CN114292587B - Composite material with low secondary electron emission coefficient and preparation method thereof - Google Patents
Composite material with low secondary electron emission coefficient and preparation method thereof Download PDFInfo
- Publication number
- CN114292587B CN114292587B CN202111650803.8A CN202111650803A CN114292587B CN 114292587 B CN114292587 B CN 114292587B CN 202111650803 A CN202111650803 A CN 202111650803A CN 114292587 B CN114292587 B CN 114292587B
- Authority
- CN
- China
- Prior art keywords
- electron emission
- secondary electron
- emission coefficient
- niobate
- composite material
- 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.)
- Active
Links
Images
Landscapes
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention provides a composite material with a low secondary electron emission coefficient and a preparation method thereof, belonging to the technical field of micro-discharge of microwave components. The present invention relates to ceramic-polymer composites and polymer PCBM/PI composites. The ceramic-polymer dielectric composite material comprises a polymer and niobate, wherein the niobate is a compound with a two-dimensional nanostructure with electronegativity; the polymer material PCBM is a powdered polymer having a negative charge. The invention utilizes the local reverse electric field formed by the electronegative material in the polymer matrix to inhibit the generation and movement of secondary collision electrons, and the secondary electron emission coefficient of the composite material is effectively reduced relative to the polymer matrix.
Description
Technical Field
The invention relates to the technical field of micro-discharge of microwave components, in particular to a composite material with a low secondary electron emission coefficient and a preparation method thereof.
Background
When particles (electrons or ions, etc.) with initial energy collide with the material surface, electrons are excited from the material surface, and if the electrons reaching the material surface have energy enough to overcome the energy barrier of the material surface, the electrons can escape from the material surface, i.e. a secondary electron emission phenomenon, and the escaped electrons are called secondary electrons. The secondary electron emission coefficient is defined as the ratio between the number of electrons (flux) emitted from the surface of the material and the number of electrons (flux) incident on the surface of the material. The phenomenon of secondary electron emission has found widespread use in a number of fields, including scanning electron microscopes, auger spectrometers, and the like. In the field of aerospace, the secondary electron emission coefficient is closely related to micro-discharge of aerospace microwave devices.
The influence of micro-discharge is very extensive, and the slight influence includes the reduction of the dielectric property of the device (including the increase of dielectric loss, the reduction of high voltage resistance and the like), and the serious influence can cause the loss of the function of the device and can not ensure the normal operation of the spacecraft. The micro-discharge effect mainly comprises three processes of generating secondary electrons in the material, moving the secondary electrons to the surface in an electric field and escaping the secondary electrons from the surface. With the continuous deepening of the exploration of the outer space in China and the increasing power of space spacecraft components, the subsequent requirement on the suppression of the micro-discharge effect of a high-power device is also increased.
Various proposals have been made to reduce the secondary electron emission coefficient of the surface of the material. Plating a layer of thin film material with very low secondary electron yield (inhibiting secondary electron emission) or very high secondary electron yield (promoting secondary electron emission) on the surface of the base material; the researchers of SLAC and KEK utilize a fine mechanical processing mode to generate groove array structures with various sizes on the surface of a material, so that the secondary electron yield of the material is greatly reduced, and the secondary electron emission is inhibited. However, for complex electronic devices, the surface of the material can only be roughened simply by methods such as surface grooving and laser etching, but the etching of the interior of the device is relatively difficult, the process flow is relatively complex, the device is not universal, and the microwave dielectric material may be damaged to a certain extent, so that the original characteristics of the microwave dielectric material are changed.
Disclosure of Invention
In view of the above, the present invention provides a composite material with a low secondary electron emission coefficient and a preparation method thereof, wherein the present invention uses negatively charged inorganic material niobate and polymer material PCBM, and a local reverse electric field to inhibit the generation of secondary collision electrons, so as to inhibit the excitation of secondary electrons, effectively inhibit the number of secondary electrons, and achieve the effect of inhibiting the secondary electron emission coefficient.
The strategy can be popularized to different flexible polymer dielectric composite materials, and a brand new feasible scheme is provided for inhibiting the secondary electron emission coefficient in the future.
The invention can be directly used for the application of the medium microwave device in the spaceflight.
It is a first object of the present invention to provide a composite material with a low secondary electron emission coefficient, said composite material comprising an electronegative filler and a polymer matrix.
Preferably, the electronegative filler is niobate or PCBM.
Preferably, the polymer matrix is at least one of polyimide and epoxy.
The polymer matrix can form a coating material with a uniform texture on the surface of the device.
Preferably, the niobate is a two-dimensional nanostructured compound that is electronegative.
Preferably, the niobate is at least one of calcium niobate, sodium niobate, potassium sodium niobate, and lithium niobate.
Preferably, the PCBM is a derivative of fullerene, being a powdered polymer having a negative charge.
Further preferably, the PCBM is at least one of [60] PCBM and [70] PCBM, the [60] PCBM is collectively referred to as [6,6] -phenyl-C61-butyric acid isopropyl ester, and the [70] PCBM is collectively referred to as [6,6] -phenyl-C71-butyric acid isopropyl ester.
The PCBM polymer is used for reducing the secondary electron emission coefficient by inhibiting the generation of electrons according to a reverse electric field generated in the PCBM polymer.
Preferably, the addition amount of the niobate is 1wt% to 90wt%, and more preferably, the addition amount of the niobate is 20wt%.
Preferably, the added amount of the PCBM is 1wt% to 60wt%, and more preferably, the added amount of the PCBM is 20wt%.
Preferably, the niobate is prepared by a solid-phase sintering method, the sample prepared by the solid-phase sintering method does not need complex process means, the technology is mature, and the prepared sample can meet the experimental requirements.
Preferably, a second object of the present invention is to provide a method for preparing a composite material with a low secondary electron emission coefficient, comprising the steps of:
(1) Uniformly mixing electronegative filler and a polymer matrix, and then coating the mixed solution on the surface of a device;
(2) Keeping the temperature at 90-110 ℃ for 1h, then increasing the temperature to 200-250 ℃ at the heating rate of 2-4 ℃/min and keeping the temperature for 1-2h to finish the curing process, thus obtaining the composite material with low secondary electron emission coefficient.
Further preferably, the preparation method of the composite material with the low secondary electron emission coefficient comprises the following steps:
(1) Placing the electronegative filler and the polymer matrix in a magnetic stirrer for fully stirring to uniformly mix the electronegative filler and the polymer matrix, then coating 1-10ml of the mixed solution on the surface of a device in a spin coating mode, uniformly spreading the mixed solution, placing the uniformly spread mixed solution in a vacuum box for vacuumizing for 2h, aiming at removing bubbles in the solution, preventing the bubbles from being burned in a curing process to influence the quality of a sample and the subsequent test, and forming a film with the thickness of 1-10 microns on the surface of the device;
(2) According to the curing process standard of the polyimide precursor, the mixture with the bubbles removed is put into a box furnace, the temperature is kept for 1h at the temperature of 100 ℃, then the temperature is raised to 225 ℃ at the heating rate of 3 ℃/min and kept for 1.5h, the curing process is completed, and therefore a thin film with uniform texture is formed on the surface of a device, and the composite material with low secondary electron emission coefficient is obtained.
And after the defoamed mixed solution is dried, an effective and uniform thin film can be formed on the surface of the device.
The invention utilizes the local reverse electric field formed by the electronegative filler in the polymer matrix to inhibit the generation and movement of secondary collision electrons, and compared with the polymer matrix, the secondary electron emission coefficient of the composite material is effectively reduced. The strategy can be popularized to different flexible polymer dielectric composite materials, and a brand new feasible scheme is provided for inhibiting the secondary electron emission coefficient in the future.
Preferably, the coating in step (1) is a spin coating technique, and the spin coating technique can make the coating more uniform and maintain good consistency, so as to form a coating material with uniform texture.
Preferably, the inert gas is nitrogen.
Compared with the prior art, the invention has the following beneficial effects:
the invention simplifies the process flow, the prepared electronegative filler has good dielectric property, the local reverse electric field formed by the inorganic material niobate with negative electricity and the polymer material PCBM with negative electricity in the polymer matrix is utilized to inhibit the generation and the movement of secondary collision electrons, and compared with the polymer matrix, the secondary electron emission coefficient of the composite material is effectively reduced, and the invention has better application prospect in the aspect of solving the micro-discharge effect on the surface of the microwave dielectric material.
Drawings
FIG. 1 shows CaNbO according to an embodiment of the present invention 3 Powder SEM test result chart;
FIG. 2 is an embodiment of the present inventionExample CaNbO 3 A graph of resistivity of the ceramic as a function of temperature;
FIG. 3 is a graph showing the results of a secondary electron emission coefficient test of the dielectric composite material of example 1 of the present invention;
FIG. 4 is a graph showing the results of a secondary electron emission coefficient test of the dielectric composite material of example 2 of the present invention;
FIG. 5 is a graph showing the results of a secondary electron emission coefficient test of a polymer composite according to example 3 of the present invention;
FIG. 6 is a graph showing the results of a secondary electron emission coefficient test of a polymer composite according to example 4 of the present invention;
FIG. 7 is a graph showing the results of the secondary electron emission coefficient test of the polymer composite material of example 5 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The test methods or test methods described in the following examples are conventional methods unless otherwise specified; the starting materials and auxiliaries are, unless specified otherwise, either obtained from customary commercial sources or prepared in customary manner.
Preparation of CaNb by solid phase sintering method 2 O 6 The technical process is as follows:
1. CaCO with the purity of 99.0 percent 3 And Nb with a purity of 99.9% 2 O 5 According to a molar ratio of 1:1, weighing raw materials, and performing ball milling twice by using a planetary ball mill to uniformly mix the raw materials, wherein the rotating speed of the ball mill is 400r/min;
2. then placing the ball-milled sample in an oven to be dried for 8-12h at the temperature of 110 ℃;
3. then 10ml of adhesive polyvinyl alcohol (PVA) is added for granulation and tabletting;
4. then, pre-sintering the dried sample (the pre-sintering temperature is generally 200 ℃ lower than the sintering temperature), wherein the pre-sintering temperature is 1250-1350 ℃, and more preferably 1250 ℃, 1300 ℃, 1325 ℃ and 1350 ℃ so as to evaporate the added adhesive PVA;
5. and finally, heating the sample subjected to pre-sintering at the temperature of 600 ℃ for 4h to enable the substances to spontaneously fill gaps among the particles, so that the density and the strength are greatly increased.
To CaNb 2 O 6 Basic Performance testing of ceramic materials
1. SEM structural testing as shown in FIG. 1, which was done to compare CaNb prepared at different sintering temperatures 2 O 6 Whether the ceramic material has a structure change or not, and the crystal grains are continuously enlarged along with the increase of the sintering temperature.
2. Electrical property test results are shown in FIG. 2, which includes a test for resistivity to compare CaNb prepared at different sintering temperatures 2 O 6 The difference in electrical properties of the ceramic material varies.
Example 1
(1) Mixing CaNb 2 O 6 Mixing the polyimide precursor and the polyimide precursor according to the proportion of 20wt%, and fully stirring by using a magnetic stirrer to uniformly mix the polyimide precursor and the polyimide precursor;
(2) Taking 1-10ml of mixed solution (namely CaNb) after fully mixing 2 O 6 Mixed solution with polyimide), the mixture is coated on the surface of an alumina substrate in a spin coating mode, the alumina substrate is placed in a vacuum box after being evenly spread, the vacuum box is vacuumized for 2 hours, and a film with the thickness of 1 to 10 microns in micron level is formed on the surface of the alumina substrate;
(3) And (3) putting the film obtained in the step (2) into a box-type furnace, preserving heat for 1h at the temperature of 100 ℃, then increasing the temperature to 225 ℃ at the heating rate of 3 ℃/min, preserving heat for 1.5h, and finishing the curing process to obtain the composite material with the low secondary electron emission coefficient.
The composite material prepared in example 1 and undoped CaNb were finally tested separately 2 O 6 The secondary electron emission coefficient of the polyimide film of (2) is shown in FIG. 3EXAMPLE 1 doping of 20wt% CNO (calcium niobate CaNb) 2 O 6 ) Then, the secondary electron emission coefficient can be effectively reduced, and the maximum value of the secondary electron emission coefficient is reduced from 2.2 to 1.42.
Example 2
The difference from example 1 is that 20wt% was replaced with 40wt% in step (1), and the rest is the same as example 1.
The composite material prepared in example 2 and undoped CaNb were finally tested separately 2 O 6 The polyimide film of (1) had a secondary electron emission coefficient, as shown in FIG. 4, and example 2, after doping 40wt% CNO, was effective in reducing the secondary electron emission coefficient, the maximum value of which was reduced from 2.2 to 1.78.
The invention contains XNbO in spin coating 3 When the powder polyimide is prepared by using an alumina substrate, the substrate material is found to be the negative charge inorganic filler XNbO by replacing different substrate materials 3 The powder had no effect. Thus effectively confirming the negatively charged inorganic filler XNbO 3 The powder can generate a local reverse electric field to effectively suppress secondary electrons.
The invention prepares the doped XNbO with different contents 3 Compared with the polyimide film without any doping, the polyimide film can effectively reduce the secondary electron emission coefficient of the polyimide.
Example 3
The difference from example 1 is that epoxy resin is used instead of polyimide in step (1), and the rest is the same as example 1.
The composite material prepared in example 3 and undoped CaNb were finally tested separately 2 O 6 The secondary electron emission coefficient of the epoxy resin thin film of (4) was effectively reduced by doping 20wt% of CNO as shown in FIG. 5 in example 3, and the maximum value of the secondary electron emission coefficient was reduced from 2.4 to 2.0.
Example 4
The difference from example 1 is that the doped calcium niobate in step (1) is replaced by sodium niobate (NaNbO) 3 ) Otherwise, the same procedure as in example 1 was repeated.
The composite prepared in example 4 and undoped NaNbO were finally tested separately 3 The polyimide film of (4) had a secondary electron emission coefficient, as shown in FIG. 6, example 4 doping of 20wt% NaNbO 3 Then, the secondary electron emission coefficient can be effectively reduced, and the maximum value of the secondary electron emission coefficient is reduced from 2.6 to 1.9.
Example 5
The difference from example 1 is that [60] is used in step (1)]PCBM substituted CaNb 2 O 6 Otherwise, the same procedure as in example 1 was repeated.
Finally, the secondary electron emission coefficients of the composite material prepared in example 5 and the polyimide film without the [60] PCBM are respectively tested, and as shown in FIG. 7, the secondary electron emission coefficient can be effectively reduced after the example 5 is doped with 20wt% [60] PCBM, the maximum value of the secondary electron emission coefficient is reduced from 2.18 to 0.9, and the effect of inhibiting the secondary electron emission coefficient is achieved.
Proved by experiments, the inorganic filler XNbO with negative electricity prepared by the invention 3 And the composite material of the polymer material PCBM can generate a local reverse electric field to further effectively inhibit secondary electrons, so that the emission coefficient of the secondary electrons on the surface is reduced from 2.4 to 0.9, and the composite material has a good application prospect in the aspect of solving the micro-discharge effect on the surface of the microwave dielectric material.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (3)
1. A preparation method of a composite material with low secondary electron emission coefficient is characterized by comprising the following steps:
(1) Uniformly mixing the electronegative filler and the polymer matrix, and then coating the mixed solution on the surface of a device;
(2) Then preserving heat for 1h at the temperature of 90-110 ℃, then increasing the temperature to 200-250 ℃ at the heating rate of 2-4 ℃/min and preserving heat for 1-2h to finish the curing process, thus obtaining the composite material with low secondary electron emission coefficient;
the electronegative filler is niobate with a two-dimensional nano structure or [60] PCBM;
the addition amount of the [60] PCBM is 20wt%;
the addition amount of the niobate is 20wt% or 40 wt%;
the niobate is prepared by a solid-phase sintering method.
2. The method of claim 1, wherein the polymer matrix is at least one of polyimide and epoxy.
3. The method for producing a composite material having a low secondary electron emission coefficient as defined in claim 1, wherein the niobate is at least one of calcium niobate, sodium niobate, potassium-sodium niobate, and lithium niobate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111650803.8A CN114292587B (en) | 2021-12-30 | 2021-12-30 | Composite material with low secondary electron emission coefficient and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111650803.8A CN114292587B (en) | 2021-12-30 | 2021-12-30 | Composite material with low secondary electron emission coefficient and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114292587A CN114292587A (en) | 2022-04-08 |
| CN114292587B true CN114292587B (en) | 2022-10-18 |
Family
ID=80973630
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111650803.8A Active CN114292587B (en) | 2021-12-30 | 2021-12-30 | Composite material with low secondary electron emission coefficient and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114292587B (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000348647A (en) * | 1999-06-02 | 2000-12-15 | Sharp Corp | Image forming device |
| CN109705502B (en) * | 2018-12-29 | 2020-05-22 | 中国科学技术大学 | Polymer-based composite material and preparation method thereof |
| CN113684453B (en) * | 2021-06-23 | 2023-07-28 | 西安空间无线电技术研究所 | Film with low secondary electron emission coefficient and preparation method thereof |
-
2021
- 2021-12-30 CN CN202111650803.8A patent/CN114292587B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN114292587A (en) | 2022-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2016387660B2 (en) | Method of preparing battery electrodes | |
| CN108232175B (en) | Graphite/lithium titanate composite negative electrode material for lithium ion battery and preparation method | |
| Zhang et al. | High-performance Ta-doped Li7La3Zr2O12 garnet oxides with AlN additive | |
| JP2015204215A (en) | Lithium ion-conducting solid electrolyte, manufacturing method thereof, and all-solid battery | |
| CN113422029A (en) | Negative electrode material, preparation method thereof and lithium ion battery | |
| CN110071280B (en) | Lithium aluminate solid electrolyte coated silicon-based negative electrode material and preparation method thereof | |
| CN114824235B (en) | Multilayer sodium-ion battery positive electrode material and preparation method thereof | |
| JP2010170854A (en) | Method of manufacturing positive electrode for nonaqueous electrolyte battery, positive electrode for nonaqueous electrolyte battery, and nonaqueous electrolyte battery | |
| WO2012161055A1 (en) | Production method for material employed in energy device and/or electrical storage device, and material employed in energy device and/or electrical storage device | |
| CN114292587B (en) | Composite material with low secondary electron emission coefficient and preparation method thereof | |
| Fang et al. | Research progress on doping modification of Ca3Co4O9 thermoelectric materials: a review | |
| CN114163231A (en) | Lead-free pulse dielectric energy storage composite ceramic material and preparation method and application thereof | |
| KR102600789B1 (en) | Silicon-graphene composite anode material and manufacturing method thereof | |
| JP2024519177A (en) | Positive electrode active material, its manufacturing method and lithium secondary battery using the same | |
| US12100800B2 (en) | Solid state electrolytes | |
| JP2007056351A (en) | Target for ion plating used for manufacturing of zinc oxide-based electroconductive film, its manufacturing method, and method for manufacturing zinc oxide-based electroconductive film | |
| CN110323436B (en) | Lithium titanate composite material and preparation method thereof, electrode plate of lithium ion battery and preparation method thereof, and lithium ion battery | |
| CN109786668A (en) | A kind of silicon-graphene combination electrode using insulation conductivity principle | |
| Huang et al. | Composites of sodium manganese oxides with enhanced electrochemical performance for sodium-ion batteries: Tailoring properties via controlling microstructure | |
| CN112117440B (en) | Method for manufacturing cathode composite and method for manufacturing all-solid-state battery | |
| KR100844894B1 (en) | Ferromagnetic semiconductor thin layer and a fabrication method thereof | |
| CN116102352B (en) | Antiferroelectric energy storage ceramic with high fatigue resistance, low electric field and high energy storage density and preparation method and application thereof | |
| Terauchi et al. | High‐performance MgO thin films for PDPs with a high‐rate sputtering‐deposition process | |
| Cho et al. | Growth of BaTiO 3-PVDF composite thick films by using aerosol deposition | |
| Shanenkova et al. | Obtaining a Composite Material for Varistor Ceramics in One Short-Time Operation Cycle of a Coaxial Magnetoplasma Accelerator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |