• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Selective solar coating. The invention relates to a selective solar coating deposited on a substrate, said coating being stable in a temperature range of between room temperature and 700ºC comprising an absorbent structure in the UV-Vis covering the substrate composed of a hybrid material of silicide -nitride (called cermet) and an anti-reflective dielectric main layer in the Vis range that covers the absorbent layer in the UV-Vis made with an oxide. In addition, the invention relates to its process of obtaining by physical vapor deposition and its use as part of a solar thermal collector. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2689556A1
    申请号:ES201631654
    申请日:2016-12-22
    公开日:2018-11-14
    发明作者:Carlos Andrés PRIETO DE CASTRO；Eva María CÉSPEDES MONTOYA；Adrián RODRÍGUEZ PALOMO；David HERNÁNDEZ PINILLA；Leopoldo ÁLVAREZ FRAGA；Félix JIMÉNEZ VILLACORTA；Esteban CLIMENT PASCUAL
    申请人:Consejo Superior de Investigaciones Cientificas CSIC；
    IPC主号:
    专利说明:

    The invention relates to a selective solar coating deposited on a substrate, said coating being stable in a temperature range between room temperature and 700 ° C comprising an ultraviolet-visible (UV-Vis) absorbent structure that covers the substrate made of a silicon-nitride hybrid material (called cermet) and an anti-reflective dielectric main layer in the Vis range that covers the UV-Vis absorbent layer made with an oxide. In addition, the invention relates to its method of obtaining by physical vapor deposition and its use as part of a solar thermal energy collector.
    STATE OF THE TECHNIQUE
    Selective solar coatings (SSC), typically prepared by physical vapor deposition (PVD) techniques [N. Selvakumar, H.C. Barshilia, “Review of physical vapor deposited (PVD) spectrally selective coatings for mid-to high-temperature solar thermal applications”, Solar Energy Materials and Solar Cells 98 (2012) 1–23], are an important component of receptors in the concentrated solar energy technology (CSP). Its optical properties should be maintained at temperatures as high as possible since the efficiency increases with the working temperature. Temperatures in a range of 600 700 ° C are required to improve the efficiency of conventional parabolic trough systems (PTC). In addition to high temperature, cermet-based absorbers are sufficiently efficient thanks to the interference achieved in a double cermet structure. The selective double cermet coating is composed of two layers with a high metal fraction by volume (called HMVF and a low metal fraction by volume (LMVF). This forms a graduated metal multilayer structure together with an anti-reflective dielectric layer (AR) in the upper part and an infrared metallic buried reflector (IR-mirror) that produces a gradual decrease in the refractive index (n) and the extinction coefficient (k).
    There are several combinations of metallic and ceramic compounds that may be possible candidates to be part of the SSC multilayer as cermet. Transition metals and oxides or nitrides are selected to form the selected cermet layer, such as: Mo-SiO2 [A. Antonaia, S. Esposito, “Method for producing a cermet-based spectrally selective coating for the receiver tube of a solar concentrator, and material thus

    obtained ”, World Intellectual Property Organization, WO2009 / 107157 A2, 2009.] and Mo – Si3N4
    [AND. Céspedes, C. Prieto, R. Escobar, J. A. Sánchez-García, “Covering that selectively absorbs visible and infrared radiation, and method for the production thereof,” World Intellectual Property Organization, WO2012172148 A1 (2013); E. Céspedes, M. Wirz, J.A. Sánchez-García, L. Alvarez-Fraga, R. Escobar-Galindo, C. Prieto, “Novel Mo – Si3N4 based selective coating for high temperature concentrating solar power applications”, Sol. Energy Mater. Sol. Cells 122 (2014) 217-225]. The main advantage of cermets to form an SSC is that excellent optical properties of the coating can be obtained by adjusting the thickness of the layer or the metal fraction by volume of the cermet. However, due to a possible progressive oxidation of the metal component of the cermet, operation in high temperature air has not been adequately addressed.
    The solar industry demands reliable coatings capable of maintaining its properties for a long operating life. Today there are no coatings available for use in air at elevated temperatures due to the reduced durability given the active behavior that it experiences in contact with atmospheric oxygen. Piromark-2500 (with solar absorbance Į = 0.96 and thermal emissivity İ = 0.90) is the commercially used reference for high temperature receiving towers [C.K. Ho, A.R. Mahoney, A. Ambrosini, M. Bencomo, A. Hall, T.N. Lambert, "Characterization of pyromark 2500 paint for high temperature solar receivers", J. Sol. Energy. Eng. 136 (2014) 014502]. This black absorbent paint has a low selectivity ratio, with high emissivity values that result in high radiative heat losses. In this line, commercially available products do not have enough selectivity to deal with the problem of thermal losses.
    In selective solar coatings prepared by PVD, based on cermets, several studies have been published in which the highest temperature of stability is below 550 ° C. It has been published that the best air stability corresponds to the multilayer cermet of MoSi2-Al2O3 which shows a slight degradation at 550 ° C [J.H. Schön, G. Binder and E. Bucher, "Performance and stability of some new high-temperature selective absorb systems based on metal / dielectric multilayers", Solar Energy Materials and Solar Cells 33 (1994) 403-416]. Another example is the Ni-Al2O3 cermet covered with SiO2, which retains its optical properties up to 500 ° C, however, a slight increase in temperature up to 550 ° C leads to a drastic degradation of the coating [T.S. Santhiaraj, R. Thangaraj,
    A. Sharabaty, M. Bhatnagar, O.P. Agnihotri, "Ni-Al2O3 selective cermet coatings for photothermal conversion up to 500 ° C", thin solid films 190 (1990) 241-254.].
    Other combinations have been tested in air at higher temperatures; for example, the stability of TiAl TiAlN TiAlON TiAlO has been published at 500 ° C for only one hour [H.

    Lei, W. ShuMao, J. Lijun, L. XiaoPeng, L. HuaLing, L. ZhiNiam, “Preparation and thermal stability on non-vacuum high temperature solar selective absorbing coatings”, Chin. Sci. Bull. 54 (2009) 1451-1454.] And TiAlN TiAlON Si3N4 at 600 ° C for two hours [H. Lei, W. ShuMao,
    J. Lijun, L. XiaoPeng, L. HuaLing, L. ZhiNiam, “Preparation and thermal stability on nonvacuum high temperature solar selective absorbing coatings”, Chin. Sci. Bull. 54 (2009) 1451-1454.]. SS Mo AlCrON AlCrOx after 168 hours at 600 ° C recorded small changes in microstructure and optical properties [H.D. Liu, T.R. Fu, M.H. Duan, Q. Wan, C. Luo, Y.M. Chen, D.J. Fu, F. Ren, Q.Y. Li, X.D. Cheng, B. Yang, X.J. Hu, "Structure and thermal stability of spectrally selective absorber based on AlCrON coating for solar-thermal conversion applications", Sol. Energy Mater. Sol. Cells 157 (2016) 108-116.].
    In previous works, a vacuum stability of SS Ag Mo-Si3N4 Si3N4 coatings has been published at 600 ° C (with values Į = 0.93 and İRT = 0.02 and İ600 ° C = 0.11) [E. Céspedes, M. Wirz, J.A. Sánchez-García, L. Alvarez-Fraga, R. Escobar-Galindo, C. Prieto, “Novel Mo – Si3N4 based selective coating for high temperature concentrating solar power applications”, Sol. Energy Mater. Sol. Cells 122 (2014) 217-225, WO2012172148 A1], which improves when the absorber is replaced by the MoSi2 – Si3N4 hybrid compound (with values Į = 0.88 and İRT = 0.02 and İ600ºC = 0.11) [D. Hernández-Pinilla, A. Rodríguez-Palomo, L. Álvarez-Fraga, E. Céspedes, J.E. Prieto, A. Muñoz-Martín, C. Prieto, “MoSi2 – Si3N4 absorb for high temperature solar selective coating”, Sol. Energy Mater. Sol. Cells 152 (2016) 141-146]. Optical properties have been recorded under vacuum annealing at 600 ° C for more than 200 hours for this SS Ag MoSi2 – Si3N4 Si3N4 stacking architecture. However, air stability remains a challenge.
    DESCRIPTION OF THE INVENTION
    The present invention discloses a selective high temperature solar coating deposited on a substrate based on a stable UV-Vis absorbent structure made with a hybrid silicide-nitride compound (called cermet) and a dielectric main anti-reflective layer in the Vis interval made with an oxide. Said selective solar coating has excellent air stability at high temperatures after indefinitely long periods of time. Such stability is based on the passivation that occurs when a film composed of a nitride of one element is covered by a layer composed of an oxide of another element other than nitride. In the coating of the present invention, the anti-reflective dielectric layer in the Vis interval is deposited on top of an absorbent structure in the UV-Vis and has a dual function: it acts as an anti-reflective layer in the Vis interval and also inhibits the
    passage of oxygen through it, preventing oxidation of the absorbent structure in the UV-Vis. The main advantages of the selective solar coating of the present invention are:
    5 x its air stability of up to 700 ° C x Its high solar absorbency and low thermal emissivity. x And its tunable capacity: the selective transition between visible absorbance and
    The infrared reflectance can be easily tuned to wavelengths, changing the thickness of the layers or the concentration of the compound.
    A first aspect of the present invention relates to a selective solar coating deposited on a substrate, said substrate is stable at a temperature of up to 700 ° C, characterized in that said selective solar coating is stable in a temperature range between room temperature and 700 ° C and comprises the following layers:
    15 x an UV-Vis absorbent structure that covers the substrate and comprises at least one main absorption film and a secondary absorption film,
    or in which each film is made with a hybrid compound of siliconuronitride or cermet,
    20 or in which the main absorption film has a fraction of metallic silicide higher in volume than the secondary absorption film, and
    or in which the main absorption film covers the substrate, x and an anti-reflective dielectric main layer in the Vis range that covers the absorbent layer in the UV-Vis and is made with AlxOy, SixOy or AlxSi1-xOy, in which the Ratio y / x varies between 1 and 2.
    The term "selective solar coating" of the present invention refers to a coating deposited on a substrate that exhibits a gradual transition of refractive index of the air to the substrate. As mentioned above, the selective solar coating of the present invention exhibits excellent air stability up to 700 ° C
    30 after indefinitely long periods of time and has high solar absorbency and low thermal emissivity.
    The substrate on which the selective solar coating of the present invention is deposited should be stable at a temperature of up to 700 ° C and should be able to reflect IR radiation, that is, it should be an IR mirror, or it should support an IR mirror
    35 on it to improve its reflectance in the IR interval. In the present invention, the UV-Vis absorbent structure that covers the substrate comprises at least one main absorption film and one secondary absorption film,
    or in which each film is made with a hybrid compound of siliconuronitride,
    5 or in which the main absorption film has a fraction of metallic silicide higher in volume than the secondary absorption film, and
    or in which the main absorption film covers the substrate. The UV-Vis absorbent structure of the present invention is preferably made of a hybrid silicide nitride compound comprising
    10 x at least one metallic silicide selected from a group consisting of MoSix, WSix, ZrSix, TiSix, CrSix or any alloy thereof, in which x varies between 1 and 2, and
    x a ceramic comprising a nitride of a metal selected from Si, Al, Cr or a mixture thereof, The absorbent structure in the UV-Vis is preferably formed by a silicon-nitride hybrid of MoSi2-Si3N4. Both absorption films, the main and the secondary, can be prepared in two different ways. In one of those ways, the cermet is deposited in multiple layers, as a result of sequential spraying.
    or of the silicide (MoSix, WSix, ZrSix, TiSix, CrSix or any alloy thereof) by means of a sputtering with argon and
    or of the nitride (a nitride of a metal selected from Si, Al, Cr or a mixture thereof) by sputtering, which reacts with argon and nitrogen to form the corresponding nitride.
    Preferably, each of the silicide layers should have an average thickness of 0.1 nm and 10 nm and the nitride layers should have an average thickness between 1 nm and 50 nm. The other method of preparation is performed by simultaneously depositing the silicide and
    The nitride by means of a joint reactive sputtering with nitrogen. The composition and metal fraction of the cermet of each film that forms the absorbent structure in the UV-Vis is controlled by means of the relative average thicknesses of the multiple layers or by means of the relative power applied to the cathodes in the case of the method of joint sputtering. In a preferred embodiment, the structure
    The absorber in the UV-Vis is between 40 nm and 200 nm thick. Preferably, the main absorption film of the absorbent structure in the UV-Vis has a thickness of
    between 20 nm and 70 nm. Preferably, the secondary absorption film of the absorbent structure in the UV-Vis has a thickness between 10 nm and 70 nm. Good absorbance values are obtained when the main absorption film of the absorbent structure in the UV-Vis, which covers the substrate, has a metal silicide fraction of between 20% and 70% by volume.
    In another preferred embodiment of the present invention, the secondary absorption film of the absorbent structure in the UV-Vis has a metal silicide fraction of between 5% and 50% by volume.
    The selective solar coating of the present invention comprises a layer
    10 main anti-reflective dielectric in the Vis range that covers the absorbent structure in the UV-Vis and is made with AlxOy, SixOy or AlxSi1-xOy, in which the ratio y / x varies between 1 and 2. Preferably, the main dielectric layer anti-reflective in the Vis interval is made with AlxOy, in which the ratio y / x varies between 1 and 2; more preferably of Al2O3 or SiO2.
    This layer is deposited by sputtering of aluminum or silicon or its oxides using an argon-oxygen gas mixture. In a preferred embodiment, the anti-reflective dielectric main layer in the Vis range has a thickness between 30 nm and 70 nm. In another preferred embodiment, the selective solar coating of the present invention
    20 is characterized in that it further comprises a secondary anti-reflective dielectric layer in the Vis interval, located between the absorbing structure in the UV-Vis and the main anti-reflective dielectric layer in the Vis interval and made with AlxNy, SixNy or CrxNy, in which the ratio y / x varies between 1 and 2. Preferably, the secondary anti-reflective dielectric layer in the Vis interval is made with SixNy, in which the ratio y / x varies between 1
    25 and 2; preferably between 1.2 and 1.4. This preferred formulation allows an improved barrier against oxidation of the absorbing structure in the UV. In another preferred embodiment, the anti-reflective dielectric layer in the Vis interval, formed by the main and secondary, anti-reflective dielectric layers in the Vis interval, has a thickness between 10 nm and 50 nm.
    Another aspect of the present invention relates to the process for obtaining the above-mentioned selective solar coating, which is characterized in that it comprises the following steps: a) depositing the absorbent structure in the UV-Vis on the substrate by sequential cathodic silicide sputtering metallic with argon and nitride layers with
    35 argon and nitrogen, and b) deposit the anti-reflective dielectric main layer in the Vis interval over the

    UV-Vis absorbent structure obtained in step (a) by spraying
    cathode of aluminum or silicon or its oxides using a gas mixture of argon
    oxygen.
    Preferably, each of the silicide layers should be 0.1 nm and 10 nm thick and the nitride layers should be between 1 nm and 50 nm thick.
    Another aspect of the present invention relates to another process for obtaining the above-mentioned selective solar coating, which is characterized in that it comprises the following steps:
    a) deposit the absorbent structure in the UV-Vis on the substrate by spraying
    joint reactive cathodic of the silicon and metal nitride layers with nitrogen, and
    b) deposit the anti-reflective dielectric main layer in the Vis interval over the
    UV-Vis absorbent structure obtained in step (a) by spraying
    cathode of aluminum, silicon or its oxides using a gas mixture of argon
    oxygen.
    In addition, depending on the nature of the layers and the thickness of the solar coating of the invention, the transition between the UV-Vis and IR regions can be conveniently moved for use from room temperature to 700 ° C, in order to improve the ratio of selectivity.
    The following aspect of the present invention relates to the process for obtaining the aforementioned solar coating which further comprises an anti-reflective dielectric secondary layer in the Vis range, located between the absorbing structure in the UV-Vis and the anti-reflective dielectric main layer in the range. Vis and made with AlxNy, SixNy or CrxNy, in which the ratio y / x varies between 1 and 2. This process is characterized by comprising: an additional stage (a´), between stage (a) and stage ( b), of deposition of the secondary anti-reflective dielectric layer in the Vis interval on the absorbing structure in the UV-Vis.
    The last aspect of the present invention relates to the solar thermal energy collector such as a conventional parabolic trough collector or a solar tower system for concentration solar thermal technology (CSP) characterized in that it comprises the selective solar coating of the The present invention deposited on the substrate, said substrate is a glass tube, a ceramic tube, a metal tube or a tube made of a metal alloy through which a fluid circulates at a temperature between room temperature and 700 ° C.
    The tube is then introduced into a vacuum chamber in order to deposit the solar coating of the present invention, that is, and the subsequent layers that form the coating, by means of a vapor phase deposition technique. An empty space

    Suitable residual should preferably have a pressure less than 1 x 10-4 mbar.
    In a preferred embodiment, the substrate is a glass tube, a metal tube or a tube made of a metal alloy with a roughness Ra of between 100 nm and 500 nm.
    In another preferred embodiment, the substrate is made of stainless steels annealed in air or made of Ni-Cr alloys.
    Unless otherwise defined, all the technical and scientific terms used in this document have the same meaning as that usually understood by an expert in the field to which this invention belongs. Methods and materials similar or equivalent to those described herein can be used to practice the present invention. "Throughout the description and the claims, the term" comprises "and its variants are not intended to exclude other features, additives, components or technical steps. Other objects, advantages and additional features of the invention will become apparent to those skilled in the art. the matter after examining the description or may be learned by practicing the invention The following examples and drawings are provided by way of illustration and are not intended to limit the present invention.
    BRIEF DESCRIPTION OF THE DRAWINGS
    Fig. 1 is a synthesis of the cross section of a coating as described in the present invention on a substrate. The numerical references correspond to the following parts and elements:
    (one)  Substratum.
    (2) IR mirror
    (3) Main absorption film in the UV-Vis interval.
    (4) Secondary absorption film in the UV-Vis interval.
    (5) Secondary anti-reflective dielectric layer in the UV-Vis range.
    (6) Main anti-reflective dielectric layer in the UV-Vis range.
    Fig. 2 shows the reflectance spectrum obtained with the coating shown in example 1, together with a reference spectrum of solar irradiance AM1.5 on the Earth's surface.
    Fig. 3 shows the reflectance spectrum obtained with the coating shown in example 2, together with a reference spectrum of AM1.5 solar irradiance on the Earth's surface.
    Fig. 4 shows the reflectance spectrum obtained with the coating shown in example 3, together with a reference spectrum of AM1.5 solar irradiance on the Earth's surface.

    EXAMPLES
    Example 1
     The Inconel®-625 alloy, taken as a substrate (1) is introduced into a vacuum chamber better than 2x10-6 mbar, in order to deposit layers by means of vapor deposition techniques.
    Once the vacuum conditions are adequate, it is possible to deposit the visible radiation absorbing layer. In this example, a double absorption hybrid has been deposited; The main absorption film (3) deposited in this example has a metal fraction of 50% by volume and the secondary absorption film (4) has a metal fraction of 10% by volume.
    In the main absorption film (3), five bilayers have been deposited successively, each consisting of 5 nm of silicon nitride and 5 nm of molybdenum disilicide. The silicon nitride layer was first deposited by sputtering silicon under a nitrogen atmosphere, to achieve the reaction, then the simultaneous sputtering of molybdenum disilicide was carried out by means of silicon and molybdenum targets, by inert argon gas.
    In the secondary absorption film (4) five bilayers were deposited successively, each of which is formed by 9 nm of silicon nitride and 1 nm of molybdenum disilicide. The silicon nitride layer was deposited by sputtering silicon in a nitrogen atmosphere, to achieve the reaction, followed by simultaneous sputtering of molybdenum disilicide by means of silicon and molybdenum targets, by inert argon gas.
    Subsequently, an anti-reflective dielectric layer was deposited in the UV-Vis (6) range of 66 nm thick made with aluminum oxide by sputtering aluminum oxide under argon atmosphere.
    This coating has been optically characterized in order to determine the absorbance and thermal emissivity. To reproduce the working conditions, annealing cycles have been performed in air for 100 hours at 600 ° C. In Fig. 2, the reflectance obtained after four cycles of annealing in air has been shown for a coating such as the one described above, in which, in comparison, the solar irradiance spectrum on the earth's surface has also been represented .
    The solar absorbance value obtained when the calculation is made between 250 nm and 2500 nm is 0.93. In addition, the value of thermal emissivity at room temperature is 0.15 (evaluated between 1 μm and 30 μm), which gives a selectivity factor of 6.2. The value of

    Emissivity calculated at 600 ° C is 0.34, which results in a selectivity factor of 2.74.
    Example 2
     The Inconel®-625 alloy, taken as a substrate (1) that is introduced into a vacuum chamber better than 2x10-6 mbar, in order to deposit layers by vapor deposition techniques.
    Once the vacuum conditions are adequate, it is possible to deposit the visible radiation absorbing layer. In this example, a double absorption hybrid has been deposited; The main absorption film (3) deposited in this example has a metal fraction of 60% by volume and the secondary absorption film (4) has a metal fraction of 10% by volume.
    In the main and secondary absorption films (3 and 4), silicon nitride and molybdenum disilicide were deposited by simultaneous sputtering of silicon targets and molybdenum disilicide, by means of a gaseous mixture of argon and nitrogen with a respective content from 80% - 20%.
    Subsequently, a double anti-reflective dielectric layer was deposited in the UV-VIS range. The secondary anti-reflective dielectric layer (5) that is 20 nm thick made of silicon nitride was deposited by means of a cathodic silicon spray under a nitrogen atmosphere and the second anti-reflective dielectric layer (6) that is 40 nm thick made of Aluminum oxide was deposited by means of a sputtering of aluminum oxide under argon.
    This coating has been optically characterized in order to determine the absorbance and thermal emissivity. To demonstrate stability at high temperatures, an annealing has been performed in air at 700 ° C for 15 hours. In Fig. 3, the reflectance obtained after annealing in air at 700 ° C is shown for a coating such as the one described above, in which, in comparison, the solar irradiance spectrum on the earth's surface has also been represented.
    The absorbance value obtained when the calculation is made between 250 nm and 2500 nm is 0.92. In addition, the emissivity value is 0.13 (evaluated between 1 μm and 30 μm), which gives a selectivity factor of 7.1. The emissivity value calculated at 700 ° C is 0.30, which results in a selectivity factor of 3.1.

    Example 3
    The AISI-321 steel, taken as a substrate (1) that has been polished to a roughness Ra of 200 nm, is brought to a temperature of 600 ° C in open air for a period of half an hour to develop a layer of anti-diffusion barrier, made with a mixed oxide of iron and chromium, which acts as a barrier layer between the steel and the main absorption film (3).
    Subsequently, once cooled, it is introduced into a vacuum chamber better than 2x10-6 mbar, in order to deposit layers using vapor deposition techniques.
    Once the vacuum conditions are adequate, it is possible to deposit the visible radiation absorbing layer. In this example, a single absorption hybrid has been deposited; The hybrid absorption film (3) deposited in this example has a metal fraction of 68% by volume. Five bilayers have been deposited successively, each consisting of 6 nm, of silicon nitride and 12.6 nm of molybdenum disilicide. The layers of silicon nitride were deposited by sputtering silicon in a nitrogen atmosphere to achieve the reaction, then the simultaneous sputtering of molybdenum disilicide was carried out by means of silicon and molybdenum targets, by inert argon gas.
    Subsequently, a double anti-reflective dielectric layer was deposited in the UV-Vis range. The secondary anti-reflective dielectric layer (5) that is 30 nm thick of silicon nitride was deposited by means of the sputtering of silicon under nitrogen atmosphere and the second anti-reflective dielectric layer (6) that is 40 nm thick of oxide of Aluminum was deposited by means of a sputtering of aluminum oxide under argon.
    This coating has been optically characterized in order to determine the absorbance and thermal emissivity. Therefore, a spectroscopic study was carried out in the UV-VIS-IR range, which covers the entire range of the solar spectrum and the wavelength range emitted by bodies at typical operating temperatures in solar collectors. In Fig. 4, the reflectance obtained after annealing in air at 500 ° C is shown for a coating like the one described above, in which the solar irradiance spectrum on the earth's surface has also been represented by comparison.
    The solar absorbance value obtained when the calculation is made between 250 nm and 2500 nm is 0.90. In addition, the thermal emissivity value is 0.18 (evaluated between 1 μm and 30 μm), which gives a selectivity factor of 5.0. The emissivity value calculated at 500 ° C is 0.38, which results in a selectivity factor of 2.4.
    权利要求:
    Claims (15)
    [1]
    1. A selective solar coating deposited on a substrate, said substrate being stable at a temperature of up to 700 ° C, characterized in that said selective solar coating 5 is stable at a temperature range between room temperature and 700 ° C and comprises the following layers :
    x an UV-Vis absorbent structure that covers the substrate and comprises at least one main absorption film and a secondary absorption film,
    10 or in which each film is made with a hybrid compound of siliconuronitride,
    or in which the main absorption film has a fraction of metallic silicide higher in volume than the secondary absorption film, and
    or in which the main absorption film is coating the substrate,
    15 x and an anti-reflective dielectric main layer in the Vis range that covers the absorbing layer in the UV-Vis and is formed by AlxOy, SixOy or AlxSi1-xOy, in which the ratio y / x varies between 1 and 2.
    [2]
    2. The selective solar coating according to claim 1, characterized in that the absorbent structure in the UV-Vis is composed of a siliconuronitride hybrid material comprising
    x at least one metallic silicide selected from a group consisting of MoSix, WSix, ZrSix, TiSix, CrSix or any alloy thereof, in which x varies between 1 and 2; Y
    25 x a ceramic comprising a nitride of a metal selected from Si, Al, Cr or a mixture thereof,
    [3]
    3. The selective solar coating according to claim 2, characterized by
    that the absorbent structure in the UV-Vis is made with a silicon-nitride hybrid of 30 MoSi2-Si3N4.
    [4]
    4. The selective solar coating according to any of claims 1 to 3, characterized in that the absorbent structure in the UV-Vis is between 40 nm and 200 nm thick.
    [5]
    5. The selective solar coating according to any one of claims 1 to
    4, characterized in that the main absorption film of the absorbent structure in the UV-Vis has a thickness between 20 nm and 70 nm.
    [6]
    6. The selective solar coating according to any one of claims 1 to
    5 5, characterized in that the secondary absorption film of the absorbent structure inUV-Vis is between 10 nm and 70 nm thick.
    [7]
    7. The selective solar coating according to any of claims 1 to
    6, characterized in that the main absorption film of the absorbent structure in the UV-Vis has a metal silicide fraction of between 20% and 70% by volume.
    [8]
    8. The selective solar coating according to any one of claims 1 to 7, characterized in that the secondary absorption film of the absorbent structure in the UV-Vis has a metal silicide fraction of between 5% and 50% by volume.
    [9]
    9. The selective solar coating according to any of claims 1 to 8, characterized in that the anti-reflective dielectric main layer in the Vis range has a thickness between 30 nm and 70 nm.
    The selective solar coating according to any of claims 1 to 9, characterized in that the main anti-reflective dielectric layer in the Vis range is made of AlxOy, SixOy or AlxSi1-xOy, in which the ratio y / x varies between 1 and 2; preferably made with Al2O3 or SiO2.
    The selective solar coating according to any one of claims 1 to 10, characterized in that it further comprises a secondary anti-reflective dielectric layer in the Vis range, located between the absorbent structure in the UV-Vis and the main anti-reflective dielectric layer in the Vis interval and made with AlxNy, SixNy or CrxNy, in which the ratio y / x varies between 1 and 2.
    [12]
    12. The selective solar coating according to any of claims 1 to 11, characterized in that the secondary anti-reflective dielectric layer in the Vis range is made with SixNy, in which the ratio y / x varies between 1 and 2; preferably between 1.2 and 1.4.
    [13]
    13. The selective solar coating according to any of claims 1 to
    12, characterized in that the anti-reflective dielectric layer in the Vis interval formed by the main and secondary, anti-reflective dielectric layer in the Vis interval, has a thickness between 10 nm and 50 nm.
    5 14. A process to obtain the selective solar coating according to any
    of claims 1 to 13, characterized in that it comprises the following steps: a) depositing the absorbent structure in the UV-Vis onto the substrate by sequential sputtering of a metal silicon with argon and the nitride layers with argon and nitrogen, Y
    10 b) depositing the anti-reflective dielectric main layer in the Vis interval on the UV-Vis absorbent structure obtained in step (a) by sputtering aluminum, silicon or its oxides using a gaseous argon-oxygen mixture.
    15. A process for obtaining the selective solar coating according to any of claims 1 to 13, characterized in that it comprises the following steps: a) depositing the absorbent structure in the UV-Vis on the substrate by joint reactive sputtering of the metal silicide and nitride layers with nitrogen, and
    20 b) depositing the anti-reflective dielectric main layer in the Vis interval on the UV-Vis absorbent structure obtained in step (a) by sputtering aluminum or aluminum oxide using a gaseous argon-oxygen mixture.
    [16]
    16. A process to obtain the selective solar coating according to any
    25 of claims 11 to 13, characterized in that it comprises an additional stage (a '), between stage (a) and stage (b), of deposition of a secondary anti-reflective dielectric layer in the Vis range on the absorbent structure in the UV-Vis.
    [17]
    17. A solar thermal energy collector such as a parabolic trough collector
    Conventional or a solar tower system for concentration solar thermal energy technology characterized in that it comprises the selective solar coating according to any of claims 1 to 13 deposited on a substrate, said substrate is a glass tube, a ceramic tube , a metal tube or a tube made of a metal alloy through which a fluid circulates at a temperature between a temperature
    35 environment and 700 ° C.
    [18]
    18. The solar thermal energy collector according to claim 17, characterized in that the substrate is a glass tube, a metal tube or a tube made of a metal alloy with a roughness Ra of between 100 nm and 500 nm.
    [19]
    19. The solar thermal energy collector according to claim 17, characterized in that the substrate is made of stainless steels or made of Ni-Cr alloys.
    FIG. one
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    同族专利:
    公开号 | 公开日
    ES2689556B1|2019-09-09|
    WO2018115565A1|2018-06-28|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    ITRM20080113A1|2008-02-29|2009-09-01|Enea Ente Per Le Nuove Tecnologie, L Energia...|METHOD FOR THE MANUFACTURE OF A CONSTRUCTIVE SELECTIVE CERMET-BASED COATING FOR THE RECEIVER TUBE OF A SOLAR CONCENTRATOR AND MATERIAL SO IT IS OBTAINED|
    US20140144426A1|2011-06-16|2014-05-29|Consejo Superior De Investigaciones Científicas |Covering that selectively absorbs visible and infrared radiation, and method for the production thereof|
    US20140261390A1|2013-03-13|2014-09-18|Brightsource Industries Ltd.|High temperature radiation-selective coating and related apparatus|
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    ES201631654A|ES2689556B1|2016-12-22|2016-12-22|SELECTIVE SOLAR COATING|ES201631654A| ES2689556B1|2016-12-22|2016-12-22|SELECTIVE SOLAR COATING|
    PCT/ES2017/070842| WO2018115565A1|2016-12-22|2017-12-22|Selective solar coating|
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