CN110983303A

CN110983303A - Preparation method of metal layer of waveguide tube and preparation method of waveguide tube

Info

Publication number: CN110983303A
Application number: CN201911162724.5A
Authority: CN
Inventors: 武勇斌; 陈巧峰; 侯仰青; 吴春邦; 方厚菲; 唐渝思; 姚展; 刘阳
Original assignee: Shanghai Ys Information Technology Co ltd
Current assignee: Shanghai Ys Information Technology Co ltd
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2020-04-10

Abstract

The invention provides a preparation method of a metal layer of a waveguide tube and a preparation method of the waveguide tube, wherein the preparation method of the metal layer comprises the following steps: providing a main salt solution comprising silver nitrate and a reducing agent solution comprising sodium gluconate; spraying a main salt solution and a reducing agent solution on the surface of a core mold of a waveguide tube simultaneously; and forming a metal layer with the main material being silver on the surface of the core mould after the main salt solution and the reducing agent solution are mixed. After the technical scheme is adopted, the electrical property of the prepared waveguide tube can be free from the influence of the external temperature by adopting the composite material with zero thermal expansion coefficient, and the electrical property is stable.

Description

Preparation method of metal layer of waveguide tube and preparation method of waveguide tube

Technical Field

The invention relates to the field of aerospace science and technology, in particular to a method for preparing a metal layer of a waveguide tube and a method for preparing the waveguide tube.

Background

The waveguide tube is mainly applied to the fields of communication, satellite ground stations, microwave measurement and the like. The waveguide is generally made of a metal material by machining or by electroplating the inner surface of a resin pipe, and the carbon fiber composite waveguide is finally formed. The carbon fiber composite waveguide mainly comprises two forming methods: a composite material waveguide is formed by solidifying and molding a composite material on a tool mold, grinding and polishing the interior of a pipe, then electroplating a metal layer, and finally combining; the other is an integral one-step molding process, a metal layer is plated on a tool mold for molding the waveguide, and after the laid composite material is cured and demoulded, the tool mold is corroded by alkaline solution, so that the metal layer is left on the inner wall of the composite material product.

The two existing preparation processes mainly have the following defects: (1) for the process of firstly curing the carbon fiber composite material pipe and then electroplating the metal layer on the inner wall of the carbon fiber composite material pipe, the adhesion of the electroplated metal layer is poor, the probability of non-uniformity of the plating layer is higher along with the increase of the length of the waveguide pipe, and the possibility of bulging of the metal plating layer is also greatly increased; (2) for the integral one-step molding process, the mold is corroded along with the demolding process, so that only one product can be prepared by one mold, the mold cost is high, the production period is long, the core mold removing time is long, each core mold needs to be soaked in an alkaline solution for five to six days and nights, and the composite material and the metal coating of the composite material can be potentially damaged.

Therefore, there is a need for a new method for preparing a metal layer of a waveguide, which does not require machining of the waveguide, and thus has a thickness much smaller than that of the metal waveguide, uses less material, and can be further reduced in weight.

Disclosure of Invention

In order to overcome the technical defects, the invention aims to provide a method for preparing a metal layer of a waveguide tube and a method for preparing the waveguide tube, wherein the electrical property of the prepared waveguide tube is not influenced by the external temperature and is stable by adopting a composite material with zero thermal expansion coefficient.

The invention discloses a preparation method of a metal layer of a waveguide tube, which comprises the following steps:

providing a main salt solution comprising silver nitrate and a reducing agent solution comprising sodium gluconate;

spraying a main salt solution and a reducing agent solution on the surface of a core mold of a waveguide tube simultaneously;

and forming a metal layer with the main material being silver on the surface of the core mould after the main salt solution and the reducing agent solution are mixed.

Preferably, the step of simultaneously spraying the main salt solution and the reducing agent solution on the core mold surface of the waveguide comprises:

loading a main salt solution and a reducing agent solution by using a double-head gun;

and spraying a main salt solution and a reducing agent solution to the surface of the core mold at a preset spraying pressure, wherein the distance between the out-of-gun mixing point of the main salt solution and the reducing agent solution and the surface of the core mold is a preset distance.

Preferably, the preset spraying pressure is 0.4-0.8 MPa;

the preset distance is 10-20 cm.

Preferably, in the step of spraying the main salt solution and the reducing agent solution to the surface of the core mold at a preset spraying pressure, the ratio of the main salt solution to the reducing agent solution sprayed by the double-headed gun is 1:1 to 1: 1.5.

Preferably, the main salt solution further comprises triethanolamine, ammonia water and ultrapure water;

the reducing agent solution also comprises hydrazine sulfate, ethanol and ultrapure water.

Preferably, the thickness of the metal layer is 1 to 500 μm.

The invention also discloses a preparation method of the waveguide tube, which comprises the following steps:

manufacturing a core mold;

the method for producing a metal layer according to claim 1, wherein a metal layer mainly made of silver is formed on the surface of the core mold;

paving carbon fiber prepreg on the surface of the metal layer;

heating in vacuum for curing and forming;

the mandrel is stripped to prepare the waveguide.

Preferably, the method for preparing a metal layer according to claim 1, wherein the steps of forming the metal layer with silver as the main material on the surface of the core mold and spreading the carbon fiber prepreg on the surface of the metal layer further include:

and electroplating the metal layer to form an electroplated metal layer with the thickness of 50-500 mu m.

Preferably, the step of electroplating the metal layer to form an electroplated metal layer having a thickness of 50-500 μm comprises:

silver cyanide and potassium cyanide are provided and electroplated on the metal layer at a temperature of between 15 and 35 ℃ using a cathodic current density of between 0.1 and 0.5 A.dm-2.

Preferably, the step of making the core mold comprises:

designing a core mold structure according to the geometric parameters of the waveguide;

and (4) modifying the core mold structure based on the thermal expansion coefficient, and processing and preparing the core mold.

After the technical scheme is adopted, compared with the prior art, the method has the following beneficial effects:

1. the thickness of the metal layer can be controlled by adjusting the technological parameters of nano spraying and electroplating;

2. the tool core film is processed on the outer surface, high dimensional precision and mirror finish are easily realized through high-precision machining and fine grinding and polishing processes, and the waveguide tube demoulded from the surface of the tool core film is high in dimensional precision and excellent in electrical property;

3. the tool core film is processed on the outer surface, and the length of the tool core film is basically not limited by the length limit of the inner hole machined by high-precision machinery, so that a waveguide tube longer than that of a waveguide tube machined by the traditional method for machining the inner surface can be prepared;

4. the demolding is simple, the preparation period is short, the mold can be repeatedly used, and the production cost is low;

5. the composite material with zero thermal expansion coefficient can ensure that the electrical property of the prepared waveguide tube is not influenced by the external temperature and the electrical property is stable;

6. due to the high specific stiffness of the composite material, the weight of the waveguide prepared by the method can be greatly reduced;

7. since no machining of the waveguide is required, the thickness is much smaller than that of the metallic waveguide, the material used is less and the weight can be further reduced.

Drawings

FIG. 1 is a schematic flow chart of a method for preparing a metal layer of a waveguide according to a preferred embodiment of the present invention;

FIG. 2 is a schematic flow chart of a method of fabricating a waveguide according to a preferred embodiment of the present invention;

FIG. 3 is a graphical representation of a waveguide curing process with prepreg in accordance with a preferred embodiment of the present invention;

FIGS. 4a-4d are graphs showing experimental results of various performance tests of a waveguide according to a preferred embodiment of the present invention;

FIG. 5 is a schematic structural view of a combined mold of waveguides according to a preferred embodiment of the present invention;

fig. 6 is a schematic structural view of a waveguide made of a carbon fiber composite material with a metal flange according to a preferred embodiment of the present invention.

Detailed Description

The advantages of the invention are further illustrated in the following description of specific embodiments in conjunction with the accompanying drawings.

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present disclosure. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

In the description of the present invention, unless otherwise specified and limited, it is to be noted that the terms "mounted," "connected," and "connected" are to be interpreted broadly, and may be, for example, a mechanical connection or an electrical connection, a communication between two elements, a direct connection, or an indirect connection via an intermediate medium, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.

In the following description, suffixes such as "module", "component", or "unit" used to denote elements are used only for facilitating the explanation of the present invention, and have no specific meaning in themselves. Thus, "module" and "component" may be used in a mixture.

Referring to fig. 1, a flow chart of a method for manufacturing a metal layer of a waveguide according to a preferred embodiment of the present invention is schematically shown, in which the method includes the following steps:

① provides a primary salt solution including silver nitrate and a reducing agent solution including sodium gluconate

The metal layer of the waveguide tube is prepared by a pure silver layer or a silver ion-containing layer. By using the silver metal layer, the metal layer with uniform thickness and good electrical property can be prepared, and the whole thickness of the metal layer is proper, so that certain rigidity can be kept in a special environment in the aerospace field.

In order to form the metal layer, a nano-spraying process such as double-head gun air spraying, single-head gun air spraying and the like is adopted for forming the metal layer. The two solutions used in the nano-spraying process are respectively a main salt solution containing silver nitrate and a reducing agent solution containing sodium gluconate according to a certain proportion, specifically, the main salt solution comprises silver nitrate, triethanolamine, ammonia water and ultrapure water, and the reducing agent solution comprises hydrazine sulfate, sodium gluconate, ethanol and ultrapure water.

② spraying main salt solution and reducing agent solution on the core mould surface of waveguide tube

After obtaining the two main salt solutions and the reducing agent solution, injecting the two main salt solutions and the reducing agent solution into two spray pipes of a double-head gun respectively, and spraying the two main salt solutions and the reducing agent solution to the surface of a core mould of a waveguide pipe at a certain distance, such as 10-20cm, from the surface of the core mould at a spraying pressure of 0.4-0.8 MPa.

③ forming a metal layer made of silver on the surface of the core mold after the main salt solution and the reducing agent solution are mixed

After the main salt solution and the reducing agent solution are sprayed to the surface of the core mold, the main salt solution and the reducing agent solution react on the surface of the core mold, silver ions are separated out, and a metal layer made of silver is formed on the surface of the core mold through solidification. The thickness of the metal layer may be 1-500 μm, preferably 5-250 μm.

In a preferred embodiment, the step of simultaneously spraying the main salt solution and the reducing agent solution on the mandrel surface of the waveguide comprises:

② -1, loading the main salt solution and the reducing agent solution by using a double-head gun;

② -2, spraying a main salt solution and a reducing agent solution to the surface of the core mould at a preset spraying pressure, wherein the distance between the mixing point outside the gun of the main salt solution and the reducing agent solution and the surface of the core mould is a preset distance, as mentioned above, the preset spraying pressure can be 0.4-0.8MPa, the preset distance can be 10-20 cm., and the ratio of the main salt solution to the reducing agent solution can be 1:1-1: 1.5.

In any of the above embodiments, the specific ratios of silver nitrate, triethanolamine, ammonia water, and ultrapure water included in the main salt solution and hydrazine sulfate, sodium gluconate, ethanol, and ultrapure water included in the reducing agent solution may be as follows:

TABLE 1

Referring to fig. 2, a flow chart of a method for manufacturing a waveguide according to a preferred embodiment of the present invention is schematically shown, in which the method includes the following steps:

① making a core mould;

according to the geometric parameter requirements of the waveguide model, a calculation model can be established first, and then the core mold structure is corrected through the thermal expansion coefficient, so that the core mold meeting the size requirements of the tool core mold can be processed and prepared.

Since the cross-sectional size of the prepared waveguide affects the electrical properties of the final product. Therefore, in order to meet the performance requirements, the dimensional accuracy of the product must be strictly controlled, and the correction can ensure the dimensional requirements of the cured product. Taking the carbon fiber composite waveguide BJ100 as an example, the cross-sectional dimension a of the waveguide product is generally required to be 19.05mm, and the cross-sectional dimension b of the waveguide product is required to be 9.525mm, and the cross-sectional dimension a of the actual die is 19.02 ± 0.01mm, and the cross-sectional dimension b of the actual die is required to be 9.51 ± 0.01mm by using 316L stainless steel as the die and taking the influence of the thermal expansion coefficient into consideration. Thus, the product after high-temperature curing can meet the requirement of dimensional precision.

By the steps of manufacturing and correcting, the core mould which is made of stainless steel, die steel, hidden steel, aluminum alloy, high-temperature plastic, glass, wood substitute and the like is finally obtained, and the surface roughness Ra of the core mould is less than or equal to 0.8 mu m.

② forming a metal layer made of silver on the surface of the core mold according to the above method;

③ spreading carbon fiber prepreg on the surface of the metal layer;

in order to meet the requirement of thermal stability of the carbon fiber composite waveguide tube in a space environment, when the carbon fiber prepreg is laid on the surface of the metal layer, a quasi-zero expansion laying design is adopted, for example, eight layers are formed according to a laying angle [0 °/45 °/90 °/45 °/] s, the thickness of a single layer is 0.05-0.2mm, and the prepreg with the total thickness of 0.4-1.6mm is formed.

The prepreg is prepared from carbon fibers from Dongli, Japan, and domestic epoxy resins under the brand names T300, T700, T1000, M40J, M55J, M60J, etc.

③ vacuum heating, curing and shaping;

the curing adopts an autoclave curing process, and the core mold with the prepreg is placed in a curing environment with the temperature of 100-230 ℃ and the pressure of 0.1-1.2 MPa. For the example of M40J/epoxy, the curing process curve can be seen in FIG. 3.

④ core stripping to prepare waveguide

After the carbon fiber composite waveguide tube is solidified and cooled at high temperature, the composite waveguide tube is separated from the core die by a die drawing process by utilizing the mismatching of the thermal expansion coefficients of the die and the carbon fiber composite material, so that the die is removed.

In a preferred embodiment, after forming a metal layer of silver as the main material on the surface of the mandrel, a metal layer is further electroplated, firstly, silver cyanide and potassium cyanide are provided, and metal with a thickness of 50-500 μm is electroplated on the metal layer at a temperature of 15-35 ℃ by using a cathode current density of 0.1-0.5 A.dm-2And (3) a layer. The material of the electroplated metal layer can be gold, silver, copper, nickel and the like. Taking the electroplated metal layer made of silver as an example: the electroplating formulation may comprise 35-45 g.L^-165-80 g.L of silver chloride^-1And (c) silver chloride (total) and 35 to 45 g.L^-1The plating time can be determined according to the thickness of the metal layer.

After the waveguide is prepared, performance testing can also be performed on the waveguide to determine whether the waveguide meets the user requirements for the use environment, such as aerospace. In particular, the following properties may be tested:

1. thermal shock resistance:

and testing whether the combination of the metal silver layer and the composite material matrix is firm or not, and whether the phenomena of layering, falling, bulging and the like occur or not by a hundred-grid knife test method through liquid nitrogen (-196 ℃) to high temperature (135 ℃) for 400 times of cold-heat circulation.

2. Electrical properties:

after the electrical performance test of the waveguide tube with the metallic silver layer, the experimental data are as follows:

serial number	Waveguide type	Waveguide length (millimeter)	Standing wave	Insertion loss (dB)
					1	Single joint BJ100	480	Is better than 1.03	Is better than 0.12
2	BJ100 combination	995	Is better than 1.05	Is better than 0.24

Referring to fig. 4a-4d, fig. 4a is standing wave ratio test data for waveguide number 1, fig. 4b is insertion loss test data for waveguide number 1, fig. 4c is standing wave ratio test data for waveguide number 2, and fig. 4d is insertion loss test data for waveguide number 2. According to test data, the standing-wave ratio test value of all waveguide tube (and the combination thereof) samples is better than 1.05, the insertion loss is better than 0.25 dB/m, and the use requirements of aerospace can be met.

Fig. 5 and 6 respectively show the structural schematic diagrams of a composite straight waveguide with a metal flange and a composite straight waveguide with a composite flange. When the composite material straight waveguide tube shown in fig. 5 is prepared, metal flanges are assembled at two ends of the prepared straight waveguide tube; when the composite material straight waveguide tube shown in fig. 6 is prepared, in the step of core mold preparation, flange end molds are connected to two ends of the core mold through bolts, and finally, after solidification is completed, the flange end molds at two ends are disassembled, so that the straight waveguide tube with the flange and conforming to the material can be directly obtained.

It should be noted that the embodiments of the present invention have been described in terms of preferred embodiments, and not by way of limitation, and that those skilled in the art can make modifications and variations of the embodiments described above without departing from the spirit of the invention.

Claims

1. A method for preparing a metal layer of a waveguide is characterized by comprising the following steps:

2. The method for producing a metal layer according to claim 1,

the step of simultaneously spraying the main salt solution and the reducing agent solution on the surface of the core mold of the waveguide comprises:

3. The method for producing a metal layer according to claim 2,

the preset spraying pressure is 0.4-0.8 MPa;

the preset distance is 10-20 cm.

4. The method for producing a metal layer according to claim 2,

in the step of spraying the main salt solution and the reducing agent solution to the surface of the core mold at a preset spraying pressure, the ratio of the main salt solution to the reducing agent solution sprayed by the double-headed gun is 1:1-1: 1.5.

5. The method for producing a metal layer according to claim 1,

the main salt solution also comprises triethanolamine, ammonia water and ultrapure water;

6. The method for producing a metal layer according to claim 1,

the thickness of the metal layer is 1-500 μm.

7. A method of making a waveguide, comprising the steps of:

manufacturing a core mold;

paving carbon fiber prepreg on the surface of the metal layer;

heating in vacuum for curing and forming;

the mandrel is stripped to prepare the waveguide.

8. The method according to claim 7,

the method for preparing a metal layer according to claim 1, wherein the steps of forming the metal layer with silver as the main material on the surface of the core mold and spreading the carbon fiber prepreg on the surface of the metal layer further comprise:

9. The method according to claim 8,

electroplating the metal layer to form an electroplated metal layer with the thickness of 50-500 mu m, wherein the step of electroplating the metal layer comprises the following steps:

10. The method according to claim 7,

the core mold manufacturing step comprises: