-power pulsed magnetron sputtering technology includes using a pure TiAl or CrAl alloy target as the cathode, with a target current density of 0.005~0.01 A / cm². 2 The frequency is 100~500 Hz, the duty cycle is 5~15%, the working gas is argon and nitrogen, the total gas pressure is 3~10 mTorr, the negative bias is 70~150 V, the deposition time is 120~240 minutes, the vertical magnetic field strength in the range of 0~7 mm at the center of the target is 48~106 mT, the vertical magnetic field strength at 10~15 mm from the center of the target is 2~20 mT, and the vertical magnetic field strength at 17~20 mm from the center of the target is 40~60 mT. The AlN-based material is TiAlN or CrAlN.
2. A strongly bonded, high-absorption AlN-based composite coating obtained by the preparation method as described in claim 1, characterized in that: The AlN-based composite coating includes a bottom dense support layer and a top loose light-absorbing layer. The top loose light-absorbing layer is continuously grown on the surface of the bottom dense support layer. The bottom dense support layer is deposited on the surface of the metal substrate. The bottom dense support layer has a densely arranged first columnar crystal structure, and the top loose light-absorbing layer has a loosely arranged second columnar crystal structure. The bottom dense support layer and the top loose light-absorbing layer are made of the same material; The bonding force between the AlN-based composite coating and the metal substrate is 25~28N; The AlN-based composite coating has an average absorbance of more than 95% in the 200-2500 nm wavelength range.
3. The strongly bonded, high-absorption AlN-based composite coating according to claim 2, characterized in that: The thickness of the bottom dense support layer is 0.3~1.0μm.
4. The strongly bonded, high-absorption AlN-based composite coating according to claim 2, characterized in that: The first columnar crystal structure has a length of 0.3~1.0μm and a diameter of 20~80nm.
5. The strongly bonded, high-absorption AlN-based composite coating according to claim 2, characterized in that: The thickness of the top loose light-absorbing layer is 1~5μm.
6. The strongly bonded, high-absorption AlN-based composite coating according to claim 2, characterized in that: The second columnar crystal structure is a slender fibrous crystal structure with a triangular pyramidal top, a grain diameter of 50~120 nm, and a spacing of 9~70 nm between adjacent grains.
7. The strongly bonded, high-absorption AlN-based composite coating according to claim 2, characterized in that: The metal matrix is made of an alloy containing at least one of iron and titanium.
8. The strongly bonded, high-absorption AlN-based composite coating according to claim 2, characterized in that: The AlN-based composite coating has an average absorbance of greater than 98% in the 300nm-800nm wavelength range.
9. The strongly bonded, high-absorption AlN-based composite coating according to claim 2, characterized in that: After the AlN-based composite coating is oxidized in air at 400-500°C for 20 hours, the absorbance in the 300-800 nm wavelength band is greater than 97%.
10. A light-absorbing structure, characterized in that, This includes the strongly bonded, high-absorption AlN-based composite coating obtained by the preparation method described in claim 1, or the strongly bonded, high-absorption AlN-based composite coating as described in claims 2-9.
11. A photoelectric device, comprising a photosensitive component, characterized in that: At least a local surface of the photosensitive element is provided with a strongly bonded, high-absorption AlN-based composite coating obtained by the preparation method of claim 1, or a strongly bonded, high-absorption AlN-based composite coating as described in claims 2-9.