WO2017013607A1 - Procédé de coloration structurale d'aluminium anodisé par formation de cristaux photoniques au moyen d'impulsions de courant - Google Patents

Procédé de coloration structurale d'aluminium anodisé par formation de cristaux photoniques au moyen d'impulsions de courant Download PDF

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Publication number
WO2017013607A1
WO2017013607A1 PCT/IB2016/054327 IB2016054327W WO2017013607A1 WO 2017013607 A1 WO2017013607 A1 WO 2017013607A1 IB 2016054327 W IB2016054327 W IB 2016054327W WO 2017013607 A1 WO2017013607 A1 WO 2017013607A1
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Prior art keywords
current density
time
metal
current
periodic pulses
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Ceased
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PCT/IB2016/054327
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English (en)
Spanish (es)
Inventor
Ernesto Julio Calvo
María Luz MARTINEZ RICCI
Leandro MISSONI
Franco OJEDA
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Consejo Nacional de Investigaciones Cientificas y Tecnicas CONICET
Inis Biotech LLC
Original Assignee
Consejo Nacional de Investigaciones Cientificas y Tecnicas CONICET
Inis Biotech LLC
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Publication of WO2017013607A1 publication Critical patent/WO2017013607A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/024—Anodisation under pulsed or modulated current or potential
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
    • C25D11/08—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing inorganic acids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
    • C25D11/10—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing organic acids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/12—Anodising more than once, e.g. in different baths
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/14—Producing integrally coloured layers
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/16—Pretreatment, e.g. desmutting
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/18—After-treatment, e.g. pore-sealing
    • C25D11/20—Electrolytic after-treatment
    • C25D11/22—Electrolytic after-treatment for colouring layers

Definitions

  • the present invention relates to the area of structural coloration of a substrate and more specifically to the structural coloration of an aluminum substrate by the formation of one-dimensional photonic crystals through a pulse anodization.
  • the coloration of aluminum by means of anodizing is widely used in applications of both structural, profiling, and even design objects.
  • Anodizing is a process of surface electrochemical oxidation that is carried out by electrolysis in an acid medium using the metal to be anodized as an anode.
  • the generated oxide acquires a nanoporous structure.
  • This nanoporous structure has pores of cylindrical geometry whose section size depends on the current densities and application times.
  • the pigments (such as anilines) diffuse into the pores of the alumina thus providing the desired color.
  • electrocolor coloring metals are electrodeposted at the bottom of the pores, and the tone of the final color, produced by interference of the light reflected in the base aluminum and in the deposited metal, depends on the amount of said deposited metal. Few electrodeposltado metals produce light colors and more produce dark colors.
  • Photon crystals for example 1-D or 1-D photon crystals, are structures with periodic structural and constitutive properties (spatial periods and refractive indices) that modify the propagation of light Incident in the structure, generating a phenomenon of destructive interference for a given Interval of wavelengths, or more specifically, colors.
  • the reflectivity in this Wavelength Range is maxlmlza, thus generating a prohibited band of the photon crystal (BPCF). Due to this principle, the color obtained is brighter at a lower cost.
  • This technique has a marked difference in the range of colors that can be obtained in comparison with the electrodeposition of metals (electrocolor), which usually results in opaque colors in the range of brown / gold tones.
  • the interference of the light that is reflected from the photonic structure can produce colors that vary according to the angle of observation. This phenomenon is due to the difference in optical paths that light travels as it travels at different angles through the material. As the angle of the light beam increases, with respect to the normal surface, the prohibited band of the photonic crystal (BPCF) shifts towards shorter wavelengths, altering the observed color. This can be understood as a shift towards the blue color as the angle of the light beam increases.
  • BPCF photonic crystal
  • This property is difficult to obtain by other coloring methods and is decoratively attractive, especially in design applications such as eyeglass frames, card holders, aerosol packaging applications, etc.
  • the times of each pulse and the amount of pulses needed to obtain a certain color with this method are very high, taking between 28 and 43 hours to color an article, according to the desired color.
  • the method requires a compensation system that regulates the time of each pulse based on the depth of the anodizing .
  • the method requires the use of high purity aluminum (99.99%).
  • US patent application US 2013/0299353 A1 in the name of Catcher Technology Co., Ltd., published on 1/14/2013 discloses a method for obtaining structural coloration on an aluminum substrate whose observed color depends on the angle of the observer.
  • said request does not disclose a direct relationship between the formation of a photonic structure and the color obtained, nor the sharpness of the resulting color. Additionally, said method does not use a multilayer photonic structure.
  • the method of coloring of the present invention requires a relatively short process time and does not require compensatory methods or complex adjustments.
  • the present invention provides a quick and economical method to produce a clear structural coloration in an aluminum substrate comprising the formation of a one-dimensional photon crystal structure in said aluminum substrate, which provides coloration by light interference without the need for pigments. , and that uses commercial grade electrolytic materials and baths.
  • the method of structural coloring of anodised aluminum of the present invention comprises the steps of:
  • a third electrodeposlclon process of a metal such as tin, nickel, cobalt, copper, etc. at the bottom of nanopores; wherein the profile of the periodic pulses used for the second anodlzaclon process is shaped as a rectangular current density profile, formed by a first maximum current density value (l max ), applied during a maximum current density time (t max ), followed by a second minimum current density value (l m ⁇ n ), applied for a period of minimum current density (t min ), where the maximum current density time and the minimum current density time determine the color obtained.
  • a metal such as tin, nickel, cobalt, copper, etc.
  • the maximum current density corresponds to l max values between 20-70 mA / cm2 and the minimum current density m ⁇ n l corresponds to between 2-40 mA / cm 2.
  • the second anodizing process uses an amount of pulses not less than 30 periodic pulses.
  • the aluminum substrate is a commercial alloy.
  • the first constant potential anodizing process is performed between 10-25 V, for 5-30 min.
  • the electrolytic bath of the first constant potential anodizing process comprises an acid selected from sulfuric, phosphoric or oxalic acid with a concentration between 5-25% w / v.
  • the electrolytic bath of the second current anodization process in the form of periodic pulses uses the same electrolytic bath as the first anodization process at constant potential.
  • the electrodeposited metal during the third electrodeposition process of a metal is nickel.
  • the third electrodeposition process of a metal is carried out using concentrated solutions of salts thereof, such as tin, nickel, cobalt, copper salts, etc.
  • the third electrodeposition process of a metal is an electrodeposition by current cycles.
  • null resting current density l rep for a resting time t re between 25-100 ms.
  • the aluminum substrate prior to the first anodization process at constant potential, is subjected to a wash with acetone or water and subsequently dried with a stream of nitrogen or dry air.
  • the aluminum substrate prior to the second current anodizing process in the form of periodic pulses, is subjected to a wash with deionized water.
  • the aluminum substrate is subjected to a wash with deionized water and subsequently dried with a stream of nitrogen or dry air.
  • the desired color is obtained by setting the maximum current density time and regulating the minimum current density time in the second current anodization process in the form of periodic pulses.
  • the desired color is obtained by setting the minimum current density time and regulating the maximum current density time in the second current anodizing process in the form of periodic pulses.
  • Figure 1 illustrates the photonic multilayer nanostructure produced by the structural coloring method of the present invention.
  • Figure 2 illustrates an example of current density pulse profile for current anodization in the form of periodic pulses according to the structural coloring method of the present invention.
  • Figure 3 illustrates an example of current density pulse profile for metal electrodeposition by current cycles according to the structural coloring method of the present invention.
  • Figure 4 shows the variation of the color obtained as a function of the thickness of one of the photonic crystal layers of the photonic structure and the observation angle according to an assay of the method of structural coloring of the present invention.
  • Figures 5a and 5b illustrate the diffuse reflectance spectra of the photon structures of the colors obtained according to the method of structural coloring of the present invention.
  • the structural coloring method of the present invention is a method for obtaining the controlled formation of a structure of one-dimensional photonic crystals on an aluminum substrate.
  • the purpose of this photonic structure is to obtain a color without pigmentation that has a variable color depending on the angle of the observer.
  • a transparent protective layer one .
  • this protective layer is to prevent the dissolution of the first layers of the photonic structure at the time of current anodizing in the form of periodic pulses; since alumina is soluble in sulfuric acid.
  • This protective layer does not modify the colors generated by the photonic structure, since it is formed so that its thickness does not interfere with the wavelengths reflected by the photonic crystal.
  • the size of the pore sections of this protective layer varies between 13 and 50 nm. 2.
  • the photonic structure itself is a one-dimensional periodic porous layer, product of an anodizing process, which defines the final color of the substrate.
  • the photonic structure is obtained by anodizing the aluminum substrate with a periodic pulse current, which is to say, with a current that varies periodically between a maximum current density and a density of minimum current
  • Said pulse current anodizing process produces a photonic nanostructure consisting of a plurality of nanometric porous layers disposed one above the other, corresponding to the anodizing pulses.
  • these types of structures are known in the art as one-dimensional photonic crystals.
  • the final color obtained depends on the index of refraction and the thickness of each layer. These two parameters of structure formation can be adjusted by controlling the density of the maximum and minimum currents in the anodizing pulses and the application time of said maximum currents and in order to obtain the desired color.
  • an electrodeposition of a metal is performed to give the structure a dark background.
  • Said dark background in conjunction with the photonic structure allows to obtain a color of greater brightness. This principle is based on the fact that the light that is reflected from the structure not only corresponds to the light reflected by the prohibited band of the photonic crystal (BPCF) but also by spurious light coming from the reflection in the aluminum, which alters the final color of the substrate.
  • the dark background product of the Metal electrodeposition absorbs the wavelengths of these unwanted reflections, allowing to obtain a more defined and brighter color.
  • the structural coloring method of the present invention comprises the steps of:
  • the substrate to be colored is washed and degreased by an acetone bath and subsequently dried in a stream of nitrogen or dry air.
  • the protective layer is formed by anodizing the aluminum substrate with direct current. This anodizing process is typically performed. maintaining a constant potential (10-25 V) for a predefined time, (5-30 min) in a solution of sulfuric acid with a concentration of 5-25% m / V.
  • the photonic nanostructure is the layer of material that provides the structural color to the aluminum substrate.
  • Said structure is formed by anodizing the aluminum substrate by means of a current in the form of periodic pulses. This anodizing process is carried out by applying numerous current pulses, preferably more than 30, in the same electrolytic bath used in the previous stage.
  • a rectangular current density pulse profile is established consisting of a positive constant maximum current density value between 20-70 mA / cm 2 , applied during a density time maximum current, followed by a positive minimum current density value between 2-40 mA / cm 2 , applied during a minimum current density time, as shown in the diagram in Figure 2. Varying the application time From these current densities in relation to each other, different colors can be obtained on the surface.
  • the substrate Prior to the metal electrodeposlclone stage, the substrate is washed with delifted water.
  • the aluminum substrate is subjected to an electrodeposition of a metal such as nickel, tin, cobalt or copper with a cycle current.
  • Said metal electrodeposition is preferably performed by applying between 250-1000 current cycles according to the current density profile illustrated in Figure 3.
  • the electrodeposited metal is nickel.
  • the substrate is washed again with deionized water and dried with a stream of nitrogen or dry air.
  • the resulting nanostructure is illustrated in Figure 1 typically with micrometric thicknesses and results in a structural, bright and crisp coloration, the color of which varies according to the angle of observation.
  • the total time of application of the method is approximately 30 minutes, unlike the techniques known in the art, whose processes can take several hours, which provides a great economy of resources with the consequent reduction of costs.
  • the refractive index and the thickness of the layers of the photonic structure modifies both parameters, while the time modifies mainly the thickness. Due to these relationships, it is substantially simpler to modify only the current application time and maintain the maximum and minimum current densities at respective fixed values. More specifically, the maximum and minimum current density values (l max , l m ⁇ n ) are set, the application time of one of the maximum current density or the minimum current density is set and the various colors are tuned varying the time of application of the other. Consequently, it is possible to synthesize different nanostructures that reflect colors throughout the visible spectrum.
  • Colors were obtained by reflection in the shades of violet, blue, green, orange, brown or brown, etc. varying the pulse times of l max and l m ⁇ personallybetween 5 and 50 seconds. In each case you can set the time t max , for example. in 5 seconds and vary the time t m ⁇ personallybetween 5 and 50 seconds. On the other hand, in a second In carrying out the method, the application time of the minimum current density l min in 20 seconds is set and the application time of the maximum current l max is varied to obtain the desired color.
  • the color obtained is variable according to the angle of observation as seen in Figure 4.
  • the color change with the angle is a characteristic property of photonic crystals, due to the difference in optical paths that light travels as it travels at different angles through the material.
  • the photonic band gap shifts towards shorter wavelengths, that is, color shift towards blue.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Abstract

L'invention concerne un procédé de coloration structurale pour colorer un substrat d'aluminium qui comprend la formation d'une nanostructure de cristaux photoniques unidimensionnels au moyen d'un procédé d'anodisation avec courant par impulsions périodiques, la couleur obtenue dépendant du temps d'application de la densité de courant maximum et/ou minimum de l'impulsion et ladite couleur variant selon l'angle d'observation.
PCT/IB2016/054327 2015-07-21 2016-07-20 Procédé de coloration structurale d'aluminium anodisé par formation de cristaux photoniques au moyen d'impulsions de courant Ceased WO2017013607A1 (fr)

Applications Claiming Priority (2)

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ARP20150102317 2015-07-21
ARP150102317A AR102806A1 (es) 2015-07-21 2015-07-21 Método de coloración estructural de aluminio anodizado por formación de cristales fotónicos mediante pulsos de corriente

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3068712A1 (fr) * 2017-07-10 2019-01-11 Constellium Rolled Products Singen Gmbh & Co.Kg Produit lamine en alliage d’aluminium ayant des couleurs iridescentes intenses
CN109989086A (zh) * 2019-04-19 2019-07-09 河北工业大学 一种具有高饱和度结构色的多孔氧化铝光子晶体薄膜的制备方法
FR3077303A1 (fr) * 2018-01-30 2019-08-02 Sgi Societe De Galvanoplastie Industrielle Procede d'anodisation et systeme associe

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3892636A (en) * 1972-06-06 1975-07-01 Riken Light Metal Ind Co Method for producing a colored oxide film on an aluminum or aluminum alloy
JP3101606B2 (ja) * 1998-06-15 2000-10-23 日本軽金属株式会社 アルミニウム材料の電解着色方法
US20130299353A1 (en) 2012-05-12 2013-11-14 Catcher Technology Co., Ltd. Method of forming interference film on surface of aluminum alloy substrate

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3892636A (en) * 1972-06-06 1975-07-01 Riken Light Metal Ind Co Method for producing a colored oxide film on an aluminum or aluminum alloy
JP3101606B2 (ja) * 1998-06-15 2000-10-23 日本軽金属株式会社 アルミニウム材料の電解着色方法
US20130299353A1 (en) 2012-05-12 2013-11-14 Catcher Technology Co., Ltd. Method of forming interference film on surface of aluminum alloy substrate

Non-Patent Citations (3)

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Title
CHEN YUTING ET AL: "On The Generation of Interferometric Colors in High Purity and Technical Grade Aluminum: An Alternative Green Process for Metal Finishing Industry", ELECTROCHIMICA ACTA, vol. 174, 20 June 2015 (2015-06-20), pages 672 - 681, XP029251053, ISSN: 0013-4686, DOI: 10.1016/J.ELECTACTA.2015.06.066 *
LIUYISEN; CHANG YI; LINGZHIYUAN; HUXING; Y LI YI: "Structural coloríng of aluminum", 2011, ELSEVIER
MIRZAEI M ET AL: "Influence of pulse currents on the nanostructure and color absorption ability of colored anodized aluminum", VACUUM, vol. 99, 1 January 2014 (2014-01-01), pages 277 - 283, XP028694784, ISSN: 0042-207X, DOI: 10.1016/J.VACUUM.2013.06.019 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3068712A1 (fr) * 2017-07-10 2019-01-11 Constellium Rolled Products Singen Gmbh & Co.Kg Produit lamine en alliage d’aluminium ayant des couleurs iridescentes intenses
WO2019011778A1 (fr) 2017-07-10 2019-01-17 Constellium Rolled Products Singen Gmbh & Co.Kg Produit laminé en alliage d'aluminium à couleurs iridescentes intenses
FR3077303A1 (fr) * 2018-01-30 2019-08-02 Sgi Societe De Galvanoplastie Industrielle Procede d'anodisation et systeme associe
CN109989086A (zh) * 2019-04-19 2019-07-09 河北工业大学 一种具有高饱和度结构色的多孔氧化铝光子晶体薄膜的制备方法
CN109989086B (zh) * 2019-04-19 2020-11-03 河北工业大学 一种具有高饱和度结构色的多孔氧化铝光子晶体薄膜的制备方法

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