EP1907607A2 - Revetement pour dispositif externe de controle thermo-optique d'elements de vehicules spatiaux, son procede de formation par micro-arcs en milieu ionise, et dispositif recouvert de ce revetement - Google Patents
Revetement pour dispositif externe de controle thermo-optique d'elements de vehicules spatiaux, son procede de formation par micro-arcs en milieu ionise, et dispositif recouvert de ce revetementInfo
- Publication number
- EP1907607A2 EP1907607A2 EP06778725A EP06778725A EP1907607A2 EP 1907607 A2 EP1907607 A2 EP 1907607A2 EP 06778725 A EP06778725 A EP 06778725A EP 06778725 A EP06778725 A EP 06778725A EP 1907607 A2 EP1907607 A2 EP 1907607A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- metal
- layer
- coating
- ceramic
- support piece
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 94
- 239000011248 coating agent Substances 0.000 title claims abstract description 81
- 238000000034 method Methods 0.000 title claims description 51
- 239000002184 metal Substances 0.000 claims abstract description 124
- 229910052751 metal Inorganic materials 0.000 claims abstract description 123
- 239000000919 ceramic Substances 0.000 claims abstract description 62
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 52
- 239000000956 alloy Substances 0.000 claims abstract description 52
- 239000004065 semiconductor Substances 0.000 claims abstract description 34
- 238000006243 chemical reaction Methods 0.000 claims abstract description 18
- 238000005524 ceramic coating Methods 0.000 claims description 42
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 41
- 239000003792 electrolyte Substances 0.000 claims description 35
- 150000003839 salts Chemical class 0.000 claims description 31
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 29
- 229910052782 aluminium Inorganic materials 0.000 claims description 28
- 150000004679 hydroxides Chemical class 0.000 claims description 26
- 229910052783 alkali metal Inorganic materials 0.000 claims description 14
- 150000001340 alkali metals Chemical class 0.000 claims description 14
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 12
- 239000010936 titanium Substances 0.000 claims description 12
- 229910052719 titanium Inorganic materials 0.000 claims description 12
- 230000003647 oxidation Effects 0.000 claims description 11
- 238000007254 oxidation reaction Methods 0.000 claims description 11
- 230000000694 effects Effects 0.000 claims description 10
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 9
- 230000015572 biosynthetic process Effects 0.000 claims description 8
- 229910052593 corundum Inorganic materials 0.000 claims description 8
- 239000010431 corundum Substances 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 7
- 230000003287 optical effect Effects 0.000 claims description 7
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 7
- 238000002604 ultrasonography Methods 0.000 claims description 7
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 6
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 6
- 229910001069 Ti alloy Inorganic materials 0.000 claims description 6
- 229910052700 potassium Inorganic materials 0.000 claims description 6
- 239000011591 potassium Substances 0.000 claims description 6
- 229910052708 sodium Inorganic materials 0.000 claims description 6
- 239000011734 sodium Substances 0.000 claims description 6
- 238000004017 vitrification Methods 0.000 claims description 6
- 239000002131 composite material Substances 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 5
- -1 potassium or sodium Chemical class 0.000 claims description 5
- 150000004760 silicates Chemical class 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 229910000838 Al alloy Inorganic materials 0.000 claims description 4
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 4
- 239000011148 porous material Substances 0.000 claims description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- 230000001464 adherent effect Effects 0.000 claims description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 230000008033 biological extinction Effects 0.000 claims description 3
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- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- 230000000593 degrading effect Effects 0.000 claims description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims description 3
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 3
- 150000002978 peroxides Chemical class 0.000 claims description 3
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- 238000006297 dehydration reaction Methods 0.000 claims description 2
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- 239000007787 solid Substances 0.000 claims description 2
- 230000006641 stabilisation Effects 0.000 claims 1
- 238000011105 stabilization Methods 0.000 claims 1
- 239000010410 layer Substances 0.000 description 154
- 239000003973 paint Substances 0.000 description 19
- 230000005855 radiation Effects 0.000 description 19
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- 239000000049 pigment Substances 0.000 description 14
- 230000004907 flux Effects 0.000 description 9
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 8
- 210000002381 plasma Anatomy 0.000 description 8
- 229920001296 polysiloxane Polymers 0.000 description 8
- 230000032683 aging Effects 0.000 description 7
- 230000035882 stress Effects 0.000 description 7
- 230000008901 benefit Effects 0.000 description 5
- ZBFOLPMOGPIUGP-UHFFFAOYSA-N dizinc;oxygen(2-);titanium(4+) Chemical compound [O-2].[O-2].[O-2].[O-2].[Ti+4].[Zn+2].[Zn+2] ZBFOLPMOGPIUGP-UHFFFAOYSA-N 0.000 description 5
- 239000011521 glass Substances 0.000 description 5
- 229910001092 metal group alloy Inorganic materials 0.000 description 5
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 238000009413 insulation Methods 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 239000011777 magnesium Substances 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 239000011787 zinc oxide Substances 0.000 description 4
- 239000004697 Polyetherimide Substances 0.000 description 3
- 239000004111 Potassium silicate Substances 0.000 description 3
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 3
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 238000005137 deposition process Methods 0.000 description 3
- 230000001066 destructive effect Effects 0.000 description 3
- 229910052735 hafnium Inorganic materials 0.000 description 3
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- VAOCPAMSLUNLGC-UHFFFAOYSA-N metronidazole Chemical group CC1=NC=C([N+]([O-])=O)N1CCO VAOCPAMSLUNLGC-UHFFFAOYSA-N 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 229920001601 polyetherimide Polymers 0.000 description 3
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 3
- 229910052913 potassium silicate Inorganic materials 0.000 description 3
- 235000019353 potassium silicate Nutrition 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000004332 silver Substances 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 229910052726 zirconium Inorganic materials 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- 239000004642 Polyimide Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- JJWKPURADFRFRB-UHFFFAOYSA-N carbonyl sulfide Chemical compound O=C=S JJWKPURADFRFRB-UHFFFAOYSA-N 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
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- 150000004677 hydrates Chemical class 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
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- 230000001590 oxidative effect Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920001721 polyimide Polymers 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 229910052566 spinel group Inorganic materials 0.000 description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 2
- 229910001887 tin oxide Inorganic materials 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- OAEQTHQGPZKTQP-UHFFFAOYSA-N 1,3,5-trichloro-2-(3,4-dichlorophenyl)benzene Chemical compound ClC1=CC(Cl)=CC(Cl)=C1C1=CC=C(Cl)C(Cl)=C1 OAEQTHQGPZKTQP-UHFFFAOYSA-N 0.000 description 1
- 229920002799 BoPET Polymers 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229910000861 Mg alloy Inorganic materials 0.000 description 1
- 239000005041 Mylar™ Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 229920004482 WACKER® Polymers 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
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- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
- B64G1/00—Cosmonautic vehicles
- B64G1/22—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
- B64G1/222—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles for deploying structures between a stowed and deployed state
-
- 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
- C25D11/026—Anodisation with spark discharge
-
- 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
-
- 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
- C25D11/26—Anodisation of refractory metals or alloys based thereon
Definitions
- Coating for an external device for the thermo-optical control of space vehicle elements its method of formation by micro-arcs in an ionized medium, and device covered with this coating.
- the present invention relates to a coating for an external device for thermo-optical control of spacecraft elements, in particular satellites, and capable of covering and / or constituting all the external radiative surfaces of a spacecraft.
- the invention also relates to a process for forming or producing this coating by micro-arcs in an inonized medium, in particular in an aqueous bath, and an external device for thermo-optical control of at least one space vehicle element.
- the device having at least one outer surface intended to be turned towards space when the spacecraft moves in the latter, and said outer surface is coated and / or consists of a coating according to the invention.
- thermal control is generally necessary in vehicles subjected to the space environment, such as satellites, interplanetary probes, orbital probes, etc ..., to maintain the electronic components or any other element embedded on such vehicles in their operating temperature range.
- thermo-optical control methods are mainly designed to balance, at the level of the space vehicle, the heat fluxes received and emitted by radiation, while maintaining an acceptable temperature level, for the operation of the elements. embedded, including optical instruments and electronic equipment.
- the space thermal environment includes the following heat sources: - the radiation emitted by the sun (about 1400 W / m 2 to 1 Astronomical Unit (AU)); the radiation emitted by other distant objects; - the radiation emitted by stars and reflected by nearby planets (for example, the reflection of solar radiation by the Earth represents about 500 W / m 2 at 200 km from the earth); the radiation emitted by planets close to a space vehicle considered (for example an artificial satellite which, 200 km from the Earth, receives from the latter a radiation of a power of about 200 W / m 2 ); . cosmic rays; and the kinetic energy of spatial particles. It can be considered that the heating of a space vehicle due to cosmic rays or collisions of this space vehicle with space particles is negligible.
- AU Astronomical Unit
- the amount of energy absorbed by the space vehicle is supplemented by the amount of heat produced inside the spacecraft, and almost all of these energies must be radiated to the space forming a heat sink. , whose temperature is close to 4 ° Kelvin.
- the solar absorptivity ⁇ characterizes the ability of the surface of a material to absorb these wavelengths (which correspond to the visible range);
- emissivity ⁇ or total emission factor characterizes the ability of a material to emit, or absorb, in the infrared band, and heat flows are governed by the Stéfan-Boltzmann law.
- the space vehicle can be subjected to a very restrictive particulate and radiative environment: the monoatomic oxygen (ATOX) is very devastating by its oxidizing and kinetic action (4 m / s), for satellites traveling in earth orbits near 300 km; - The ultraviolet rays, which provide little heat, strongly increase the aging of some materials, especially some polymers (which they break or recombine chains); - ⁇ radiation has destructive energy effects on certain materials and components; and electrons and protons, in addition to an electrical impact, causing a generation of electrical voltages that can cause arcing, can cause aging of materials.
- ATOX monoatomic oxygen
- FIGS. 1 and 2 schematically represent a spacecraft 1 equipped with an external thermo-optical control device 7 receiving the solar radiation 5 and discharging internal heat 3 dissipated in particular by an equipment 2 internal to the spacecraft 1.
- the device 7 shown with a substantially circular disk shape and associated with the overall cylindrical structure of the vehicle 1 in Figure 1 is shown schematically in diametral section, so with a flat parallelepiped shape and associated with a platform also in section parallelepipedal diameter of the vehicle 1 in Figure 2.
- thermo-optical control device such as the device 7, whose external face 8, (see FIG. ie the face turned towards the space, is very radiative, that is to say with high thermal emissivity ⁇ , and possibly, and preferably also, very reflective, that is to say with low solar absorptivity ⁇ to maximize the reflected flux 6.
- the so-called internal face 9 of the device 7, that is to say say the face of the device 7 qu i is in vis-à-vis the spacecraft 1, must be sufficiently electrically conductive, to avoid destructive electrostatic discharge.
- ⁇ e f ( ⁇ , T). ( ⁇ v + ⁇ ⁇ s), where f ( ⁇ , T) is a function of the emissivity ⁇ and the absolute temperature T, this function increasing as the emissivity ⁇ increases.
- thermo-optical control devices can be classified into two general categories: - so-called “active” devices implementing active methods of thermal control using temperature control techniques; these active methods require the use of moving parts, such as movable flap radiators, and are energy-consuming; the reliability of these devices is therefore affected by the wear of moving parts and by the use of electronic components; however, these methods have the advantage of allowing a finer regulation inside the spacecraft; and so-called “passive” devices which implement passive thermal control methods based on an appropriate geometrical design of the spacecraft and on a judicious choice of the materials constituting the device, according to their physical, electrical and thermal properties; these methods do not consume energy and do not use any moving parts, so that the passive devices are therefore extremely reliable; these passive methods involve heat sinks with high heat capacity, fusible materials providing the energy necessary for phase changes, thermal insulators such as glass-epoxy composites, as well as thermo-optical coatings.
- Passive devices for example radiators external or solar shields, are mostly coated with a coating to effectively reflect the incident solar radiation (the coating therefore has a low coefficient of absorptivity ⁇ ), while having an emissivity factor ⁇ very high for allow it to evacuate heat to the cold space, which is why these coatings are called "cold coatings".
- the cold coatings of the state of the art, for passive thermo-optical control devices are made by white paints, so-called SSM (Second Surface Mirror) coatings consisting of two diopters, the first allowing light, second mirror, or optical solar reflectors commonly referred to as OSR (Optical Sun Reflector) characterized by a low coefficient of absorptivity ⁇ (typically between 0.1 and 0.2) and a high hemispheric emissivity coefficient ⁇ (typically between 0.8 and
- non-conductive white paint binder: potassium silicate
- pigment zinc orthotitanate
- - ⁇ 0.13
- ⁇ 0.80
- binding agent silicone with RTV 121 trade name of the company RHONE POULENC and purified by the CNES (National Center for Space Studies)
- pigment zinc orthotitanate coated with potassium silicate
- binding agent purified silicone RTV 121 (RHONE POULENC) CNES, - pigment: calcined zinc oxide,
- binder purified silicone RTV 121 (RHONE POULENC) CNES, pigment: zinc oxide with commercial designation SP
- non-conductive white paint, binder potassium silicate
- PCBZ conductive white paint
- binder RHODORSIL 10336 (RHONE POULENC) brand silicone purified by CNES
- pigment zinc orthostannate
- PCBT conductive white paint
- binder silicone with the trade name R4-3117 from American company DOW CORNING purified by CNES
- pigment orthotitanate tin
- Antistatic white paint (highly conductive of electricity),
- RTV 121 silicone (RHONE POULENC) purified by CNES,
- binder resin of commercial name K of the German company WACKER, purified by CNES, pigment: zinc orthotitanate and doped pigments,
- the cold coatings commonly referred to as OSR are glass platelets (Corning 7940 fused silica, cerium-doped glass or CMX glass) coated with silver on the inside.
- the passive devices of the so-called SSM and OSR types can also be covered, outwardly, with a layer of tin oxide and indium which is a transparent and electrically conductive layer, and they are glued on panels. of structure using organic adhesives.
- thermo-optical coatings called cold coatings (paints, OSR, SSM)
- paints find their limit when the space environment hardens, especially when the temperature, radiation and the effects of electrostatic charges increase, in particular when the spacecraft approaches the Sun (and is typically at a distance of between 0.2 and 0.5 AU from the latter).
- the binders of the paints (with the exception of the silicate binders) and the adhesives of the so-called SSM and OSR devices comprise at least one organic constituent which does not accept excessively high temperatures (in all cases certainly not greater than 400 ° C.).
- silicate binders have too high solar absorptivity characteristics, and are highly sensitive to radiation.
- the difference between their coefficient of expansion and that of the support is a highly limiting factor at high temperature.
- SSM Cold coatings known as SSM induce problems of electrostatic charges. Moreover, all these cold coatings (paints, SSM, OSR) lose their quality in the presence of strong radiation (in particular ultraviolet) and proton flux, like those commonly encountered in the space environment, especially when a vehicle space is getting closer to the Sun.
- strong radiation in particular ultraviolet
- proton flux like those commonly encountered in the space environment, especially when a vehicle space is getting closer to the Sun.
- this ceramic type OSR is an amorphous material, when this coating is exposed to irradiations such as ultraviolet rays and / or protons, some of its characteristics, including optical transmission, evolve unfavorably over time.
- this amorphous material is very electrically insulating, it can not evacuate the electrical charges from the space. Very significant potentials are thus established between the structure of the spacecraft and this amorphous coating, up to destructive breakdown voltages of electronic components.
- thermo-optical coating intended essentially to cover external surfaces of passive type thermo-optical control devices, possibly associated with active-type thermo-optical control devices.
- the coating according to the invention overcomes the various disadvantages of the coatings of the state of the art, as presented above.
- An object of the invention is to obtain a coating for external thermo-optical control device of at least one spacecraft element, the coating according to the invention having very specific characteristics, useful for space applications of thermal control , such as those described above, and in particular a very high hemispheric emissivity, and advantageously and simultaneously, a very low solar absorptivity, and moreover, that a very good temperature resistance, and an absence of aging or very limited aging in a harsh environment such as the space environment.
- the invention proposes a coating for an external device for thermo-optical control of at least one space vehicle element, which is characterized in that it is realized by a treatment of conversion of at least one external surface of at least one metal support piece of said external device, and resists the radiative stresses encountered in space, said coating comprising:
- said external layer having a characteristic of low solar absorptivity ⁇
- the outer and inner layers covering said outer surface of said metallic support part being made of ceramics different from one layer to another and issuing from different crystalline forms of the metal or alloy of said metal support part, said crystalline forms of the layers; external and internal interpenetrating at the interface between the two layers, and said crystalline form of the inner layer interpenetrating with the metal or alloy of said metal support piece,
- outer and inner layers having together a characteristic of high hemispheric emissivity ⁇ ,
- the characteristics of solar absorptivity ⁇ of the outer layer, and the emissivity characteristics ⁇ of the two outer and inner layers being such that the ratio ⁇ / ⁇ is less than about 30%, and preferably less than 20%.
- the ceramics of the outer and inner layers are derived from crystalline forms such that is provided the high hemispheric emissivity required for the intended application, while the ceramic or ceramics constitutive of the inner layer is or are such that the strong adhesion of this inner layer to the metal support piece and the acceptance of the differential expansion stresses of this inner ceramic layer with respect to the metal support piece are provided, and that the ceramic or ceramic the outer layer is or is such that the low solar absorptivity required for the intended application is proven, and thus the ratio of the absorptivity to the emissivity of the coating is favorably low, the coating thus constituted of the two aforementioned layers providing good resistance to radiative stresses encountered in space.
- the outer layer has a solar absorptivity characteristic of less than about 0.20, and preferably less than 0.15.
- said outer and inner layers together have an emissivity characteristic ⁇ greater than about 0.75, and preferably between 0.8 and 0.9.
- the coating according to the invention thus has the great advantage of a small ratio of the solar absorptivity ⁇ to the hemispherical emissivity ⁇ ( ⁇ / ⁇ ⁇ 30% and preferably ⁇ 20%).
- the metal or metal alloy of the support piece can be chosen so that ceramics from different crystalline forms of this metal or this alloy provide a coating that is resistant to temperatures of at least 200 ° C. even, because of the ceramic (s) constitutive (s) of the inner layer of the coating, there is advantageously interpenetration of the crystal form (s) of said inner layer with the metal or alloy of the metal support piece.
- the crystalline forms of the outer and inner layers advantageously interpenetrate at the interface between the two layers.
- the ceramics of the layers of the coating are crystalline forms of a metal or alloy of the "semiconductor" or "valve-effect" type of the metal support part, because these so-called “semi-precious metals” such as aluminum and titanium, as well as magnesium, hafnium and zirconium, have the advantage of having an interesting mechanical strength / weight ratio and are suitable for a wide range of applications such as astronautics and aeronautics, especially for moving parts with loads and significant mechanical deformation stresses, on the one hand, and, secondly, lend themselves favorably to the formation of microarcs during the deposition of such a coating by a method of electrolytic conversion of oxidation by micro-arcs plasma, by physicochemical reaction of transformation of the metal or of the treated semi-conductor alloy, in order to obtain a ceramic coating than on the surface of a metal part made of this metal or semiconductor alloy, as specified below.
- this inner layer is ceramic accepting strong deformations, which may be greater than 100%, and essentially consisting of salts, hydroxides and the oxide phase. less enthalpy metal or alloy of said metal support piece.
- the outer layer is of excellent quality when this layer
- the outer shell is white ceramic denser than that of the inner layer, and essentially consists of the oxide phase of at least one highly enthalpy crystal form of the metal or alloy of said metal support member.
- the outer layer is covered, outwardly, by a transparent vitrified ceramic layer, which provides this improvement in the emissivity while maintaining the low absorptivity of the said outer layer.
- the ceramic coating of the invention is therefore always supported by an electrically conductive metal material.
- the metal or alloy of this material is advantageously aluminum or an aluminum alloy, titanium or a titanium alloy, which is recommended for very high operating temperatures (beyond 300 0 C), or optionally, magnesium or a magnesium alloy.
- the coating according to the invention is produced by converting treatment of at least one outer surface of an aluminum or aluminum alloy support piece, its inner layer is advantageously an aluminum / alumina interface layer with a high concentration of aluminum. salts, of hydroxides, and of the bohemite phase of Al 2 O 3 aluminum oxide, while its outer layer is of dense white ceramic, consisting essentially of crystalline aluminum oxide ⁇ AI 2 O 3 called corundum.
- the outermost part of the outer layer of the coating is made with a very high concentration of corundum, preferably greater than 90%.
- said high concentration of low density forms (salts, hydroxides and bohemite phase of Al 2 O 3 ) of the inner layer at the interface with the metal or metallic alloy support improves resistance to high thermal amplitudes, resulting for example from a passage of a temperature of - 100 0 C to + 300 0 C.
- the coating according to the invention is produced by a conversion treatment of at least one outer surface of a titanium or titanium alloy support part
- its inner layer is advantageously an interface layer between the titanium or said titanium alloy, on the one hand, and on the other hand, at least one amorphous titanium oxide, and salts, hydroxides and brookite and anatase phases of TiU2 titanium oxide, while its outer layer is made of white and dense ceramic essentially consisting of crystalline titanium oxide TiO 2 called the rutile form.
- An advantage of this coating is that the high concentration of the low density forms of the salts, hydroxides, and TiO 2 brookite and anatase phases in the inner layer at the interface with the support metal or metal alloy improves, in this case also, resistance to strong thermal differences, such as the change from ambient temperature to a temperature of + 700 ° C.
- the outermost part of the outer layer of the coating according to the invention has a high concentration of the rutile form, preferably greater than 70%.
- the subject of the invention is also a process for forming a ceramic coating specific to the invention and as presented above, on at least one external surface of at least one so-called “semiconductor” or “valve-effect” metal or alloy support piece, which is a development and improvement of the electrolytic oxidation process for obtaining a ceramic coating on the surface of a metal or semiconductor alloy, described in patent document FR 2 808 291 or EP 1276920, to which reference will be made for further details on this subject.
- this patent document discloses an electrolytic oxidation process by micro-arcs plasma in order to obtain a ceramic coating on the surface of a metal having semiconductor properties, such as aluminum, titanium, magnesium, hafnium, zirconium and their alloys, by physicochemical reaction of transformation of the treated metal or alloy, the method of immersing the metal part to be coated in an electrolytic bath composed of an aqueous solution of alkali metal hydroxide , such as potassium or sodium, and an oxyacid salt of an alkali metal, the metal part forming one of the electrodes, and to apply to the electrodes a generally triangular signal voltage having at least one forward slope and a backward slope, with variable form factor during the process, generating a controlled current in its intensity, its shape and its ratio between the positive intensity and the intensity negative.
- a metal having semiconductor properties such as aluminum, titanium, magnesium, hafnium, zirconium and their alloys
- thermo-optical properties namely:
- the inner layer, between the outer layer and the metal support piece ensuring excellent adhesion to the metal or alloy of this support piece, and making it possible to compensate for large expansion gaps between the outer layer of the coating, on the one hand, and the metal or alloy of the support piece, on the other hand.
- the process according to the invention for the formation of a ceramic coating as presented above on at least one external surface of at least one support piece made of metal or alloy called “semiconductor”, or “valve effect”, by electrolytic conversion of oxidation by micro arcs ionized medium of said metal or semiconductor alloy, is characterized in that said electrolytic conversion is obtained by a treatment in several stages, in aqueous bath or in a gaseous plasma, and that after a first step of forming an electrically insulating layer, essentially hydroxides, then a second step of forming the outer layer of ceramic coating under said electrically insulating layer, a third step consists in forming the ceramic of the inner layer, also under said electrically insulating layer.
- the process according to the present invention is characterized in that, in the second step, the aqueous electrolyte is of low oxyacidic salt concentration of said alkali metal, such as potassium or sodium, and of low concentration of hydroxide and / or peroxide of an alkali metal, and the third step is carried out in a bath very concentrated in oxyacid salt of an alkali metal, so as to promote the growth of hydroxide with a voltage and current profile electrode applied to the electrodes, the anode of which is at least partially constituted by said support piece made of metal or semiconductor alloy, chosen such that the extinction of the micro-ar it is done quickly, so as to keep a low temperature of oxide formation.
- the second step is of low oxyacidic salt concentration of said alkali metal, such as potassium or sodium, and of low concentration of hydroxide and / or peroxide of an alkali metal
- the third step is carried out in a bath very concentrated in oxyacid salt of an alkali metal, so as to promote the growth of
- the electrolyte is advantageously and strongly cooled in order to keep the ceramic deposit cold.
- the insulation resistance decreases as the temperature increases.
- the insulation resistance must be the largest, and therefore the lowest temperature.
- the second step ultrasound is emitted into the electrolyte during this step.
- at least one salt for example copper and / or lanthanum, is advantageously introduced into the electrolytic bath; so as to promote the growth of a high enthalpy oxide form.
- the temperature of the electrolyte is increased, for example by reducing the intensity of its circulation, and preferably the entire bath is kept under pressure in an autoclave container, to avoid boiling the water of the electrolyte.
- the temperature of the insulator is increased, and thus its resistivity.
- the method of the invention advantageously comprises a fourth step, which may consist in removing the electrically insulating layer formed during the first step.
- the removal of the electrically insulating layer can be carried out in a dissolving bath of hydroxides and salts, for example a bath of weakly concentrated hydrofluoric acid or potassium hydroxide.
- ultrasound is emitted simultaneously and advantageously in the dissolving bath, so as to exert a pore suppressing compacting action remaining in the ceramic deposit after removal of the electrically insulating layer.
- the fourth step of removing the electrically insulating layer can be carried out using at least one mechanical operation, for example by microbeading and / or polishing, so as to remove a porous surface area rich in hydroxides and salts, in particular of silicates, of the ceramic deposit.
- the latter comprises a fourth step of vitrifying the electrically insulating layer made in the first step, so as to make it transparent and improve the emissivity without degrading the solar reflection, vitrification comprising a dehydration of hydroxides, for example, by the action of a high temperature, in a furnace or using a pulsed power laser this step making it possible to further improve the emissivity, without degrading the reflectivity solar.
- the invention further relates to an external thermo-optical control device of at least one space vehicle element, having at least one outer surface intended to be turned towards space when the space vehicle moves in the latter, and coated with a coating resistant to thermal and radiative stresses specific to the space environment, and with high emissivity and low absorptivity, and the external device according to the invention is characterized in that it comprises at least one metal support piece, a metal or alloy called semiconductor and having said at least one outer surface, which is covered with a ceramic coating of the invention and as presented above.
- the support piece is a metal outer layer of said metal or semiconductor alloy of a thermal mattress consisting of a multilayer set of low-emissivity sheets, each of which sheet consists of a synthetic core coated on both sides with a layer of aluminum, two neighboring sheets being kept separated by a fretted web, for example glass fiber or tergal, the ceramic coating covering said metal layer said thermal mattress.
- the latter comprises at least one composite panel of nida structure covered, on at least one outer face, with an aluminum skin, the ceramic coating covering the outer face of said aluminum skin.
- the ceramic coating covers at least one external face of a massive metallic support piece, made of metal or semiconductor alloy, belonging to equipment, such as optical sensor, support structure, waveguide or electronic housing of the spacecraft, projecting outwardly on an outer face of the platform of said spacecraft.
- FIG. 1 and 2 show schematically a spacecraft with an external thermo-optical control device, as previously described to present the main constraints imposed by the space thermal environment to a spacecraft such as an artificial satellite;
- FIG. 3 is a diagrammatic cross-sectional representation of a metal support piece made of metal or alloy based on a so-called semiconductor metal, of which an outer face (facing the space in which the spacecraft is moving) is covered with a coating according to the invention, the metal support part belonging to or constituting the external thermo-optical control device;
- - Figure 4 is a schematic cross-sectional view of an electrolyte bath tank with electrodes, electrolyte circulation lines and ultrasound generator, for implementing the method according to the invention of deposit, by micro-arches in an aqueous bath of a ceramic coating according to the invention; and
- FIGS. 5, 6 and 7 schematically represent, in cross-section, three examples of an external device for thermo-optical control of at least one space vehicle element, and of which an external surface (intended to be turned towards space when the spacecraft moves in the latter) is coated with a coating according to the invention, these three examples being respectively a multilayer thermal mattress with a metal outer layer supporting a coating according to the invention, a composite panel NIDA structure with outer skin in metal or semiconductor alloy coated with a coating according to the invention, and a massive metal shell of a spacecraft equipment, an outer surface of which is covered with a coating according to the invention.
- FIG. 3 there is shown at 12 a metal part forming part of an external thermo-optical control device such as 7 of FIGS. 1 and 2, or constituting such a device 7, and which is a support piece or metallic substrate.
- This coating consists essentially of two layers 10 and 11, which are much more differentiated from each other and from the metal support part 12 in the drawing than they actually are.
- the ceramic coating thus comprises a so-called outer layer 10, with a low coefficient of solar absorptivity ⁇ ( ⁇ less than 0.20 and preferably less than or equal to 0.15 typically) and which, in combination with a so-called internal layer 11, constitutes a coating with a high hemispheric emissivity coefficient ⁇ ( ⁇ being greater than 0.75 and typically between 0.8 and 0.9), and the inner layer 11 extends between the metal support piece 12 and the outer layer 10, is very adherent to the metal of the support piece 12 by accepting differential expansion stresses, so as to make it possible to make up for large differences in expansion between the metal or semiconductor alloy 12 and the outer layer 10 of ceramic , the coating is
- ⁇ low less than about ⁇ 30% and preferably less than 20%.
- the layers 10 and 11 together constitute an advantageous embodiment of the outer face such as 8 (in Figure 2) of the external thermo-optical control device 7 of Figures 1 and 2,
- the inner layers 11 and external 10 covering the metal support part 12 consist of different ceramics from crystalline forms different from the metal or semiconductor alloy of the metal part 12.
- the inner layer 11 is of low density ceramic, bonded to the metal support part 12 by interpenetration between the metal or alloy of this piece 12 and the ceramic of the inner layer 11, which is a ceramic accepting strong deformations, and mainly consisting of salts, hydroxides and the least enthalpy oxide phase of the metal of the support piece 12 or metal at the base of the alloy of this piece 12.
- the outer layer 10 of the ceramic coating By against the outer layer 10 of the ceramic coating is a dense ceramic (denser than that of the inner layer 11) and white, consisting mainly of metal oxides of at least one highly enthalpy crystalline form of said semiconductor metal. the piece 12 or the base of the alloy of this piece 12.
- the ceramic of the outer and inner layers 11 is generated from titanium, this ceramic is mainly composed of the phases of titanium dioxide: rutile, brookite and, to a lesser extent, anatase.
- concentration of brookite, silicates, hydrates and spinels is greater in the inner layer 11, near the metal substrate 12, which gives this inner layer 11 the ability to absorb the differential expansions, compared to the expansions of the metal part 12, in which the ceramic of the inner layer 11 is encrusted by electrolytic growth of oxidation by micro-arcs plasma in ionized medium, and in particular in aqueous bath, as described below with reference to FIG.
- this inner layer 11 it is noted that the silicates, hydrates and spinels it contains are encrusted impurities, which provide this inner layer 11 a mechanical function of flexibility facilitating the absorption of the aforementioned differential expansions.
- the outer layer 10 is itself substantially subdivided into two sub-layers, the inner sub-layer of which, in contact with the inner layer 11, has a high rutile concentration, preferably greater than 70 %, giving the white color providing low absorptivity throughout the solar spectrum, and is covered by the external sublayer (outward) vitrified ceramic, so transparent, improving the hemispherical emissivity.
- the titanium oxide called rutile form is crystalline ⁇ TiO2 form
- the high concentration of the rutile form in the outer layer 10 allows both to obtain a high whiteness, and thus improve the characteristics low absorptivity, and simultaneously improves the high emissivity characteristic, which corresponds to a very low surface resistivity.
- the outermost part of the outer layer (10) is the part of the coating which has the highest concentration, preferably greater than 70%, of the rutile form, which provides the whiteness and characteristics of low absorption and / or high emissivity.
- the brookite and anatase phases of the TiO 2 low titanium oxide improve the resistance to strong thermal differences, such as the from an ambient temperature to a temperature of + 700 ° C, the ceramic coating thus formed being resistant to temperatures exceeding several hundred degrees Celsius.
- the ceramic of the layers 10 and 11 is generated from aluminum or an aluminum-based alloy, then if the metal support piece 12 is made of aluminum or an aluminum-based alloy, the inner layer 11 made by conversion treatment on this piece 12 is a high concentration (preferably greater than 70%) interface layer of the bohemite phase of aluminum oxide A12O3, salts and hydroxides, while outer layer 10 has a high concentration
- dense and white ceramic mainly consisting of crystalline aluminum oxide ⁇ A12O3 called corundum.
- a very high concentration (preferably greater than 90%) of corundum is produced in the outermost part of the outer layer 10, in order to obtain a great whiteness of this layer 10 and thus to improve its low characteristics. absorptivity and, simultaneously, high emissivity hemispherical, corresponding to a very low surface resistivity.
- the layers 10 and 11 of the ceramic coating according to the invention can be obtained by a method, according to the invention, comprising several steps of electrolytic conversion of oxidation by micro-arcs of the metal or of the semiconductor alloy of the support piece 12 in an ionized medium, which may be an oxidizing gas plasma, or an aqueous bath, as described below with reference to FIG. 4.
- an ionized medium which may be an oxidizing gas plasma, or an aqueous bath
- a tank is shown diagrammatically at 13, preferably insoluble stainless steel, containing a bath 14 of electrolyte, in which are dipped two electrodes, including a cathode 15 also insoluble stainless steel, and an anode 16, which is constituted or enveloped by the metal support piece 12 of metal or alloy semiconductor, the cathode 15 and the anode 16 being each connected to a source of electric current by one respectively of the two electrical conductors 17.
- Side walls of the tank 13 are crossed by lines 18 of electrolyte, these conduits for treating the electrolyte in closed circuit, outside the tank 13, as indicated by the arrows in Figure 4, for reasons indicated below.
- the electrolyte 14 is a water-based solution which comprises at least one oxyacid salt of an alkali metal (potassium or sodium) and an alkali metal hydroxide, which may be the same metal or, most often, a metal alkali different from that corresponding to the oxyacid salt.
- This electrolyte 14 serves, in a first step, to put the outside of the metal part 12 to be coated at potential of the cathode 15.
- the electrolyte 14 is then used to convey the electric current from the cathode 15 to the anode 16, during the existence of the arcs plasmas.
- the electrolyte may contain additional grains of suspended material which will combine with the creation of the coating.
- These additional material grains may be PTFE grains to soften the friction, or diamond grains to cure the ceramic coating.
- the electrolyte 14 removes calories created by the Joule effect, because the passage of the electrical current from the cathode 15 to the anode 16.
- the cathode 15 conducts the electric current and is insoluble in the electrolyte 14, for which reason it is made of stainless steel or nickel, in particular.
- this piece 12 of metal or semiconductor alloy first naturally covers an electrically insulating layer in the first phase of the process.
- the first step is therefore to create an electrically insulating layer on the outer surface of the metal part 12 to be coated with ceramic coating, the electrically insulating layer being mainly formed of hydroxides.
- This insulating layer may be created by an electric current or by one of the anodic oxidation commonly used by electrolysis.
- This electrically insulating layer necessary for the initialization of the deposition process, has no particular quality, and will therefore be destroyed at the end of the process in several stages of deposition of the ceramic coating, or, advantageously, enhanced by vitrification, as explained herein. below.
- the second step consists in creating the outer layer 10 of ceramic, which is the main layer, having the desired thermo-optical characteristics, in particular for the aforementioned spatial applications.
- This outer layer 10 is dense because the pores of this layer, if they are larger than a fraction of the wavelength of the incident light, become light absorption sites.
- This outer layer 10 is white because a low solar absorptivity is desired and, being very white, this layer 10 thus reflects all the wavelengths of the solar spectrum. For this reason, this outer layer 10 consists mainly of oxides forming high temperatures (corundum for a support part 12 made of aluminum and rutile for a titanium support part 12).
- this second step the formation of hydroxides is avoided as much as possible, since the latter are sensitive to radiation, and their presence in this dense and external layer of the coating would weaken the latter by accelerating its aging in the harsh environment. what constitutes the space environment.
- this second step is carried out in an aqueous electrolyte of low concentration of oxyacid salt of an alkali metal (potassium or sodium for example) and low concentration of hydroxides and / or peroxides of an alkali metal, typically 2 at 20 g / 1.
- the electrolyte bath 14 is thus changed or its concentration is progressively changed by appropriate treatment of the electrolyte 14 in closed circuit by the lines 18, and outside the tank 13. This stage of formation of the layer outer 10 of dense ceramic coating under the electrically insulating layer produced in the first step, is continued until the microarray boot voltages exceed about 1000 volts.
- ultrasound may be introduced into the electrolyte bath 14, and for this purpose an ultrasonic generator 19 may be disposed against and under the bottom of the vessel.
- electrolyte bath 14 of particular salts for example copper and / or lanthanum, favoring the crystalline phase, that is to say, promoting the growth of a form of oxide with high enthalpy.
- the electrolyte 14 is strongly cooled in order to keep the ceramic deposit as cold as possible. Indeed, the insulation resistance of the deposit decreases with temperature. So, to have an important Joule effect when creating micro-arcs, the isolation resistance must be great.
- the third step of the process, to create the inner layer 11 or interface layer is performed in a bath of electrolyte 14 very concentrated (almost saturated) oxyacid salt of an alkali metal, such as potassium or sodium, so to promote the growth of hydroxides.
- the voltage / current profile of the electric current applied to the electrodes 15-16 ie the shape factors of the electric current, the value of the potential, the frequency, and the value of the intensity of the current applied to the electrodes, are chosen so that the extinction of micro-arcs occurs quickly, in a time less than about a microsecond, to lower the temperature of the arc.
- the circulation of the electrolyte 14 is, during this third step, less intense, in order to increase the temperature of the electrolyte 14, and therefore the temperature of the insulating coating, and therefore its resistivity.
- the entire bath can be kept under pressure in an autoclave container, made by a sealing the tank 13 or by placing this tank 13 in an autoclave container.
- the electrically insulating layer, formed during the first step is removed during a fourth step, which, for example, is implemented in a dissolving bath of hydroxides and salts, for example a weakly concentrated hydrofluoric acid bath, or potassium hydroxide, because it is in the presence of amphoteric elements.
- ultrasound is advantageously also emitted in the dissolving bath, so as to create micro-implosions of the interface, and thus an action of ultrasonic compaction, making it possible to remove pores remaining. in the ceramic deposit, after removal of the electrically insulating layer.
- the fourth step of removing the electrically insulating layer may be carried out by at least one mechanical operation.
- it may be a polishing, or a micro-blasting (projection of micro-metal balls), so as to remove the porous surface portion and rich in hydroxides and salts (silicates ...) constituting this electrically insulating layer.
- the electrically insulating layer which has deposited during the first step is not removed, but enhanced, being vitrified in a fourth step, this vitrification being ensured by dehydrating the hydroxides of this electrically insulating layer by the action of a high temperature, for example by passing through an oven, or exposure of this electrically insulating layer to a pulsed power laser.
- This vitrification has the effect of making transparent this layer, which becomes the outer sub-layer of the outer layer 10 of Figure 3, the emissivity is improved without degradation of solar reflection.
- This method of depositing the ceramic coating in particular in its advantageous variant comprising the vitrification of the electrically insulating layer deposited during the first step, makes it possible to obtain a coating (10-11) having very specific characteristics, useful for spatial applications of thermo-optical control, such as those presented above, namely a very high hemispheric emissivity, a very low solar absorptivity, a very good temperature resistance, non-aging in the harsh environment that is the space environment, and a very good adhesion to semiconductor metal supports, thanks to a flexibility of the inner layer 11 accepting significant thermoelastic deformation and folding.
- this type of ceramic coating can be used on board space vehicles such as artificial satellites, on several forms of structures for external thermo-control devices, of which three examples are described below, without not
- this type of coating can be used on any external radiative surface of space vehicles.
- the first example of application is a multilayer thermal mattress with a semiconducting external metal layer covered with a ceramic coating according to the invention, as shown in FIG.
- This thermal mattress is commonly called MLI (Multi Layers Insulation) in the field of space industries, and consists of a multilayer assembly of sheets 21 of low emissivity.
- MLI Multi Layers Insulation
- Each of the sheets 21 consists of a core or core layer made of a synthetic material, for example those known under the trademark Kapton or Mylar, which is coated on both sides with an aluminum layer deposited by evaporation. under vacuum.
- Each sheet 21 is kept separated from a neighboring sheet 21 by a fretted web 22, made for example of glass or "TERGAL ®".
- Said outer layer 23 is a metal layer made of a metal or semiconductor alloy, on the outer face of which is produced by conversion treatment an outer coating 24 of ceramic, according to the invention.
- the entire outer metal layer 23 and the outer coating 24 thus has a thickness ranging for example from about 60 microns to about 100 microns.
- the ceramic coating 24 of the outer metal layer 23 receives the solar flux in the visible band, and emits in the infrared in a band and with a flow that is a function of its temperature. For a large solar flux, the temperature of the outer ceramic coating 24 may exceed about 300 0 C, temperature that this coating 24 is perfectly able to sustainably withstand, for the reasons mentioned above.
- the second example of application shown in FIG. 6 is a NIDA structure panel that can be used for the external walls of an artificial satellite, in particular in geostationary orbit.
- the walls or walls north and south of such a satellite are structural elements to provide a function of radiators.
- the antenna reflectors of such satellites are also structural elements, having a perfectly defined shape, and should not vary according to thermal variations.
- thermo-optical properties such as DC ⁇ the absorptivity ⁇ emissivity ratio is very low.
- NIDA (honeycomb) composite panels such as the panel 25 of FIG. 6, are often used, covered on each of its two faces.
- the third example, shown in Figure 7, is that of a metal casing 28, made of aluminum or titanium alloy, constituting a casing or box, fixed projecting outwards on an outer face of the platform 29 of a satellite, and made in the form of a solid piece of a semiconductor alloy, whose outer faces are covered with an outer ceramic coating 30 according to the invention, the entire envelope 28 and the coating 30 may have a thickness of a few millimeters.
- Such metal shells 28 can accommodate equipment such as optical sensors, antenna support structures, waveguides or any other electronic boxes to be placed outside the platform of the satellite or spacecraft. The external surfaces of these equipments will thus present the thermo-optical properties their
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Abstract
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FR0507968A FR2889205B1 (fr) | 2005-07-26 | 2005-07-26 | Revetement pour dispositif externe de controle thermo-optique d'elements de vehicules spatiaux, son procede de formation par micro-arcs en milieu ionise, et dispositif recouvert de ce revetement |
PCT/FR2006/001533 WO2007012712A2 (fr) | 2005-07-26 | 2006-06-29 | Revetement pour dispositif externe de controle thermo-optique d'elements de vehicules spatiaux, son procede de formation par micro-arcs en milieu ionise, et dispositif recouvert de ce revetement |
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US9352855B2 (en) * | 2013-04-09 | 2016-05-31 | Lockheed Martin Corporation | Heat generating transfer orbit shield |
RU2660747C2 (ru) * | 2015-08-31 | 2018-07-09 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Тольяттинский государственный университет" (ТГУ) | Износостойкое оксидное покрытие алюминиевых сплавов |
JP6722514B2 (ja) * | 2016-05-27 | 2020-07-15 | 株式会社アストロスケール | 捕獲プレート、宇宙用装置及び捕獲方法 |
CN108977866B (zh) * | 2018-08-21 | 2023-07-21 | 烟台大学 | 一种激光辅助喷雾微弧氧化装置 |
EP3931104A1 (fr) * | 2019-03-01 | 2022-01-05 | Ecole Polytechnique Federale De Lausanne (Epfl) | Système de capture adapté pour capturer des objets orbitaux, en particulier à des fins de désatellisation |
CN110167318B (zh) * | 2019-04-29 | 2021-01-15 | 中国科学院西安光学精密机械研究所 | 一种温控系统及电子学箱体 |
CN110804753B (zh) * | 2019-12-04 | 2021-04-02 | 中国电子科技集团公司第十二研究所 | 一种合金表面复合热控涂层的制备方法 |
CN113943964A (zh) * | 2020-07-15 | 2022-01-18 | 中国科学院上海硅酸盐研究所 | 钛合金表面热控耐磨损涂层及其制备方法 |
RU2764476C1 (ru) * | 2021-09-09 | 2022-01-17 | Акционерное общество «Обнинское научно-производственное предприятие «Технология» им. А.Г.Ромашина» | Способ изготовления термостойкой сотовой трехслойной конструкции |
CN113879564B (zh) * | 2021-10-28 | 2024-05-28 | 上海交通大学 | 兼顾卫星姿态控制与热量控制的装置、设备及系统 |
CN114262885B (zh) * | 2021-11-17 | 2023-06-02 | 中国电子科技集团公司第三十八研究所 | 一种超低发射率功能涂层的制备方法 |
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US3087872A (en) * | 1960-09-15 | 1963-04-30 | Sprague Electric Co | Electrolytic capacitor and method for producing same |
JPH0641640B2 (ja) * | 1987-05-28 | 1994-06-01 | 東海金属株式会社 | チタン及びチタン合金の陽極酸化処理法 |
IL109857A (en) * | 1994-06-01 | 1998-06-15 | Almag Al | Electrolytic process and apparatus for coating metals |
RU2081213C1 (ru) * | 1995-06-02 | 1997-06-10 | Геннадий Георгиевич Нечаев | Способ микродугового нанесения покрытия на поверхность изделия |
US6245436B1 (en) * | 1999-02-08 | 2001-06-12 | David Boyle | Surfacing of aluminum bodies by anodic spark deposition |
FR2808291B1 (fr) * | 2000-04-26 | 2003-05-23 | Mofratech | Procede electrolytique d'oxydation pour l'obtention d'un revetement ceramique a la surface d'un metal |
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2005
- 2005-07-26 FR FR0507968A patent/FR2889205B1/fr not_active Expired - Fee Related
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2006
- 2006-06-29 WO PCT/FR2006/001533 patent/WO2007012712A2/fr active Application Filing
- 2006-06-29 US US11/996,660 patent/US20080220262A1/en not_active Abandoned
- 2006-06-29 EP EP06778725A patent/EP1907607A2/fr not_active Withdrawn
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WO2007012712A2 (fr) | 2007-02-01 |
FR2889205A1 (fr) | 2007-02-02 |
WO2007012712A3 (fr) | 2007-09-20 |
US20080220262A1 (en) | 2008-09-11 |
FR2889205B1 (fr) | 2007-11-30 |
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