CA2044642A1 - Material absorbing electromagnetic radiation in the visible and infra-red band, and method of manufacturing it - Google Patents
Material absorbing electromagnetic radiation in the visible and infra-red band, and method of manufacturing itInfo
- Publication number
- CA2044642A1 CA2044642A1 CA 2044642 CA2044642A CA2044642A1 CA 2044642 A1 CA2044642 A1 CA 2044642A1 CA 2044642 CA2044642 CA 2044642 CA 2044642 A CA2044642 A CA 2044642A CA 2044642 A1 CA2044642 A1 CA 2044642A1
- Authority
- CA
- Canada
- Prior art keywords
- manufacturing
- layer
- substrate
- infra
- porous layer
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/32—Radiation-absorbing paints
Abstract
TITLE OF THE INVENTION
"Material absorbing electromagnetic radiation in the visible and infra-red band, and method of manufacturing it"
TEXT OF THE ABSTRACT
A body adapted to absorb visible light and infra-red radiation comprising a substrate (1) covered with a coating, is characterized in that this coating comprises a porous layer (3) formed of pigments adapted to absorb infra-red radiation in a thermoplastic binder.
(Figure 1D)
"Material absorbing electromagnetic radiation in the visible and infra-red band, and method of manufacturing it"
TEXT OF THE ABSTRACT
A body adapted to absorb visible light and infra-red radiation comprising a substrate (1) covered with a coating, is characterized in that this coating comprises a porous layer (3) formed of pigments adapted to absorb infra-red radiation in a thermoplastic binder.
(Figure 1D)
Description
20~64~
The invention concerns the forming on a substrate of a coating which strongly absorbs electromagnetic radiation over a broad band of wavelengths, from visible light up to and including the far infra-red (from wavelength in the order of one micron up to wavelengths of at least 100 to 200 ~m, preferably up to around 500 ~m).
A coating of this kind is in particular required to cover the baffles of space telescopes, i.e. generally cylindrical parts through which incident radiation passes and the purpose of which is to absorb as much as possible of the spurious radiation which compromises the quality of observation (for example the inherent radiation of the Earth and/or the reflection from the latter of sunlight, or any other albedo, etc). It should be borne in mind that, generally speaking, the quality of observation improves as the wavelength extends farther into the infra-red, provided of course that sources of infra-red radiation near the place of observation can be eliminated.
A coating of this kind can have other applications, in the field of scientific (:in particular optical) instrumentation among others, or in the simulation on the Earth of the conditions applying in deep space.
At present there are only two types of coating capable of meeting the a~sorption requirements in this wide a spectral band (beyond 80 to 100 ~m).
One is a rough paint, HERBERTS 1002E (there is an electrically conductive variant with the reference 1356H), which in principle is applied to a smooth substrate. This paint is in practise very difficult to use (including in cases where the substrate is flat or practically so) as the roughness needed to trap the radiation is created as layers are built up in accordance with extremely strict rules which are not always easy to ; . , ., :, ~ ~ ~, ,,' ~ ' ~, : . ~
204~6~2 follow: in particular, the evaporation of the solvenks must be strictly controlled between successive layers (not too much, nor too little), and depends on many parameters including the conditions (aging, etc) of the paint; because of the large number of parameters, the best way to use this paint is under "visual" human control; the results are somewhat random.
A coating called "MARTIN BLACK" developed by the US
company MARTIN MARIETTA DENVER AEROSPACE is described in US patent 4 111 762. This coating is black, resembles velvek and offers excellent performance up to around 80 ~m. It has numerous interesting characteristics, especially for space applications, such as low outgassing, excellent resistance to thermal cycling and lS low parkicle contamination. It has the disadvantage of being obtained by anodization, however, so that it can be applied only to aluminum alloy substrate. It is also difficult to prepare and, most importantly, extremely fragile: the slightest contact damages it irreperably, which considerably complicates handling.
This coating has been improved as described in US
patent 4 589 972 and is still under development in this new version under the name " INFR~ BLACK". This coating has absorption capacity to around 180 to 200 ~m, but has the same drawbacks as "MARTIN BLACK", namely its extreme fragileness and its restriction to aluminum alloy substrates.
Materials such as stainless steel, invar and titanium conventionally used in space applications, especially in optical instruments (where there is o~ten khe requirement to minimize thermal expansion) cannot be coated with "MARTIN BLACK" or " INF~A BLACK" and coating them with the aforementioned HERBERTS paint yields highly random results.
The invention is directed to alleviating khe aforementioned disadvantages by proposing a coating providing absorption which varies little with wavelength over a wide band of wavelengths from the visible up to a wavelength beyond 100 ~m, typically beyond 200 ~m and even up to 500 ~m, suitable for a great variety of substrates (metals, and also ceramics, even plastics materials, etc) by a method that is easy to use and reliable (it is easily automated) and at moderate cost.
This coating will be advantageously adapted to withstand thermal cycling, low temperatures (infra-red observations are often conducted near 0 KELVIN), and to give rise to only limited outgassing.
To this end the invention proposes a body adapted to absorb visible light and infra-red radiation comprising a substrate covered with a coatingr characterized in that this coating comprises a porous layer formed of pigments adapted to absorb infra-red radiation in a thermoplastic binder.
According to preferred fea~ures of the invention, some of which may be combined:
- the porous layer also comprises mineral additives, - the porous layer also contains carbon black, - the binder is an equal parts mixture of polyamide and polyoxymethylene, - the pigments comprise a mixture of "VAT BLUE 4" and "VAT BROWN 3" pigments, - said porous layer is deposited onto a rough surface, - said porous layer covers a rough sub-layer deposited onto the substrate, - said sub-layer has a roughness of at least 100 ~m Ra, - the substrate is metal and the sub-layer is nickel aluminide, - said coating has a roughness RT of at least 200 ~m.
The invention further consists in a me-thod of manufacturing a body adapted to absorb visible light and .. ` . , i ` ~
The invention concerns the forming on a substrate of a coating which strongly absorbs electromagnetic radiation over a broad band of wavelengths, from visible light up to and including the far infra-red (from wavelength in the order of one micron up to wavelengths of at least 100 to 200 ~m, preferably up to around 500 ~m).
A coating of this kind is in particular required to cover the baffles of space telescopes, i.e. generally cylindrical parts through which incident radiation passes and the purpose of which is to absorb as much as possible of the spurious radiation which compromises the quality of observation (for example the inherent radiation of the Earth and/or the reflection from the latter of sunlight, or any other albedo, etc). It should be borne in mind that, generally speaking, the quality of observation improves as the wavelength extends farther into the infra-red, provided of course that sources of infra-red radiation near the place of observation can be eliminated.
A coating of this kind can have other applications, in the field of scientific (:in particular optical) instrumentation among others, or in the simulation on the Earth of the conditions applying in deep space.
At present there are only two types of coating capable of meeting the a~sorption requirements in this wide a spectral band (beyond 80 to 100 ~m).
One is a rough paint, HERBERTS 1002E (there is an electrically conductive variant with the reference 1356H), which in principle is applied to a smooth substrate. This paint is in practise very difficult to use (including in cases where the substrate is flat or practically so) as the roughness needed to trap the radiation is created as layers are built up in accordance with extremely strict rules which are not always easy to ; . , ., :, ~ ~ ~, ,,' ~ ' ~, : . ~
204~6~2 follow: in particular, the evaporation of the solvenks must be strictly controlled between successive layers (not too much, nor too little), and depends on many parameters including the conditions (aging, etc) of the paint; because of the large number of parameters, the best way to use this paint is under "visual" human control; the results are somewhat random.
A coating called "MARTIN BLACK" developed by the US
company MARTIN MARIETTA DENVER AEROSPACE is described in US patent 4 111 762. This coating is black, resembles velvek and offers excellent performance up to around 80 ~m. It has numerous interesting characteristics, especially for space applications, such as low outgassing, excellent resistance to thermal cycling and lS low parkicle contamination. It has the disadvantage of being obtained by anodization, however, so that it can be applied only to aluminum alloy substrate. It is also difficult to prepare and, most importantly, extremely fragile: the slightest contact damages it irreperably, which considerably complicates handling.
This coating has been improved as described in US
patent 4 589 972 and is still under development in this new version under the name " INFR~ BLACK". This coating has absorption capacity to around 180 to 200 ~m, but has the same drawbacks as "MARTIN BLACK", namely its extreme fragileness and its restriction to aluminum alloy substrates.
Materials such as stainless steel, invar and titanium conventionally used in space applications, especially in optical instruments (where there is o~ten khe requirement to minimize thermal expansion) cannot be coated with "MARTIN BLACK" or " INF~A BLACK" and coating them with the aforementioned HERBERTS paint yields highly random results.
The invention is directed to alleviating khe aforementioned disadvantages by proposing a coating providing absorption which varies little with wavelength over a wide band of wavelengths from the visible up to a wavelength beyond 100 ~m, typically beyond 200 ~m and even up to 500 ~m, suitable for a great variety of substrates (metals, and also ceramics, even plastics materials, etc) by a method that is easy to use and reliable (it is easily automated) and at moderate cost.
This coating will be advantageously adapted to withstand thermal cycling, low temperatures (infra-red observations are often conducted near 0 KELVIN), and to give rise to only limited outgassing.
To this end the invention proposes a body adapted to absorb visible light and infra-red radiation comprising a substrate covered with a coatingr characterized in that this coating comprises a porous layer formed of pigments adapted to absorb infra-red radiation in a thermoplastic binder.
According to preferred fea~ures of the invention, some of which may be combined:
- the porous layer also comprises mineral additives, - the porous layer also contains carbon black, - the binder is an equal parts mixture of polyamide and polyoxymethylene, - the pigments comprise a mixture of "VAT BLUE 4" and "VAT BROWN 3" pigments, - said porous layer is deposited onto a rough surface, - said porous layer covers a rough sub-layer deposited onto the substrate, - said sub-layer has a roughness of at least 100 ~m Ra, - the substrate is metal and the sub-layer is nickel aluminide, - said coating has a roughness RT of at least 200 ~m.
The invention further consists in a me-thod of manufacturing a body adapted to absorb visible light and .. ` . , i ` ~
2 ~ 2 infra-red radiation. in which method a coating is deposited onto a substrate, characterized in that it comprises a stage during which a porous layer of powder comprising a mixture of pigmen-ts adapted to absorb infra-red radiation and a thermoplastic binder is deposited by thermal sputtering.
It will be understood that because of its porous character the surface layer is fundamentally different from a layer of paint.
According to further preferred features of the invention, some of which may be combined with each other ~
- said thermoplastic sputtering is carried out usinq an oxypropane flame qun, - said layer is deposited in a number of passes, - the layer also contains mineral additives, - the porous layer also contains carbon black, - the binder is a mixture of equal parts of polyamide and polyoxymethylene, - the pigments are "VAT ~LUE 4" and "~AT ~ROWN 3" pigments, - the powder has a particle size of less than 100 ~m, - the porous layer is deposited onto a rough surface.
- this rough surface is formed by depositing by thermal sputtering a rough sub-layer on the substra~e, - this sputtering is achieved using an oxyacetylene flame-gun, - the substrate bein~ metallic, the sub-layer is nickel aluminide.
It will be understood that the method in accordance with the invention applies to a qreat variety of subsrates, metals or otherwise, and is easy to use, even on non-plane substrates, provided that the ~eometry of the body concerned does not prevent access to a thermal sputlering gun.
Obiects, characteristiGs and advantages of the invention will emerge from the following description given by way of non-limiting example with reference to the appended drawings in which :
- fiqures lA through lD show four successive phases in the preparation of an absorbent body in accordance with the invention, shown in cross-section, .:: . , . .:
, ~ ;
20~6~2 - figure 2 is a diagram showing the equipment employed, and - figure 3 is a graph showing, for each of a number of absorbent bodies in accordance with the invention and from the prior art, the percentage of radiation reflecte~
as a function of the wavelength of the incident radiation.
Figures lA through lD shown in cross-section the preparation of an absorbent body 10 in accordance with the invention starting from an initially smooth substrate l made from metal, for example (in practise stainless steel).
In a first phase the surface of the metal substrate 1 is prepared by fine sand blasting to obtain the surface state of figure lB (this typically represents a roughness in the order of 4 to 5 ~m Ra).
In a second phase, which is recommended to achieve satis~actory absorption at wavelengths beyond 100 ~m, a rough sub-layer 2 is applied by thermal sputtering of a material which adheres strongl~r to the substrate in question (this is preferably a sub-layer of nickel aluminide which adheres strongly (by way of an exothermal reaction) to most metals used in space applications (stainless steel, aluminum alloy, invar - preferably coated with chemical nickel -)).
This material is deposited with an oxy-acetylene flame gun with the parameters deliberately set to obtain a high degree of roughness.
To give a numerical example, a 4.75 mm diameter rod of nickel aluminide is employed, the thermal sputtering parameters being:
- oxygen pressure : 4.8 bars, - acetylene pressure: 1.2 bars, - SF air nozzle; pressure 4 bars.
Figure 2 is a schematic diagram showing the flame 204~642 gun 11 of any appropriate known type with its powder feed 12 and oxygen/acetylene feed 13. A gun of this kind genera~es a considerable amount of heat and the substrate is therefore advantageously cooled on the side opposite the surface to be coated. To reduce the generation of heat the flame gun can advantageously be replaced with an electrical arc gun.
Consideration may also be given to using a mechanical process to roughen the substrate, provided that its thickness enables it to withstand such treâtment without overall deformation (more than 1 to 2 mm).
Chemical attack may also be considered (in the case of plastics material substrates, for example).
When the sub-layer 2 has been formed (see figure lC) a porous absorbent layer 3 is deposited in the form of a powder made up of a fine ground mixture of pigments which are highly absorbent in the infra-red band (in practise known organic pigments) and a thermoplastic binder. Other additives of any appropriate known type may be added to meet other complementary objectives (for example electrical conductivity using carbon black,or mineral additives).
Note that it is standard practise to use such pigments in a heat-cured binder (paints) but not in a thermoplastic binder.
A thermoplastic binder is easier to use because, unlike heat-cured binders, it changes very little with time. On the other hand, its chemical nature (presence of polar groups on the polymer) must be carefully chosen to achieve strong adhesion to the metal. This adhesion will be favo~ed by the use of a rough substrate (the sub-layer 2).
As the pigments are usually organic, in theory it is necessary to keep their temperature below a relatively low threshold, typically in the order of 20~ C and the .
:: .: -: : . .. ~ :
-20~4642 associated binder's softening temperature must not be significantly higher than this threshold.
In this example the powder comprises 60~ of a mixture of equal parts of polyamide (PA-ll) and polyoxymethylene and 40% of a mixture of equal parts of ~V~T BLUE 4 and VAT BROWN 3 pigments. The combination is ground to obtain a particle size below 100 ~m.
The porous absorbent layer 3 is deposited by thermal sputtering, under less severe thermal conditions than those for the sub-layer 2, which conditions are compatible with the nature of the pigments.
An oxypropane flame gun is used, for example. This is preferably of a special type (SP2) for plastics material powders, featuring lateral injection. The lS sputtering parameters are, for example:
- oxygen pressure: 3 bars, - propane pressure: 3 bars, - air pressure: 1.1 bars, - powder distribution: pressure 3 bars.
This layer is advantageously ~ormed in a number of passes (for example, four pass~s with a thickness of 50 ~Im~ each pass taking a few Eractions of a second);
this, combined possibly with cooling of the back of the substrate, makes it possible to keep the temperature of 2S the powder to around 100C.
For ~he combination (sub-layer, if any and layer) a valley dep~h (roughness coefficient RT) is chosen in practise which is near (or even greater than) the nominal observation wavelength (200 ~m in the numerical example given here) with a Ra-roughness coefficient slightly lower than this (from 100 to lS0 ~m).
Tests have shown that a 2+3 coating of this kind offers good resistance to thermal cycling (30 cycles between 4K and 300K, for example).
Figure 3 provides a comparison of various ma-terials . .
, "... , . : ~,.: : ', . , ~44~
from the point of view of specular reflection at T = 7K
as a function of the wavelength between 20 and 450 -500 ~m.
Curve I (in full line) represents a body coated with a 400 ~m layer of HERBERTS 1002E paint. Note that the reflection coefficient R remains below 20% up to around 400 ~m.
The dotted line curve II represents a sample in accordance with the invention comprising a layer deposited directly onto the smooth substrate. The coefficient R remains below 20% up to around 180 ~m.
The dashed line curve III represents a sample as in figure lD, and therefore comprising a porous layer on a rough sub~layer (with the substrate possibly being bare from place to place, at the bottom of the valleys). Note that the coefficient R remains below 20~ up to wavelengths of more than 350 ~Im~ being equivalent to that of layer I (the difference is less than the accuracy of the measurement).
It will therefore be understood that the invention has surprisingly enabled a level of performance appro~imating that of HERBERTS 1002E paint to be achieved with an entirely rudimentary and therefore inexpensive method of implementation.
It goes without saying that the foregoing description has been given by way of non-limiting example only and that numerous variations may be put forward by those skilled in the art with departing from the scope of the invention.
It will be understood that because of its porous character the surface layer is fundamentally different from a layer of paint.
According to further preferred features of the invention, some of which may be combined with each other ~
- said thermoplastic sputtering is carried out usinq an oxypropane flame qun, - said layer is deposited in a number of passes, - the layer also contains mineral additives, - the porous layer also contains carbon black, - the binder is a mixture of equal parts of polyamide and polyoxymethylene, - the pigments are "VAT ~LUE 4" and "~AT ~ROWN 3" pigments, - the powder has a particle size of less than 100 ~m, - the porous layer is deposited onto a rough surface.
- this rough surface is formed by depositing by thermal sputtering a rough sub-layer on the substra~e, - this sputtering is achieved using an oxyacetylene flame-gun, - the substrate bein~ metallic, the sub-layer is nickel aluminide.
It will be understood that the method in accordance with the invention applies to a qreat variety of subsrates, metals or otherwise, and is easy to use, even on non-plane substrates, provided that the ~eometry of the body concerned does not prevent access to a thermal sputlering gun.
Obiects, characteristiGs and advantages of the invention will emerge from the following description given by way of non-limiting example with reference to the appended drawings in which :
- fiqures lA through lD show four successive phases in the preparation of an absorbent body in accordance with the invention, shown in cross-section, .:: . , . .:
, ~ ;
20~6~2 - figure 2 is a diagram showing the equipment employed, and - figure 3 is a graph showing, for each of a number of absorbent bodies in accordance with the invention and from the prior art, the percentage of radiation reflecte~
as a function of the wavelength of the incident radiation.
Figures lA through lD shown in cross-section the preparation of an absorbent body 10 in accordance with the invention starting from an initially smooth substrate l made from metal, for example (in practise stainless steel).
In a first phase the surface of the metal substrate 1 is prepared by fine sand blasting to obtain the surface state of figure lB (this typically represents a roughness in the order of 4 to 5 ~m Ra).
In a second phase, which is recommended to achieve satis~actory absorption at wavelengths beyond 100 ~m, a rough sub-layer 2 is applied by thermal sputtering of a material which adheres strongl~r to the substrate in question (this is preferably a sub-layer of nickel aluminide which adheres strongly (by way of an exothermal reaction) to most metals used in space applications (stainless steel, aluminum alloy, invar - preferably coated with chemical nickel -)).
This material is deposited with an oxy-acetylene flame gun with the parameters deliberately set to obtain a high degree of roughness.
To give a numerical example, a 4.75 mm diameter rod of nickel aluminide is employed, the thermal sputtering parameters being:
- oxygen pressure : 4.8 bars, - acetylene pressure: 1.2 bars, - SF air nozzle; pressure 4 bars.
Figure 2 is a schematic diagram showing the flame 204~642 gun 11 of any appropriate known type with its powder feed 12 and oxygen/acetylene feed 13. A gun of this kind genera~es a considerable amount of heat and the substrate is therefore advantageously cooled on the side opposite the surface to be coated. To reduce the generation of heat the flame gun can advantageously be replaced with an electrical arc gun.
Consideration may also be given to using a mechanical process to roughen the substrate, provided that its thickness enables it to withstand such treâtment without overall deformation (more than 1 to 2 mm).
Chemical attack may also be considered (in the case of plastics material substrates, for example).
When the sub-layer 2 has been formed (see figure lC) a porous absorbent layer 3 is deposited in the form of a powder made up of a fine ground mixture of pigments which are highly absorbent in the infra-red band (in practise known organic pigments) and a thermoplastic binder. Other additives of any appropriate known type may be added to meet other complementary objectives (for example electrical conductivity using carbon black,or mineral additives).
Note that it is standard practise to use such pigments in a heat-cured binder (paints) but not in a thermoplastic binder.
A thermoplastic binder is easier to use because, unlike heat-cured binders, it changes very little with time. On the other hand, its chemical nature (presence of polar groups on the polymer) must be carefully chosen to achieve strong adhesion to the metal. This adhesion will be favo~ed by the use of a rough substrate (the sub-layer 2).
As the pigments are usually organic, in theory it is necessary to keep their temperature below a relatively low threshold, typically in the order of 20~ C and the .
:: .: -: : . .. ~ :
-20~4642 associated binder's softening temperature must not be significantly higher than this threshold.
In this example the powder comprises 60~ of a mixture of equal parts of polyamide (PA-ll) and polyoxymethylene and 40% of a mixture of equal parts of ~V~T BLUE 4 and VAT BROWN 3 pigments. The combination is ground to obtain a particle size below 100 ~m.
The porous absorbent layer 3 is deposited by thermal sputtering, under less severe thermal conditions than those for the sub-layer 2, which conditions are compatible with the nature of the pigments.
An oxypropane flame gun is used, for example. This is preferably of a special type (SP2) for plastics material powders, featuring lateral injection. The lS sputtering parameters are, for example:
- oxygen pressure: 3 bars, - propane pressure: 3 bars, - air pressure: 1.1 bars, - powder distribution: pressure 3 bars.
This layer is advantageously ~ormed in a number of passes (for example, four pass~s with a thickness of 50 ~Im~ each pass taking a few Eractions of a second);
this, combined possibly with cooling of the back of the substrate, makes it possible to keep the temperature of 2S the powder to around 100C.
For ~he combination (sub-layer, if any and layer) a valley dep~h (roughness coefficient RT) is chosen in practise which is near (or even greater than) the nominal observation wavelength (200 ~m in the numerical example given here) with a Ra-roughness coefficient slightly lower than this (from 100 to lS0 ~m).
Tests have shown that a 2+3 coating of this kind offers good resistance to thermal cycling (30 cycles between 4K and 300K, for example).
Figure 3 provides a comparison of various ma-terials . .
, "... , . : ~,.: : ', . , ~44~
from the point of view of specular reflection at T = 7K
as a function of the wavelength between 20 and 450 -500 ~m.
Curve I (in full line) represents a body coated with a 400 ~m layer of HERBERTS 1002E paint. Note that the reflection coefficient R remains below 20% up to around 400 ~m.
The dotted line curve II represents a sample in accordance with the invention comprising a layer deposited directly onto the smooth substrate. The coefficient R remains below 20% up to around 180 ~m.
The dashed line curve III represents a sample as in figure lD, and therefore comprising a porous layer on a rough sub~layer (with the substrate possibly being bare from place to place, at the bottom of the valleys). Note that the coefficient R remains below 20~ up to wavelengths of more than 350 ~Im~ being equivalent to that of layer I (the difference is less than the accuracy of the measurement).
It will therefore be understood that the invention has surprisingly enabled a level of performance appro~imating that of HERBERTS 1002E paint to be achieved with an entirely rudimentary and therefore inexpensive method of implementation.
It goes without saying that the foregoing description has been given by way of non-limiting example only and that numerous variations may be put forward by those skilled in the art with departing from the scope of the invention.
Claims (22)
1. Body adapted to absorb visible light and infra-red radiation comprising a substrate (1) covered with a coating, characterized in that this coating comprises a porous layer (3) formed of pigments adapted to absorb infra-red radiation in a thermoplastic binder.
2. Body according to claim 1 , characterized in that the porous layer also comprises mineral additives.
3. Body according to claim 1 or claim 2, characterized in that the porous layer also contains carbon black.
4. Body according to any one of claims 1 to 3, characterized in that the binder is an equal parts mixture of polyamide and polyoxymethylene.
5. Body according to any one of claims 1 to 4, characterized in that the pigments comprise a mixture of "VAT BLUE 4" and "VAT BROWN 3" pigments.
6. Body according to any one of claims 1 through 5, characterized in that said porous layer is deposited onto a rough surface.
7. Body according to claim 6, characterized in that said porous layer covers a rough sub-layer deposited onto the substrate.
8. Body according to claim 7, characterized in that said sub-layer has a roughness of at least 100 µm Ra.
9. Body according to claim 7 or claim 8, characterized in that the substrate is metal and the sub-layer is nickel aluminide.
10. Body according to any one of claims 1 through 9, characterized in that said coating has a roughness RT
of at least 200 µm.
of at least 200 µm.
11. Method of manufacturing a body adapted to absorb visible light and infra-red radiation, in which method a coating is deposited onto a substrate, characterized in that it comprises a stage during which a porous layer of powder comprising a mixture of pigments adapted to absorb infra-red radiation and a thermoplastic binder is deposited by thermal sputtering.
12. Manufacturing method according to claim 11, characterized in that said thermoplastic sputtering is carried out using an oxypropane flame gun.
13. Manufacturing method according to claim 11 or claim 12, characterized in that said layer is deposited in a number of passes.
14. Manufacturing method according to any one of claims 11 through 13, characterized in that the layer also contains mineral additives.
15. Manufacturing method according to any one of claims 11 through 14, characterized in that the porous layer also contains carbon black.
16. Manufacturing method according to any one of claims 11 through 15, characterized in that the binder is a mixture of equal parts of polyamide and polyoxymethylene.
17. Manufacturing method according to any one of claims 11 through 16, characterized in that the pigments are "VAT BLUE 4" and "VAT BROWN 3" pigments.
18. Manufacturing method according to any one of claims 11 through 17, characterized in that the powder has a particle size of less than 100 µm.
19. Manufacturing method according to any one of claims 11 through 18, characterized in that the porous layer is deposited onto a rough surface.
20. Manufacturing method according to claim 19, characterized in that the rough surface is obtained by depositing a rough sub-layer onto the substrate by thermal sputtering.
21. Manufacturing method according to claim 20, characterized in that an oxyacetylene flame gun is used for said sputtering.
22. Manufacturing method according to claim 20 or claim 21, characterized in that the substrate is metal and said layer is nickel aluminide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9008016 | 1990-06-26 | ||
| FR9008016A FR2663753B1 (en) | 1990-06-26 | 1990-06-26 | OPTICALLY ABSORBING BODY IN THE FIELD OF THE VISIBLE AND INFRARED, AND A MANUFACTURING METHOD. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2044642A1 true CA2044642A1 (en) | 1991-12-27 |
Family
ID=9398016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2044642 Abandoned CA2044642A1 (en) | 1990-06-26 | 1991-06-14 | Material absorbing electromagnetic radiation in the visible and infra-red band, and method of manufacturing it |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0463906B1 (en) |
| JP (1) | JPH04226170A (en) |
| CA (1) | CA2044642A1 (en) |
| DE (1) | DE69106786T2 (en) |
| ES (1) | ES2066384T3 (en) |
| FR (1) | FR2663753B1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19549311C2 (en) * | 1995-12-29 | 1999-12-23 | Deutsch Zentr Luft & Raumfahrt | Infrared calibration radiator and method for its production and its use |
| DE19549310C2 (en) * | 1995-12-29 | 1999-12-23 | Deutsch Zentr Luft & Raumfahrt | Infrared calibration lamp with large aperture and its use as a receiver |
| DE19757321A1 (en) * | 1997-12-23 | 1999-07-01 | Forschungszentrum Juelich Gmbh | Optical component with a surface provided for optical applications |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4111762A (en) * | 1975-01-31 | 1978-09-05 | Martin Marietta Corporation | Optically black coating and process for forming it |
| US4589972A (en) * | 1984-07-30 | 1986-05-20 | Martin Marietta Corporation | Optically black coating with improved infrared absorption and process of formation |
| EP0246342B1 (en) * | 1986-05-21 | 1991-07-24 | Gerd Hugo | Coating materials with a reduced emissivity in the spectral range of the heat radiation |
-
1990
- 1990-06-26 FR FR9008016A patent/FR2663753B1/en not_active Expired - Fee Related
-
1991
- 1991-06-11 EP EP19910401534 patent/EP0463906B1/en not_active Expired - Lifetime
- 1991-06-11 ES ES91401534T patent/ES2066384T3/en not_active Expired - Lifetime
- 1991-06-11 DE DE1991606786 patent/DE69106786T2/en not_active Expired - Fee Related
- 1991-06-14 CA CA 2044642 patent/CA2044642A1/en not_active Abandoned
- 1991-06-25 JP JP15322891A patent/JPH04226170A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE69106786D1 (en) | 1995-03-02 |
| FR2663753B1 (en) | 1992-10-09 |
| ES2066384T3 (en) | 1995-03-01 |
| EP0463906A1 (en) | 1992-01-02 |
| EP0463906B1 (en) | 1995-01-18 |
| JPH04226170A (en) | 1992-08-14 |
| DE69106786T2 (en) | 1995-05-24 |
| FR2663753A1 (en) | 1991-12-27 |
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