CN111992721A

CN111992721A - Shell, electronic equipment and manufacturing method of shell

Info

Publication number: CN111992721A
Application number: CN202010768110.8A
Authority: CN
Inventors: 王晓安
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2020-08-03
Filing date: 2020-08-03
Publication date: 2020-11-27
Anticipated expiration: 2040-08-03
Also published as: CN111992721B

Abstract

The application discloses casing, electronic equipment and manufacturing method of casing thereof, wherein, the casing includes: the base material is cobalt chromium molybdenum alloy, and the base material is obtained by performing injection molding on cobalt chromium molybdenum alloy powder through metal powder. Through the mode, the shell has better performance, the cost of the shell can be reduced, and the shell is friendly to the health of a user.

Description

Shell, electronic equipment and manufacturing method of shell

Technical Field

The present disclosure relates to the field of housing technology of electronic devices, and more particularly, to a housing, an electronic device and a method for manufacturing the housing.

Background

Due to appearance and functional requirements, many production and living appliances, such as electronic devices, household appliances, and the like, have a housing.

And according to the requirements of function and appearance, the shell can be made of materials such as metal and high polymer materials, and in the manufacturing process, the shell can be processed by adopting a corresponding processing method according to the characteristics of the materials.

Disclosure of Invention

The technical problem mainly solved by the application is to provide a shell, an electronic device and a manufacturing method of the shell, so that the shell has better performance, the cost of the shell can be reduced, and the shell is more friendly to the health of a user.

In order to solve the technical problem, the application adopts a technical scheme that: the shell comprises a base material, wherein the base material is cobalt-chromium-molybdenum alloy, and the base material is obtained by performing metal powder injection molding on cobalt-chromium-molybdenum alloy powder.

In order to solve the technical problem, the application adopts a technical scheme that: provided is a method for manufacturing a housing of an electronic device, the method comprising: providing cobalt chromium molybdenum alloy powder; performing metal powder injection molding on the cobalt-chromium-molybdenum alloy powder to obtain a molded base material; and carrying out post-treatment on the base material to obtain the shell.

In order to solve the above technical problem, another technical solution adopted by the present application is: the electronic equipment comprises a shell and a functional device, wherein the shell is defined with an accommodating space; the functional device is accommodated in the accommodating space; the shell is the shell or is manufactured by the manufacturing method of the electronic equipment shell.

The beneficial effect of this application is: different from the prior art, the shell comprises the base material, wherein the base material is cobalt-chromium-molybdenum alloy, so that the shell has high strength and surface hardness, is wear-resistant and corrosion-resistant, and is friendly to the body health of a user when the shell is used; furthermore, the base material is obtained by injection molding of the cobalt-chromium-molybdenum alloy powder through the metal powder, so that adverse effects caused by work hardening can be reduced, the difficulty in processing the cobalt-chromium-molybdenum alloy is reduced, and the cost of the shell is reduced.

Drawings

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

FIG. 1 is a schematic structural view of an embodiment of the housing of the present application;

FIG. 2 is a schematic flow chart illustrating an embodiment of a method for manufacturing a housing of an electronic device according to the present disclosure;

FIG. 3 is a schematic flow chart of step S10 in FIG. 2;

FIG. 4 is a scanning electron microscope image of a cobalt-chromium-molybdenum alloy after being atomized into powder according to an embodiment of the method for manufacturing a housing of an electronic device of the present application;

FIG. 5 is another schematic flow chart of step S10 in FIG. 2;

FIG. 6 is a schematic flow chart of step S20 in FIG. 2;

FIG. 7 is a scanning electron microscope photograph of a cobalt chromium molybdenum alloy of comparative example 1 after sintering;

FIG. 8 is a scanning electron microscope photograph of a cobalt chromium molybdenum alloy of comparative example 2 after sintering;

FIG. 9 is a scanning electron microscope photograph of a sintered Co-Cr-Mo alloy in example 1 of a method of manufacturing a housing of an electronic device according to the present application;

FIG. 10 is a scanning electron microscope photograph of a sintered Co-Cr-Mo alloy in example 2 of a method of manufacturing a housing of an electronic device according to the present application;

FIG. 11 is a scanning electron microscope photograph of a sintered Co-Cr-Mo alloy in example 3 of a method of making a housing for an electronic device of the present application;

FIG. 12 is a schematic flow chart of step S30 in FIG. 2;

fig. 13 is a flowchart of step S34 in fig. 12;

FIG. 14 is another schematic flow chart of step S30 in FIG. 2;

fig. 15 is a schematic structural diagram of an embodiment of an electronic device according to the present application.

Detailed Description

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

The present application provides a housing, which in an embodiment may be a housing of an electronic device, such as a mobile phone, a watch, a tablet computer, a notebook computer, an intelligent bracelet, or a housing of other devices involved in daily life, such as a household appliance.

In this embodiment, the housing may include a substrate. The housing may be formed of a base material alone, and may be obtained directly by molding a raw material and then performing appropriate processing; the substrate may be formed with other film layers formed thereon, and for example, a color layer, a texture pattern layer, a brightness enhancing layer, and the like may be further formed on the substrate after the substrate is obtained, thereby forming the housing together.

In the related art, the substrate of the housing, such as the housing of an electronic device, can be plastic, aluminum alloy, stainless steel, titanium alloy, ceramic or wood, carbon fiber, etc.

However, aluminum alloys such as 6061/7A01/5052 aluminum alloy have tensile strength of not less than 200MPa, yield strength of not less than 170MPa, surface hardness of 200-300HV after anodic oxidation, and are easy to collide and damage and generate deformation when being impacted by a large force of a hard object.

Stainless steel, such as 304/316/316L stainless steel, can be used as a shell material, but the nickel content is high, which easily causes allergy to users using the electronic device; the stainless steel material has dark glossiness, and the shell is more textured by electroplating or physical vapor deposition toning in the later period in the manufacturing process, so that the process is more complicated, and the cost of the shell is increased to a certain extent.

The other materials cannot meet the use requirements of users due to high cost, low strength, poor appearance and the like.

In this embodiment, the material of the substrate is cobalt chromium molybdenum alloy, specifically, it may be non-magnetic cobalt chromium molybdenum alloy, for example, cobalt chromium molybdenum alloy with a magnetic permeability less than 1.01, wherein the magnetic permeability of the substrate may be detected by a magnetic permeability measuring apparatus. The cobalt-chromium-molybdenum alloy is one of cobalt-based alloys, and the non-magnetic cobalt-chromium-molybdenum alloy has high strength and surface hardness, and is wear-resistant and corrosion-resistant; and the cobalt-chromium-molybdenum alloy hardly contains nickel or contains trace nickel, so that the cobalt-chromium-molybdenum alloy has good biocompatibility, and is relatively friendly to the body health of a user when the shell is used.

It should be noted that the cobalt-chromium-molybdenum alloy has the characteristic of work hardening, so that if the method of forging and machining by a numerical control machine in the related art is adopted for manufacturing, the manufacturing is time-consuming, the loss of a cutter is large, and the production cost is further increased.

The base material in this embodiment can be obtained by metal powder injection molding (MIM) of cobalt-chromium-molybdenum alloy powder. The forming is carried out by adopting the MIM technology, so that the phenomenon that the cobalt-chromium-molybdenum alloy is hardened by adopting a conventional forming mode is avoided, the processing difficulty of the cobalt-chromium-molybdenum alloy can be reduced, the processing time is shortened, and the production cost can be reduced.

Specifically, in an embodiment, the content of the silicon element in the substrate by mass is not greater than 1.0%, and in some application scenarios, may also be not greater than 0.8%, and specifically may be 0.8%, 0.6%, 0.4%, 0.2%, zero, and the like; the oxygen content is not more than 0.1% by mass, and can be 0.1%, 0.08%, 0.06%, 0.04%, 0.02% or zero, for example; the content of nickel element is not more than 0.5% by mass, and may be, for example, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, zero, or the like.

It should be noted that, in this embodiment, the content of the nickel element in the base material is low, so that when the base material is used by a user, the probability of causing allergy to the user is low, and the base material is friendly to the physical health of the user.

Further, the presence of silicon element is advantageous for the injection molding of metal powder, but if the silicon content is too high, the hard phase of silicon oxide may be formed and detached during the subsequent sintering, or voids may be generated, which is disadvantageous for the properties of the resulting substrate, such as compactness. In the embodiment, the mass percentage of silicon in the base material can be controlled to be not more than 1.0%, and within the range, the injection molding of the metal powder can be facilitated, and excessive silicon oxide hard phases are not formed in the sintering process, so that the compactness of the base material is improved to a certain extent. Specifically, it may be achieved by controlling the silicon content in the raw materials when melting the cobalt-chromium-molybdenum alloy, or alternatively, the cobalt-chromium-molybdenum alloy powder may be formed with an appropriate silicon content range.

In addition, the presence of oxygen also forms oxide impurities during the melting of the cobalt-chromium-molybdenum alloy and during the sintering in the forming stage, which is detrimental to the compactness of the substrate. In the embodiment, the mass percentage of the oxygen element in the base material can be controlled to be not more than 0.1 percent, so that the content of oxide impurities formed in the smelting and sintering processes is reduced, and the compactness of the base material is improved. Specifically, the method can be realized by selecting oxygen-free or low-oxygen-content raw materials during smelting of the cobalt-chromium-molybdenum alloy and reducing the oxygen content in a smelting environment and an environment in a subsequent forming process.

Specifically, the base material in the present embodiment may contain the following elements: cobalt, chromium, molybdenum, silicon, manganese, iron, nickel, carbon, oxygen, sulfur and the like, wherein the mass percentages of the components are respectively shown in the following table 1:

TABLE 1 table of elements contained in the base material and their contents

Specifically, the mass percentage of the chromium element may be 27%, 28%, 29%, 30%, etc., the mass percentage of the molybdenum element may be 5%, 6%, 7%, etc., the mass percentage of the manganese element may be 1.0%, 0.8%, 0.6%, 0.4%, 0.2%, zero, etc., the mass percentage of the iron element may be 0.75%, 0.5%, 0.25%, zero, etc., the mass percentage of the carbon element may be 0.15%, 0.1%, 0.05%, zero, etc., the mass percentage of the sulfur element may be 1.0%, 0.5%, zero, etc., and the balance may be the cobalt element.

The content of each element in the base material can be detected by using an atomic absorption spectrophotometer, an x-ray photoelectron spectrometer, a fourier transform infrared spectrometer, an inductively coupled atomic emission spectrometer and the like, and the detection is not particularly limited herein.

The effect of the mass percentage of silicon and oxygen on the densification of the substrate is illustrated by the following specific examples and comparative examples. It should be noted that, in the following comparative example 1, the base material contains the elements other than the silicon element by mass in the ranges provided in the above embodiments of the present application; the base material in comparative example 2 satisfies the ranges provided in the above embodiments of the present application in terms of the mass% of other elements in addition to the mass% of the oxygen element; the base materials in examples 1-3 satisfy the ranges provided in the above embodiments of the present application, except for the mass percentages of all elements. The results of the measurements of the indexes related to the denseness of the substrates in the examples and the comparative examples are shown in table 2 below:

TABLE 2 results of measurement of indexes related to denseness of respective substrates

Item	Silicon content	Oxygen content	Porosity of the material	Maximum pore diameter	Density of
						Comparative example 1	1.1％	0.07％	1.04％	38μm	7.83g/cm³
Comparative example 2	0.63％	0.1％	0.87％	42μm	7.9g/cm³
						Example 1	0.64％	0.07％	0.32％	9μm	8.2g/cm³
Example 2	0.61％	0.06％	0.21％	7μm	8.19g/cm³
						Example 3	0.56％	0.06％	0.38％	8μm	8.26g/cm³

It should be noted that, in table 2 above, the content of silicon and the content of oxygen are the mass percentage content of the silicon element and the oxygen element in the base material, respectively, the porosity is the porosity of the base material, the maximum pore diameter is the maximum pore diameter of the pores in the base material, and the density is the density of each base material. As can be seen from Table 2, the substrate in comparative example 1 had a relatively high silicon content, corresponding significantly higher porosity, significantly larger maximum pore diameter of pores, and relatively lower density than examples 1-3; the substrate of comparative example 2 has a higher oxygen content, a relatively higher porosity, a significantly larger maximum pore size, and a relatively lower density than examples 1-3. This further demonstrates that the substrate having the silicon content and oxygen content defined in the above embodiments of the present application has superior densification.

Further, in one embodiment, the density of the substrate is not less than 8.1g/cm³For example, it may be 8.1g/cm³、8.15g/cm³、8.20g/cm³Etc.; the porosity of the substrate may be less than 0.5%, specifically may be 0.45%, 0.4%, 0.35%, 0.3%, 0.25%, 0.2%, etc.; and the size of the pores in the substrate can be not more than 10nm, and in some application scenes, the pores are not more than 8nm, or not more than 7nm and the like.

The density of the substrate may be measured by a density measuring instrument, or the average density of the substrate may be measured manually by a liquid discharge method or the like. The porosity and pore diameter of the substrate can be measured by a Scanning Electron Microscope (SEM), a transmission electron microscope (transmission electron microscope), an X-ray diffractometer, or the like.

The density of the base material in the embodiment is high, the porosity is low, and the pores are small, so that the density of the base material is high, the reliability of the shell can be improved, and the appearance effect of the shell is influenced to a certain extent.

Further, in an embodiment, the surface roughness of the substrate is not more than 80nm, and specifically, the surface roughness of the substrate may be 70nm, 60nm, 50nm, 40nm, or the like. Among them, the surface roughness of the substrate can be measured by a surface roughness measuring instrument. Secondly, the above surface roughness of the substrate can be achieved by a polishing process in the manufacturing process, or by a combination of other surface treatment processes and the polishing process.

In addition, the peripheral dimensional tolerance of the substrate may be ± 0.05mm, and the flatness tolerance may be ± 0.05 mm. Wherein, can further carry out the plastic to the substrate that obtains after through MIM technique shaping, and control the peripheral dimension and the flatness tolerance of substrate in the shaping in-process and be in above-mentioned scope, thereby make the size of the substrate that obtains more accurate.

Further, in one embodiment, the hardness of the substrate may be 250-350HV1 Vickers, the yield strength is not less than 520MPa, and the maximum tensile strength is not less than 800 MPa. The hardness of the substrate can be measured by a vickers hardness tester, but may also be measured by other hardness testers, such as a brinell hardness tester, a microhardness tester, a rockwell hardness tester, and the like. The yield strength and the maximum tensile strength of the substrate can be measured by a tensile tester.

Specifically, the performance parameters of the cobalt-chromium-molybdenum alloy substrate and the 316L stainless steel formed by the MIM technique in this embodiment are shown in table 3 below:

TABLE 3 comparison of Material Performance of cobalt chromium molybdenum alloy substrates with 316L stainless steels under MIM Process

As can be seen from table 3 above, compared with 316L stainless steel formed by MIM, the density, hardness, yield strength, and maximum tensile strength of the base material in this embodiment are all greater, and the time for corrosion in the salt spray test is longer, so as to further illustrate that the base material in this embodiment has higher compactness, and stronger mechanical properties and corrosion resistance. By adopting the base material, the shell in the embodiment has higher density, stronger mechanical property and corrosion resistance.

Further, referring to fig. 1, in one embodiment, the housing may include a substrate 10 and an anti-fingerprint layer 20, and the anti-fingerprint layer 20 may be formed on one side of the substrate 10.

Specifically, the anti-fingerprint layer 20 may be formed on the surface of the substrate 10 by evaporation, coating, or the like.

The fingerprint-resistant layer 20 in this embodiment may be a perfluoropolyether fingerprint-resistant layer, or may be another type of fingerprint-resistant layer 20, and is not particularly limited herein.

It should be noted that the thickness of the fingerprint-resistant layer 20 may be 5-25nm, such as 5nm, 10nm, 15nm, 20nm, 25nm, etc., and the water contact angle may be greater than 105 °, such as 106 °, 108 °, 110 °, etc., so that the housing in this embodiment has excellent fingerprint resistance and is convenient for users to use. Among them, the water contact angle of the anti-fingerprint layer 20 can be measured by a contact angle tester.

The present application further provides a method for manufacturing a housing of an electronic device, which can be used to manufacture the housing applied to the electronic device in the embodiment of the present application.

Referring to fig. 2, fig. 2 is a schematic flow chart illustrating a method for manufacturing a housing of an electronic device according to an embodiment of the present disclosure. The electronic device may be a mobile phone, a watch, a tablet computer, a notebook computer, an intelligent bracelet, and the like, and is not limited specifically here. The method for manufacturing the housing of the electronic device in this embodiment may include:

step S10: providing cobalt chromium molybdenum alloy powder;

in the related art, the housing of the electronic device may be made of plastic, aluminum alloy, stainless steel, titanium alloy, ceramic, wood, carbon fiber, or the like.

Stainless steel, such as 304/316/316L stainless steel, can be used as a shell material, but the nickel content is high, which easily causes allergy to users using the electronic device; moreover, the stainless steel material has dark glossiness, and the color is required to be adjusted by later electroplating or physical vapor deposition in the manufacturing process to show more texture, so the process is complicated.

Other materials cannot meet the use requirements of users due to high cost, low strength, poor appearance and the like.

In this embodiment, a case of an electronic device is made of a cobalt-chromium-molybdenum alloy. The cobalt-chromium-molybdenum alloy is one of cobalt-based alloys, and has the properties of high strength, surface hardness, wear resistance and corrosion resistance; the cobalt-chromium-molybdenum alloy contains little nickel or trace nickel, and has good biocompatibility, so that the cobalt-chromium-molybdenum alloy is friendly to the body health of users when electronic equipment is used.

The cobalt-chromium-molybdenum alloy powder used in the embodiment can be purchased directly from the market, or can be obtained by smelting and pulverizing raw materials, as long as the components, the performance and the like can meet the use requirements.

Step S20: performing metal powder injection molding on the cobalt-chromium-molybdenum alloy powder to obtain a molded base material;

In the embodiment, the cobalt-chromium-molybdenum alloy is molded by adopting the MIM technology, so that the cobalt-chromium-molybdenum alloy is prevented from being processed and hardened by adopting a conventional mode, the processing difficulty of the cobalt-chromium-molybdenum alloy can be reduced, the processing time is shortened, and the production cost is reduced.

Step S30: and carrying out post-treatment on the substrate to obtain the shell.

After the cobalt-chromium-molybdenum alloy powder is molded by MIM technology to obtain the base material, the base material may be further subjected to post-treatments such as shaping, heat treatment, surface treatment, etc., which improve the properties and the shape of the base material, so as to obtain a case that meets the requirements of the electronic device in terms of the function and the shape of the case.

In the above manner, the shell of the electronic device prepared by using the cobalt-chromium-molybdenum alloy powder has the properties of high strength, surface hardness, wear resistance and corrosion resistance, and is friendly to the health of a user when the corresponding electronic device is used; furthermore, the cobalt-chromium-molybdenum alloy powder is processed and molded by adopting a metal powder injection molding technology, so that the processing difficulty of the cobalt-chromium-molybdenum alloy can be reduced, the processing time is shortened, and the production cost of the shell of the electronic equipment is reduced.

Further, referring to fig. 3, in one embodiment, the step S10 may include:

step S11: smelting raw materials of the cobalt-chromium-molybdenum alloy to obtain the cobalt-chromium-molybdenum alloy;

specifically, the cobalt-chromium-molybdenum alloy melted in the present embodiment may contain the following elements: cobalt, chromium, molybdenum, silicon, manganese, iron, nickel, carbon, oxygen, sulfur and the like, wherein the mass percentages of the components can be shown in the following table 4:

TABLE 4 content of Co-Cr-Mo alloy elements

Specifically, in the cobalt-chromium-molybdenum alloy in the present embodiment, the mass percentage of the chromium element may be 27%, 28%, 29%, 30%, etc., the mass percentage of the molybdenum element may be 5%, 6%, 7%, etc., the mass percentage of the manganese element may be 1.0%, 0.8%, 0.6%, 0.4%, zero, etc., the mass percentage of the iron element may be 0.75%, 0.5%, 0.25%, zero, etc., the mass percentage of the carbon element may be 0.15%, 0.1%, 0.05%, zero, etc., the mass percentage of the sulfur element may be 1.0%, 0.5%, zero, etc., and the balance may be the cobalt element.

In this embodiment, raw materials with a suitable ratio may be selected according to the content table of the elements of the cobalt-chromium-molybdenum alloy powder for smelting, and in addition, the raw materials may be selected from simple substances or compound materials, which is not limited herein.

It should be noted that the presence of elemental silicon is advantageous for metal powder injection molding, but at too high a silicon content, the resulting substrate properties are adversely affected due to the exfoliation of the hard phase of silicon oxide formed during subsequent sintering. In the present embodiment, the content of silicon is controlled to not more than 1.0% by mass, within this range, the metal powder injection molding can be facilitated, and the formation of excessive silicon oxide hard phases in the subsequent sintering process is prevented.

In the present embodiment, the raw material of the cobalt-chromium-molybdenum alloy may be vacuum-melted by a vacuum melting furnace, for example, an electromagnetic induction furnace.

Step S12: and carrying out gas atomization on the cobalt-chromium-molybdenum alloy to prepare powder, thus obtaining the cobalt-chromium-molybdenum alloy powder.

Wherein, high-purity nitrogen gas and the like can be adopted for atomization powder preparation.

It should be noted that, in the related art, a water atomization method may also be used to prepare powder from the cobalt-chromium-molybdenum alloy, but in this embodiment, a gas atomization powder preparation method is used, which can reduce the oxygen content of the obtained cobalt-chromium-molybdenum alloy powder compared to a water atomization method, so that the oxygen content is not higher than 600ppm, thereby facilitating the improvement of the density of the base material when sintering is performed at the later stage of injection molding, reducing the content of oxides generated by sintering, reducing adverse effects caused by the oxides, and thus improving the performance of the housing.

In an application scenario, a 500-fold SEM image of the cobalt-chromium-molybdenum alloy powder obtained after pulverization by gas atomization is shown in fig. 4.

In addition, in some application scenarios, the particle size of the cobalt-chromium-molybdenum alloy powder obtained after atomization powder preparation can meet the requirement, so that further powder screening of the cobalt-chromium-molybdenum alloy powder is not needed. In some application scenarios, due to factors of atomization conditions such as equipment used for atomization, the particle size of the cobalt-chromium-molybdenum alloy powder obtained after atomization powder making cannot meet subsequent requirements, and therefore further powder sieving is needed to obtain powder with a proper particle size.

Furthermore, in one embodiment, referring to fig. 5, in addition to the steps S11 and S12, the step S10 further includes:

step S13: and after the gas atomization powder preparation, sieving the obtained cobalt-chromium-molybdenum alloy powder to obtain the cobalt-chromium-molybdenum alloy powder with a preset granularity.

Wherein, the preset granularity may be: 21-23 μm for D90, 9-11 μm for D50, and 3-5 μm for D10, i.e., 90% of the cobalt-chromium-molybdenum alloy powder with a particle size of not more than 21-23 μm, 50% of the powder with a particle size of not more than 9-11 μm, and 10% of the powder with a particle size of not more than 3-5 μm. Of course, in practical application, the specific screening can be further combined with practical situations, for example, in an application scenario, the screened cobalt-chromium-molybdenum alloy powder has 90% of the particle size of not more than 22 μm, 50% of the particle size of not more than 10 μm, and 10% of the particle size of not more than 4 μm.

Specifically, the cobalt-chromium-molybdenum alloy powder can be sieved by using a powder sieving machine, and the particle size of the sieved cobalt-chromium-molybdenum alloy powder can meet the requirement by adjusting the powder sieving parameters of the powder sieving machine.

It should be noted that when the cobalt-chromium-molybdenum alloy powder satisfies the above-mentioned predetermined particle size, the powder is relatively fine and smooth, so that the sintering density of the base material can be increased, the surface pores can be reduced and reduced, and the density of the base material can be increased when the base material is subsequently sintered.

In one embodiment, the tap density of the resulting cobalt chromium molybdenum alloy powder may be 4.9 to 5.05g/cm³E.g. 4.9g/cm³、4.95g/cm³、5.0g/cm³、5.05g/cm³Etc.; the loose density can be more than 4.0g/cm³E.g. 4.05g/cm³、4.10g/cm³And the like.

Further, referring to fig. 6, in one embodiment, the step S20 may include:

step S21: mixing and banburying cobalt-chromium-molybdenum alloy powder and a binder, and performing granulation treatment to obtain cobalt-chromium-molybdenum alloy particles;

the binder used may be a polymer particle binder, and the mass percentage of the cobalt-chromium-molybdenum alloy powder to the total mass of the binder may be 9% to 11%, for example, 9%, 10%, 11%.

Specifically, the binder may be a polymer particle binder containing Polyoxymethylene (POM) as a main component.

In this embodiment, the feeding internal mixer may be used to mix and mix the cobalt-chromium-molybdenum alloy powder and the binder, the mixing temperature may be 180-.

Further, after banburying is finished, a granulator can be used for granulation treatment to obtain cobalt-chromium-molybdenum alloy particles, and then the cobalt-chromium-molybdenum alloy particles are cooled and stored in vacuum for later use.

Step S22: performing metal powder injection molding on the cobalt-chromium-molybdenum alloy particles to obtain a molded cobalt-chromium-molybdenum alloy;

specifically, after cobalt-chromium-molybdenum alloy particles are obtained through granulation, the cobalt-chromium-molybdenum alloy particles can be injected into a mold cavity by an injection molding machine in a heating and plasticizing state for solidification and molding. Specifically, the injection temperature can be 180-195 deg.C, the injection pressure can be 150-180MPa, the pressure can be 60-80MPa, and the injection speed can be 20-60 cm/s.

The injection temperature, injection pressure, holding pressure and injection speed can be selected according to actual requirements, for example, the injection temperature can be 180 ℃, 185 ℃, 190 ℃, 195 ℃ and the like; the injection pressure may be 150MPa, 160MPa, 170MPa, 180MPa, etc., the holding pressure may be 60MPa, 70MPa, 80MPa, etc., and the injection speed may be 20cm/s, 30cm/s, 40cm/s, 50cm/s, 60cm/s, etc.

The mold used for injection molding may be designed according to the shape, structure, and the like of the housing of the electronic device.

After the injection molding is finished, the cobalt-chromium-molybdenum alloy can be placed on a tray, and particularly, the cobalt-chromium-molybdenum alloy can be placed on an alumina ceramic plate, so that circulation in the subsequent process is facilitated.

Step S23: degreasing the formed cobalt-chromium-molybdenum alloy to remove the binder;

in this embodiment, the binder in the formed cobalt-chromium-molybdenum alloy may be removed by chemical or thermal decomposition.

In an application scenario, the formed cobalt-chromium-molybdenum alloy can be placed on an alumina ceramic plate, and the substrate is subjected to catalytic degreasing treatment for 3-5 hours at the temperature of 105-115 ℃ and in the atmosphere of 98% concentrated nitric acid.

Specifically, the temperature at which the degreasing treatment is performed may be 105 ℃, 110 ℃, 115 ℃, and the degreasing treatment time may be 3 hours, 4 hours, 5 hours, or the like, and may be set as appropriate, as long as the binder can be removed.

Step S24: and sintering the degreased cobalt-chromium-molybdenum alloy in a protective atmosphere to obtain the base material.

Specifically, the partial pressure of the protective atmosphere can be 4-6kPa, the degreased cobalt-chromium-molybdenum alloy can be heated to 1300-1350 ℃, and the temperature is kept for 2-5 hours, so that the cobalt-chromium-molybdenum alloy is densified to obtain the base material. Wherein the sintered density of the obtained substrate can be more than 8.1g/cm³。

The protective atmosphere can be nitrogen atmosphere, hydrogen atmosphere, argon atmosphere and the like, and the cobalt-chromium-molybdenum alloy can be prevented from being oxidized by sintering in the protective atmosphere.

In an application scenario, cobalt chromium molybdenum powders with different particle sizes are prepared according to the schemes in the related art and the processes in the above embodiments of the present application, and after banburying, molding and degreasing are performed under the same conditions, the molded and degreased cobalt chromium molybdenum powders are further sintered at different temperatures in a vacuum sintering furnace under a nitrogen atmosphere, and the conditions of the obtained base material are shown in table 5 and fig. 7-11 below after heat preservation for 5 hours.

TABLE 5 sintering results of cobalt chromium molybdenum alloys

In table 5 above, the particle size of the cobalt chromium molybdenum alloy powder corresponding to comparative example 1 is larger than the particle size of the cobalt chromium molybdenum alloy powder defined in the above-described manufacturing method embodiment of the present application, and the sintering temperature corresponding to comparative example 2 is lower than the sintering temperature defined in the above-described manufacturing method embodiment of the present application; the particle size and sintering temperature of the corresponding cobalt chromium molybdenum alloy powders in examples 1-3 were within the ranges defined in the above-described embodiments of the fabrication method of the present application.

Table 5 above provides the powder particle size of the alloy powder used in the metal powder injection molding, the sintering temperature during sintering after molding, the porosity of the obtained sintered substrate, the thickness of the dense layer, and the corresponding SEM images for each comparative example and example. In some application scenarios, the porosity and the dense layer thickness may be obtained by SEM or may be obtained by other methods, which are not specifically limited herein.

As can be seen from the data in table 5, the porosity of the sintered substrate of comparative example 1 is the highest, the thickness of the dense layer is the thinnest, the porosity of the sintered substrate of comparative example 2 is relatively higher, and the thickness of the dense layer is thinner; the sintered substrates of examples 1-3, on the other hand, had significantly lower porosity and a significantly thicker dense layer than those of comparative examples 1-2. Also, it is clear from the corresponding FIGS. 7-11 that the dense layer of comparative example 1 is the thinnest and most porous, followed by comparative example 2, while the dense layers of examples 1-3 are all thicker and less porous. This further illustrates that the base material obtained according to the alloy powder particle size and sintering temperature defined in the manufacturing method of the above embodiment of the present application has higher compactness.

Further, referring to fig. 12, in one embodiment, the step S30 may include:

step S32: carrying out finish machining treatment on the base material to obtain the base material with a preset shape;

in this embodiment, the base material may be subjected to a finish machining process by a numerically controlled machine tool, specifically, the base material may be machined according to the actual structure of the housing. For example, when the manufactured shell is a middle frame of a smart watch, the glass position, the lower cover and other assembling positions of the watch frame can be processed through a finish machining technology, so that subsequent assembly is facilitated.

It should be noted that, because the cobalt-chromium-molybdenum alloy is molded by the metal powder injection molding method in the present application, the hardness of the obtained cobalt-chromium-molybdenum alloy substrate is lower than that of other processing methods, so that the processing time is shorter when the fine processing is performed, the processing time is saved, the loss of the tool is reduced, and the production cost is reduced.

Step S34: and polishing the base material with the preset shape to ensure that the surface roughness of the base material is not more than 80 nm.

When the base material is polished, a corresponding polishing method, such as mechanical polishing, chemical polishing and the like, can be selected according to the hardness, surface flatness and surface roughness of the base material before polishing, the surface flatness and surface roughness required to be achieved, a single polishing procedure or multiple polishing procedures can be adopted, and a proper polishing wheel and an appropriate abrasive material can be selected.

In one embodiment, specifically referring to fig. 13, step S34 may include:

step S341: roughly polishing the base material by using a first polishing wheel and a first grinding material to ensure that the surface roughness of the roughly polished base material is 800-;

step S342: performing middle polishing on the roughly polished base material by using a second polishing wheel and a second abrasive material to ensure that the surface roughness of the middle polished base material is 150-350 nm;

step S343: and performing fine polishing on the polished base material by using a third polishing wheel and a third abrasive material so that the surface roughness of the fine polished base material is less than 80 nm.

Wherein, the first polishing wheel, the second polishing wheel and the third polishing wheel can be one of a cloth wheel, a hemp wheel, a nylon wheel, a wiring wheel, a wind wheel, a wool wheel and the like. The first abrasive, the second abrasive, and the third abrasive may each be an abrasive containing diamond, silicon carbide, or alumina particles, or the like.

Specifically, in one embodiment, the first, second, and third polishing wheels may be a hard wind wheel, a medium wind wheel, and a white cloth wheel, respectively. The first abrasive may be a bulk polishing wax containing alumina particles having a particle size of 500-800nm, the second abrasive may be a bulk polishing wax containing alumina particles having a particle size of 100-300nm, and the third abrasive may be a bulk polishing wax containing alumina particles having a particle size of 30-50 nm.

In practical operation, when rough polishing is performed, the rotating speed of the first polishing wheel can be 2500-; the polishing time may be 2-4 min. For example, 2min, 3min, 4min, etc.; after rough polishing, the removal amount of the base material may be 0.05 to 0.1mm, specifically, 0.05mm, 0.07mm, 0.09mm, 0.1mm, or the like.

When the polishing is performed, the rotation speed of the second polishing wheel can be 3000-; the polishing time can be 1-3min, specifically 1min, 2min, 3min, etc.; after the middle polishing, the removal amount of the substrate may be 0.02 to 0.03mm, for example, 0.02mm, 0.025mm, 0.03mm, or the like.

When the fine polishing is performed, the rotating speed of the third polishing wheel can be 3000-; the polishing time can be 1-3min, specifically 1min, 2min, 3min, etc.; after the fine polishing, the amount of substrate removed may be less than 1 μm, such as 0.95 μm, 0.90 μm, and the like.

Of course, the rotation speed of the polishing wheel, the polishing time, the removal amount of the substrate, and the like in each polishing process can be appropriately adjusted according to the actual polishing conditions, and are not particularly limited herein.

It should be noted that the hardness of the surface of the molded substrate is relatively high, the target polishing effect is difficult to achieve by polishing with a common abrasive, the cobalt-chromium-molybdenum alloy is easy to oxidize, and if the heat dissipation is not good, oxidized particles are easy to generate, so that the brightness of the surface of the polished substrate is low.

In the above manner, by the design of each polishing process and the matching of the rotation speed, polishing time and the like of the polishing wheel, the abrasive material and the polishing wheel in each process, after the cobalt-chromium-molybdenum alloy substrate obtained by metal powder injection molding is polished, lower surface roughness can be obtained, surface sand holes and other defects can be reduced, and the polishing effect can be further improved.

A set of comparative examples and three sets of examples are provided below, respectively, and the substrates polished in each comparative example and example were prepared and finished according to the above-described embodiments of the present application. The data of the results obtained after polishing each comparative example and example according to the corresponding parameters are shown in table 6 below.

Table 6 substrate polishing data

As can be seen from table 6 above, in examples 1 to 3, the surface roughness of the substrate obtained after polishing is low and the polishing effect is good when the substrate is polished according to the polishing method in the above embodiment of the present application; the comparative example was not polished according to the polishing method described in the present application, and for example, the polishing wheel, abrasive, etc. used in the polishing process were not consistent with those in the present application, and the final surface roughness was high, and the polishing effect was clearly inferior to that of examples 1 to 3.

Further, referring to fig. 14, in one embodiment, the step S30 may include:

step S31: shaping the sintered base material to ensure that the peripheral dimensional tolerance of the base material is +/-0.05 mm and the flatness tolerance is +/-0.05 mm;

when the base material is shaped, the base material can be shaped according to the requirements of the shell of the electronic equipment on flatness, peripheral dimension and the like. Specifically, a 25 ton oil press may be used in conjunction with a specially made tooling to correct the peripheral dimensions and flatness of the substrate.

the step S32 is the same as the step S32 of the previous embodiment, and the related details refer to the previous embodiment and are not described herein again.

Step S33: carrying out sand blasting treatment on the base material with the preset shape;

the base material after the finish machining in the embodiment is subjected to sand blasting treatment, so that burrs generated in the finish machining process can be removed, the surface of the base material is smoother, and the requirements of subsequent processes are met.

Specifically, in the present embodiment, a sand blasting machine may be used to spray ceramic sand with a diameter of 20 to 50 μm onto the substrate, but the type and particle size of the sand may be selected according to actual needs, for example, copper ore sand, quartz sand, silicon carbide sand, iron sand, sea sand, etc. may be sprayed, and the particle size may be 25 to 45 μm, 30 to 40 μm, etc., and is not limited thereto.

Step S34: polishing the base material with the preset shape to ensure that the surface roughness of the base material is not more than 80 nm;

the step S34 is the same as the step S34 of the previous embodiment, and the related details refer to the previous embodiment and are not described herein again.

Step S35: and forming an anti-fingerprint layer on the polished substrate.

The anti-fingerprint layer can be formed on the surface of the polished substrate by evaporation, coating and the like, and specifically can be a perfluoropolyether anti-fingerprint layer.

Specifically, the thickness of the anti-fingerprint layer may be 5-25nm, such as 5nm, 10nm, 15nm, 20nm, 25nm, etc., and the water contact angle may be greater than 105 °, such as 106 °, 108 °, 110 °, etc., so that the manufactured housing of the electronic device has excellent fingerprint resistance.

It should be noted that, in the actual operation process, the substrate may be cleaned according to the need, for example, the substrate surface may be cleaned with water, cleaning agent, etc. after the sand blasting to remove fine sand grains, oil stain residues, etc. on the substrate surface, so that the substrate surface is in a clean state before the next polishing process is performed, so as to avoid affecting the subsequent polishing effect. For example, after polishing the substrate and before forming the anti-fingerprint layer, the surface of the substrate may be cleaned to remove oil stains and the like generated on the surface of the substrate in the polishing process, so as to meet the requirement of cleanliness of the evaporated anti-fingerprint layer.

Referring to fig. 15, the present application further provides an electronic device, which may be a mobile phone, a watch, a tablet computer, a notebook computer, an intelligent bracelet, and the like.

The watch may include a case 10 and a functional device 20, wherein the case 10 defines an accommodating space 11, and the functional device 20 may be accommodated in the accommodating space 11.

In particular, the case 10 may be a middle frame, a battery cover of a watch.

It should be noted that the housing may be a housing in the above-mentioned embodiment of the present application, or a housing manufactured by a manufacturing method in the above-mentioned embodiment of a manufacturing method of a housing of an electronic device, and for details, please refer to the above-mentioned embodiments, and details are not described here.

The above embodiments are merely examples and are not intended to limit the scope of the present disclosure, and all modifications, equivalents, and flow charts using the contents of the specification and drawings of the present disclosure or those directly or indirectly applied to other related technical fields are intended to be included in the scope of the present disclosure.

Claims

1. A housing, comprising:

the base material is cobalt chromium molybdenum alloy, and the base material is obtained by performing injection molding on cobalt chromium molybdenum alloy powder through metal powder.

2. The housing of claim 1,

the silicon element, the oxygen element and the nickel element in the base material meet the following requirements: at least one of the base material containing silicon element not more than 1.0 wt%, oxygen element not more than 0.1 wt% and nickel element not more than 0.5 wt%.

3. The housing of claim 1,

the substrate satisfies a density of not less than 8.1g/cm³At least one of a porosity of less than 0.5% and pores of no more than 10 nm.

4. The housing of claim 1,

the base material satisfies at least one of a surface roughness of not more than 80nm, a peripheral dimensional tolerance of ± 0.05mm, and a flatness tolerance of ± 0.05 mm.

5. The housing of claim 1,

the base material satisfies at least one of a hardness of 250-350HV1 in Vickers hardness, a yield strength of not less than 520MPa, a maximum tensile strength of not less than 800MPa, and a magnetic permeability of less than 1.01.

6. The housing of claim 1, further comprising:

and the anti-fingerprint layer is formed on one side of the substrate, wherein the thickness of the anti-fingerprint layer is 5-25nm, and the water contact angle is larger than 105 degrees.

7. A method for manufacturing a shell of an electronic device, comprising:

providing cobalt chromium molybdenum alloy powder;

performing metal powder injection molding on the cobalt-chromium-molybdenum alloy powder to obtain a molded base material;

and carrying out post-treatment on the base material to obtain the shell.

8. The manufacturing method according to claim 1, wherein the particle size of the cobalt-chromium-molybdenum alloy powder satisfies: 21-23 μm for D90, 9-11 μm for D50, 3-5 μm for D10, and 4.9-5.05g/cm for tap density³Loose density greater than 4.0g/cm³。

9. The method of claim 1, wherein the step of providing a cobalt chromium molybdenum alloy powder comprises:

smelting a raw material of a cobalt-chromium-molybdenum alloy to obtain the cobalt-chromium-molybdenum alloy;

and carrying out gas atomization on the cobalt-chromium-molybdenum alloy to prepare powder, thus obtaining the cobalt-chromium-molybdenum alloy powder.

10. The method of claim 3, wherein the step of providing a cobalt chromium molybdenum alloy powder further comprises:

and after the gas atomization powder preparation, sieving the obtained cobalt-chromium-molybdenum alloy powder to obtain the cobalt-chromium-molybdenum alloy powder with a preset granularity.

11. The method according to claim 1, wherein the step of performing metal powder injection molding on the cobalt-chromium-molybdenum alloy powder to obtain a molded base material comprises:

mixing and banburying the cobalt-chromium-molybdenum alloy powder and a binder, and performing granulation treatment to obtain cobalt-chromium-molybdenum alloy particles;

performing metal powder injection molding on the cobalt-chromium-molybdenum alloy particles to obtain a molded cobalt-chromium-molybdenum alloy;

degreasing the formed cobalt-chromium-molybdenum alloy to remove the binder;

and sintering the degreased cobalt-chromium-molybdenum alloy in a protective atmosphere to obtain the base material.

12. The manufacturing method of claim 6, wherein the binder is a polymer particle binder, accounts for 9-11% of the total mass of the cobalt-chromium-molybdenum alloy powder and the binder, and the cobalt-chromium-molybdenum alloy powder and the binder are mixed and banburied and granulated to obtain the cobalt-chromium-molybdenum alloy particles, and the method comprises the following steps:

mixing the cobalt-chromium-molybdenum alloy powder with the binder, banburying at 180-190 ℃ for 60-90min, and performing granulation treatment to obtain the cobalt-chromium-molybdenum alloy particles;

a step of performing metal powder injection molding on the cobalt-chromium-molybdenum alloy particles to obtain a molded cobalt-chromium-molybdenum alloy, including:

performing metal powder injection molding on the cobalt-chromium-molybdenum alloy particles under the conditions that the injection temperature is 180-;

the step of degreasing the formed cobalt-chromium-molybdenum alloy to remove the binder comprises the following steps:

degreasing the base material at the temperature of 105-115 ℃ and in the atmosphere of 98% concentrated nitric acid for 3-5 hours to remove the binder;

sintering the degreased cobalt-chromium-molybdenum alloy in a protective atmosphere to obtain the base material, wherein the sintering process comprises the following steps:

heating the degreased cobalt-chromium-molybdenum alloy to 1300-1350 ℃ in a protective atmosphere with the partial pressure of 4-6kPa, and preserving the heat for 2-5 hours to obtain the base material, wherein the sintering density of the base material is more than 8.1g/cm³。

13. The method of claim 1, wherein the step of post-treating the substrate comprises:

carrying out finish machining treatment on the base material to obtain the base material with a preset shape;

and polishing the base material with the preset shape to enable the surface roughness of the base material to be not more than 80 nm.

14. The method according to claim 8, wherein the step of polishing the substrate having the predetermined profile so that the surface roughness of the substrate is not more than 80nm comprises:

roughly polishing the base material by using a first polishing wheel and a first grinding material to ensure that the surface roughness of the roughly polished base material is 800-2000 nm;

performing middle polishing on the roughly polished base material by using a second polishing wheel and a second abrasive material to ensure that the surface roughness of the middle polished base material is 150-350 nm;

and performing fine polishing on the medium-polished base material by using a third polishing wheel and a third abrasive material, so that the surface roughness of the fine-polished base material is less than 80 nm.

15. The manufacturing method according to claim 9, wherein the first polishing wheel is a hard wind wheel, the first abrasive comprises alumina particles with a particle size of 500-800nm, and when the substrate is roughly polished, the rotation speed of the first polishing wheel is 2500-5000r/min, and the rough polishing time is 2-4 min;

the second polishing wheel is a medium wind wheel, the second abrasive comprises alumina particles with the particle size of 100-;

the third polishing wheel is a white cloth wheel, the third abrasive comprises alumina particles with the particle size of 30-50nm, when the base material is subjected to fine polishing, the rotating speed of the third polishing wheel is 3000-5000r/min, and the fine polishing time is 1-3 min.

16. The method of claim 8, wherein the step of post-treating the sintered substrate further comprises:

before the finish machining treatment, shaping the sintered base material so that the peripheral dimensional tolerance of the base material is +/-0.05 mm and the flatness tolerance is +/-0.05 mm;

before the polishing treatment, carrying out sand blasting treatment on the base material with the preset shape;

forming an anti-fingerprint layer on the polished substrate.

17. An electronic device, comprising:

a housing defining an accommodating space;

the functional device is accommodated in the accommodating space;

wherein the shell is the shell according to any one of claims 1 to 6 or is manufactured by the manufacturing method according to any one of claims 7 to 16.