CN117126560A - Low-resistance inorganic thermal control coating and preparation method thereof - Google Patents
Low-resistance inorganic thermal control coating and preparation method thereof Download PDFInfo
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- CN117126560A CN117126560A CN202311079344.1A CN202311079344A CN117126560A CN 117126560 A CN117126560 A CN 117126560A CN 202311079344 A CN202311079344 A CN 202311079344A CN 117126560 A CN117126560 A CN 117126560A
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- 238000000576 coating method Methods 0.000 title claims abstract description 123
- 239000011248 coating agent Substances 0.000 title claims abstract description 113
- 238000002360 preparation method Methods 0.000 title description 16
- 239000004111 Potassium silicate Substances 0.000 claims abstract description 79
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 claims abstract description 79
- 229910052913 potassium silicate Inorganic materials 0.000 claims abstract description 79
- 235000019353 potassium silicate Nutrition 0.000 claims abstract description 79
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000011347 resin Substances 0.000 claims abstract description 35
- 229920005989 resin Polymers 0.000 claims abstract description 35
- 239000011787 zinc oxide Substances 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 19
- 239000003973 paint Substances 0.000 claims abstract description 9
- 238000005507 spraying Methods 0.000 claims abstract description 9
- 230000008569 process Effects 0.000 claims abstract description 8
- 239000000945 filler Substances 0.000 claims description 22
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims description 19
- 238000003756 stirring Methods 0.000 claims description 19
- 238000002156 mixing Methods 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 230000004048 modification Effects 0.000 claims description 9
- 238000012986 modification Methods 0.000 claims description 9
- 239000006087 Silane Coupling Agent Substances 0.000 claims description 8
- 239000000843 powder Substances 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 239000000758 substrate Substances 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 3
- 238000012360 testing method Methods 0.000 abstract description 32
- 239000011230 binding agent Substances 0.000 abstract description 11
- 238000010521 absorption reaction Methods 0.000 abstract description 10
- 230000003287 optical effect Effects 0.000 abstract description 6
- 239000000853 adhesive Substances 0.000 abstract description 5
- 230000001070 adhesive effect Effects 0.000 abstract description 5
- 238000005336 cracking Methods 0.000 abstract description 4
- 238000005187 foaming Methods 0.000 abstract description 2
- 239000012767 functional filler Substances 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 13
- 239000002390 adhesive tape Substances 0.000 description 4
- 230000001502 supplementing effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 241001455273 Tetrapoda Species 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 229910052809 inorganic oxide Inorganic materials 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000005382 thermal cycling Methods 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
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
- C09D1/00—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
- C09D1/02—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances alkali metal silicates
-
- 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
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/60—Additives non-macromolecular
- C09D7/61—Additives non-macromolecular inorganic
-
- 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
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/70—Additives characterised by shape, e.g. fibres, flakes or microspheres
Abstract
Disclosed herein is a method of preparing a low resistance inorganic thermal control coating; the invention aims to solve the problem of antistatic property of the existing paint type thermal control coating for the spacecraft; the low-resistance crisis thermal control coating is prepared by binder, paint is prepared, spraying, curing and other processes; the coating uses modified high-stability potassium silicate resin solution as a binder, and tetrapod-like zinc oxide as a conductive network functional filler. The low-resistance inorganic thermal control coating prepared by the invention has the appearance of almost white, the thickness of 120-150 mu m, the solar absorption ratio of 0.15+/-0.02, the hemispherical emissivity of 0.90+/-0.02, the total mass loss TML of less than 1%, the volatile CVCM of less than 0.1% and the volume resistivity of less than or equal to 1X 107 omega-m, and has no phenomena of cracking, peeling, foaming and the like after 100 times of high-temperature thermal cycle test at-100 ℃, and has stable optical performance and good adhesive force, thereby basically meeting the requirements of a spacecraft on antistatic thermal control coating.
Description
Technical Field
The invention belongs to the technical field of preparation of thermal control materials, and particularly relates to a low-resistance inorganic thermal control coating and a preparation method thereof.
Background
The thermal control coating is an important component of a satellite thermal control system, is coated on the outer surface of a satellite, and adjusts the surface thermal balance temperature of the satellite through the self thermal physical property solar absorption ratio and hemispherical emissivity, so that the purpose of thermal control is achieved. In addition, the geomagnetic sub-storm environment with the geosynchronous orbit (GEO) has serious charge-discharge effect, and the subsidence electrons of the polar orbit can cause charge to accumulate on the satellite surface thermal control coating, when the breakdown threshold is exceeded, the satellite surface discharges, which can bring about great damage to the satellite, and the new generation of satellite thermal control coating must have antistatic capability.
In recent decades, thermal control coatings have received wide attention from the aerospace kingdoms of the world, and a plurality of series of thermal control coatings suitable for different orbital environments have been developed. Conventional thermal control coatings include paint-based coatings, electrochemical coatings, secondary surface mirror-type thermal control coatings. The coating type thermal control coating has the characteristics of excellent optical performance, simple application process, strong adhesion, wide applicable base materials, low cost and the like, and can be widely applied to a satellite thermal control system. The invention relates to a coating type white heat control coating which is used as a passive heat control system and belongs to a solar reflection type coating, and the coating type white heat control coating mainly comprises inorganic oxide, a binder and a curing agent, wherein the filler adopted by the invention plays a leading role in the conductivity and optical performance of the coating.
The invention adopts the modified high-stability potassium silicate resin binder and the low-resistance tetrapod-like zinc oxide filler to prepare the low-resistance inorganic thermal control coating by spray coating and other processes, the preparation method is simple and easy to implement, and the obtained thermal control coating has the advantages of stable and controllable quality, wide light absorption range and the like.
Disclosure of Invention
The invention aims at solving the problems existing in the prior art and provides a low-resistance inorganic thermal control coating and a preparation method thereof. The thermal control layer is mainly used for high-orbit spacecrafts such as space satellites, has the characteristics of low resistivity, low absorption, high emission, high stability and the like, and the inorganic filler mainly provides the characteristics of low resistance, low absorption, high emission and the like, and the inorganic potassium silicate binder has high space stability.
The aim of the invention can be achieved by the following scheme:
the invention provides a low-resistance inorganic thermal control coating, which is obtained by spraying a thermal control coating formed by mixing low-resistance filler and modified high-stability potassium silicate resin on a substrate.
Preferably, the low-resistance filler is tetrapod-like zinc oxide, the appearance is white loose powder, the particle size is between 100 and 200 meshes, and the resistance is between 103 and 105 Ω & m. The zinc oxide has good space stability, and secondly, the tetrapod-shaped zinc oxide has semiconductor characteristics and certain conductivity. The filler with low heat conductivity coefficient is not suitable to be used, so that the heat conductivity coefficient and the resistivity of the satellite heat control coating are increased, and the use condition of the heat control coating is not facilitated.
Preferably, the preparation method of the modified high-stability potassium silicate resin comprises the following steps: the low-modulus potassium silicate solution reacts with silica sol to obtain a high-modulus potassium silicate solution; and (3) carrying out organic modification by adopting a silane coupling agent to obtain a modified high-stability potassium silicate resin solution.
The invention provides a preparation method of a low-resistance inorganic thermal control coating, which comprises the following steps:
step one, preparing modified high-stability potassium silicate resin: mixing the low-modulus potassium silicate solution and the silica sol, and stirring for reaction to obtain a high-modulus potassium silicate solution; adding a silane coupling agent for modification to obtain a modified high-stability potassium silicate resin solution;
step two, preparing a coating: adding low-resistance filler powder into the modified high-stability potassium silicate resin solution, mixing and stirring, adding a solvent, mixing and stirring uniformly to obtain a thermal control coating;
preparing a low-resistance inorganic thermal control coating: and spraying the obtained thermal control coating on the substrate, standing and curing to obtain the low-resistance inorganic thermal control coating.
Preferably, in the first step, the mass fraction of the low modulus potassium silicate solution is 60-90%, and the solvent is water; the modulus of the low modulus potassium silicate is 1-2; the modulus of the high modulus potassium silicate is 3-5. The film forming property of the high-modulus potassium silicate on the market at present is common, so that self-made high-modulus potassium silicate is adopted. The self-made potassium silicate has good film forming property, strictly controls the types and the dosage of additives and auxiliaries, and has good spatial stability. The low modulus potassium silicate has poor film forming property, is easy to absorb water, causes poor stability of a coating, and is easy to fall off/crack and the like.
Preferably, in the first step, the mass ratio of the low modulus potassium silicate to the silica sol is 1:1.0: -1:2.5. the silane coupling agent accounts for 0.5 to 1.0 percent of the mass of the high modulus potassium silicate solution.
Preferably, in the first step, the silica sol comprises one or more of acidic silica sol, neutral silica sol and alkaline silica sol.
Preferably, in the first step, the stirring reaction speed is 1000-1500 r/min, and the temperature is 30-60 ℃.
Preferably, in the first step, the silane coupling agent includes one or more of KH550, KH560, KH 570.
Preferably, in the second step, the mass ratio of the modified high-stability potassium silicate resin to the low-resistance filler powder is 1:1.0-1:2.5, preferably 1:1.0-1:2. the solvent is water, the adding amount of the water is regulated, the viscosity of the paint is suitable for spraying, and the viscosity of the paint can be measured by a four-viscosity cup for 14-17 seconds.
Preferably, in the third step, the standing time is 6-12h, the curing temperature is 60-100 ℃ and the curing time is 12-24h.
Preferably, in step three, the thickness of the resulting coating is 120-150 μm.
The invention adopts inorganic binder and tetrapod-like zinc oxide to prepare the satellite thermal control layer, and has good space stability (the inorganic binder potassium silicate has good space stability relative to organic binder resin) and low resistivity (relative to common zinc oxide and common thermal control layer).
Compared with the prior art, the invention has the following beneficial effects:
(1) The tetrapod-like zinc oxide not only has the characteristics of stable property and low solar absorption ratio of common zinc oxide in a space environment, but also has the characteristic of low resistance, and can form a conductive network in a thermal control coating to reduce the resistance of the coating; the potassium silicate is an inorganic binder, has stable performance, obviously improves film forming property along with the increase of modulus, and has better optical performance.
(2) The low-resistance inorganic thermal control coating prepared from the coating composition has the advantages of low solar absorption ratio, high hemispherical emissivity, low volume resistance and the like, ensures the running reliability of a spacecraft, and meets the requirements of the spacecraft on the space environment stability and antistatic property of the coating type thermal control coating.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a schematic illustration of a low resistance inorganic thermal control coating of the present invention;
FIG. 3 is a graph of spectral reflectance of the coating of example 3;
fig. 4 is a graph of the low resistance inorganic thermal control coating of example 3 before and after a high temperature test, wherein the left graph is before a thermal cycle test and the right graph is after a thermal cycle test.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The following examples, which are presented to provide those of ordinary skill in the art with a detailed description of the invention and to provide a further understanding of the invention, are presented in terms of implementation and operation. It should be noted that the protection scope of the present invention is not limited to the following embodiments, and several adjustments and improvements made on the premise of the inventive concept are all within the protection scope of the present invention.
The invention relates to a low-resistance inorganic thermal control coating and a preparation method thereof, as shown in figure 1, comprising the following steps: step one, preparing modified high-stability potassium silicate resin: reacting the low-modulus potassium silicate solution with silica sol with different mass ratios at a certain temperature and a certain stirring speed to obtain high-modulus potassium silicate solutions with different moduli; modifying the prepared high-modulus potassium silicate solution by adopting different silane coupling agents to obtain a modified high-stability potassium silicate resin solution; step two, preparing a coating: adding low-resistance filler powder with different mass ratios into the modified high-stability potassium silicate resin binder, mixing and stirring, adding a solvent, mixing and stirring uniformly; preparing a low-resistance inorganic thermal control coating: spraying finishing paint, namely spraying the paint, standing for 6-12h, and curing for 12-24h at 60-100 ℃; the low-resistance inorganic thermal control coating can be prepared, and the structure is shown in figure 2.
Example 1
The embodiment relates to a low-resistance inorganic thermal control coating and a preparation method thereof.
The low-resistance inorganic thermal control coating of the embodiment consists of tetrapod-like zinc oxide filler and modified high-stability potassium silicate resin binder.
Preparing modified high-modulus inorganic potassium silicate resin: low modulus potassium silicate solution (75% mass fraction) with modulus 1 with silica sol (SiO 2 .nH 2 O，SiO 2 60% by mass) of the silica sol, wherein the mass ratio of the potassium silicate to the silica sol is 1:1, reacting at 30 ℃ and 1000r/min to obtain a high-modulus potassium silicate solution with the modulus of 3; adopting KH550 (1.0% of the mass of the high modulus potassium silicate solution) to carry out organic modification on the prepared high modulus potassium silicate solution to obtain modified high stability potassium silicate resin solution;
preparing a coating: adding tetrapod-like zinc oxide (particle size is 100-200 meshes, resistance is 103-105 Ω.m) filler into modified high-stability potassium silicate resin solution with modulus of 3, mixing and stirring, supplementing proper amount of water (controlling viscosity of the paint, measuring by coating four viscosity cups, 15 s), ultrasonic mixing, stirring for 3h to uniformity; the mass ratio of the modified high-modulus potassium silicate to the tetrapod-like zinc oxide filler is 1:1.
preparing a low-resistance inorganic thermal control coating: in the process of preparing the coating, the coating is sprayed, kept stand for 6 hours, and cured for 24 hours at 60 ℃ to prepare the low-resistance inorganic thermal control coating, wherein the thickness of the coating is about 124 mu m.
Example 2
The embodiment relates to a low-resistance inorganic thermal control coating and a preparation method thereof.
This embodiment is basically the same as embodiment 1 except that:
preparing modified high-modulus inorganic potassium silicate resin: the mass ratio of the low-modulus potassium silicate solution to the silica sol is 1:1.5, and the reaction is carried out at 40 ℃ under the condition of 1100r/min to obtain a high-modulus potassium silicate resin solution with the modulus of 4; carrying out organic modification on the prepared high-modulus potassium silicate solution by using KH550 to obtain a modified high-stability potassium silicate resin solution;
preparing a coating: adding tetrapod-like zinc oxide filler into modified high-stability potassium silicate resin solution with modulus of 3, mixing and stirring, supplementing proper water, ultrasonically mixing, and stirring for 3h to uniformity; the mass ratio of the modified high-modulus potassium silicate to the tetrapod-like zinc oxide filler is 1:1.5.
preparing a low-resistance inorganic thermal control coating: in the process of preparing the coating, the coating is sprayed, kept stand for 8 hours, and cured for 20 hours at 70 ℃ to prepare the low-resistance inorganic thermal control coating, wherein the thickness of the coating is about 130 mu m.
Example 3
The embodiment relates to a low-resistance inorganic thermal control coating and a preparation method thereof.
This embodiment is basically the same as embodiment 1 except that:
preparing modified high-modulus inorganic potassium silicate resin: the mass ratio of the low-modulus potassium silicate solution to the silica sol is 1:2, and the reaction is carried out at 50 ℃ and 1400r/min to obtain a high-modulus potassium silicate solution with the modulus of 5; carrying out organic modification on the prepared high-modulus potassium silicate solution by using KH550 to obtain a modified high-stability potassium silicate resin solution;
preparing a coating: adding tetrapod-like zinc oxide filler into modified high-stability potassium silicate resin solution with modulus of 3, mixing and stirring, supplementing proper water, ultrasonically mixing, and stirring for 3h to uniformity; the mass ratio of the modified high-modulus potassium silicate to the tetrapod-like zinc oxide filler is 1:2.0.
preparing a low-resistance inorganic thermal control coating: in the process of preparing the coating, the coating is sprayed, kept stand for 10 hours, and cured for 16 hours at 80 ℃ to prepare the low-resistance inorganic thermal control coating, wherein the thickness of the coating is about 138 mu m, the spectrum reflectivity curve chart of the coating is shown in figure 3, the diagrams before and after the high-low temperature test are shown in figure 4, and the left diagram is before the thermal cycle test and after the thermal cycle test of the right diagram.
Example 4
The embodiment relates to a low-resistance inorganic thermal control coating and a preparation method thereof.
This embodiment is basically the same as embodiment 1 except that:
preparing modified high-modulus inorganic potassium silicate resin: the mass ratio of the low-modulus potassium silicate solution to the silica sol is 1:2.5, and the reaction is carried out at 60 ℃ and 1500r/min to obtain a high-modulus potassium silicate resin solution with the modulus of 6; carrying out organic modification on the prepared high-modulus potassium silicate solution by using KH550 to obtain a modified high-stability potassium silicate resin solution;
preparing a coating: adding tetrapod-like zinc oxide filler into modified high-stability potassium silicate resin solution with modulus of 6, mixing and stirring, supplementing proper water, ultrasonically mixing, and stirring for 3h to uniformity; the mass ratio of the modified high-modulus potassium silicate to the tetrapod-like zinc oxide filler is 1:2.5.
preparing a low-resistance inorganic thermal control coating: in the process of preparing the coating, the coating is sprayed, kept stand for 12 hours, and cured for 12 hours at 100 ℃ to prepare the low-resistance inorganic thermal control coating, wherein the thickness of the coating is about 145 mu m. Example 4 the film forming properties of the coating were poor due to the too high proportion of tetrapod-like zinc oxide filler in the coating.
Comparative example 1
The comparative example relates to a low-resistance inorganic thermal control coating and a preparation method thereof.
This comparative example is basically the same as example 1, except that: the potassium silicate is not modified, and the low-modulus potassium silicate is directly used.
Comparative example 2
The comparative example relates to a low-resistance inorganic thermal control coating and a preparation method thereof.
This comparative example is basically the same as example 1, except that: the tetrapod-like zinc oxide was replaced with conventional zinc oxide.
The coating prepared in the comparative example has poor film forming property and is easy to absorb water, so that the coating has poor space stability and is subject to the phenomena of falling off/cracking and the like.
Comparative example 3
The comparative example relates to a low-resistance inorganic thermal control coating and a preparation method thereof.
This comparative example is basically the same as example 1, except that: the low modulus potassium silicate solution with the modulus of 1 is directly mixed with silica sol, does not react, and is added with tetrapod zinc oxide.
The coating prepared in the comparative example has poor film forming property, and the silica sol is easier to absorb water, so that the coating has poor space stability and is subject to the phenomena of falling off/cracking and the like.
The low resistance inorganic thermal control coatings of examples 1, 2, 3 and 4 above were tested for performance as follows:
coating thickness test
The thickness of the coating was measured using a MiniTest600 thickness gauge manufactured by EPK company, germany. The measurement range is 0-300 μm, and the error is + -2 μm. The thickness of the coating is 124-145 μm, which meets the requirements of technical indexes 120-150 μm.
Adhesion test
The general specification test requirements of the GJB2704A-2006 spacecraft thermal control coating are met. And (3) tightly attaching the adhesive tape with the peel strength of 2-4N/cm to the middle area of the coating, wherein the distance from the edge is not less than 3mm. One end of the tape was pulled up by hand and the tape was set at 90 ° to the surface. After the adhesive tape is pulled away from the surface slowly (about 5 mm/s), the adhesive tape does not fall off in comparative examples 2, 1, 2 and 3, the technical index requirements are met, and the adhesive tape falls off in comparative examples 1 and 4 and does not meet the use requirements.
Solar absorptance test
The test uses an LAMBDA950 ultraviolet-visible-near infrared spectrophotometer (UV/VIS/NIR Spectrophotometer) from America, eimer (Perkin Elmer) to measure the solar absorption ratio of low resistance inorganic thermal control coatings. The measurable wavelength range is 200nm to 2500nm, the resolution of the instrument is 0.1nm, the bandwidth is less than or equal to 0.05nm, the stray light is less than or equal to 0.00008 percent A, the noise is less than 0.0008A, the photometer repeatability is less than 0.0001A, the baseline drift is less than 0.0002A/h, and the baseline is flat: 0.001A, good stability, high baseline flatness, and extremely low stray light. In the experiment, the step length was set to 5nm and the slit width was set to 4nm.
Hemispherical emissivity test
The hemispherical emissivity of the sample in the 3-35 μm band at room temperature was measured using a TEMP 2000A emissivity measuring instrument developed by AZ techenology corporation, usa, with a measurement accuracy of ±3% and a full band repeatability of ±0.5%.
TABLE 1 solar absorption and emissivity of coating
Volume resistivity test
Reference standard GBT 31838.2-2019 section 2, solid insulation dielectric and resistance properties: resistance characteristics (DC method) volume resistance and volume resistivity "test conditions were as follows:
test voltage 100V;
TABLE 2 electrical properties of coatings
Vacuum gassing property test
Vacuum bleed test was performed with reference to standard GJB2704A-2006, under the following conditions:
sample pretreatment: maintaining at 23+ -1deg.C and humidity 45%RH+ -10%RH for 24 hr; the heated temperature of the sample is 125+/-1 ℃; the collection temperature of the condensable volatile is 25 ℃; the test pressure is less than or equal to 7 multiplied by 10 -3 Pa; the heat preservation time is 24 hours;
balance test sensitivity: l μg.
Testing to calculate Total Mass Loss (TML), condensable Volatiles (CVCM) of the material in vacuum; as shown in table 3.
TABLE 3 vacuum gassing performance of coatings
Thermal cycle testing
The method adopts a temperature impact box (model ZTS010, shanghai up to environmental test equipment Co., ltd.) and under the standard requirement of GJB2704A-2006, the test conditions are as follows after 100 times of thermal cycles at the temperature ranging from minus 100 ℃ to plus 100 ℃ under the normal atmospheric condition:
test temperature: the high temperature end temperature is 100 ℃, and the low temperature end temperature is set to be-100 ℃; cycling for 100 times; temperature control error: high temperature + -5 ℃ and low temperature + -10 ℃; the thermal cycling device should have two constant temperature zones of different temperatures, with the sample 10s being transferred from one constant temperature zone to the other; preserving heat for 10min at the high temperature and low temperature ends to ensure that the temperature of the test piece is the same as the ambient temperature; dehumidifying measures should be taken during the test to prevent frosting on the surface of the test piece.
Test results: the modified coating has good appearance after 100 times of high-temperature and low-temperature heat cycle at-100 to +100 ℃, stable optical performance and good adhesive force, and meets the technical index requirement.
In combination with table 1, table 2 and test results, the properties of the low resistance inorganic thermal control coating of the present invention are as follows:
appearance: white, even coating surface, no bubble, no crack, no peeling and no falling off;
thickness: 120-150 μm;
solar absorption ratio: 0.15+/-0.02;
hemispherical emissivity: 0.90+/-0.02;
the volume resistivity is less than or equal to 1 multiplied by 10 7 Ω·m；
Thermal cycle test: after the coating meets 100 times of high-temperature low-temperature heat cycle tests at-100 to +100 ℃, the coating has no phenomena of cracking, peeling, foaming and color change, stable optical performance and good adhesive force;
vacuum air release performance: all satisfy TML <1%, CVCM <0.1%.
In conclusion, the low-resistance inorganic thermal control coating has good coating adhesive force on the basis of ensuring good thermal control performance (solar absorption ratio and hemispherical emissivity) of the coating, is simple and easy to learn in coating construction, has strong feasibility, and has good adhesive force after being subjected to a temperature impact test for 100 times at-100 to +100 ℃.
The foregoing describes specific embodiments of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the claims without affecting the spirit of the invention.
Claims (10)
1. The low-resistance inorganic thermal control coating is characterized in that the thermal control coating is obtained by spraying a thermal control coating formed by mixing low-resistance filler and modified high-stability potassium silicate resin on a substrate;
the modified high-stability potassium silicate resin is prepared by a method comprising the following steps: the low-modulus potassium silicate reacts with the silica sol to obtain high-modulus potassium silicate; and (3) carrying out organic modification by adopting a silane coupling agent to obtain the modified high-stability potassium silicate resin.
2. The low resistance inorganic thermal control coating according to claim 1, wherein the low resistance filler is tetrapod-like zinc oxide, is white loose powder in appearance, has a particle size of 100-200 mesh, and has a resistance of 103-105 Ω -m.
3. A method of preparing the low resistance inorganic thermal control coating of claim 1, comprising the steps of:
step one, preparing modified high-stability potassium silicate resin: mixing the low-modulus potassium silicate solution and the silica sol, and stirring for reaction to obtain a high-modulus potassium silicate solution; adding a silane coupling agent for modification to obtain a modified high-stability potassium silicate resin solution;
step two, preparing a coating: adding low-resistance filler powder into the modified high-stability potassium silicate resin solution, mixing and stirring, adding a solvent, mixing and stirring uniformly to obtain a thermal control coating;
preparing a low-resistance inorganic thermal control coating: and spraying the obtained thermal control coating on the substrate, standing and curing to obtain the low-resistance inorganic thermal control coating.
4. A method according to claim 3, wherein in step one, the modulus of the low modulus potassium silicate is 1 to 2; the modulus of the high modulus potassium silicate is 3-5; the mass ratio of the low modulus potassium silicate to the silica sol is 1:1.0-2.5.
5. The process according to claim 3, wherein in the first step, the stirring reaction is carried out at a speed of 1000 to 1500r/min and at a temperature of 30 to 60 ℃.
6. The method according to claim 3, wherein in the first step, the silane coupling agent comprises one or more of KH550, KH560 and KH 570.
7. The method according to claim 3, wherein in the second step, the solvent is water, and the viscosity of the paint after the solvent is added is 14 to 17 seconds as measured by a four-step viscometer.
8. The method according to claim 3, wherein in the second step, the mass ratio of the modified highly stable potassium silicate resin to the low-resistance filler powder is 1:1.0-2.5.
9. The method according to claim 3, wherein in the third step, the standing time is 6 to 12 hours, the curing temperature is 60 to 100 ℃ and the curing time is 12 to 24 hours.
10. A method according to claim 3, wherein in step three, the thickness of the resulting coating is 120-150 μm.
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| CN202311079344.1A CN117126560A (en) | 2023-08-24 | 2023-08-24 | Low-resistance inorganic thermal control coating and preparation method thereof |
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| CN202311079344.1A CN117126560A (en) | 2023-08-24 | 2023-08-24 | Low-resistance inorganic thermal control coating and preparation method thereof |
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