TWI668334B - Aluminum alloy shell and its preparation method and personal electronic devices - Google Patents

Abstract

The invention discloses an aluminum alloy casing, a preparation method thereof and a personal electronic device, the aluminum alloy casing comprising an aluminum alloy base body (1) and an oxide film layer (2) having slits thereon (1) 3) the oxide film layer (2) comprises an inner anodized film layer (21) and an outer anodized film layer (22); the inner anodized film layer (21) has an inner anodized film layer nanopore The outer anodized film layer (22) has an outer anodized film layer nanopore, and the inner layer of the anodized film layer and the outer layer of the anodized film layer are each independently filled with a dyeing dye. The aluminum alloy casing is seen as a continuous metal layer from the outer surface of the casing, and the slit in the metal layer can be used as an antenna groove. The oxide film layer on the surface of the metal layer plays a good shielding effect, so that the surface of the slit is invisible, the casing is clean and smooth, and has a good metal texture.

Description

Aluminum alloy casing, preparation method thereof and personal electronic device

The present invention relates to the field of material chemistry, and in particular to an aluminum alloy casing, a method of preparing the same, and a personal electronic device.

The mobile phone antenna is a device for receiving signals on a mobile phone. Currently, smart phones on the market are mostly built-in antennas, which requires that the back cover of the mobile phone cannot shield the signal. Metals absorb electromagnetic waves very strongly. When wifi, 2G, and 3G signals are injected into metal materials, absorption and attenuation are generated. Electromagnetic waves cannot reach the signal receiving module, resulting in signal shielding. Therefore, for the metal body phone, how to solve the signal shielding problem is one of the keys to its design and manufacture. At present, metal body mobile phones use antenna slot and injection molding to solve the problem of body signal shielding, such as the upper and lower antenna slots of HTC ONE, the side antenna slots of iphone5/5s, etc., although it can prevent signal shielding. However, it caused certain damage to the overall structure of the metal body, affecting the cleanliness and continuity of its appearance. At the same time, the plastic visible in the outer casing destroyed the overall metal texture of the fuselage.

It is an object of the present invention to provide an aluminum alloy casing, a method of manufacturing the same, and a personal electronic device in which the appearance of the antenna slot of the aluminum alloy casing is not visible.

In order to achieve the above object, a first aspect of the present invention provides an aluminum alloy casing comprising an aluminum alloy substrate and an oxide film layer covering the surface of the aluminum alloy substrate; the aluminum alloy substrate having a slit thereon The slit has an outer opening and an inner opening respectively on the outer side surface and the inner side surface of the aluminum alloy base, and the oxide film layer closes the outer opening of the slit; the oxide film layer includes an inner anodized film layer and an outer layer anode An oxide film layer; the inner anodized film layer has an inner anodized film layer nanopore, and the outer anodized film layer has an outer anodized film layer nanopore, and the inner anodized film layer has a pore size of a nanopore 30-100 nm; the outer anodized film layer has a pore diameter of 10-50 nm, and the pore diameter of the inner anodized film layer nanohole is larger than the pore diameter of the outer anodized film layer nanopore, the inner layer anode The oxide film layer nanopore and the outer anodized film layer are each independently filled with a dyeing dye, and the dyeing dye includes an organic dye.

Preferably, the density of the inner anodized film nanopore is 550-900/m 2 , and the density of the outer anodized film nanopore is 200-550/m 2 .

Preferably, the organic dye comprises at least one of the Oku 420 dye, the 415 dye, and the 419 dye.

Preferably, the oxide film layer has a color depth L value of 0-30, a color │A│ value of 0-2, a color │B│ value of 0-2, and a dyeing depth of more than 23 μm.

Preferably, the oxide film layer has a hardness of 320 HV _0.1 -500 HV _0.1 .

Preferably, the inner anodized film layer has a thickness of from 1 to 60 μm μm; and the outer anodized film layer has a thickness of from 1 to 60 μm.

Preferably, the slit has a width of 0.5 to 10 mm, and the number of the slits is 1-10.

Preferably, the slit divides the aluminum alloy substrate into at least two pieces insulated from each other.

Preferably, the slit is filled with an insulator.

A second aspect of the present invention provides a method for preparing an aluminum alloy casing, the method comprising the steps of: a. performing an first anodizing treatment on the aluminum alloy substrate to obtain a first anodized aluminum alloy substrate, the first Anodizing treatment, the aluminum alloy substrate is covered with an outer anodized film layer containing an outer anodized film layer nanopore, the outer anodized film layer nanopore has a pore diameter of 10-50 nm; b, the step obtained in step a The first anodized aluminum alloy substrate is subjected to a first dyeing treatment to obtain a first dyed aluminum alloy substrate, and the first dyeing treatment causes the outer anodized film layer to be filled with a dyeing dye in the nanopore; c. The first dyed aluminum alloy substrate obtained in step b is subjected to a second anodizing treatment to obtain a second anodized aluminum alloy substrate, and the second anodizing treatment causes the aluminum alloy substrate to be covered with an inner layer anode An inner anodized film layer of an oxide film layer nanopore having a pore diameter of 30-100 nm; d, the first step obtained in step c The second anodized aluminum alloy substrate is subjected to a second dyeing treatment to obtain a second dyed aluminum alloy substrate, and the second dyeing treatment causes the inner anodized film layer nanopore and/or the outer anodized film layer. The rice hole is filled with a dyeing dye; e, the aluminum alloy base portion of the second dyed aluminum alloy substrate obtained in step d is partially removed to form a slit, and the slit is outside the aluminum alloy substrate An outer opening and an inner opening are respectively formed on the surface and the inner side surface, and the oxide film layer closes the outer opening of the slit.

Preferably, the density of the inner anodized film nanopore is 550-900/m 2 , and the density of the outer anodized film nanopore is 200-550/m 2 .

Preferably, the first anodizing treatment comprises contacting the aluminum alloy substrate with a first aqueous solution containing sulfuric acid and oxalic acid, and the content of sulfuric acid is 90-260 parts by weight based on 1000 parts by weight of the first aqueous solution, oxalic acid The content is 4-25 parts by weight; the second anodizing treatment comprises contacting the aluminum alloy substrate with a second aqueous solution containing sulfuric acid, and the content of sulfuric acid is 110-360 parts by weight based on 1000 parts by weight of the second aqueous solution. .

Preferably, the first anodizing treatment is performed under a pulse current, and the condition of the first anodizing treatment is: the pulse waveform of the current is a forward square wave pulse, the duty ratio is 30-99%, and the frequency of the current 100-1000 Hz, current density is 2-8 A/dm ² , voltage is 30-60 V, temperature is 0-20 ° C, time is 10-80 min; the second anodizing treatment is performed under direct current, the second anodizing The treatment conditions are: a voltage of 13-20 V, a temperature of 5-25 ° C, and a time of 5-60 min.

Preferably, the first dyeing treatment comprises contacting the first anodized aluminum alloy substrate with an organic dye; and the second dyeing treatment comprises contacting the second anodized aluminum alloy substrate with an organic dye; The organic dye includes at least one of the Oku 420 dye, the 415 dye, and the 419 dye.

Preferably, the conditions of the first dyeing treatment are: a temperature of 25-65 ° C, a time of 5-50 min; and a condition of the second dyeing treatment: a temperature of 25-65 ° C, and a time of 5-50 min.

Preferably, the outer anodized film layer has a color depth L of 0-30, a color │A│ value of 0-2, a color │B│ value of 0-2, and a dyeing depth of more than 23 μm.

Preferably, the method further comprises: sealing the second dyed aluminum alloy substrate obtained in step d, and then performing the operation of step e.

Preferably, in step e, the outer surface and a portion of the inner surface of the second dyed aluminum alloy substrate are covered with a protective layer, and then the oxide film layer and the aluminum alloy substrate of the portion not covered with the protective layer are removed. The slit is formed, the removal including at least one of laser engraving removal, numerically controlled machine tool removal, and chemical etching removal.

Preferably, the method further includes the step of filling the slit with an insulator.

A third aspect of the invention provides an aluminum alloy casing prepared by the method of the second aspect of the invention.

According to a fourth aspect of the invention, there is provided a personal electronic device comprising the aluminum alloy casing of the first or third aspect of the invention.

With the above technical solution, the present invention provides that the aluminum alloy casing is a continuous metal layer as seen from the outer surface of the casing, and the slit in the metal layer can be used as an antenna groove. The oxide film layer on the surface of the metal layer plays a good shielding effect, so that the slit is not visible, the casing is clean and smooth, and has a good metal texture. In addition, the higher hardness of the oxide film layer gives the aluminum alloy casing excellent wear resistance, shock resistance and corrosion resistance.

Other features and advantages of the invention will be described in detail in the detailed description which follows.

The specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the disclosure.

A first aspect of the present invention provides an aluminum alloy casing comprising an aluminum alloy base 1 and an oxide film layer 2 covering the surface of the aluminum alloy base 1; the aluminum alloy base 1 has a slit 3 thereon, The slit 3 has an outer opening 4 and an inner opening 5 respectively on the outer side surface and the inner side surface of the aluminum alloy base 1, and the oxide film layer 2 closes the outer opening 4 of the slit; the oxide film layer 2 may include at least a layer of an inner anodized film layer 21 and at least one outer layer of anodized film layer 22; the inner anodized film layer 21 has an inner anodized film layer nanopore, and the outer layer anodized film layer 22 has an outer layer anodized Membrane nanopore, the inner anodized film layer nanopore and the outer anodized film layer nanopore are each independently filled with a dye, and the dye includes an organic dye. In the present invention, the "outer surface" of the aluminum alloy substrate refers to the side away from the device body when used in the rear case of a personal electronic communication device such as a mobile phone, and the "inside surface" refers to the device. One side of the fuselage. The aluminum alloy casing provided by the invention can be used for the back shell of a personal electronic communication device such as a mobile phone, and the slit can be used as an antenna slot without signal shielding.

1 is a structural view of a specific embodiment of an aluminum alloy casing provided by the first aspect of the present invention. As shown in FIG. 1, the oxide film layer 2 includes an inner anodized film layer 21 and an outer layer anode. Oxide film layer 22.

According to the first aspect of the invention, the inner anodized film layer nanopore may have a pore diameter of 30-100 nm; the outer anodized film layer nanopore may have a pore diameter of 10-50 nm, and the inner layer anodized film layer nanometer. The pore size of the pores is larger than the pore diameter of the nanopores of the outer anodized film layer. The inner anodized film layer nanopore may have a density of 550-900 particles/square micrometer, and the outer anodized film layer nanopore may have a density of 200-550 pieces/square micrometer. The pore size of the nanopore in the oxide film layer can be measured by a JSM-7600F thermal field scanning electron microscope. The surface of the unsealed anodized film is photographed at a magnification of 100,000 times, and the nanopore per unit area is calculated. The average pore diameter is the pore diameter of the nanopore in the oxide film layer. The density of the nanopore can be measured by a JSM-7600F thermal field scanning electron microscope. When the magnification is 20000-100000 times, the unsealed oxide film is photographed on the surface to calculate the nanopore or nai per unit area. The number of rice tubes is the density of the nanopores.

According to the first aspect of the present invention, in order to make the oxide film layer have a shielding property so that the slit is apparently invisible, the inner layer of the anodized film layer and the outer layer of the anodized film layer may be independently filled in each other. There are dyeing dyes. The dyeing dye may include an organic dye, and further, the organic dye may include at least one of the Oku 420 dye, the 415 dye, and the 419 dye. The oxide film layer 2 is filled with a dyeing dye so that the oxide film layer 2 has a color depth L value of 0-30, a color │A│ value of 0-2, a color │B│ value of 0-2, and a dyeing depth of more than 23 μm. The meanings of the color depth L value, the color │ A │ value and the color │ B │ value are well known to those skilled in the art, and the color depth L value refers to the depth of the color, and the darker the color, the smaller the L value, the lighter the color. The larger the value; the color │A│ value refers to the absolute value of the red-green phase value measured by the color difference meter. When the A value is positive, it represents red, the A value is negative, it represents green; the color │B│ value refers to the yellow color measured by the color difference meter. The absolute value of the blue phase value. When the B value is positive, it represents yellow. When the B value is negative, it represents blue. In the present invention, the color depth L value, the color │ A │ value, and the color │ B │ value are measured using an ICS-90 ion chromatograph of Dai An China Co., Ltd. The depth of dyeing refers to the thickness of the film from the surface of the oxide film to the saturation or near saturation of the dye in the lower layer of the nanopore.

The aluminum alloy casing provided by the first aspect of the invention has high hardness, and the oxide film layer 2 may have a hardness of 320 HV _0.1 -500 HV _0.1 , and has good wear resistance, shock resistance and corrosion resistance. The surface hardness of the oxide film layer can be measured by directly measuring the surface hardness of the oxide film by the HV-100 type instrument of Shanghai Aolong Xingdi Testing Equipment Co., Ltd. The test conditions are: pressure 1N, holding time 10s.

According to the first aspect of the invention, the inner anodized film layer 21 may have a thickness of from 1 to 60 μm, preferably from 5 to 30 μm; and the outer anodized film layer 22 may have a thickness of from 1 to 60 μm, preferably 5 - 30 μm.

According to the first aspect of the invention, the width of the slit 3 may be any width suitable as an antenna groove, and may be, for example, 0.5 to 10 mm, preferably 1 to 3 mm. The number and position of the slits 3 can be designed according to actual needs. For example, the number of the slits 3 can be 1-10, preferably 1-3. The presence of the slit 3 can separate the aluminum alloy base 1 into at least two pieces insulated from each other; the presence of the slit 3 can also partially partition the aluminum alloy base 1, and the separated aluminum alloy base 1 can also be a unitary piece. In order to ensure that the antenna in the personal electronic communication device can receive the signal and ensure the continuity of the aluminum alloy casing, the slit 3 can be filled with an insulator, and the type of the insulator can be conventionally used in the art, for example, a gel material or the like. .

The aluminum alloy casing provided by the first aspect of the invention is a continuous metal layer as seen from the outer side surface of the casing, and the slit in the metal layer is filled with an insulator, which can be used as an antenna groove. The oxide film layer on the surface of the metal layer is filled with the dyeing dye, and since the pore diameter of the inner anodized film layer nanopore is larger than that of the outer anodized film layer, the dyeing dye is more easily and more deposited in the inner layer anodizing. Membrane layer. The oxide film layer has a certain color depth and plays a good shielding effect, so that the slit is invisible, the casing is clean and smooth, and has a good metal texture. In addition, the higher hardness of the oxide film layer gives the aluminum alloy casing excellent wear resistance, shock resistance and corrosion resistance.

A second aspect of the present invention provides a method for preparing an aluminum alloy casing, the method comprising the steps of: a. performing an first anodizing treatment on the aluminum alloy substrate to obtain a first anodized aluminum alloy substrate, the first Anodizing treatment, the aluminum alloy substrate is covered with an outer anodized film layer containing an outer anodized film layer nanopore, the outer anodized film layer nanopore has a pore diameter of 10-50 nm; b, the step obtained in step a The first anodized aluminum alloy substrate is subjected to a first dyeing treatment to obtain a first dyed aluminum alloy substrate, and the first dyeing treatment causes the outer anodized film layer to be filled with a dyeing dye in the nanopore; c. The first dyed aluminum alloy substrate obtained in step b is subjected to a second anodizing treatment to obtain a second anodized aluminum alloy substrate, and the second anodizing treatment causes the aluminum alloy substrate to be covered with an inner layer anode An inner anodized film layer of an oxide film layer nanopore having a pore diameter of 30-100 nm; d, the first step obtained in step c The second anodized aluminum alloy substrate is subjected to a second dyeing treatment to obtain a second dyed aluminum alloy substrate, and the second dyeing treatment causes the inner anodized film layer nanopore and/or the outer anodized film layer. The rice hole is filled with a dyeing dye; e, the aluminum alloy base portion of the second dyed aluminum alloy substrate obtained in step d is partially removed to form a slit, and the slit is outside the aluminum alloy substrate An outer opening and an inner opening are respectively formed on the surface and the inner side surface, and the oxide film layer closes the outer opening of the slit. The density of the nanopores of the inner anodized film layer may be 550-900 pieces/square micrometer, and the density of the nanopores of the outer anodized film layer may be 200-550 pieces/square micrometer.

According to a second aspect of the present invention, prior to the first anodizing treatment of the aluminum alloy substrate, a pretreatment may be performed, which is well known to those skilled in the art and may include, for example, alkali etching, neutralization, and polishing. Washing and other steps.

According to a second aspect of the invention, the first anodizing treatment may comprise contacting the aluminum alloy substrate with a first aqueous solution containing sulfuric acid and oxalic acid. Wherein, the content of sulfuric acid may be 90-260 parts by weight, preferably 160-190 parts by weight, based on 1000 parts by weight of the first aqueous solution; the content of oxalic acid may be 4-25 parts by weight, preferably 6- 10 parts by weight. The first anodizing treatment is performed under a pulse current, and the first anodizing treatment condition may be: a temperature of 0-20 ° C, a pulse waveform of the current is a forward square wave pulse, and a duty ratio of 30-99%, The current has a frequency of 100-1000 Hz, a current density of 2-8 A/dm ² , a voltage of 30-60 V, and a time of 10-80 min. In actual operation, the aluminum alloy substrate may be subjected to a first anodizing treatment in an anodizing bath containing the first aqueous solution under the above conditions.

According to the second aspect of the present invention, in order to make the oxide film layer have opacity so that the slit is apparently invisible, the first anodizing treatment may be performed on the first anodized aluminum alloy substrate after the first anodizing treatment. deal with. The first dyeing treatment may include contacting the first anodized aluminum alloy substrate with an organic dye, and the organic dye may include at least one of the Oku 420 dye, the 415 dye, and the 419 dye, and the concentration of the organic dye may be suitable. In any ratio, preferably, the concentration of the organic dye is 10-20 g/L. The conditions of the first dyeing treatment may be: a temperature of 25 to 65 ° C, preferably 40 to 60 ° C, and a time of 5 to 50 min, preferably 20 to 40 min. The first dyeing treatment causes the outer anodized film layer to be filled with a dyeing dye in the nanopore.

According to a second aspect of the invention, the second anodizing treatment may comprise contacting the aluminum alloy substrate with a second aqueous solution containing sulfuric acid. The content of sulfuric acid may be 110-360 parts by weight, preferably 180-200 parts by weight, based on 1000 parts by weight of the second aqueous solution. The second anodizing treatment is performed under direct current, and the second anodizing treatment may be performed under the conditions of a voltage of 13-20 V, a temperature of 25-65 ° C, and a time of 5-50 min. In actual operation, after the first dyeing treatment, the aluminum alloy substrate can be quickly transferred to the anodizing bath containing the second aqueous solution for the second anodizing treatment. The hardness of the oxide film layer formed on the surface of the aluminum alloy substrate is 320-500 HV _0.1 .

According to the second aspect of the present invention, in order to further improve the hiding property of the oxide film layer, the second anodizing treatment may be subjected to a second dyeing treatment on the second anodized aluminum alloy substrate. The second dyeing treatment may include contacting the second anodized aluminum alloy substrate with an organic dye, and the organic dye may include at least one of the Oku 420 dye, the 415 dye, and the 419 dye, and the concentration of the organic dye may be suitable. In any ratio, preferably, the concentration of the organic dye is 10-20 g/L. The second dyeing treatment may be carried out at a temperature of 25 to 65 ° C, preferably 40 to 60 ° C, for a period of 5 to 50 minutes, preferably 20 to 40 minutes. The second dyeing treatment causes the inner anodized film layer nanopore and/or the outer anodized film layer nanopore to be filled with a dyeing dye.

According to the second aspect of the invention, the operations of steps a to d can be repeated a plurality of times, and then the operation of step e is performed. The multiple dyeing treatment can make the outer anodized film layer have a color depth L of 0-30, a color │A│ value of 0-2, a color │B│ value of 0-2, and a dyeing depth of more than 23 μm.

According to the second aspect of the present invention, in order to improve the anti-pollution and anti-corrosion performance of the oxide film layer, the method may further include: sealing the second dyed aluminum alloy substrate obtained in the step d, and then performing the sealing The operation of step e. The method for sealing the hole is well known to those skilled in the art, for example, it may be a high temperature sealing hole or a cold sealing hole, and the high temperature sealing hole may be an aluminum alloy substrate covered with an oxide film layer at a temperature of 90-95 ° C. The water is treated for 15-20 min; the cold-sealed hole may be an aluminum alloy substrate covered with an oxide film layer at room temperature in contact with a plugging liquid containing nickel fluoride or the like. The sealing hole is preferably a high temperature sealing hole.

According to the second aspect of the present invention, those skilled in the art can understand that in the step of anodizing, the outer surface and the inner surface of the aluminum alloy substrate are covered with an oxide film layer, so that in order to form the slit of the aluminum alloy substrate, In the step e, the outer surface and the inner side surface of the second dyed aluminum alloy substrate may be covered with a protective layer, and then the oxide film layer and the aluminum alloy substrate of the portion not covered with the protective layer are removed, that is, removed. The portion is an oxide film layer of an inner side surface of the aluminum alloy substrate which is not covered with the protective layer and an aluminum alloy substrate to form the slit. The protective layer is a substance which is physically or chemically covered on the surface of the aluminum alloy substrate so that the oxide film layer and the aluminum alloy substrate covered with the protective layer portion are not damaged, and may be, for example, an ink coating or a silicone film layer. The ink may be of a conventional type on the market, for example, may be a UV ink; the silicone film may also be commercially available, for example, a green silicone protective film of the GHT2545G model available from Shenzhen Ximeng Electronics Co., Ltd. After the protective layer is covered, the oxide film and the aluminum alloy substrate on the surface of the aluminum alloy substrate not covered with the protective layer may be removed by a method including, but not limited to, laser engraving removal, numerically controlled machine tool removal, and chemical etching removal. The operation steps and conditions of the laser engraving and chemical etching can be used conventionally in the art. For example, the conditions of the laser engraving can be: power 70-110, laser light travel speed of 1980-2020 mm/s, frequency of 10-50 kHz; The chemical etching may include: contacting the aluminum alloy substrate with an etching solution containing ferric chloride and hydrochloric acid, wherein the content of the ferric chloride is 70-90 parts by weight based on 100 parts by weight of the etching solution, and hydrochloric acid The content is 4-8 parts by weight, the water content is 10-15 parts by weight, the chemical etching temperature may be 20-35 ° C, and the time may be 10-30 minutes. The laser engraving and CNC can remove the oxide film layer and part of the aluminum alloy substrate, and the chemical etching can further remove all the aluminum alloy substrates.

According to a second aspect of the invention, after the oxide film layer and the aluminum alloy substrate which are not covered with the protective layer portion are removed, the method further comprises the step of filling the slit with an insulator. The kind of the insulator may be conventionally used in the art, and may be, for example, a gel material or the like. In order to further make the slit apparently invisible, the color of the gelatinous material is preferably other colors that are non-transparent. Solid particles may also be added to the gel material to produce a reflective effect, which may further improve the concealability of the slit. The solid particles may include a metal element or a metal oxide, and the metal element may be silver and/or aluminum, etc., the metal oxide may It is titanium dioxide and/or aluminum oxide.

According to the second aspect of the invention, after the colloid is filled into the slit, the aluminum alloy casing has been substantially prepared, and only the protective layer is removed. If the protective layer is an ink coating, the method of removing the protective layer may be performed by using a paint stripper which can dissolve the ink coating but does not react with the oxide film layer, the aluminum alloy substrate and the insulator in the slit. For immersion, the paint stripper is commercially available, for example, it can be a paint remover of SH-665 model purchased from Dongguan Sihui Surface Treatment Technology Co., Ltd.

A third aspect of the invention provides an aluminum alloy casing prepared by the method of the second aspect of the invention.

According to a fourth aspect of the invention, there is provided a personal electronic device comprising the aluminum alloy casing of the first or third aspect of the invention.

The invention is further illustrated by the following examples, but does not limit the invention.

In the examples, the morphology of the oxide film layer, the pore diameter of the nanopore in the oxide film layer, and the density of the nanopore were measured by a scanning electron microscope of JSM-7600F model manufactured by JEOL Ltd., and the magnification was 100,000 times. Example

The aluminum alloy substrate is pretreated, including alkali etching, neutralization, chemical polishing and water washing. Then, the pretreated aluminum alloy substrate is placed in an anodizing bath containing an aqueous solution containing sulfuric acid and oxalic acid to perform a first anodizing treatment, and the content of sulfuric acid is 180 parts by weight based on 1000 parts by weight of the aqueous solution, and oxalic acid is used. The content is 8 parts by weight, the condition is: the pulse waveform of the current is a forward square wave pulse, the duty ratio is 80%, the current frequency is 800 Hz, the current density is 4 A/dm ² , the temperature is 10 ° C, and the time is 25 min. An outer anodized film layer having a thickness of 15 μm was obtained, the outer pore anodized film layer had a pore diameter of 25 nm, and the outer anodized film layer had a nanopore density of 365 particles/square micrometer. Then, the aluminum alloy substrate is placed in an organic dye tank for the first dyeing treatment, the dye is Okuno 420 dye, the concentration is 20 g/L, and the dyeing treatment condition is: the temperature is 50 ° C, and the time is 30 min. After the first dyeing treatment is finished, the aluminum alloy substrate and the hanger are quickly transferred to an anodizing bath containing an aqueous solution containing sulfuric acid for a second anodizing treatment, and the content of sulfuric acid is 190 based on 1000 parts by weight of the aqueous solution. In parts by weight, the anode conditions are: a voltage of 15 V, a temperature of 19 ° C, and a time of 35 min, thereby forming an inner anodized film layer having a thickness of 15 μm and an inner anodized film between the outer anodized film layer and the aluminum alloy substrate. The pore size of the layer of the nanopore is 30 nm, and the density of the inner anodized film layer is 760 particles/square micrometer. Then, the second anodized aluminum alloy substrate is placed in an organic dye tank for the second dyeing treatment, the dye is Okuno 420 dye, the concentration is 20 g/L, and the dyeing treatment condition is: the temperature is 50 ° C, the time is 30 min. . The aluminum alloy substrate was then placed in water at 95 ° C for high temperature sealing for 20 min. The outer surface and part of the inner surface of the aluminum alloy substrate are covered with a silicone protective film (a green silicone protective film of GHT2545G model purchased from Shenzhen Ximeng Electronics Co., Ltd.) to form a protective layer, and the uncovered portion is subjected to laser engraving to remove The oxide film layer and part of the aluminum alloy substrate of the part are as follows: the power is 70%, the laser light travel speed is 3000 mm/s, the frequency is 80 KHz, and then the aluminum alloy substrate is placed in a container containing an etching solution for chemical etching and etching. The composition and content of the liquid are: 80 parts by weight of the etching solution, the content of ferric chloride is 80 parts by weight, the content of hydrochloric acid is 8 parts by weight, the content of water is 12 parts by weight, and the etching temperature is room temperature. The etching time was 10 minutes. After the chemical etching, the aluminum alloy substrate in the region not covered by the protective layer was completely removed to form one slit, and the width of the slit was 2 mm. Fill the slit with a white gelatinous material. Finally, the silicone protective film layer is removed to obtain the aluminum alloy casing provided in the embodiment. The scanning electron micrograph of the oxide film layer of the aluminum alloy shell prepared in this embodiment is shown in Fig. 2. It can be seen that the oxide film layer has a composite film interface of an inner anodized film layer and an outer anodized film layer. Scanning electron micrographs of the cross section of the outer anodized film layer and the cross section of the anodized film layer of the inner layer are shown in Fig. 3 and Fig. 4. It can be seen that the inner anodized film layer has a nanopore having a larger pore diameter. Scanning electron micrographs of the surface of the outer anodized film layer and the bottom of the anodized film layer are shown in Figures 5 and 6. Comparative example 1

The difference from the embodiment is that the present comparative example does not perform the steps of the second anodizing treatment and the second dyeing treatment. Comparative example 2

The difference from the embodiment is that the present comparative example does not perform the steps of the first anodizing treatment and the first dyeing treatment. Test example

The dyeing depth, color depth L value, color A value, color B value, and hardness of the aluminum alloy casing of the examples and Comparative Examples 1-2 were tested. The results are shown in Table 1.

The test method of dyeing depth is: using Axio Imsger Alm type metallographic microscope of Zeiss Optical Instrument International Trading Co., Ltd., the depth of dyeing is judged by observing the difference of the color of the cross section of the anodized film. The depth of dyeing refers to the thickness of the film from the surface of the oxide film to the saturation or near saturation of the dye in the lower layer of the nanopore.

The test method of the color depth L value, the color A value and the color B value is: using the ICS-90 ion chromatograph instrument of Dai An China Co., Ltd., the measurement is performed by directly measuring the surface.

The test method of hardness is: using Shanghai Aolong Xingdi Testing Equipment Co., Ltd., HV-100 type instrument, by directly measuring the surface hardness of the oxide film, the test conditions are: pressure 1N, dwell time 10s.

The test method of the appearance effect is as follows: taking the photographed aluminum alloy shell to take photos, using the photoshop software to take the color of the antenna slot portion and other parts of the aluminum alloy shell in the photograph, and the color of the antenna slot portion is recorded as color1 (R ₁ , G ₁ , B ₁ ), the color of other parts is recorded as color2(R ₂ , G ₂ , B ₂ ), and the average value V of the color component deviation of color1 and color2 is calculated according to formula (I), when V is between 0.8 and 1.2 The difference between the color of the film layer and the other parts of the antenna is difficult to distinguish with the naked eye, that is, the antenna slot is not visible, and the antenna slot is visible. Formula (I)

Then, the prepared aluminum alloy casing is placed on a horizontal surface, and the surface of the aluminum alloy casing is irradiated with light of 45° with a horizontal plane, and the photoshop software is used to find whether the surface of the aluminum alloy casing has shadows or bright spots. When the oxide film layer of the antenna groove portion of the aluminum alloy case has defects such as protrusions or depressions, the protrusions or depressions are illuminated by light to form a shadow or a bright spot, and vice versa, there is no shadow or bright spot. Table 1

It can be seen that the aluminum alloy casing provided by the present invention sees a continuous metal layer from the outer surface of the casing, and the oxide film layer on the surface of the metal layer plays a good shielding effect, so that the slit is invisible and the casing is clean and smooth. Has a good metal texture. In addition, the higher hardness of the oxide film layer gives the aluminum alloy casing excellent wear resistance, shock resistance and corrosion resistance.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments, and various simple modifications of the technical solutions of the present invention can be made within the scope of the technical idea of the present invention. These simple variations are within the scope of the invention.

It should be further noted that the specific technical features described in the above specific embodiments may be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention has various possible combinations. The method will not be explained otherwise.

In addition, any combination of the various embodiments of the present invention may be carried out as long as it does not deviate from the idea of the present invention, and it should also be regarded as the disclosure of the present invention.

1‧‧‧Aluminum alloy matrix

2‧‧‧Oxide film

3‧‧‧Slit

4‧‧‧Outside opening

5‧‧‧ inside opening

21‧‧‧Inner anodized film

22‧‧‧Outer anodized film

The drawings are intended to provide a further understanding of the disclosure, and are intended to be a part of the description. In the drawings: FIG. 1 is a structural view of a specific embodiment of an aluminum alloy casing provided by the present invention; FIG. 2 is an inner anodized film layer and an outer anodized film of an aluminum alloy casing prepared by the embodiment. Sectional scanning electron micrograph of the layer interface; Fig. 3 is a scanning electron micrograph of the outer layer of the anodized film layer of the aluminum alloy shell prepared in the example; Fig. 4 is an anodizing of the inner layer of the aluminum alloy shell prepared by the embodiment Scanning electron micrograph of the cross-section of the film; Fig. 5 is a scanning electron micrograph of the surface of the outer anodized film of the aluminum alloy shell prepared in the example; Fig. 6 shows the inner anodized film of the aluminum alloy shell prepared by the embodiment of Fig. Bottom scanning electron micrograph.

Claims (20)

An aluminum alloy casing comprising an aluminum alloy substrate and an oxide film layer covering the surface of the aluminum alloy substrate; wherein the aluminum alloy substrate has a slit on the aluminum An outer side opening and an inner side opening are respectively defined on the outer side surface and the inner side surface of the alloy base, and the oxide film layer closes the outer opening of the slit; the oxide film layer comprises an inner anodized film layer and an outer anodized film layer The inner anodized film layer has an inner anodized film layer nanopore, and the outer anodized film layer has an outer anodized film layer nanopore, and the inner layer of the anodized film layer has a pore diameter of 30-100 nm; the outer anodized film layer has a pore diameter of 10-50 nm, and the inner layer of the anodized film layer has a pore diameter larger than a pore diameter of the outer anodized film layer nanopore, and the inner layer is anodized. The film nanopore and the outer anodized film layer are each independently filled with a dyeing dye, and the dyeing dye comprises an organic dye. The aluminum alloy casing according to claim 1, wherein the density of the inner anodized film nanopore is 550-900/mm, and the density of the outer anodized film nanopore is 200-550 / square micron. The aluminum alloy casing according to claim 1, wherein the organic dye comprises at least one of the Oku 420 dye, the 415 dye, and the 419 dye. The aluminum alloy casing according to claim 1, wherein the oxide film layer has a color depth L of 0-30, a color │A│ value of 0-2, and a color │B│ value of 0-2. The dyeing depth is greater than 23 μm. The aluminum alloy casing according to claim 1, wherein the oxide film layer has a hardness of 320 HV _0.1 -500 HV _0.1 . The aluminum alloy casing according to claim 1, wherein the inner anodized film layer has a thickness of from 1 to 60 μm; and the outer anodized film layer has a thickness of from 1 to 60 μm. The aluminum alloy casing according to claim 1, wherein the slit has a width of 0.5 to 10 mm, and the number of the slits is 1-10. The aluminum alloy casing according to claim 1 or 7, wherein the slit divides the aluminum alloy base into at least two pieces insulated from each other. The aluminum alloy casing according to claim 1, wherein the slit is filled with an insulator. A method for preparing an aluminum alloy casing, comprising the steps of: a. performing a first anodizing treatment on the aluminum alloy substrate to obtain the first anodized aluminum alloy substrate, the first anode Oxidation treatment, the aluminum alloy substrate is covered with an outer anodized film layer containing an outer anodized film nanopore, the outer anodized film layer nanopore has a pore diameter of 10-50 nm; b, the step obtained in step a The first anodized aluminum alloy substrate is subjected to a first dyeing treatment to obtain a first dyed aluminum alloy substrate, and the first dyeing treatment is such that the outer anodized film layer is filled with a dyeing dye in the nanopore; c. The first dyed aluminum alloy substrate obtained in step b is subjected to a second anodizing treatment to obtain a second anodized aluminum alloy substrate, and the second anodizing treatment causes the aluminum alloy substrate to be covered with a An inner anodized film layer of an inner anodized film layer of nanopores, the inner layer of the anodized film layer has a pore diameter of 30-100 nm; d, which is obtained in step c The second anodized aluminum alloy substrate is subjected to a second dyeing treatment to obtain a second dyed aluminum alloy substrate, and the second dyeing treatment is performed to make the inner anodized film layer nanopore and/or outer layer anode The nanopore of the oxide film layer is filled with a dyeing dye; e, the aluminum alloy substrate portion of the second dyed aluminum alloy substrate obtained in step d is partially removed to form a slit, wherein the slit is The outer side surface and the inner side surface of the aluminum alloy base body are respectively provided with an outer side opening and an inner side opening, and the oxide film layer closes the outer opening of the slit. The method of claim 10, wherein the density of the inner anodized film nanopore is 550-900/m 2 , and the density of the outer anodized film nanopore is 200-550. / square micron. The method of claim 10, wherein the first anodizing treatment comprises contacting the aluminum alloy substrate with a first aqueous solution containing sulfuric acid and oxalic acid, based on 1000 parts by weight of the first aqueous solution. The content of sulfuric acid is 90-260 parts by weight, and the content of oxalic acid is 4-25 parts by weight; the second anodizing treatment comprises contacting the aluminum alloy substrate with a second aqueous solution containing sulfuric acid, and using 1000 parts by weight of the second aqueous solution as The basis, the content of sulfuric acid is 110-360 parts by weight. The method of claim 12, wherein the first anodizing treatment is performed under a pulse current, and the condition of the first anodizing treatment is: a pulse waveform of the current is a forward square wave pulse, and the duty is The ratio is 30-99%, the current frequency is 100-1000 Hz, the current density is 2-8 A/dm ² , the voltage is 30-60 V, the temperature is 0-20 ° C, and the time is 10-80 min; the second anodizing treatment The second anodizing treatment is carried out under the conditions of a voltage of 13-20 V, a temperature of 5-25 ° C, and a time of 5-60 min. The method of claim 10, wherein the first dyeing treatment comprises contacting the first anodized aluminum alloy substrate with an organic dye; the second dyeing treatment comprises oxidizing the second anodizing The treated aluminum alloy substrate is contacted with an organic dye; the organic dye includes at least one of the Oku 420 dye, the 415 dye, and the 419 dye. The method of claim 14, wherein the condition of the first dyeing treatment is: a temperature of 25-65 ° C, a time of 5-50 min; and a condition of the second dyeing treatment: a temperature of 25-65 °C, time is 5-50min. The method of claim 10, wherein the outer anodized film layer has a color depth L of 0-30, a color │A│ value of 0-2, and a color │B│ value of 0-2. The dyeing depth is greater than 23 μm. The method of claim 10, wherein the method further comprises: sealing the second dyed aluminum alloy substrate obtained in step d, and then performing the operation of step e. The method of claim 10, wherein in step e, the outer surface and a portion of the inner surface of the second dyed aluminum alloy substrate are covered with a protective layer, and then the portion of the protective layer is not covered. The oxide film layer and the aluminum alloy substrate are removed to form the slit, and the removal includes at least one of laser engraving removal, numerically controlled machine tool removal, and chemical etching removal. The method of claim 10, wherein the method further comprises the step of filling the slit with an insulator. A personal electronic device, comprising the aluminum alloy casing according to any one of claims 1 to 9.