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CN-122013277-A - Preparation method for constructing multi-size light absorption coating by doping low-refractive-index particles

CN122013277ACN 122013277 ACN122013277 ACN 122013277ACN-122013277-A

Abstract

A preparation method for constructing a multi-size light absorption coating by doping particles with low refractive index relates to a preparation method for a light absorption coating. The invention aims to improve the absorptivity and emissivity of black coatings used in the existing heat protection field. The SiO 2 nano particles are used as doped particles, the coating is obtained through a plasma electrolytic oxidation method, siO 2 NPs are doped into the coating, so that the surface of the coating has low equivalent refractive index, reflection can be effectively reduced, the coating has a multi-size micro-nano surface structure, forward scattering can be enhanced by the nano structure, absorption and scattering of light in a solar spectrum range are promoted by the coating, light scattering of an infrared wave band is promoted by the coating due to the micro-protrusion structure, optical path is increased, and infrared emission performance of the coating is improved. The excellent absorption and emission properties allow the coating to have good thermal control properties, with great potential for long-term use outdoors and under extreme environmental conditions.

Inventors

  • YAO ZHONGPING
  • ZHANG XUDONG
  • LU SONGTAO
  • WU XIAOHONG

Assignees

  • 哈尔滨工业大学

Dates

Publication Date
20260512
Application Date
20260209

Claims (10)

  1. 1. The preparation method for constructing the multi-size light absorption coating by doping low-refractive-index particles is characterized by comprising the following steps of: 1. Polishing the TC4 plate by using sand paper, and cleaning to obtain a treated TC4 plate; 2. preparing an electrolyte: Dissolving SiO 2 nano particles, sodium polyphosphate, EDTA, sodium hexametaphosphate, feSO 4 , sodium metasilicate, nickel acetate and ammonium metavanadate into deionized water to obtain electrolyte; 3. And connecting the treated TC4 plate with the positive electrode of a power supply, connecting an electrolytic tank with the negative electrode of the power supply, pouring electrolyte into the electrolytic tank, continuously stirring, preparing a coating on the TC4 plate by adopting a plasma electrolytic oxidation technology, washing and drying after the reaction is finished, and obtaining the low-refractive-index particle doped construction multi-size light absorption coating.
  2. 2. The method for preparing the multi-size light absorbing coating constructed by doping low-refractive-index particles according to claim 1, wherein in the first step, the TC4 plate is polished by sequentially using 600#, 800#, 1200# and 1500# sand paper, and then is cleaned by sequentially using absolute ethyl alcohol and acetone, so that the treated TC4 plate is obtained.
  3. 3. The preparation method of the multi-size light-absorbing coating constructed by doping low-refractive-index particles, which is disclosed in claim 1, is characterized in that the particle size of SiO 2 nano particles in the second step is 15-200 nm, and the concentration of SiO 2 nano particles in the electrolyte in the second step is 0.25-1.5 g/L.
  4. 4. The method for preparing the multi-size light-absorbing coating by doping low-refractive-index particles according to claim 1, wherein the concentration of sodium polyphosphate in the electrolyte in the second step is 0.5-2 g/L.
  5. 5. The method for preparing the multi-size light-absorbing coating by doping low-refractive-index particles according to claim 1, wherein the concentration of EDTA in the electrolyte in the second step is 15-25 g/L.
  6. 6. The method for preparing the multi-size light-absorbing coating by doping low-refractive-index particles according to claim 1, wherein the concentration of sodium hexametaphosphate in the electrolyte in the second step is 4-5 g/L.
  7. 7. The method for preparing the multi-size light-absorbing coating by doping low-refractive-index particles according to claim 1, wherein the concentration of FeSO 4 in the electrolyte in the second step is 4-6 g/L.
  8. 8. The method for preparing the multi-size light-absorbing coating by doping low-refractive-index particles according to claim 1, wherein the concentration of sodium metasilicate in the electrolyte in the second step is 5-7 g/L.
  9. 9. The preparation method of the multi-size light-absorbing coating constructed by doping low-refractive-index particles according to claim 1, wherein the concentration of nickel acetate in the electrolyte in the second step is 4-6 g/L, and the concentration of ammonium metavanadate in the electrolyte in the second step is 2-4 g/L.
  10. 10. The preparation method of the multi-size light-absorbing coating constructed by doping low-refractive-index particles is characterized in that the plasma electrolytic oxidation technology in the third step adopts 350-450V voltage, 20-30% duty ratio, 800-1000 Hz frequency and 10-20 min reaction time, and the washing in the third step is carried out by sequentially using distilled water and absolute ethyl alcohol.

Description

Preparation method for constructing multi-size light absorption coating by doping low-refractive-index particles Technical Field The invention relates to a preparation method of a light-absorbing coating, in particular to a preparation method of a multi-size light-absorbing coating constructed by doping particles with low refractive index. Background The black thermal control coating with high light absorptivity and emissivity is coated on the surface of the spacecraft component, and can be widely used for enhancing the heat absorption or heat dissipation capacity of the spacecraft component. Processes for preparing black thermal control coatings are diverse, including laser cladding, chemical vapor deposition, hydrothermal processes, and Plasma Electrolytic Oxidation (PEO). Among them, PEO is attracting attention because of its low cost, low pollution, easy operation, and the advantages of the prepared coating such as excellent thermal control properties, reliable mechanical strength, good thermal stability, and sufficient bonding strength. Plasma Electrolytic Oxidation (PEO) is a surface treatment technique suitable for aluminum, magnesium, titanium and alloys thereof, and can be used to prepare different types of thermal control coatings. One significant advantage of PEO technology is the ability to control the morphology of the resulting coating by adjusting process parameters, thereby affecting its light absorption properties. However, the ability to adjust the light absorption characteristics of the coating by varying the process parameters is limited, and under certain conditions, such as high voltage or low frequency, the coating composition may become non-uniform, even with blistering, which can adversely affect the optical and mechanical properties of the coating. Another significant advantage of PEO technology is its ability to introduce elemental doping from an electrolyte. By adding ferric salt, cupric salt, nickel salt and the like into the electrolyte, corresponding oxide is generated on the surface of the coating, and besides ion doping can be carried out in the electrolyte, particle doping can also be carried out in the electrolyte. TiO 2,Cr2O3, graphene (rGO) and other particles are added into the electrolyte, so that the coating composition is improved, and the morphology of the coating is regulated and controlled. The elemental doping has a significant advantage over adjusting the process parameters in enhancing the light absorption properties by changing the constituent structure of the coating. However, a reasonable and accurate choice of doping substances is critical to improving coating performance and currently faces a great challenge. Disclosure of Invention The invention aims to improve the absorptivity and emissivity of a black coating used in the existing thermal protection field, and provides a preparation method for constructing a multi-size light absorption coating by doping particles with low refractive index. The preparation method for constructing the multi-size light absorption coating by doping low-refractive-index particles comprises the following steps: 1. Polishing the TC4 plate by using sand paper, and cleaning to obtain a treated TC4 plate; 2. preparing an electrolyte: Dissolving SiO 2 nano particles, sodium polyphosphate, EDTA, sodium hexametaphosphate, feSO 4, sodium metasilicate, nickel acetate and ammonium metavanadate into deionized water to obtain electrolyte; 3. And connecting the treated TC4 plate with the positive electrode of a power supply, connecting an electrolytic tank with the negative electrode of the power supply, pouring electrolyte into the electrolytic tank, continuously stirring, preparing a coating on the TC4 plate by adopting a plasma electrolytic oxidation technology, washing and drying after the reaction is finished, and obtaining the low-refractive-index particle doped construction multi-size light absorption coating. The principle of the invention is as follows: According to the invention, siO 2 nano particles (SiO 2 NPs) are used as doped particles, a PEO-50-1.0 coating is obtained through a plasma electrolytic oxidation method (PEO), the SiO 2 NPs are doped into the coating, so that the surface of the PEO-50-1.0 coating has a low equivalent refractive index and can effectively reduce reflection, the PEO-50-1.0 coating has a multi-size micro-nano surface structure, the nano structure can enhance forward scattering, the PEO-50-1.0 coating can be promoted to absorb and scatter light in a solar spectrum range, the micro-protrusion structure can promote the coating to scatter light in an infrared band, the optical path is increased, and the infrared emission performance of the PEO-50-1.0 coating is improved. The excellent absorption and emission properties allow for a PEO-50-1.0 coating with good thermal control properties. The invention takes TC4 as a substrate, and prepares a layer of ceramic coating with a multi-size micro-nano structure o