阅读说明：本技术 一种超薄热管的制备方法 (Preparation method of ultrathin heat pipe ) 是由 赵航 伍春霞 伍晓宇 唐恒 徐斌 朱立宽 高畅 萧永昌 于 2019-10-29 设计创作，主要内容包括：本发明公开了一种超薄热管的制备方法,包括以下步骤：(1):设计热管,制备与金属热管内部具有相同结构的模具电极；(2):在电铸盐溶液中加入散热型粉末搅拌均匀,得到电铸液；(3):将模具电极夹在电解槽上,并向电解槽中倒入电铸液,设置电铸参数并采用三电极电源进行电铸加工,得电铸层；步骤(4):将电铸层取下并清洗、烘干、刻蚀获得与模具电极形状及尺寸相同的具有微结构的金属薄膜；(5):将金属薄膜折叠,并沿边缘焊接得到具有焊接缺口的热管；步骤(6)：将热管压力整形,并从焊接缺口处对热管内腔中抽真空,抽真空完毕后填充工作液体,将焊接缺口密封得到超薄热管。本发明的制备方法能够灵活的控制超薄散热管的厚度。(The invention discloses a preparation method of an ultrathin heat pipe, which comprises the following steps: (1) designing a heat pipe, and preparing a die electrode with the same structure as the inner part of the metal heat pipe; (2) adding heat dissipation type powder into electroforming salt solution and uniformly stirring to obtain electroforming solution; (3) clamping a mould electrode on an electrolytic bath, pouring electroforming liquid into the electrolytic bath, setting electroforming parameters and performing electroforming processing by adopting a three-electrode power supply to obtain an electroforming layer; taking down the electroforming layer, cleaning, drying and etching to obtain a metal film with the same shape and size as the electrode of the die and a microstructure; (5) folding the metal film and welding along the edge to obtain the heat pipe with a welding gap; and (6): and (4) pressure shaping the heat pipe, vacuumizing the inner cavity of the heat pipe from the welding gap, filling working liquid after vacuumizing is finished, and sealing the welding gap to obtain the ultrathin heat pipe. The preparation method of the invention can flexibly control the thickness of the ultrathin radiating pipe.)

1. The preparation method of the ultrathin heat pipe is characterized by comprising the following steps of:

(1) designing a heat pipe, and preparing a die electrode with the same structure as the inner part of the metal heat pipe for later use;

(2) adding heat dissipation type powder into the electroforming salt solution, and uniformly stirring to obtain electroforming solution for later use;

(3) clamping the mould electrode on an electrolytic bath, pouring the electroforming solution into the electrolytic bath, setting electroforming parameters and performing electroforming processing by adopting a three-electrode power supply to obtain an electroforming layer;

(4) taking down the electroforming layer, cleaning, drying and etching to obtain a metal film with a microstructure, which has the same shape and size as the mold electrode;

(5) folding the metal film, and welding along the edge to obtain the heat pipe with a welding gap;

(6) and (4) pressure shaping the heat pipe, vacuumizing the inner cavity of the heat pipe from the welding gap, filling cooling liquid after vacuumizing is finished, and sealing the welding gap to obtain the ultrathin heat pipe.

2. The method as claimed in claim 1, wherein the heat-dissipating powder in step (2) is graphene and/or carbon nanotubes, and the mass-to-volume ratio of the heat-dissipating powder to the electroforming solution is 10mg (500) mL.

3. The method for manufacturing an ultra-thin heat pipe as claimed in claim 1, wherein in the step (2), the stirring time is 20-30min, and the stirring temperature is 23-30 ℃.

4. The method for manufacturing an ultrathin heat pipe as claimed in claim 1, wherein the step (3) of electroforming by using a three-electrode power supply comprises the following specific steps: and connecting the die electrode as a working electrode, taking copper as a counter electrode and taking mercurous sulfate as a reference electrode.

5. The method for manufacturing an ultrathin heat pipe as claimed in claim 1, wherein the drying temperature in the step (4) is 80-100 ℃ and the drying time is 1-2 h.

6. The method for manufacturing an ultra-thin heat pipe as claimed in claim 1, wherein the pressure for the pressure shaping in the step (6) is 4-5 KPa.

Technical Field

The invention relates to the technical field of heat pipes, in particular to a preparation method of an ultrathin heat pipe.

Background

In practical production application, heat pipes with the overall thickness of less than 2mm are collectively called as ultra-thin heat pipes, and comprise one-dimensional heat pipes and vapor chambers. At present, ultrathin heat pipes are widely used in mobile electronic devices such as smart phones, tablet computers, laptop computers and smart watches. In recent years, due to rapid development of the field of mobile internet, people have rapidly increased demand for mobile smart devices such as smart phones and tablet computers, and new requirements for performance and portability of the mobile devices are provided, which accelerates development of high performance and light weight, but also causes a series of heat dissipation problems. The development of ultra-thin heat pipes is an effective means for solving the problem of heat dissipation of light and thin electronic equipment in a narrow space, and is a necessary trend in the development of heat pipe technology. Therefore, the ultra-thin heat dissipation device with high heat conductivity, high cooling capacity, high stability and high plasticity has extremely important practical significance and application value for the application of electronic components, electric power, petroleum, chemical engineering, metallurgy and other related fields.

According to the discussion of the current research situation and development trend of the ultrathin micro heat pipe by the professor of the soup courage of the university of southern China, the stable operation of the ultrathin heat pipe depends on the permeation and backflow speed of liquid in the liquid absorption core and the capillary pressure provided by the liquid absorption core, and the permeability and the capillary pressure of the liquid absorption core are two main performance parameters influencing the heat transfer performance and the heat transfer limit of the ultrathin heat pipe. The liquid absorption core is used as a core component of the ultrathin heat pipe and is the most critical factor for determining the heat transfer performance of the heat pipe. Wicks can therefore be divided into three broad categories, depending on their different structural types: sintered wick structures, grooved wick structures, and composite wick structures. The specific methods for preparing different wick structures at present mainly include vacuum coating, high-speed spinning broaching formation, plowing-broaching formation, chemical etching, electric spark machining, powder sintering, screen-covering groove wick, and the like. In the prior art, the minimum thickness of the sintered wick structure micro heat pipe is 0.4mm, the minimum thickness of the ultrathin heat pipe with the groove-shaped wick structure is 0.3mm, and the thickness of the ultrathin heat pipe with the composite wick structure is less than 1 mm.

However, the existing preparation method of the ultrathin heat pipe has many defects, so that the manufacture of the heat pipe with high heat dissipation and ultrathin characteristics is greatly restricted, and the industrial popularization is difficult. It mainly embodies in following several respects:

① the surface strength is low, and cracks or micro-structure falling are easy to occur;

②, the process is complicated and the manufacturing cost is high;

③ are inefficient to manufacture and are not suitable for high volume manufacturing or efficient use;

④, the process is not flexible, it is difficult to machine wicks of different thickness requirements or it is not very well controlled as to the relationship between the machining parameters and the quality of the machined surface.

In recent years, micro electroforming is widely used as a brand new micromachining technology for manufacturing micro devices, and can be used for copying a high-precision, high-compactness and ultrathin micro structure surface with a submicron level on the surface of a die electrode. However, there is no report on the production of high-performance ultra-thin heat pipes by electroforming.

Therefore, how to provide a method for manufacturing a high-performance ultrathin heat pipe, which can improve the production efficiency and control the processing thickness, is a problem that needs to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the present invention provides a method for manufacturing an ultra-thin heat pipe with high performance

In order to achieve the purpose, the invention adopts the following technical scheme: a preparation method of an ultrathin heat pipe comprises the following steps:

(1) customizing: selecting the material of the heat pipe according to the requirement of the ultrathin heat pipe, and designing the size and the outline of the heat pipe; designing the material, size and contour of the die electrode according to the material, size and contour of the heat pipe; simultaneously, designing a surface microstructure of the die electrode according to the requirement on the inner surface structure of the ultrathin heat pipe;

cutting the heat pipe into required size and contour shape by mechanical processing or special processing technology according to the designed mould electrode; processing the heat pipe into a die electrode with a microstructure for later use;

(2) adding heat dissipation type powder into the electroforming salt solution, and uniformly stirring to obtain electroforming solution for later use;

(3) clamping the mould electrode on an electrolytic bath, pouring the electroforming solution into the electrolytic bath, setting electroforming parameters and performing electroforming processing by adopting a three-electrode power supply to obtain an electroforming layer;

(4) taking down the electroforming layer, sequentially cleaning the electroforming layer for 10 minutes by using acetone, alcohol and deionized water, drying and etching to obtain a metal film with a microstructure, wherein the shape and the size of the metal film are the same as those of a die electrode;

(5) folding the metal film, and welding along the edge to obtain the heat pipe with a welding gap;

(6) and (4) pressure shaping the heat pipe, vacuumizing the inner cavity of the heat pipe from the welding gap, filling cooling liquid after vacuumizing is finished, and sealing the welding gap to obtain the ultrathin heat pipe.

The invention has the beneficial effects that: the metal film with the surface microstructure is prepared in an electroforming mode, and has good permeation reflux characteristics; the heat dissipation powder is introduced into an electroforming forming process, so that a composite material film is formed by the heat dissipation powder and an electroforming layer, and the apparent specific area and the heat conductivity of the metal film are further increased; the thickness of the ultrathin radiating pipe is flexibly controlled by controlling electroforming processing parameters; the heat pipe or the vapor chamber with different sizes and shapes can be obtained by designing the size and the outline of the die electrode, and the method is suitable for large-scale industrial production.

Preferably, the machining mode on the heat pipe can adopt a wire cut electrical discharge machining mode, a precise grinding process or a single-point diamond turning mode. The processing method in the present invention is not limited to the above method.

The wire cut electrical discharge machining is suitable for machining small-batch and switch complex parts, single pieces and trial products, the machining period is short, a specific shape is not needed, and the design and manufacturing cost of the electrode can be saved; the cutting speed is very high by adopting a precision grinding process, and the small residual area on the surface of a workpiece is ensured, so that the extremely small surface roughness is obtained; the single-point diamond turning is adopted to improve the surface shape precision of the optical part and obtain extremely small roughness.

Preferably, in the step (2), the electroforming salt solution includes:

when copper is selected as an electrode material, the ratio of the mass of the blue vitriol to the volume of the concentrated sulfuric acid to the volume of the concentrated hydrochloric acid is 100g:10mL:0.1 mL; the specific operation of electroforming the salt solution is as follows: copper sulfate pentahydrate, concentrated sulfuric acid and concentrated hydrochloric acid are stirred uniformly and added with deionized water to obtain an electroforming salt solution.

When nickel is selected as an electrode material, 350g of nickel sulfamate, 10g of nickel chloride, 35g of boric acid and deionized water are mixed to obtain an electroforming salt solution; the specific operation of electroforming the salt solution is as follows: deionized water is added into nickel sulfamate, nickel chloride and boric acid to obtain an electroforming salt solution.

Preferably, in the step (2), the heat dissipation powder is graphene and/or carbon nanotubes, and the volume ratio of the mass of the heat dissipation powder to the volume of the electroforming solution is 10mg:500 mL.

The beneficial effects are that: in order to obtain a casting layer with good mechanical property and high heat dissipation performance, heat dissipation powder with both a reinforcing agent and a heat conduction effect is introduced into electroforming solution, so that the powder is accumulated on the surface of a core mold together with metal atoms under ultrasonic stirring, and the mechanical property and the heat conductivity of the casting layer are further enhanced. Meanwhile, the heat dissipation type powder is mixed in the metal atom casting layer, so that the internal stress of the metal is improved.

Preferably, in the step (2), the stirring time is 20-30min, and the stirring temperature is 23-30 ℃.

More preferably, ultrasonic stirring is adopted, and the stirring frequency is 19-20KHz

Preferably, in step (3), the electroforming parameters are set according to the selected heat pipe.

Preferably, in the step (3), the electroforming process using the three-electrode power supply specifically includes: and connecting the die electrode as a working electrode, taking copper as a counter electrode and taking mercurous sulfate as a reference electrode. The counter electrode is not limited to the copper electrode.

Preferably, in the step (4), the drying temperature is 80-100 ℃, and the drying time is 1-2 h.

Preferably, in the step (6), the pressure of the pressure shaping is 4-5 KPa. The vacuum pumping is carried out until the pressure is 10^-2Pa

The beneficial effects are that: the adoption of pressure shaping can ensure high precision, good operating conditions and high productivity, and is easy to realize large-scale industrial production.

According to the technical scheme, compared with the prior art, the invention provides the preparation method of the ultrathin heat pipe, ① can accurately reproduce the fine characteristics of the surface precision of the core mold reaching the nanometer level and prepare the ultrathin heat pipe with the thickness lower than 0.3mm, ② can process parts which are difficult to process in the traditional technology, ③ can realize automatic production and comprehensively improve production efficiency, ④ can process the surfaces of the parts with different thicknesses, ⑤ can obtain the heat pipes or heat equalizing plates with different sizes and shapes by designing the size and the outline of a mold electrode and is suitable for large-scale industrial production, ⑥ can process parts with the structure denser than that of the traditional casting material and has strong variability of the structure, ⑦ is relatively simple in process and lower in equipment cost, and the heat pipes made of different materials such as iron and nickel can be prepared by adopting different electrodes and electroforming liquid on the same equipment, so that the process flexibility is strong.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a heat pipe according to the present invention;

FIG. 2 is a cross-sectional view of a heat pipe according to the present invention;

FIG. 3 is a schematic diagram of a die electrode and a metal film according to the present invention;

FIG. 4 is a schematic diagram of step (6) provided by the present invention;

wherein, 1-heat pipe, 2-mould electrode, 3-metal film, 4-welding gap, 5-welding trace.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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.