CN114466543A

CN114466543A - Electronic equipment shell assembly, preparation method thereof and electronic equipment

Info

Publication number: CN114466543A
Application number: CN202210116632.9A
Authority: CN
Inventors: 陈江
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2022-02-07
Filing date: 2022-02-07
Publication date: 2022-05-10

Abstract

The application discloses an electronic equipment shell assembly, a preparation method thereof and electronic equipment. The electronic equipment shell assembly comprises a middle plate, wherein the middle plate comprises a middle plate body and a metal middle frame, the metal middle frame is arranged along the circumferential direction of the middle plate body and is connected with the middle plate body, and the middle plate body comprises metal magnesium or magnesium alloy; the ceramic oxide layer is arranged on the surface of the middle plate body, and micropores are prefabricated on the surface of the ceramic oxide layer; the resin layer is arranged on the surface of one side, far away from the middle plate body, of the ceramic oxide layer. Therefore, the electronic equipment shell assembly is good in corrosion resistance, light in weight, high in hardness, good in wear resistance and heat resistance and capable of achieving good appearance effect and texture.

Description

Electronic equipment shell assembly, preparation method thereof and electronic equipment

Technical Field

The application belongs to the technical field of materials, and particularly relates to an electronic equipment shell assembly, a preparation method of the electronic equipment shell assembly and electronic equipment.

Background

At present, electronic equipment such as smart phones, palm computers and the like are widely applied and become important components of people in work and life, and shells of the electronic equipment are generally of metal middle frame structures, so that the corrosion resistance, the wear resistance and the decoration performance of the electronic equipment can be improved and enhanced by carrying out anodic oxidation on the electronic equipment. In order to realize the light weight of the shell, high magnesium alloy is adopted as a medium plate material in the related technology, and because the high magnesium alloy has higher magnesium content and higher product activity and is easy to react violently when meeting acid, if the high magnesium alloy is not well protected in the surface treatment process of anodic oxidation and the like, the product can be seriously corroded; in addition, during natural storage, the surface often corrodes due to the presence of moisture in the air.

Disclosure of Invention

In one aspect of the present application, an electronic device housing assembly is presented. The electronic device housing assembly includes: the middle plate comprises a middle plate body and a metal middle frame, the metal middle frame is arranged along the circumferential direction of the middle plate body and is connected with the middle plate body, and the middle plate body comprises metal magnesium or magnesium alloy; the ceramic oxide layer is arranged on the surface of the middle plate body, and micropores are prefabricated on the surface of the ceramic oxide layer; the resin layer is arranged on the surface of one side, far away from the middle plate body, of the ceramic oxide layer. Therefore, the electronic equipment shell assembly is good in corrosion resistance, light in weight, high in hardness, good in wear resistance and heat resistance and capable of achieving good appearance effect and texture.

In another aspect of the present application, a method of making an electronic device housing assembly is presented. The method comprises the following steps: providing a middle plate, wherein the middle plate comprises a middle plate body and a metal middle frame, the metal middle frame is arranged along the circumferential direction of the middle plate body and is connected with the middle plate body, and the middle plate body comprises metal magnesium or magnesium alloy; forming a ceramic oxide layer with micropores on the surface of the middle plate body by adopting a micro-arc oxidation method; and forming a resin layer on the surface of the ceramic oxide layer on the side far away from the middle plate body by adopting an electrophoresis method. Therefore, the method is simple in process and high in yield, can obviously improve the corrosion resistance, hardness, wear resistance and heat resistance of the shell assembly, reduces the overall weight of the shell assembly, and can realize better appearance and texture of the shell.

In yet another aspect of the present application, an electronic device is presented. The electronic device includes: the electronic device shell assembly or the electronic device shell assembly prepared by the method for preparing the electronic device shell assembly; the display screen assembly is connected with the electronic equipment shell assembly, and an installation space is defined between the display screen assembly and the electronic equipment shell assembly; and the mainboard is arranged in the installation space and is electrically connected with the display screen assembly. Thus, the electronic device has all the features and advantages of the electronic device housing assembly and the method for preparing the electronic device housing assembly, which are not described herein again. Generally, the electronic device is light in overall weight, and is excellent in corrosion resistance, wear resistance, heat resistance, and hardness.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic cross-sectional structure of an electronic device housing assembly in a thickness direction thereof according to an embodiment of the present application.

Fig. 2 is a test chart of local bubbling on the surface of an ink layer formed by electrostatic spraying in a boiling test in the related art.

Fig. 3 is a surface topography of a ceramic oxide layer formed on a surface of a mid-plate body according to an embodiment of the present application.

Fig. 4 is a schematic cross-sectional structure view of an electronic device housing assembly along a thickness direction thereof according to still another embodiment of the present application.

FIG. 5 is a flow chart of a method of preparing an electronic device housing assembly according to one embodiment of the present application.

Fig. 6 is an external structural view of an electronic device housing assembly according to an embodiment of the present application.

Fig. 7 is a test chart of the surface roughness of the ceramic oxide layer manufactured according to example 1 of the present application.

FIG. 8 is a surface micropore topography for a ceramic oxide layer made according to example 1 of the present application.

Figure 9 is a graph of the anodized exterior appearance of a mid-plate product treated according to comparative example 1 of the present application.

Figure 10 is a graph of the anodized exterior appearance of a mid-plate product treated according to comparative example 2 of the present application.

Figure 11 is a graph of the anodized exterior appearance of a mid-plate product treated according to comparative example 3 of the present application.

Description of reference numerals:

middle plate: 10; the medium plate body: 11; a metal middle frame: 12; oxidizing the ceramic layer: 20; resin layer: 30, of a nitrogen-containing gas; an aluminum oxide layer: 40; electronic device housing assembly: 100.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.

In one aspect of the present application, an electronic device housing assembly is presented. According to an embodiment of the present application, as understood with reference to fig. 1, the electronic device housing assembly 100 includes: the middle plate 10, the middle plate 10 includes a middle plate body 11 and a metal middle frame 12, the metal middle frame 12 is disposed along the circumference of the middle plate body 11 and connected with the middle plate body 11, the middle plate body 11 includes metal magnesium or magnesium alloy; the ceramic oxide layer 20, the ceramic oxide layer 20 is arranged on the surface of the middle plate body 11, and micropores are preformed on the surface of the ceramic oxide layer 20; a resin layer 30, the resin layer 30 being provided on a surface of the ceramic oxide layer 20 on a side away from the middle plate body 11. Therefore, the electronic equipment shell assembly is good in corrosion resistance, light in weight, high in hardness, good in wear resistance and heat resistance and capable of achieving good appearance effect and texture. It can be understood that, in the middle plate 10, the thickness of the metal middle frame 12 may be the same as that of the middle plate body 11, or may be smaller than or larger than that of the middle plate body 11, and in addition, the metal middle frame 12 may flexibly select a connection structure and a connection angle with the middle plate body 11 according to actual requirements such as the actual shape of the housing and the size of the electronic device, wherein the connection mode of the two may be direct connection or indirect connection; in addition, the whole surface of the middle plate body 11, including the surface near the electronic device display screen assembly side and the surface far from the electronic device display screen assembly side, is formed with a ceramic oxide layer. In addition, it can be understood that the electronic device housing assembly described in the present application may be a composite board used for preparing the housing, a back cover as a part of the electronic device body, an additional protective housing that can be used for the electronic device alone, or the like, or a part of the electronic device housing.

According to the embodiment of the application, in order to solve the problem of metal corrosion susceptibility, a conventional operation method is to form a protective coating on the surface of the metal, such as electrostatic spraying or micro-arc oxidation. The electrostatic spraying is a coating method which utilizes a corona discharge principle to enable atomized coating to be charged negatively under the action of a high-voltage direct-current electric field and to be adsorbed on the surface of a positively charged substrate for discharging, a spraying device generally adopts an electrostatic spraying high-voltage power supply, the coating required to be used in the electrostatic spraying has low resistivity (5-50M omega cm), and an ink coating sprayed by the electrostatic spraying has the advantage of uniform thickness, but is not suitable for being used as a bottom coating and cannot flexibly adopt a multi-layer ink system; in addition, after electrostatic spraying, even if the ink is well cured, the problem of poor compactness of the ink coating still exists, nano or micron-sized micropores still exist on the surface of the ink coating, water vapor can contact with a material substrate through the micropores so as to react, bubbles can be generated locally (a bad picture is shown in figure 2), the defects are very obvious in the high-temperature water boiling process or the anodic oxidation hole sealing process, and the water vapor is easy to penetrate through the ink; meanwhile, the problem of thin oil hanging exists at the edge position or the groove position of the substrate support, and the substrate is easily corroded due to the influence of strong acid/high temperature in the anodic oxidation process. The micro-arc oxidation process mainly depends on matching and adjustment of electrolyte and electrical parameters, under the action of instantaneous high temperature and high pressure generated by arc discharge, a modified ceramic coating which mainly comprises matrix metal oxide and is supplemented with electrolyte components grows on the surface of metal, and the modified ceramic coating has the advantages that firstly, the surface hardness of the material can be greatly improved, the microhardness can reach 1000-2000 HV, and can reach 3000HV at most, and can be comparable with hard alloy, and the hardness greatly exceeds the hardness of high-carbon steel, high-alloy steel and high-speed tool steel after heat treatment; and secondly, the wear-resistant steel has good wear resistance, heat resistance and corrosion resistance. However, although the coating formed by micro-arc oxidation has better corrosion resistance, the coating cannot withstand the high-temperature corrosion of strong acid (85 wt% phosphoric acid or 98 wt% sulfuric acid) in the anodic oxidation process, and the coating is easily reacted with the strong acid in the anodic oxidation process at high temperature in the anodic oxidation process, so that the coating is corroded, and the protection effect is lost. In order to solve the above problems, the inventors have found that a micro-arc oxidation process can be used to form a ceramic coating on the surface of a metal substrate, form micro-pores on the surface of the ceramic coating, and then attach a resin coating on the surface of the micro-arc oxidation coating by an electrophoresis process, thereby providing a better protection effect for the metal substrate. Thus, with respect to the electronic device housing assembly 100 of the present application, by forming the ceramic oxide layer 20 pre-formed with micro pores on the surface of the middle plate body 11 including metallic magnesium or magnesium alloy (the surface morphology of the ceramic oxide layer is understood with reference to fig. 3), because the ceramic oxide layer 20 has a certain corrosion resistance and dense pores on the surface, the ceramic oxide layer can have a good bonding force with the resin layer 30, and the resin layer 30 is utilized to achieve a further corrosion prevention effect, thereby the dual functions of the ceramic oxide layer 20 and the resin layer 30 can be utilized to generate better corrosion protection effect on magnesium or magnesium alloy, the electronic equipment shell component can achieve excellent anti-corrosion effect even in the anodic oxidation process, has good anti-corrosion performance, and the light-weight composite material has light weight, higher hardness, better wear resistance and heat resistance, and can realize better appearance effect and texture.

According to an embodiment of the present invention, the pore size of the ceramic oxide layer 20 may be 2 μm to 6.5 μm, for example, may be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 4 μm, or 5.5 μm; alternatively, the roughness Ra of the ceramic oxide layer 20 may be 0.7 to 1.3, for example, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, or 1.25, and the like, and the pore diameter of the ceramic oxide layer 20 may be 2 μm to 6.5 μm and the roughness Ra may be 0.7 to 1.3. The inventor finds that the roughness and the micropore diameter of the ceramic oxide layer both influence the adhesive force and the corrosion prevention effect of the resin layer, and if the roughness or the micropore diameter of the ceramic oxide layer are too small, the adhesive force of the ceramic oxide layer to the resin layer is poor, so that the effective combination of the ceramic oxide layer and the resin layer is difficult to ensure; if the roughness of the oxide ceramic layer is too large, the corrosion prevention effect of the oxide ceramic layer is reduced, and the resin layer is difficult to achieve the complete water vapor barrier effect, so that the whole corrosion prevention effect is influenced; if the pore diameter of the micropores of the ceramic oxide layer is too large, the porosity of the ceramic oxide layer is relatively small, and the anti-corrosion effect of the ceramic oxide layer on the ceramic plate body can be influenced; by controlling the aperture of the micropores in the ceramic oxide layer to be 2-6.5 μm or the roughness Ra of the ceramic oxide layer to be 0.7-1.3, the bonding strength between the resin layer and the ceramic oxide layer and the overall anti-corrosion effect can be considered at the same time, and even if the metal middle frame is subjected to anodic corrosion, the magnesium middle plate body can also have a better anti-corrosion effect.

According to the embodiment of the present invention, the thickness of the ceramic oxide layer 20 may be 10 μm to 15 μm, for example, 10.5mm, 11 μm, 11.5mm, 12 μm, 12.5mm, 13 μm, 13.5mm, 14 μm, or 14.5 μm, etc., and the thickness of the resin layer 30 may be 40 μm to 50 μm, for example, 41mm, 42 μm, 43mm, 44 μm, 45mm, 46 μm, 47mm, 48 μm, or 49 μm, etc. The inventor finds that the corrosion resistance of the middle plate body can be obviously improved along with the increase of the thicknesses of the ceramic oxide layer and the resin layer, but considering the factors of reducing the thickness of the shell, lightening the shell, reducing the cost and the like, the ceramic oxide layer and the resin layer are expected to achieve better corrosion resistance effect on the premise of lower overall thickness; compared with the resin layer, the water and oxygen barrier property of the ceramic oxide layer is better, if the thickness of the ceramic oxide layer is too small, the influence on the overall corrosion resistance of the medium plate body is larger, and the expected corrosion resistance effect is difficult to achieve; if the thickness of the resin layer is too small, the ceramic oxide layer is difficult to be well protected in the strong acid high-temperature environment of anodic oxidation; in addition, since the thickness of the ceramic oxide layer and the resin layer formed at the end portion of the middle plate and the groove portion (e.g., the edge of the middle plate body and the connection region thereof with the metal bezel) is relatively thin compared to other regions, it is also difficult to ensure effective protection of the end portion of the middle plate and the groove portion when the thickness of the ceramic oxide layer is excessively thin or the thickness of the resin layer is excessively thin. Through control oxide ceramic layer and resin layer be above-mentioned thickness scope respectively in this application, not only can realize the all-round protection to the median plate body, can also make oxide ceramic layer and resin layer have lower whole thickness under the prerequisite that has high corrosion resistance to can further satisfy the comprehensive demand to low thickness of casing, lightweight, the high corrosion resistance of median plate body etc..

According to an embodiment of the present invention, the ceramic oxide layer 20 may be formed by a micro-arc oxidation method. In the actual operation process, the compositions of the electrolytes used for micro-arc oxidation are different for different substrates, for example, the respective suitable electrolytes for aluminum alloy, titanium alloy and magnesium alloy are different. For the magnesium-containing substrate of the present application, the electrolyte employed by the micro-arc oxidation process may include: the micro-arc oxidation device comprises phytic acid and/or soluble phytate, calcium-containing electrolyte, soluble alkali, aluminate and/or aluminum hydroxide and a buffering agent, wherein the buffering agent comprises at least one selected from sodium silicate, sodium carbonate and boron, and the phytic acid and/or the soluble phytate serving as an additive can better inhibit the phenomenon of violent discharge of a micro-arc oxidation tip so as to stabilize the micro-arc oxidation process; the electrolyte containing calcium can increase the conductivity of the electrolyte and can be used as a slow release agent to avoid over severe local reaction; the soluble alkali is used for providing hydroxide ions and participating in the micro-arc oxidation process; sodium silicate, sodium carbonate, boric acid (namely the existence form of boron), aluminate and aluminum hydroxide are used for adjusting and stabilizing the pH value of the electrolytic bath solution, simultaneously generated anions are deposited on the surface of a metal anode, and an oxide is generated by arc melting, so that the compactness of a micro-arc oxidation layer (namely a ceramic oxide layer) is improved. In addition, the phytic acid and/or the soluble phytate can influence the film forming and the pore diameter of the ceramic oxide layer, and the calcium-containing electrolyte, aluminate and aluminum hydroxide can influence the growth and the thickness of the ceramic oxide layer. Further, the pH value of the electrolyte can be 9-12, and the inventor finds that if the pH value of the electrolyte is too low, namely the concentration of hydroxide ions is too low, the micro-arc oxidation process can be slowed down, the formation and the effect of the ceramic oxide layer can be influenced, and if the pH value of the electrolyte is too high, the micro-arc oxidation film can be over-corroded, and the inherent performance of the magnesium medium plate body can be influenced. It is to be understood that the type of the soluble base in the present application is not particularly limited, and may be selected by those skilled in the art according to actual needs, for example, the soluble base may be sodium hydroxide or potassium hydroxide.

According to the specific embodiment of the invention, although the micro-arc oxidation can achieve a very good effect on corrosion prevention of the magnesium alloy in principle, the process itself adopts a discharge reaction generated by an electric arc generated by high voltage (more than 1000V), the process cost is high, and the efficiency is low, therefore, the process parameters are expected to be reduced and the preparation efficiency is expected to be improved on the premise of satisfying the effective growth of the ceramic oxide layer; in addition, the film layer generated by the micro-arc oxidation is an oxide film, and is easily reacted with strong acid (85 wt% phosphoric acid or 98 wt% sulfuric acid) in the anodic oxidation process of the metal middle frame at high temperature, so that the coating is corroded, the magnesium alloy substrate is corroded, and the protection effect is lost. However, in the related process of micro-arc oxidation of magnesium alloy, it is difficult to prepare a micro-arc oxidation ceramic layer with a thickness of 10 μm or more, and the formation time of the micro-arc oxidation ceramic layer with a thickness of several micrometers is long, usually up to several hours or more. However, since different metals (alloys) are suitable for different electrolyte compositions, it is considered to solve the above problems by improving the composition of the micro-arc oxidation electrolyte. To the magnesium system medium plate body of this application, the electrolyte that micro-arc oxidation adopted can include: 30 g/L-40 g/L (such as 35 g/L) of potassium phytate, 3 g/L-50 g/L (such as 20g/L, 30g/L, 40g/L and the like) of calcium-containing electrolyte, 30 g/L-50 g/L (such as 35g/L, 40g/L, 45g/L and the like) of sodium hydroxide, 10 g/L-20 g/L (such as 12g/L, 15g/L, 18g/L and the like) of sodium carbonate, 5 g/L-50 g/L (such as 20g/L, 30g/L, 40g/L and the like) of sodium silicate, 30 g/L-50 g/L (such as 35g/L, 40g/L, 45g/L and the like) of boron, 5 g/L-50 g/L (such as 10g/L, or, 20g/L, 30g/L, 40g/L, etc.), wherein boron is present in the form of boric acid, the inventors have found that changes in the amount of potassium phytate significantly affect the pore size and porosity of the ceramic oxide layer, the change of the dosage of the calcium-containing electrolyte, the aluminate and/or the aluminum hydroxide can obviously influence the film forming thickness of the ceramic oxide layer, and the selection of the electrolyte with the composition and the proportion is more favorable for obtaining the ceramic oxide layer with expected micropore diameter, roughness and thickness, the micro-arc oxidation process is controllable, the problem of local over-drastic phenomenon is avoided, and meanwhile, a ceramic oxide layer with the thickness not less than 10 mu m (such as 10 mu m-20 mu m or even higher) can be obtained in lower voltage and shorter processing time, the electrolyte is particularly suitable for high-magnesium alloy medium plate bodies, such as high-magnesium medium plate bodies with the magnesium content of not less than 85 wt%. It can be understood that the cost of potassium phytate in the electrolyte is high, the content change of the potassium phytate is sensitive to the surface morphology of the oxide ceramic membrane, and the dosage of other components can be flexibly regulated by taking the dosage of the potassium phytate as a reference in the actual operation process.

Further, for the electrolyte with the component distribution ratio, the process parameters of the micro-arc oxidation method can meet at least one of the following conditions: the voltage is 350V-370V, the time is 4 min-5 min, the duty ratio is 10% -12%, the frequency is 800 Hz-1200 Hz, the temperature is 25-35 ℃, for example, the voltage can be 355V, 360V or 365V, the time can be 4.2min, 4.5min or 4.8min, the duty ratio can be 10.5%, 11% or 11.5%, the frequency can be 900Hz, 1000Hz or 1100Hz, the temperature can be 28 ℃, 30 ℃ or 32 ℃, the inventor finds that the voltage of micro-arc oxidation is too low, the growth of the film layer is slow, and the thickness of the film layer is thin; with the increase of the micro-arc oxidation voltage, the pore diameter of the obtained micro-pores of the ceramic oxide layer is increased, but if the micro-arc oxidation voltage is too high, the compactness of the film layer is poor, and the micro-arc oxidation film layer is easy to crack; the longer the micro-arc oxidation time is, the larger the thickness of the obtained ceramic oxide layer is, and the better the compactness is; as the duty ratio becomes larger, the thickness and hardness of the formed ceramic oxide layer increase, but at the same time, the surface of the ceramic oxide layer becomes rougher and microcracks increase; in addition, the frequency also influences the roughness of the ceramic oxide layer, as the frequency increases, the corrosion potential of the micro-arc oxidation film layer moves forward, the corrosion current density decreases, the impedance value becomes large, the corrosion resistance is improved, and the protective effect of the film layer on the matrix is obviously enhanced; moreover, the micro-arc oxidation reaction speed is faster along with the temperature rise, and aiming at the electrolyte, the micro-arc oxidation process is controlled, so that a ceramic oxide layer with the micropore diameter of 2-6.5 mu m, the roughness Ra of 0.7-1.3 and the thickness of 10-15 mu m can be obtained more favorably, therefore, the corrosion resistance effect of the magnesium middle plate body can be improved, the high bonding strength of the ceramic oxide layer and a subsequently formed resin layer can be ensured, the micro-arc ceramic oxide layer with the thickness of more than 10 micrometers can be obtained within a few minutes under low voltage, the micro-arc oxidation efficiency is obviously improved, the process cost is reduced, and the bottleneck that the thickness limit of the micro-arc ceramic oxide layer is only a few micrometers, the voltage required by micro-arc oxidation is high, the micro-arc oxide layer with the thickness of a few micrometers needs hours for obtaining the micro-arc oxide layer with the thickness of a few micrometers, the process cost is high and the efficiency is low in the related technology is overcome.

According to an embodiment of the present invention, the resin layer 30 may be an epoxy resin layer. Compared with resin systems such as an acrylic acid system, a polyurethane system and the like, the epoxy resin has higher crosslinking degree, and the high crosslinking degree is more favorable for improving the water and oxygen barrier capability of a resin layer and improving the overall anti-corrosion effect; furthermore, the epoxy resin layer also has better insulating property, and the insulating property of the shell assembly can be improved. In addition, the epoxy resin layer can be dispersed with the colored paste, and the epoxy resin can shrink to a certain extent, so that if the cross-linking degree of the epoxy resin is higher, the epoxy resin is easy to shrink and crack at the end part and the groove part of the middle plate (such as the edge of the middle plate body and the connecting area between the edge and the metal middle frame of the middle plate body). It is understood that the kind of the color paste is not particularly limited, and those skilled in the art can flexibly select the color paste according to actual needs as long as the color paste can achieve better effect of resisting shrinkage cracking, for example, the color paste may include carbon powder, or only carbon powder.

According to an embodiment of the present invention, the epoxy layer may be formed using an electrophoresis process. The adopted electrophoretic liquid can be composed of epoxy resin emulsion, color paste and water, wherein the epoxy resin emulsion can comprise epoxy resin and an auxiliary agent, the auxiliary agent can comprise a cosolvent, the dispersibility and the solubility of the epoxy resin in the electrophoretic liquid can be improved by adding the cosolvent, and other resin materials except the epoxy resin can be not added. Furthermore, the auxiliary agent can also comprise a cross-linking agent, and the cross-linking degree of the epoxy resin can be improved by adding the cross-linking agent, so that the water and oxygen resistant barrier performance of the epoxy resin layer is improved, and the corrosion resistance of the middle plate body is improved. It can be understood that the epoxy resin used in the electrophoretic solution may be a multifunctional epoxy resin (e.g., greater than or equal to 3, for example, 6 to 10 functionality can be selected), which is more favorable for improving the crosslinking degree and the protection effect of the epoxy resin layer. Further, the electrophoretic fluid used may include: 16 wt% -24 wt% of epoxy resin emulsion, 3 wt% -5 wt% of color paste and the balance of water, for example, the mass proportion of the epoxy resin emulsion in the electrophoretic fluid can be 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt% or 23 wt%, etc., the mass proportion of the color paste in the electrophoretic fluid can be 3.5 wt%, 4 wt% or 4.5 wt%, etc., the inventor finds that if the resin content in the electrophoretic fluid is too high, the resin layer is obviously shrunk, the problem of cracking caused by the shrinkage of the resin is easily occurred at the root part, the end part and the groove part of the supporting edge, such as the edge of the middle plate body and the connecting area of the middle plate body and the metal middle frame; if the content of the color paste is too low, the problem of shrinkage cracking of the resin is difficult to effectively slow down, and if the content of the color paste is too high, the water vapor blocking rate of the resin layer is obviously reduced, so that the corrosion resistance effect is influenced; furthermore, the mass ratio of the epoxy resin to the auxiliary agent in the epoxy resin emulsion can be controlled to be about 6:4, and for example, the mass ratio can be (5.5-6.5): (3.5-4.5), the mass ratio of the epoxy resin emulsion to the color paste can be further controlled to be about 5:1, and for example, the mass ratio can be (4.5-5.5): 1, thereby being more beneficial to solving the problem of shrinkage cracking of the epoxy resin layer and improving the overall anti-corrosion effect. Furthermore, according to the composition of the electrophoresis solution, the voltage adopted by the electrophoresis process can be 188V-192V, such as 189V, 190V or 191V, the electrophoresis temperature can be 27-29 ℃, such as 28 ℃, and the electrophoresis time can be 10 min.

According to an embodiment of the present invention, the metal middle frame 12 may be an aluminum middle frame with an aluminum oxide layer 40 (understood with reference to fig. 4) on the surface. The aluminum middle frame can be a metal aluminum middle frame or an aluminum alloy middle frame, for example, the aluminum alloy middle frame can be selected, the aluminum alloy middle frame is low in cost and light in weight, the processing technology is mature, the processing difficulty is low, the rate of finished products is high, and the aluminum alloy middle frame can further meet the requirements of light weight and high cost performance on the premise of meeting the appearance effect when used for electronic equipment. Further, an aluminum oxide film can be formed on the surface of the aluminum alloy middle frame through anodic oxidation, so that the corrosion resistance, the wear resistance and the decoration of the metal middle frame are obviously improved and enhanced. It is understood that, when the ceramic oxide layer and the resin layer are formed on the middle plate body, in order to form the protective layer on all surfaces of the middle plate body, the whole middle plate is generally treated, and thus, before the metal middle frame is anodized to form the aluminum oxide layer, the ceramic oxide layer and the resin layer formed on the surface of the metal middle frame are removed and then anodized.

According to an embodiment of the present invention, the magnesium content of the middle plate body 11 may be not less than 85 wt%, for example, a magnesium alloy having a magnesium content of 90 wt% or 95 wt% and more, wherein the selection of the middle plate body having a high magnesium content is more due to the reduction of the overall thickness of the housing assembly. It is understood that the kind of the magnesium alloy having the magnesium content of not less than 85 wt% is not particularly limited, and those skilled in the art can flexibly select the magnesium alloy according to actual needs. According to a specific example of the present application, the middle plate body 11 may be a rare earth magnesium alloy material, and preferably may be a rare earth magnesium alloy material with a magnesium content of not less than 90 wt%, wherein the middle plate body made of the material is selected to be not only light in weight, but also the introduction of the rare earth material is beneficial to improving the thermal conductivity of the magnesium alloy middle plate body, so as to improve the heat dissipation effect of the housing assembly.

Based on the same inventive concept, in another aspect of the present application, a method of manufacturing an electronic device case assembly is presented. Referring to fig. 5, the method includes:

01: providing a middle plate

According to an embodiment of the present invention, as understood in conjunction with fig. 1, there is provided a middle plate 10, wherein the middle plate 10 includes a middle plate body 11 and a metal middle frame 12, the metal middle frame 12 is disposed along a circumferential direction of the middle plate body 11 and connected to the middle plate body 11, and the middle plate body 11 includes metal magnesium or a magnesium alloy, for example, a high magnesium alloy having a magnesium content of not less than 85 wt%. The middle plate body, the metal middle frame, the connection mode and structure of the middle plate body and the metal middle frame are described in the foregoing, and are not described in detail here. In addition, it is understood that the thicknesses of the middle plate body and the metal middle frame are not particularly limited, and those skilled in the art can flexibly select the thicknesses according to actual situations.

02: forming a ceramic oxide layer with micropores on the surface of the middle plate body by adopting a micro-arc oxidation method

The roughness of the ceramic oxide layer 20 having pores formed on the surface of the middle plate body 11, the pore size of the pores, and the thickness of the ceramic oxide layer according to an embodiment of the present invention have been described in detail previously and will not be described again. In addition, when the ceramic oxide layer is formed on the surface of the middle plate body, the entire middle plate may be micro-arc oxidized in order to ensure that the ceramic oxide layer is formed on all surfaces of the middle plate body. Wherein, before the micro-arc oxidation of the centering plate, a neutral degreasing agent can be adopted to degrease the centering plate in advance so as to remove oil stains and other impurities on the surface of the centering plate, then twice water washing is carried out in sequence so as to fully remove the degreasing agent and residual impurities, and then the micro-arc oxidation is carried out; after the micro-arc oxidation is completed, the middle plate can be washed by water to remove the electrolyte on the surface of the middle plate, and then the middle plate is transferred to an ultrasonic hot water washing device to be washed by water again to remove the electrolyte remained in the micropores of the ceramic oxide layer.

It can be understood that when the middle plate is transferred to the ultrasonic hot water washing device for washing again, acid liquor in the environment and impurities or deposited acid on the surface of the clamping device can also pollute the middle plate in the transfer process, so that the middle plate and the clamping device can be simultaneously sprayed and washed in the transfer process, the ultrasonic hot water washing is performed after the spraying and washing is completed, and the middle plate is dried after the ultrasonic hot water washing is completed. It is understood that the conditions for drying the middle plate after ultrasonic hot water washing are not particularly limited, and those skilled in the art can flexibly select the conditions according to actual conditions. In addition, when the surface of the medium plate is degreased, the type of the selected neutral degreasing agent is not particularly limited, and those skilled in the art can flexibly select the neutral degreasing agent according to actual conditions, for example, the neutral degreasing agent may include, but is not limited to, sodium gluconate, EDTA-4Na, sodium tripolyphosphate, sodium dihydrogen phosphate, alkylphenol, aliphatic polyether, and the like.

According to the embodiment of the invention, for the magnesium-containing middle plate body 11, especially for the high-magnesium alloy middle plate body, the electrolyte adopted by the micro-arc oxidation method may include: the electrolyte comprises phytic acid and/or soluble phytate, calcium-containing electrolyte, soluble alkali, aluminate and/or aluminum hydroxide and a buffering agent, wherein the buffering agent comprises at least one selected from sodium silicate, sodium carbonate and boron, and the pH value of the electrolyte can be 9-12. The functions of the components in the electrolyte, the adverse effects of too large and too small pH values, and the beneficial effects of selecting the electrolyte have been described in detail above, and are not described in detail herein.

According to the embodiment of the invention, for the magnesium-containing middle plate body 11, especially for the high-magnesium alloy middle plate body, the electrolyte adopted by the micro-arc oxidation method may include: 30-40 g/L potassium phytate, 3-50 g/L calcium-containing electrolyte, 30-50 g/L sodium hydroxide, 10-20 g/L sodium carbonate, 5-50 g/L sodium silicate, 30-50 g/L boron and 5-50 g/L aluminate and/or aluminum hydroxide; aiming at the electrolyte, the process parameters of the micro-arc oxidation method can meet at least one of the following conditions: the voltage is 350V-370V, the time is 4 min-5 min, the duty ratio is 10% -12%, the frequency is 800 Hz-1200 Hz, and the temperature is 25-35 ℃. The reasons and the beneficial effects of the electrolyte composition and the reasons and the beneficial effects of the microarc oxidation process parameter control are explained in detail in the foregoing, and are not described again here.

03: forming a resin layer on the surface of the oxide ceramic layer far away from the middle plate body by electrophoresis

The material and thickness of the resin layer 30 formed on the surface of the ceramic oxide layer 20 according to the embodiment of the present invention have been described in detail above, and will not be described herein again. In addition, the entire middle plate may be handled when preparing the resin layer. Wherein, the middle plate with the ceramic oxide layer can be degreased by adopting a neutral degreasing agent in advance, then washed twice to fully remove the degreasing agent and residual impurities, and then subjected to electrophoresis; and after the electrophoresis is finished, washing twice to remove residual electrophoretic liquid, and finally drying.

It can be understood that, in order to avoid the pollution to the middle plate caused by impurities such as acid liquor in the environment, impurities on the surface of the clamping device or deposited acid liquor, the middle plate and the clamping device can be sprayed and washed simultaneously after being washed, and then dried. It is understood that the conditions for drying the board are not particularly limited, and those skilled in the art can flexibly select the conditions according to actual situations, for example, drying at 200 ℃ for about 30min may be performed. In addition, the kind of the neutral degreasing agent selected when degreasing the middle plate with the ceramic oxide layer is not particularly limited, and those skilled in the art can flexibly select the neutral degreasing agent according to the actual situation, for example, the neutral degreasing agent may include but is not limited to sodium gluconate, EDTA-4Na, sodium tripolyphosphate, sodium dihydrogen phosphate, alkylphenol, aliphatic polyether, coco quaternary ammonium salt, silicone, polyether, and the like.

According to an embodiment of the present invention, the electrophoretic fluid used in the electrophoresis method may include: 16-24 wt% of epoxy resin emulsion, 3-5 wt% of color paste and the balance of water, wherein the epoxy resin emulsion comprises epoxy resin and an auxiliary agent. Wherein in the epoxy resin emulsion, the content of the epoxy resin can be 55-65 wt%, and the auxiliary agent can comprise a cosolvent; alternatively, the adjuvant may include a co-solvent and a cross-linking agent. The process parameters of the electrophoresis method can meet at least one of the following conditions: the voltage is 188V-192V, the temperature is 27-29 ℃, and the time is 10 min. The reason and the beneficial effect of the composition of the electrophoretic fluid and the reason and the beneficial effect of the micro-electrophoresis process parameter are selected and described in detail in the foregoing, and are not described again here.

According to the embodiment of the invention, when the metal middle frame is made of the aluminum alloy material, the corrosion resistance, the wear resistance and the decoration of the middle frame can be improved through anodic oxidation, namely, the method for preparing the electronic equipment shell assembly can further comprise the following steps: and carrying out anodic oxidation on the metal middle frame. In addition, in order to realize the effective proceeding of the anodic oxidation, the method can also comprise removing the resin layer and the ceramic oxide layer on the surface of the metal middle frame before the anodic oxidation. It is understood that the flow of the anodic oxidation process and the main chemical liquid are not particularly limited, and those skilled in the art can flexibly select the anodic oxidation process according to the actual situation, for example, as follows: degreasing, performing NaOH alkaline etching at 60 ℃, stripping a black film by using nitric acid, performing chemical polishing by using 98 wt% of sulfuric acid and 85 wt% of phosphoric acid at the temperature of more than 80 ℃, stripping the black film by using dilute nitric acid, sanding by using ammonium bifluoride, stripping a black magic by using dilute nitric acid, performing secondary chemical polishing by using 98 wt% of sulfuric acid, 85 wt% of phosphoric acid and concentrated nitric acid at the temperature of more than 80 ℃, performing anodic oxidation at 18 ℃ and under the condition of sulfuric acid with the concentration of 200g/L, and sealing holes under the conditions of more than 95 ℃ and the pH value of 5-6.

It can be understood that the method for manufacturing an electronic device housing assembly according to the embodiment of the present application and the electronic device housing assembly described above are proposed based on the same inventive concept, and all the features and advantages described for the electronic device housing assembly described above are also applicable to the method for manufacturing an electronic device housing assembly, and are not repeated herein.

In summary, the method for manufacturing an electronic device housing assembly according to the above embodiments of the present application and the electronic device housing assembly described above have at least the following advantages: 1. the method has the advantages of low process cost, high efficiency and high yield, can also obviously improve the corrosion resistance, hardness, wear resistance and heat resistance of the shell assembly, reduce the overall weight of the shell assembly and realize better appearance and texture of the shell; 2. the problem that the high-magnesium alloy middle plate is easy to corrode can be effectively solved; 3. the problems that the voltage adopted by the existing micro-arc oxidation process is high, the thickness of the obtained micro-arc oxidation film layer is only a few micrometers, the process cost is high and the efficiency is low can be solved; 4. after the metal middle frame is subjected to anodic oxidation, the surface appearance of the middle plate is not abnormal, and the middle plate can pass reliability limit tests, such as a boiling test, a neutral salt spray test and a cold and hot shock test.

In yet another aspect of the present application, an electronic device is presented. The electronic device includes: the foregoing electronic device housing assembly 100, or an electronic device housing assembly manufactured using the foregoing method of manufacturing an electronic device housing assembly; the display screen assembly is connected with the electronic equipment shell assembly 100, and an installation space is defined between the display screen assembly and the electronic equipment shell assembly; and the mainboard is arranged in the mounting space and is electrically connected with the display screen assembly. Thus, the electronic device has all the features and advantages of the previous electronic device housing assembly and the previous method for preparing the electronic device housing assembly, which are not described herein again. Generally, the electronic equipment has light weight as a whole, and is good in corrosion resistance, wear resistance, heat resistance and hardness.

It is understood that the specific type of the electronic device in the present application is not particularly limited, and those skilled in the art can flexibly select the electronic device according to the actual situation, for example, the electronic device may be a mobile phone, a smart watch, a palm computer, a PDA, or a notebook computer. The electronic device may be any of various types of computer system devices that are mobile or portable and perform wireless communication. In particular, the electronic device may be a mobile or smart phone, a portable gaming device, a laptop, a PDA, a portable internet appliance, a music player and data storage device, other handheld devices and devices such as a watch, an in-ear headset, a pendant, a headset, etc., and may also be other wearable devices (e.g., a Head Mounted Device (HMD) such as electronic glasses, electronic clothing, an electronic bracelet, an electronic necklace, an electronic tattoo, or a smart watch). In some embodiments of the present application, as shown in fig. 6, the electronic device may be a mobile phone, wherein the electronic device housing assembly 100 may serve as a rear cover of the mobile phone. It is understood that the electronic device includes the necessary structure or components of the conventional electronic device in addition to the electronic device housing assembly, and the mobile phone includes the necessary structure or components of the conventional mobile phone such as a glass cover, a display panel, an audio processing module, a camera module, a touch screen, and the like in addition to the electronic device housing assembly.

It is specifically stated that, in the description of the present application, unless explicitly stated or limited otherwise, the terms "connected" and "connected" are to be interpreted broadly, e.g. as a fixed connection, a detachable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The present invention is described below with reference to specific examples, which are intended to illustrate the present invention and should not be construed as limiting the scope of the present invention. The examples do not specify particular techniques or conditions, according to techniques or conditions described in the literature in the field or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

Example 1

1.1, provide the medium plate, the medium plate includes magnesium alloy body and aluminum alloy center, and the aluminum alloy center sets up and links to each other with the magnesium alloy body along the circumference of magnesium alloy body.

1.2 forming a ceramic oxide layer with micropores on the surface of the middle plate by using a micro-arc oxidation method

The micro-arc oxidation electrolyte comprises the following components: 35g/L of potassium phytate, 30g/L of calcium-containing electrolyte, 15g/L of sodium carbonate, 50g/L of sodium silicate, and the weight ratio of boron: 40g/L, anhydrous aluminum hydroxide: 35g/L, sodium hydroxide: 40g/L and the solvent is water.

Micro-arc oxidation parameter conditions: the voltage is 360V, the time is 4.5min, the temperature is 30 ℃, the duty ratio is 10 percent, and the frequency is 800 Hz.

The thickness of the formed oxide ceramic layer is 10 to 15 μm, and the roughness Ra is 0.7 to 1.1. Wherein, the roughness, the micropore appearance and the pore diameter of the surface of the oxidized ceramic layer are respectively shown in fig. 7 and fig. 8, and as can be seen from fig. 8, the pore diameter of the micropores forming the surface of the oxidized ceramic layer is 2.8 μm-6.3 μm.

1.3, forming a resin layer on the surface of the ceramic oxide layer far away from the middle plate by adopting an electrophoresis method

The composition of the electrophoretic fluid is as follows: 20 wt% of epoxy resin emulsion, 4 wt% of color paste and solvent water. Wherein the proportion of the epoxy resin in the epoxy resin emulsion is 60 wt%, the proportion of the cosolvent is 40 wt%, and the color paste is carbon powder.

Electrophoresis parameter conditions: the voltage is 190V, the temperature is 28 ℃, and the time is 10 min.

Drying after electrophoresis is finished, wherein the drying condition is as follows: 200 deg.C, 30 min.

The thickness of the formed epoxy resin layer is 45-50 μm.

And (3) carrying out reliability limit test on the treated middle plate:

(a) extreme Water boil test

Boiling test conditions: 80 ℃ and 2 h.

And (3) testing results: the appearance is free from any abnormality.

(b) Neutral salt spray test

Salt spray test conditions: neutral salt spray: 5 wt% NaCl; the pH value is 6.5-7.2; temperature of the test cell: 35 +/-1 ℃; test time 24 h.

And (3) testing results: the appearance is not abnormal.

(c) Series test

1) Accelerated anode + neutral salt spray or copper salt test

Carrying out anodic oxidation on the obtained middle plate aluminum alloy middle frame, and then carrying out neutral salt spray test:

and (3) anode testing: alkaline etching (NaOH, 60 ℃), desmutting (nitric acid), chemical polishing (98 wt% sulfuric acid and 85 wt% sulfuric acid, >80 ℃), desmutting (dilute nitric acid), sanding (ammonium bifluoride), desmutting (dilute nitric acid), secondary chemical polishing (98 wt% sulfuric acid, 85 wt% phosphoric acid and concentrated nitric acid, >80 ℃), anodic oxidation (sulfuric acid, 200g/L, 18 ℃), sealing (pH: 5-6, >95 ℃).

Neutral salt spray: 5 wt% NaCl; the pH value is 6.5-7.2; temperature of the test cell: 35 +/-1 ℃; test time 96 h.

Carrying out copper salt accelerated test after carrying out anodic oxidation on the obtained middle plate aluminum alloy middle frame:

the anode test conditions were as above.

Copper salt accelerated test: the temperature is 50 +/-1 ℃, the concentration of NaCl is 50g/L, and the concentration of copper dichloride is 0.02 g/L; the pH value is 3-3.3 (adjusted by glacial acetic acid), and the test time is as follows: and (6) 96 h.

2) Anode + high temperature high humidity storage

And (3) carrying out high-temperature and high-humidity storage test after carrying out anodic oxidation on the obtained middle plate aluminum alloy middle frame:

the anode test conditions were as above.

High temperature and high humidity storage conditions: temperature: 65. + -.1 ℃ humidity: 93 ± 2%, time: 168 h.

3) Anode + cold-hot impact

And (3) carrying out a cold and hot impact test after carrying out anodic oxidation on the obtained middle plate aluminum alloy middle frame:

the anode test conditions were as above.

Cold and hot shock conditions: high temperature: 75 ℃, low temperature: -40 ℃, switching time: 1h, 40 times.

Test results of the series test: the appearance is not abnormal after the test.

Comparative example 1

The micro-arc oxidation electrolyte comprises the following components: 20g/L of potassium phytate, 30g/L of calcium-containing electrolyte, 15g/L of sodium carbonate, 50g/L of sodium silicate, and the weight ratio of boron: 40g/L, anhydrous aluminum hydroxide: 35g/L, sodium hydroxide: 40g/L and the solvent is water.

Micro-arc oxidation parameter conditions: the voltage is 360V, the time is 2.5min, the temperature is 30 ℃, the duty ratio is 10 percent, and the frequency is 800 Hz.

The thickness of the formed oxide ceramic layer is 5 to 10 μm, and the roughness Ra is 0.3 to 0.7.

The thickness of the formed epoxy resin layer is 45-50 mu m.

Carrying out anodic oxidation on the middle plate aluminum alloy middle frame obtained by treatment: appearance of the middle plate after the anode: the electrophoretic paint surface bubbled (as shown in fig. 9), losing the protective effect on the substrate. Reason analysis: the oxidized ceramic layer has low roughness and poor bonding strength with the epoxy resin layer, and the micro-arc oxidation layer has small thickness and weak corrosion resistance, so that the base material is corroded in the anodic oxidation process, the electrophoresis layer falls off, and bubbles are generated.

Comparative example 2

The thickness of the formed oxide ceramic layer is 10 to 15 μm, and the roughness Ra is 0.7 to 1.1.

Electrophoresis parameter conditions: the voltage is 190V, the temperature is 28 ℃, and the time is 4 min.

The thickness of the formed epoxy resin layer is 25-30 μm.

Carrying out anodic oxidation on the middle plate aluminum alloy middle frame obtained by treatment: appearance of the middle plate after the anode: the electrophoretic paint cracks at the edge or hole location (as shown in fig. 10). Reason analysis: the electric resin layer is thin, the water vapor barrier effect is poor, and in the anodic oxidation process, corrosive elements such as hydrogen ions penetrate through the electrophoretic layer to react with the micro-arc oxidation layer and the base material, so that the base material or the electrophoretic layer falls off.

Comparative example 3

The micro-arc oxidation electrolyte comprises: 35g/L potassium phytate, 30g/L calcium-containing electrolyte, 15g/L sodium carbonate, 50g/L sodium silicate, boron: 40g/L, anhydrous aluminum hydroxide: 35g/L, sodium hydroxide: 40g/L and the solvent is water.

The composition of the electrophoretic fluid is as follows: 20 wt% of epoxy resin emulsion, 2 wt% of color paste and solvent water. Wherein the proportion of the epoxy resin in the epoxy resin emulsion is 60 wt%, the proportion of the cosolvent is 40 wt%, and the color paste is carbon powder.

The thickness of the formed epoxy resin layer is 45-50 μm.

Carrying out anodic oxidation on the middle plate aluminum alloy middle frame obtained by treatment: appearance of the middle plate after the anode: the electrophoretic paint cracks at the edge or hole site and the electrophoretic paint edge chalks (as shown in FIG. 11). Reason analysis: the content of the color paste is low, and the reduction effect on the shrinkage rate of the resin is not obvious.

Results and conclusions: in the embodiment of the application, the micro-arc oxidation is adopted to form the ceramic oxide layer with micropores on the surface of the middle plate, and then the electrophoresis is adopted to generate a layer of epoxy resin coating on the surface of the ceramic oxide layer to protect the surface of the magnesium alloy, so that the magnesium alloy product is prevented from being corroded due to high activity of magnesium in the processing or using process. The technical scheme can enable the magnesium alloy to withstand the etching of strong acid (98 wt% of sulfuric acid, 85 wt% of phosphoric acid or concentrated nitric acid) and withstand the long-time water boiling of high-temperature acidic liquid (1 hr, the temperature is 96 ℃, and the pH value is 5-6). After anodic oxidation, the product can pass 96h neutral salt spray test and 96h copper salt accelerated test, and general processing or surface treatment or corrosion of the magnesium alloy surface in a use scene can be avoided from a design end.

In the description of the present application, reference to the description of the terms "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.

Claims

1. An electronic device housing assembly, comprising:

the middle plate comprises a middle plate body and a metal middle frame, the metal middle frame is arranged along the circumferential direction of the middle plate body and is connected with the middle plate body, and the middle plate body comprises metal magnesium or magnesium alloy;

the ceramic oxide layer is arranged on the surface of the middle plate body, and micropores are prefabricated on the surface of the ceramic oxide layer;

the resin layer is arranged on the surface of one side, far away from the middle plate body, of the ceramic oxide layer.

2. The electronic device housing assembly of claim 1, wherein the pores of the ceramic oxide layer have a pore size of 2 μ ι η to 6.5 μ ι η; and/or the roughness Ra of the ceramic oxide layer is 0.7-1.3.

3. The electronic device housing assembly of claim 1, wherein the ceramic oxide layer has a thickness of 10 μm to 15 μm, and the resin layer has a thickness of 40 μm to 50 μm.

4. The electronic device housing assembly of any one of claims 1-3, wherein the resin layer is an epoxy layer having a colored paste dispersed therein.

5. The electronic device housing assembly of claim 4, wherein the color paste comprises carbon powder.

6. The electronic device housing assembly of claim 1 or 5, wherein the metal middle frame is an aluminum middle frame, and an aluminum oxide layer is disposed on a surface of the aluminum middle frame.

7. An electronic device housing assembly according to any one of claims 1 to 3, wherein the magnesium content of the midplane body is not less than 85 wt%.

8. The electronic device housing assembly of any one of claims 1 to 3, wherein the middle plate body is made of a rare earth magnesium alloy.

9. A method of making an electronic device housing assembly, comprising:

providing a middle plate, wherein the middle plate comprises a middle plate body and a metal middle frame, the metal middle frame is arranged along the circumferential direction of the middle plate body and is connected with the middle plate body, and the middle plate body comprises metal magnesium or magnesium alloy;

forming a ceramic oxide layer with micropores on the surface of the middle plate body by adopting a micro-arc oxidation method;

and forming a resin layer on the surface of the ceramic oxide layer on the side far away from the middle plate body by adopting an electrophoresis method.

10. The method of claim 9, wherein the electrolyte used in the micro-arc oxidation process comprises: phytic acid and/or soluble phytate, calcium-containing electrolyte, soluble base, aluminate and/or aluminium hydroxide, a buffer comprising at least one selected from sodium silicate, sodium carbonate and boron; and/or the pH value of the electrolyte is 9-12.

11. The method of claim 10, wherein the electrolyte comprises: 30-40 g/L of potassium phytate, 3-50 g/L of calcium-containing electrolyte, 30-50 g/L of sodium hydroxide, 10-20 g/L of sodium carbonate, 5-50 g/L of sodium silicate, 30-50 g/L of boron, and 5-50 g/L of aluminate and/or aluminum hydroxide.

12. The method according to claim 10 or 11, characterized in that the process parameters of the micro-arc oxidation method meet at least one of the following conditions: the voltage is 350V-370V, the time is 4 min-5 min, the duty ratio is 10% -12%, the frequency is 800 Hz-1200 Hz, and the temperature is 25-35 ℃.

13. The method according to claim 9, wherein the electrophoresis method uses an electrophoresis liquid comprising: 16-24 wt% of epoxy resin emulsion, 3-5 wt% of color paste and the balance of water, wherein the epoxy resin emulsion comprises epoxy resin and an auxiliary agent.

14. The method according to claim 13, wherein in the epoxy resin emulsion, the content of the epoxy resin is 55-65 wt%, and the auxiliary agent comprises a cosolvent; alternatively, the adjuvant comprises a co-solvent and a cross-linking agent.

15. The method according to claim 13 or 14, wherein the process parameters of the electrophoresis method satisfy at least one of the following conditions: the voltage is 188V-192V, the temperature is 27-29 ℃, and the time is 10 min.

16. The method of claim 9, further comprising: and carrying out anodic oxidation on the metal middle frame.

17. The method of claim 16, further comprising: and removing the resin layer and the ceramic oxide layer on the surface of the metal middle frame before the anodic oxidation.

18. An electronic device, comprising:

the electronic device housing component of any one of claims 1 to 8, or the electronic device housing component produced by the method of any one of claims 9 to 17;

the display screen assembly is connected with the electronic equipment shell assembly, and an installation space is defined between the display screen assembly and the electronic equipment shell assembly; and

the mainboard is arranged in the installation space and electrically connected with the display screen assembly.