CN113388753A

CN113388753A - Alloy with capillary structure and preparation method thereof

Info

Publication number: CN113388753A
Application number: CN202110692571.6A
Authority: CN
Inventors: 沈伟
Original assignee: Individual
Current assignee: Beijing Kujie Technology Co ltd
Priority date: 2021-06-22
Filing date: 2021-06-22
Publication date: 2021-09-14
Anticipated expiration: 2041-06-22
Also published as: CN113388753B; WO2022267080A1

Abstract

The invention provides an alloy with a capillary structure, wherein the surface of the alloy is provided with a capillary pipe network which is a capillary structure consisting of a plurality of mutually communicated grain boundary channels; also provides a preparation method thereof and a soaking plate prepared by the alloy. The invention has the beneficial effects that: the alloy with the capillary structure solves the problem that the existing ultrathin soaking plate is difficult to break through the lower limit of the thickness of 300 microns, realizes the integration of the capillary structure and an alloy substrate, greatly improves the service life of the ultrathin soaking plate on the premise of the same heat transfer efficiency, simultaneously, the integrated structure completely avoids the problem that a sintered copper net and copper powder fall off, and can ensure that the heat transfer performance of the alloy is basically unchanged after the alloy is repeatedly bent for at least 20 times at 90 degrees.

Description

Alloy with capillary structure and preparation method thereof

Technical Field

The invention relates to the technical field of materials, in particular to the technical field of alloy materials, and particularly relates to an alloy with a capillary structure, a preparation method of the alloy and a soaking plate prepared from the alloy.

Background

With the development of consumer electronics, high-power electronic devices, and the like toward higher power, the heat dissipation requirements for chips are more and more prominent. Meanwhile, the existing electronic products are continuously developed towards ultra-thinness and miniaturization, and the requirements on heat dissipation materials are more and more strict. At present, a soaking plate is used as an ultrahigh thermal conductivity material and is widely applied to products such as 5G mobile phones, computers and the like. The ultrathin soaking plate is mainly made of copper or copper alloy, the middle sintered copper mesh is used as a capillary liquid absorbing core, and the thickness of the copper mesh is larger than 50 micrometers, so that the whole thickness of the ultrathin soaking plate is difficult to reduce to be within 300 micrometers.

At present, a common VC ultrathin soaking plate adopts a sintered copper mesh capillary wick structure, the overall thickness of VC is about 0.4mm, and the thinnest can only reach 0.35 mm. The main reason is that the thickness of the copper mesh is 0.08mm, so that the overall thickness of the VC is difficult to be reduced to be within 0.3 mm. (see the summary and the technology of 5G novel heat dissipation material: ultra-thin Vapor Chamber (VC) enterprise resources, the website is https:// www.sohu.com/a/434129352_ 120867180).

Under the restriction of the existing etching technology, at present, only a capillary groove with the width larger than 100 micrometers can be etched on the surface of copper, but because the capillary width of 100 micrometers can hardly form a capillary siphon effect on liquid working media such as water, an etching structure cannot be directly used for replacing a silk screen structure capillary core.

If the thickness of the existing vapor chamber product is within 300 microns, a thinner capillary wick is required to replace the current wire mesh structure. Meanwhile, the conventional external capillary core structures such as a sintered wire mesh and sintered copper powder have the risk of failure of the soaking plate due to easy falling off after long-term use.

The copper metal material used for the soaking plate consists of a plurality of copper crystal grains, and crystal grain boundaries exist among the crystal grains, and are continuously distributed on the surface and the inside of the copper metal.

Disclosure of Invention

Aiming at the defects in the prior art, the invention considers the special corrosion treatment of the crystal boundary on the metal surface, and the treated crystal boundary is communicated to form a network groove structure to provide a capillary structure for the transmission of liquid working media such as water, thereby providing the alloy with the capillary structure and the preparation method thereof.

In order to achieve the purpose, the technical scheme provided by the invention is as follows: an alloy with a capillary structure, wherein the surface of the alloy is provided with a capillary pipe network, and the capillary pipe network is a capillary structure consisting of a plurality of mutually communicated grain boundary channels.

The crystal grains are small crystals that develop through formation of crystal nuclei (crystal centers) and crystal growth during crystallization of the metal, and adjacent crystals are in contact with each other during growth, thereby obtaining an irregular shape. The grain boundaries are interfaces between grains having the same structure but different orientations, the shape of the grain boundaries is determined by the phase relation of surface tension, and the shape, structure and distribution of the grain boundaries in the polycrystalline body are called as grain boundary configuration. The atomic arrangement on the grain boundary is looser than that in the grain boundary, so the grain boundary is easy to corrode (thermal erosion, chemical corrosion), and the grain boundary is exposed after corrosion.

In the prior art, aiming at the research of the grain boundary, a novel inorganic material is manufactured by controlling the composition, the structure, the phase state and the like of the grain boundary, the idea is changed, the physical structure of the grain boundary is taken as the research direction, and the grain boundary is used as a capillary circuit, so that the integrated design of a capillary pipeline network and alloy metal is realized, and the brand new application of the grain boundary structure is expanded.

Further, in the alloy with the capillary structure, the width of the grain boundary channel is 1-50 μm. May be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm.

Further, in the alloy with the capillary structure, the width of the grain boundary channel is 2-20 μm.

Capillary phenomenon, a very specific physical phenomenon, is essentially the attraction of a liquid surface to a solid surface. The prior research finds that the capillary rise phenomenon has the following characteristics:

1. both in air and in vacuum;

2. the capillary phenomenon exists not only in the cylindrical capillary but also in two parallel solid plates;

3. the rising height of the liquid in the capillary tube is independent of the wall thickness of the capillary tube;

4. the width of the capillary pipeline has an important influence on the occurrence of capillary sites, and the effective capillary siphon effect on the liquid working medium can not be basically formed after the width of the capillary groove etched on the metal surface is larger than 100 mu m.

Therefore, in the present technique, the width of the grain boundary channel is controlled to be within 2 to 20 μm, preferably 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm.

Further, the alloy with the capillary structure is a copper alloy with a copper element content of 90% by mass or more.

Further, in the alloy with the capillary structure, the copper alloy is a phosphorus copper alloy, a nickel copper alloy or a chromium copper alloy.

Further, in the alloy with the capillary structure, the phosphorus element content in the phosphorus-copper alloy is 0.03-0.35% by mass percent; in the nickel-copper alloy, the content of nickel element is 0.9-1.3% by mass percent; in the chromium-copper alloy, the content of chromium element is 0.5-1.5% by mass percent.

The inventor finds that the alloy surface of the copper metal alloy conventionally used in the field generally has a grain boundary formed by a large number of grains, and the copper alloy per se belongs to a metal alloy with wide application range and has excellent physical and chemical properties. The copper alloy has excellent electric and heat conducting performance, high corrosion resistance to atmosphere and water, and certain diamagnetic performance because copper is a diamagnetic substance. Moreover, the copper alloy generally has good processing performance and certain special mechanical properties, and the processing performance shows that the copper alloy has good plasticity and is easy to be cold and hot formed; the special mechanical properties mean that the copper alloy has good antifriction property, wear resistance, high elasticity and fatigue resistance.

Based on the characteristics, the inventor takes copper alloy, particularly copper alloy with the copper element content of more than 90 percent as base metal for constructing a grain boundary communicated capillary structure, so that the copper alloy has wider application field. Among the copper alloys, the three most commonly used copper alloys are phosphorus copper alloy, nickel copper alloy and chromium copper alloy, and the phosphorus, chromium and nickel elements contained in the three copper alloys can effectively improve various performances of the copper alloys and give full play to the technical advantages of the copper alloys.

The second invention of the present invention provides a method for preparing the alloy with the capillary structure, which comprises the following steps:

s1, casting treatment:

casting the alloy raw material by a conventional method, and cooling to obtain an alloy crude product;

s2, hot rolling treatment:

hot rolling the crude alloy product at a preset hot rolling temperature by adopting a conventional method;

s3, surface milling treatment:

milling the alloy crude product after hot rolling by adopting a conventional method;

s4, cold rolling treatment:

cooling and cold rolling the milled alloy crude product by adopting a conventional method;

s5, solution treatment:

carrying out solution treatment on the cold-rolled alloy crude product at a preset solution temperature by adopting a conventional method, and then cooling;

s6, pre-aging treatment:

carrying out aging treatment on the alloy crude product after solution cooling at a preset aging temperature by adopting a conventional method to obtain an alloy basic semi-finished product;

s7, low-temperature annealing treatment:

carrying out low-temperature annealing treatment on the alloy base semi-finished product under the condition that the oxygen partial pressure is greater than 10000 Pa;

s8, hydrotreating:

carrying out hydrogenation reaction treatment on the alloy base semi-finished product under the condition that the hydrogen partial pressure is greater than 20000 Pa;

s9, cleaning:

and cleaning to remove reaction products at the grain boundary to obtain the alloy product with the grain boundary communicated capillary structure.

In the preparation method, the steps S1-S6 are conventional operation methods, wherein the fusion casting temperature is 1150-1300 ℃, the hot rolling temperature is 750-900 ℃, the cold rolling temperature is room temperature, the solid solution temperature is 720-880 ℃, the solid solution time is 1-10 hours, the pre-aging temperature is 300-550 ℃, and the pre-aging time is more than 1 hour; preferably, 2 to 5 hours.

Further, in the preparation method of the alloy with the capillary structure, in the low-temperature annealing treatment, the oxygen partial pressure is greater than 10000Pa, the annealing temperature is 100-500 ℃, and the annealing time is greater than 10 minutes;

in the hydrogenation treatment, the hydrogen partial pressure is more than 20000Pa, the hydrogenation treatment temperature is 500-850 ℃, and the treatment time is more than 10 minutes;

in the cleaning treatment, the cleaning method is direct washing or ultrasonic cleaning; the cleaning agent is pure water, and the surface cleanliness SPC grade of the cleaned alloy is less than or equal to 4.

The low-temperature annealing treatment temperature of the copper and the copper alloy is between 100 and 500 ℃, and the internal stress can be removed. Meanwhile, oxides precipitated under the temperature condition may be concentrated at grain boundaries. The oxidation and precipitation processes are accelerated by applying a certain oxygen partial pressure in the low-temperature annealing process, so that a large amount of copper oxides are enriched at the crystal boundary position. The oxide film formed in the oxygen partial pressure low-temperature annealing process has two layers, wherein the outer layer is copper oxide, and the inner layer is cuprous oxide. Through the control of temperature and time, a certain width of copper oxide reactant is formed at the grain boundary.

Carrying out hydrogenation heat treatment at the temperature of 500-850 ℃, dissolving hydrogen in copper and carrying out reduction reaction with copper oxide and cuprous oxide to generate copper and water molecules. In the process, the pressure increase and the crystal boundary expansion at the crystal boundary can occur, so that a reaction product at the crystal boundary on the surface is separated and falls off from the copper and copper alloy matrix, and finally a groove of a communicated network structure is formed at the crystal boundary.

The third invention of the invention is to provide a soaking plate, which is made of the alloy with the capillary structure.

Further, the thickness of the soaking plate is less than 300 μm.

The soaking plate is a vacuum cavity with a fine structure on the inner wall, is usually made of copper or copper alloy, is also a component which is most commonly used by copper alloy and has the best effect, and has the main action principle as follows: when heat is conducted to the evaporation zone from the heat source, the cooling liquid in the cavity starts to generate the gasification phenomenon of the cooling liquid after being heated in the environment with low vacuum degree, at the moment, heat energy is absorbed, the volume rapidly expands, the whole cavity is rapidly filled with gaseous cooling medium, and the condensation phenomenon can be generated when the gaseous working medium contacts a relatively cold zone. The heat accumulated during evaporation is released by the condensation phenomenon, and the condensed cooling liquid returns to the evaporation heat source through the capillary tube of the microstructure, and the operation is repeated in the cavity.

The crystal boundary communicated capillary structure 'integrated' copper alloy constructed by the technology can completely abandon the technology that the copper mesh needs to be sintered in the traditional soaking plate, and can effectively solve the technical problems that the copper mesh falls off and the copper mesh has larger thickness and can trouble technicians in the field for many years.

The invention has the beneficial effects that: the alloy with the capillary structure provided by the invention has the advantages that the 'integrated' design of the capillary pipe network and the alloy metal is designed in a breakthrough manner, and the brand new application of the crystal boundary structure is expanded; by adopting the control and limitation of the crystal boundary width of the technology, the capillary siphon effect can be effectively realized; the grain boundary communicated capillary structure is constructed on the copper alloy, and then the soaking plate prepared from the copper alloy solves the problem that the existing ultrathin radiating fin or soaking plate cannot break through the lower limit of 300 micrometers, not only is the integration of the capillary structure and the copper alloy substrate realized, but also the service life of the ultrathin soaking plate is greatly prolonged on the premise of the same heat transfer efficiency, and meanwhile, the integration structure can also effectively avoid the problem that a copper net falls off.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a scanning electron microscope image of the grain boundary channel trench structure of the soaking plate base material phosphor-copper alloy of example 5 magnified 500 times, wherein the scale is 300 μm.

FIG. 2 is a scanning electron microscope image of the grain boundary channel trench structure magnified 1000 times by the phosphor-copper alloy of the soaking plate substrate in example 5, wherein the scale is 100 μm.

FIG. 3 is a scanning electron microscope image of the grain boundary channel trench structure magnified 2000 times by the phosphor-copper alloy of the soaking plate substrate in example 5, wherein the scale is 50 μm.

FIG. 4 is a scanning electron microscope image of the grain boundary channel trench structure magnified 10000 times for phosphor-copper alloy of the soaking plate substrate in example 5, wherein the scale is 10 μm.

FIG. 5 is a scanning electron microscope image of the grain boundary channel trench structure magnified 400 times by the Ni-Cu alloy of the soaking plate substrate in example 6, wherein the scale is 50 μm.

FIG. 6 is a scanning electron microscope image of the grain boundary channel trench structure of the soaking plate substrate of example 7, wherein the scale is 50 μm, and the magnification is 330 times.

FIG. 7 shows that the thickness of the soaking plate of example 7 is 247 μm as a result of measuring the thickness of the soaking plate at a certain time.

FIG. 8 is a schematic view showing a method of testing thermal conductivity of the soaking plate of example 6.

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.

Example 1:

the alloy with the capillary structure is characterized in that the surface of the alloy is provided with a capillary pipe network which is a capillary structure consisting of a plurality of mutually communicated grain boundary channels; the width of the grain boundary channel is 1-50 μm; preferably 2-20 μm, and can be selected from 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, and 20 μm.

The alloy with the capillary structure is a copper alloy with the copper element content of more than or equal to 90 percent according to mass percent; the copper alloy is phosphorus copper alloy, nickel copper alloy or chromium copper alloy; in the phosphorus-copper alloy, the content of phosphorus element is 0.03-0.35% by mass percent; in the nickel-copper alloy, the content of nickel element is 0.9-1.3% by mass percent; in the chromium-copper alloy, the content of chromium element is 0.5-1.5% by mass percent.

Example 2:

the method for preparing the alloy having the capillary structure as in example 1, comprising the steps of:

s1, casting treatment:

s2, hot rolling treatment:

s3, surface milling treatment:

s4, cold rolling treatment:

s5, solution treatment:

s6, pre-aging treatment:

s7, low-temperature annealing treatment:

under the condition that the oxygen partial pressure is more than 10000Pa, the annealing temperature is 100-500 ℃, and the annealing time is more than 10 minutes; carrying out low-temperature annealing treatment on the alloy base semi-finished product;

the low-temperature annealing treatment temperature of the copper and the copper alloy is between 100 and 500 ℃, and the internal stress can be removed. Meanwhile, oxides precipitated under the temperature condition may be concentrated at grain boundaries. The oxidation and precipitation processes are accelerated by applying a certain oxygen partial pressure in the low-temperature annealing process, so that a large amount of copper oxides are enriched at the crystal boundary position. The oxide film formed in the oxygen partial pressure low-temperature annealing process has two layers, wherein the outer layer is copper oxide, and the inner layer is cuprous oxide. Forming a copper oxide reactant with a certain width at a grain boundary through controlling temperature and time;

s8, hydrotreating:

under the condition that the hydrogen partial pressure is more than 20000Pa, the hydrotreating temperature is 500-850 ℃, and the treatment time is more than 10 minutes; carrying out hydrogenation reaction treatment on the alloy base semi-finished product;

carrying out hydrogenation heat treatment at the temperature of 500-850 ℃, dissolving hydrogen in copper and carrying out reduction reaction with copper oxide and cuprous oxide to generate copper and water molecules. In the process, the pressure at the crystal boundary is increased and the crystal boundary is enlarged, so that a reaction product at the surface crystal boundary is separated from the copper and copper alloy matrix and falls off, and finally a groove of a communicated network structure is formed at the crystal boundary, the groove provides a channel for the transmission of liquid working media such as water and the like, and the groove has extremely small flow resistance and can simultaneously meet the requirements of high transmission and low flow resistance of the capillary liquid absorption core;

s9, cleaning:

cleaning and removing reaction products at the grain boundary to obtain an alloy product with a grain boundary communicated capillary structure; the cleaning method is direct washing or ultrasonic cleaning; the cleaning agent is pure water, and the surface cleanliness SPC grade of the cleaned alloy is less than or equal to 4.

In the preparation method, the steps S1-S6 are conventional operation methods, wherein the fusion casting temperature is 1150-1300 ℃, the hot rolling temperature is 750-900 ℃, the cold rolling temperature is room temperature, the solid solution temperature is 720-880 ℃, the solid solution time is 1-10 hours, the pre-aging temperature is 300-550 ℃, and the pre-aging time is more than 1 hour; preferably, the casting temperature is 1200 ℃, the hot rolling temperature is 800 ℃, the cold rolling temperature is room temperature, the solid solution temperature is 800 ℃, the solid solution time is 5.5 hours, the pre-aging temperature is 425 ℃, and the pre-aging time is 4 hours.

Example 3:

a soaking plate made of the alloy with the capillary structure of example 1 or the alloy with the capillary structure prepared by the preparation method of example 2; the thickness of the soaking plate is less than 300 mu m; the average measurement value is about 255 μm to 300 μm, and the minimum thickness can reach 247 μm.

Example 4:

the soaking plate is made of phosphorus-copper alloy with a grain boundary communicated capillary structure, the thickness of the soaking plate is 300 mu m, and the phosphorus-copper alloy comprises 6.0 percent of tin, 0.2 percent of phosphorus and the balance of copper according to mass percentage; the surface of the phosphor copper alloy is provided with a plurality of mutually communicated grain boundary capillary channels, the width of the capillary channels is thick and thin, and the capillary channels are respectively about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm and 20 μm;

the preparation method of the phosphorus-copper alloy comprises the following steps:

s1, casting treatment:

adopting a conventional method to cast a phosphorus-copper alloy raw material, and cooling to obtain a phosphorus-copper alloy crude product;

s2, hot rolling treatment:

hot rolling the crude product of the phosphorus-copper alloy at a preset hot rolling temperature by adopting a conventional method;

s3, surface milling treatment:

milling the hot-rolled crude product of the phosphorus-copper alloy by a conventional method;

s4, cold rolling treatment:

cooling and cold rolling the milled phosphor-copper alloy crude product by adopting a conventional method;

s5, solution treatment:

carrying out solution treatment on the cold-rolled phosphorus-copper alloy crude product at a preset solution temperature by adopting a conventional method, and then cooling;

s6, pre-aging treatment:

carrying out aging treatment on the crude product of the phosphorus-copper alloy after solution cooling at a preset aging temperature by adopting a conventional method to obtain a basic semi-finished product of the phosphorus-copper alloy;

s7, low-temperature annealing treatment:

carrying out low-temperature annealing treatment on the phosphorus-copper alloy basic semi-finished product under the condition of oxygen partial pressure of 10000 Pa; the annealing temperature is 430 ℃, and the annealing time is 45 minutes;

s8, hydrotreating:

carrying out hydrogenation reaction treatment on the phosphorus-copper alloy basic semi-finished product under the condition of hydrogen partial pressure of 20000 Pa; the hydrotreating temperature is 630 ℃, and the treatment time is 110 minutes;

s9, cleaning:

and directly washing with pure water to remove reaction products at the grain boundary, wherein the surface cleanliness SPC grade of the cleaned phosphorus-copper alloy is equal to 4 grade, and obtaining the phosphorus-copper alloy product with the grain boundary communicated capillary structure.

Example 5:

the soaking plate is made of a phosphor-copper alloy with a grain boundary communicated capillary structure, the thickness of the soaking plate is 283 mu m, and the phosphor-copper alloy comprises 6.5 percent of tin, 0.1 percent of phosphorus and the balance of copper according to mass percentage; the surface of the phosphor copper alloy is provided with a plurality of mutually communicated grain boundary capillary channels, the width of the capillary channels is thick and thin, and the capillary channels are respectively about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm and 20 μm;

s1, casting treatment:

s2, hot rolling treatment:

s3, surface milling treatment:

s4, cold rolling treatment:

s5, solution treatment:

s6, pre-aging treatment:

s7, low-temperature annealing treatment:

carrying out low-temperature annealing treatment on the phosphorus-copper alloy basic semi-finished product under the condition of oxygen partial pressure of 12000 Pa; the annealing temperature is 390 ℃, and the annealing time is 50 minutes;

s8, hydrotreating:

carrying out hydrogenation reaction treatment on the phosphorus-copper alloy base semi-finished product under the condition of the hydrogen partial pressure of 22000 Pa; the hydrotreating temperature is 660 ℃, and the treatment time is 100 minutes;

s9, cleaning:

and directly washing with pure water to remove reaction products at the grain boundary, wherein the surface cleanliness SPC grade of the cleaned phosphorus-copper alloy is equal to 3 grade, and obtaining the phosphorus-copper alloy product with the grain boundary communicated capillary structure.

FIGS. 1-4 show the scanning electron microscope pictures of grain boundary channel trench structure of soaking plate substrate P-Cu alloy magnified 500, 1000, 2000, 10000 times respectively.

Example 6:

the soaking plate is made of nickel-copper alloy with a grain boundary communicated capillary structure, the thickness of the soaking plate is 272 microns, the nickel-copper alloy comprises 1.1% of nickel, 0.25% of phosphorus, 0.3% of the rest, and the balance of copper according to the mass percentage; the surface of the nickel-copper alloy is provided with a plurality of mutually communicated grain boundary capillary channels, the width of the grain boundary capillary channels is thick and thin, and the width of the grain boundary capillary channels is about 1 mu m, 2 mu m, 3 mu m, 4 mu m, 5 mu m, 6 mu m, 7 mu m, 8 mu m, 9 mu m, 10 mu m, 11 mu m, 12 mu m, 13 mu m, 14 mu m, 15 mu m, 16 mu m, 17 mu m, 18 mu m, 19 mu m and 20 mu m respectively;

the preparation method of the nickel-copper alloy comprises the following steps:

s1, casting treatment:

casting a nickel-copper alloy raw material by adopting a conventional method, and cooling to obtain a crude nickel-copper alloy product;

s2, hot rolling treatment:

hot rolling the crude nickel-copper alloy product at a preset hot rolling temperature by adopting a conventional method;

s3, surface milling treatment:

milling the hot-rolled nickel-copper alloy crude product by a conventional method;

s4, cold rolling treatment:

cooling and cold rolling the milled nickel-copper alloy crude product by adopting a conventional method;

s5, solution treatment:

carrying out solution treatment on the cold-rolled nickel-copper alloy crude product at a preset solution temperature by adopting a conventional method, and then cooling;

s6, pre-aging treatment:

carrying out aging treatment on the crude nickel-copper alloy product after solution cooling at a preset aging temperature by adopting a conventional method to obtain a basic semi-finished nickel-copper alloy product;

s7, low-temperature annealing treatment:

carrying out low-temperature annealing treatment on the nickel-copper alloy basic semi-finished product under the condition of 14000Pa oxygen partial pressure; the annealing temperature is 450 ℃, and the annealing time is 40 minutes;

s8, hydrotreating:

carrying out hydrogenation reaction treatment on the nickel-copper alloy basic semi-finished product under the condition of hydrogen partial pressure 24000 Pa; the hydrotreating temperature is 720 ℃, and the treatment time is 80 minutes;

s9, cleaning:

and directly washing with pure water to remove reaction products at the grain boundary, wherein the surface cleanliness SPC grade of the cleaned nickel-copper alloy is equal to 4 grade, and thus obtaining the nickel-copper alloy product with the grain boundary communicated capillary structure.

FIG. 5 shows the scanning electron microscope image of the grain boundary channel groove structure of the soaking plate substrate nickel-copper alloy with 400 times magnification.

Example 7:

the soaking plate is made of chromium-copper alloy with a grain boundary communicated capillary structure, the thickness of the soaking plate is 247 micrometers, and as shown in figure 7, the chromium-copper alloy comprises 1% of chromium, 0.11% of zirconium and the balance of copper according to the mass percentage; the surface of the chromium-copper alloy is provided with a plurality of mutually communicated grain boundary capillary channels, the widths of the grain boundary capillary channels are rough and fine, and the widths of the grain boundary capillary channels are respectively about 1 mu m, 2 mu m, 3 mu m, 4 mu m, 5 mu m, 6 mu m, 7 mu m, 8 mu m, 9 mu m, 10 mu m, 11 mu m, 12 mu m, 13 mu m, 14 mu m, 15 mu m, 16 mu m, 17 mu m, 18 mu m, 19 mu m and 20 mu m;

the preparation method of the chromium-copper alloy comprises the following steps:

s1, casting treatment:

casting the chromium-copper alloy raw material by a conventional method, and cooling to obtain a chromium-copper alloy crude product;

s2, hot rolling treatment:

hot rolling the chromium-copper alloy crude product at a preset hot rolling temperature by adopting a conventional method;

s3, surface milling treatment:

milling the hot-rolled chromium-copper alloy crude product by a conventional method;

s4, cold rolling treatment:

cooling and cold rolling the milled chromium-copper alloy crude product by adopting a conventional method;

s5, solution treatment:

carrying out solution treatment on the cold-rolled chromium-copper alloy crude product at a preset solution temperature by adopting a conventional method, and then cooling;

s6, pre-aging treatment:

carrying out aging treatment on the chromium-copper alloy crude product subjected to solid solution cooling at a preset aging temperature by adopting a conventional method to obtain a chromium-copper alloy basic semi-finished product;

s7, low-temperature annealing treatment:

carrying out low-temperature annealing treatment on the chromium-copper alloy basic semi-finished product under the condition of oxygen partial pressure of 15000 Pa; the annealing temperature is 410 ℃, and the annealing time is 55 minutes;

s8, hydrotreating:

carrying out hydrogenation reaction treatment on the chromium-copper alloy basic semi-finished product under the condition of hydrogen partial pressure 25000 Pa; the hydrotreating temperature is 690 ℃, and the treatment time is 90 minutes;

s9, cleaning:

and directly washing with pure water to remove reaction products at the grain boundary, wherein the surface cleanliness SPC grade of the chromium-copper alloy after cleaning is equal to 3 grade, and obtaining the chromium-copper alloy product with the grain boundary communicated capillary structure.

FIG. 6 shows the scanning electron microscope pictures of the grain boundary channel groove structure of the soaking plate substrate chromium-copper alloy with 330 times magnification.

Example 8:

the heat sinks or heat spreader plates obtained according to examples 4-7 were compared to existing conventional commercial products (sintered copper mesh) in a multi-directional technical parameter comparison, which are the ivo handset iQOO Pro5G version (with official test heat spreader plate thickness of about 0.4mm, i.e. 400 μm), as shown in tables 1-4 below.

TABLE 1 comparison of the thickness parameters of the products at equal areas (average of 3 different samples)

	Thickness measurement 1	Thickness measurement 2	Thickness measurement 3	Average of three thickness measurements
					Commercially available product	352μm	376μm	403μm	377μm
Example 4	302μm	307μm	291μm	300μm
					Example 5	281μm	290μm	278μm	283μm
Example 6	273μm	270μm	273μm	272μm
					Example 7	247μm	258μm	260μm	255μm

As can be seen from Table 1, the thickness of the existing commercial ultrathin soaking plate made of copper alloy material cannot exceed 300 μm, but the thickness of the ultrathin soaking plate made of copper alloy material is greatly reduced and the integral compression of the heat conducting part of the electronic device is realized by removing the sintered copper mesh and adopting the grain boundary grooves to replace the traditional capillary structure of the sintered copper mesh.

TABLE 2 comparison of the changes in heat transfer performance (equivalent thermal conductivity) due to the number of times of bending

As can be seen from table 2, the performance of the existing commercially available copper alloy material soaking plate after being bent at 90 ° for 5 times is not much different (slightly lower) from that of the grain boundary trench soaking plate of the present invention, but the performance parameters of the existing commercially available copper alloy material soaking plate after being bent at 90 ° for 20 times are greatly reduced. In fact, after the existing commercially available vapor chamber product is simply bent for 2-3 times, the phenomenon of copper mesh falling off, capillary pipeline blockage and the like can be caused due to the large change of the internal stress, and the vapor chamber product cannot work normally. The grain boundary structure of the grain boundary groove soaking plate provided by the invention is difficult to change by bending, and as can be seen from the table 2, the grain boundary structure is basically not influenced by bending for 5 times and 20 times, and in the actually manufactured product, the most limited bending times of the product can reach 32 times, which is completely incomparable with the existing commercial product.

Table 3 results obtained after testing the vapor chamber of example 6 using the heat conduction test method

Thermal conductivity test methods in table 3:

the thermal conductivity is found by the following thermal conductivity equation: q ═ kAdT/dx.

Wherein: k is the thermal conductivity, q is the input power, A is the VC axial cross-sectional area, and dT/dx is the temperature gradient along the length direction (from Origin fit curve).

As can be seen from table 3 and fig. 8, the soaking plate made of copper alloy material provided by the present invention can still realize effective conduction of heat flow in a bent state, and it is fully demonstrated that the grain boundary trench provided by the present invention can effectively form capillary siphon effect on liquid working medium, thereby further realizing stable heat flow circulation cooling of the soaking plate.

The service life of the existing commercial soaking plate made of copper alloy materials is greatly reduced because the sintered copper mesh is easy to fall off. The grain boundary groove soaking plate provided by the invention has no difference with the heat transfer efficiency of the existing copper alloy material soaking plate, and the materials of nickel copper and chromium copper are even slightly higher than the commercial products, which fully indicates that the invention can completely replace the existing soaking plate products.

TABLE 4 comparison of surface cleanliness

	SPC classes
		Commercially available product	SPC3 stage
Example 4	SPC4 stage
		Example 5	SPC3 stage
Example 6	SPC4 stage
		Example 7	SPC3 stage

It can be seen from table 4 that the SPC grade (i.e., surface cleanliness grade) of the present invention can completely meet the requirements of the existing commercially available products, and it is fully demonstrated that the cleaning method provided by the present invention, in combination with the oxygen partial pressure and hydrogen partial pressure treatment of the present invention, can completely and effectively clean the reaction products at the surface grain boundaries, thereby realizing the grain boundary channel communication process with minimal flow resistance.

In table 4, the surface particle cleanliness class relates to a particle size of 0.05 μm to 500 μm, and provides a class formula of surface cleanliness for quantitative classification:

wherein, C_SPC；D: the maximum allowable concentration of particles with a specified particle size or more per square meter of surface, and C is an integer number;

n: the number of grades, i.e. the numbers 1 to 8, corresponds to the measured particle size D (μm);

d: a specified particle size in microns;

k: constant 1 μm.

TABLE 5 Standard grading Table for surface cleanliness

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The alloy with the capillary structure is characterized in that the surface of the alloy is provided with a capillary pipe network, and the capillary pipe network is of the capillary structure consisting of a plurality of mutually communicated grain boundary channels.

2. The alloy with a capillary structure of claim 1, wherein the width of the grain boundary channel is 1-50 μm.

3. An alloy with a capillary structure according to claim 2, wherein the width of the grain boundary channel is 2-20 μm.

4. The alloy with the capillary structure according to claim 1, wherein the alloy is a copper alloy containing 90% by mass or more of copper element.

5. An alloy with a capillary structure according to claim 4, characterized in that the copper alloy is a phosphor copper alloy, a nickel copper alloy or a chromium copper alloy.

6. The alloy with the capillary structure as claimed in claim 5, wherein the phosphorus-copper alloy contains 0.03-0.35% of phosphorus element by mass; in the nickel-copper alloy, the content of nickel element is 0.9-1.3% by mass percent; in the chromium-copper alloy, the content of chromium element is 0.5-1.5% by mass percent.

7. The method for preparing an alloy with a capillary structure according to any one of claims 1 to 6, comprising the steps of:

s1, casting treatment:

s2, hot rolling treatment:

s3, surface milling treatment:

s4, cold rolling treatment:

s5, solution treatment:

s6, pre-aging treatment:

s7, low-temperature annealing treatment:

s8, hydrotreating:

s9, cleaning:

8. The method of claim 7, wherein the alloy having a capillary structure,

in the low-temperature annealing treatment, the oxygen partial pressure is greater than 10000Pa, the annealing temperature is 100-500 ℃, and the annealing time is greater than 10 minutes;

9. A soaking plate, characterized in that the soaking plate is made of the alloy having a capillary structure according to any one of claims 1 to 8.

10. A soaking plate according to claim 9, wherein the thickness of the soaking plate is less than 300 μm.