CN106926627A - A kind of Al-alloy casing and preparation method thereof - Google Patents

Abstract

The invention discloses an aluminum alloy shell, wherein, the outer surface of the aluminum alloy shell has a convex portion and a concave portion, and an oxide film of the convex portion and an electrophoretic decoration layer of the convex portion are sequentially formed on the convex portion, and the concave portion Concave oxide film or concave electrophoretic decoration layer, the surface of the convex electrophoretic decoration layer has a gloss of 90-105, the surface of the concave oxide film has a gloss of 5-25 or the surface of the concave electrophoretic decoration layer Has a gloss level of 0.5-5. The invention also discloses a preparation method of the aluminum alloy shell. The aluminum alloy shell of the present invention has a convex-concave three-dimensional texture, and has a high-gloss convex surface and a non-high-gloss concave surface.

Description

A kind of aluminum alloy casing and preparation method thereof

technical field

The invention relates to an aluminum alloy shell and a preparation method thereof.

Background technique

With the development of electronic technology, more and more electronic products appear in our lives, such as mobile phones, tablet computers, e-books, etc. Most of the shells of these electronic products use plastic shells. The requirements of the industry continue to increase, and more and more electronic products use metal casings. On the one hand, the metal casing has a better protective effect than the plastic casing, and on the other hand, its unique metal texture is also an important reason why the metal casing has attracted more and more attention.

At present, the main purpose of surface treatment of metal casings of electronic products is decoration and protection. Among the existing surface treatment methods for metal casings, anodic oxidation, micro-arc oxidation and hard anodic oxidation All can achieve the above two effects, but in terms of decoration, the appearance of the treated metal shell is single in decoration and texture.

Therefore, the metal casing obtained by adopting the above-mentioned surface treatment technology has a single decorative appearance and texture. It is necessary to develop an aluminum alloy shell with good appearance decoration and three-dimensional texture and a preparation method thereof.

Contents of the invention

In order to solve the problem of single appearance decoration and single texture of the mobile phone casing in the prior art, the purpose of the present invention is to provide an aluminum alloy casing and a preparation method thereof. Convex and non-high gloss concave.

In order to achieve the above object, the present invention provides an aluminum alloy casing, which is characterized in that the outer surface of the aluminum alloy casing has a convex portion and a concave portion, and the convex portion oxide film and the convex portion electrophoresis are sequentially formed on the convex portion. The decorative layer, the concave part has a concave oxide film or the concave electrophoretic decoration layer, the surface of the convex electrophoretic decoration layer has a gloss of 90-105, the surface of the concave oxide film has a gloss of 5-25 or the The surface of the concave electrophoretic decoration layer has a glossiness of 0.5-5

Preferably, the height difference between the convex part and the concave part is 0.05-0.2mm.

Preferably, the convex oxide film and the concave oxide film have different colors.

The present invention also provides a method for preparing an aluminum alloy shell, wherein the preparation method sequentially includes:

Step a, performing the first anodic oxidation on the surface of the aluminum alloy shell substrate,

Step b, forming an electrophoretic decoration layer on the surface of the aluminum alloy shell base through the first electrophoresis,

Step c, mechanically polishing the surface of the aluminum alloy shell substrate after the first electrophoresis,

Step d, engraving a texture pattern on the surface of the aluminum alloy shell substrate by means of laser engraving,

Step e, performing second electrophoresis or second anodic oxidation or hard anodic oxidation or micro-arc oxidation on the textured pattern portion on the surface of the aluminum alloy housing base.

Preferably, the first anodic oxidation and/or the second anodic oxidation includes forming an anodic film by anodic oxidation after pre-treating the surface of the aluminum alloy housing substrate.

Preferably, the pretreatment includes: using 50-60g/L sodium hydroxide to carry out alkali etching at 50-70°C for 3-20s, using 200-300ml/L nitric acid to carry out neutralization at 15-25°C for 10 seconds -20s, use chemical polishing solution containing 650-750ml/L phosphoric acid and 350-250ml/L sulfuric acid at 90°C for 5-20s.

Preferably, the anodic oxidation includes using 190-200 g/L sulfuric acid to oxidize the surface of the aluminum alloy shell substrate at an anode voltage of 13-17V at 10-21° C. for 15-50 min.

Preferably, the first electrophoresis and/or the second electrophoresis includes electrophoresis using an electrophoresis solution with a pH value of 7-9 at a temperature of 28-32°C and a voltage of 140-200V for 1-3 minutes.

Preferably, the hard anodizing includes oxidation at 5-12° C. for min using a hard anodizing solution.

Preferably, the hard anodizing solution contains 170-270g/L sulfuric acid and 8-20g/L oxalic acid.

Preferably, the micro-arc oxidation includes oxidation at 20-30° C. for 40-100 min using a micro-arc oxidation electrolyte.

Preferably, the micro-arc oxidation electrolyte contains 0.02-0.05 mol/L sodium silicate and 0.03-0.07 mol/L sodium hydroxide.

Preferably, the preparation method further comprises after step b and before step d:.

The present invention also provides an aluminum alloy shell, which is prepared by the preparation method of the aluminum alloy shell of the present invention.

Through the above technical scheme, first anodize the surface of the aluminum alloy shell substrate first, then form an electrophoretic decoration layer through the first electrophoresis, and then perform mechanical polishing on the surface of the aluminum alloy shell substrate after the first electrophoresis, and then use radium Carving engraves texture patterns on the surface of the aluminum alloy shell base to form a concave-convex effect, by performing second electrophoresis or second anodic oxidation or hard anodic oxidation or micro-arc oxidation on the texture pattern on the surface of the aluminum alloy shell base , thereby producing an aluminum alloy shell with a convex-concave three-dimensional texture and having a high-gloss convex surface and a non-high-gloss concave surface.

Other features and advantages of the present invention will be described in detail in the following detailed description.

detailed description

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

According to the aluminum alloy casing of the present invention, wherein, the outer surface of the aluminum alloy casing has a convex portion and a concave portion, and the convex portion oxide film and the convex portion electrophoretic decoration layer are sequentially formed on the convex portion, and the concave portion has a concave portion Oxide film or concave electrophoretic decoration layer, the surface of the convex electrophoretic decoration layer has a gloss of 90-105, the surface of the concave oxide film has a gloss of 5-25 or the surface of the concave electrophoretic decoration layer has a gloss of 0.5 Glossiness of -5. By forming protrusions and recesses on the outer surface of the aluminum alloy housing, the aluminum alloy housing can have a convex-concave three-dimensional texture. In addition, by polishing the oxide film of the protrusions formed on the surface of the protrusions, the protrusions The surface of the oxide film presents a high-gloss effect. In the present invention, the glossiness refers to the extent to which the surface of the oxide film is close to a mirror surface, which can be measured by methods known in the art, for example, it can be measured using a gloss meter.

In the present invention, the method for forming the protrusions and recesses on the outer surface of the aluminum alloy shell, and the method for forming the oxide film on the protrusions on the protrusions and the oxide film on the recesses on the recesses are as described in the method for preparing the aluminum alloy shell described later. describe.

According to the preparation method of the aluminum alloy shell of the present invention, in a preferred situation, different colors can be formed in the oxide film on the convex portion and the oxide film on the concave portion. By forming different colors in the oxide film of the convex part and the oxide film of the concave part, the aluminum alloy shell can have film layers of different colors.

According to the preparation method of the aluminum alloy shell of the present invention, the preparation method comprises in sequence:

Step a, performing the first anodic oxidation on the surface of the aluminum alloy shell substrate,

Step b, performing anti-etching protection on the area on the surface of the aluminum alloy shell substrate where a pattern needs to be formed to form a protective film,

Step c, mechanically polishing the surface of the aluminum alloy shell substrate after the first electrophoresis,

Step d, forming a pattern layer in the area where the pattern needs to be formed by etching,

Step e, deprotecting the area where the patterned layer is formed on the surface of the aluminum alloy shell substrate,

Step e, performing a second anodic oxidation on the surface of the base body of the aluminum alloy shell.

According to the preparation method of the aluminum alloy shell of the present invention, in order to obtain the highlighting effect of the aluminum alloy shell, after the electrophoretic decoration layer is formed by the first electrophoresis, the surface of the base body of the aluminum alloy shell after the first electrophoresis is mechanically polished. The anodized film layer on the surface of the aluminum alloy shell substrate is polished by a mechanical polishing machine, so that the overall thickness of the anodized film layer is reduced by about 2 μm, so that the surface of the anodized film presents a bright and reflective effect, forming a high-gloss surface with high gloss , and then carry out laser engraving to make the surface have a concave-convex difference of 0.05-0.2mm through laser engraving, resulting in the effect of concave-convex three-dimensional texture.

The aluminum alloy shell substrate used in the present invention is not particularly limited, and various aluminum alloy shell bodies of industrial standard 1000-7000 series, die-cast aluminum alloy or die-cast aluminum alloy can be used; the aluminum alloy shell body described in the present invention The shell base is an aluminum alloy shell body of various shapes and structures commonly used by those skilled in the art, and the present invention is not particularly limited. Various shapes and structures of the aluminum alloy shell base can be completed by machining. The aluminum alloy casing of the present invention can be used for casings of mobile phones, tablet computers, electron beams, and the like.

According to the preparation method of the aluminum alloy shell of the present invention, in step a, before the first anodic oxidation is performed on the surface of the aluminum alloy shell base, the surface of the aluminum alloy shell base can be subjected to sandblasting or wire drawing treatment. In the present invention, the sandblasting can be carried out by methods known in the art. For example, after the surface of the aluminum alloy shell substrate is polished with a grinder, ceramic sand of 80-400 mesh can be used to spray the aluminum alloy at 0.1-0.24 MPa. The surface of the base body of the shell is sandblasted to make the surface of the base body of the aluminum alloy shell appear sandy. The wire-drawing treatment can be performed by methods known in the art, for example, the surface of the aluminum alloy shell base can be drawn with a wire-drawing machine with a wire-drawing wheel of No. 400-1200 to obtain the required wire-drawn texture from coarse to fine.

According to the preparation method of the aluminum alloy shell of the present invention, preferably, the first anodic oxidation and/or the second anodic oxidation may include forming an anodic film by anodic oxidation after pretreatment of the surface of the aluminum alloy shell substrate. There is no special requirement on the thickness of the formed anode film, usually 6-10 μm.

According to the preparation method of the aluminum alloy shell of the present invention, preferably, the purpose of the pretreatment is to clean the surface of the aluminum alloy shell base to ensure that a uniform anodic film is formed on the surface of the aluminum alloy shell base through anodic oxidation, It can include: use 50-60g/L sodium hydroxide at 50-70°C for 3-20s, use 200-300ml/L nitric acid at 15-25°C for 10-20s, use 650 - 750ml/L phosphoric acid and 350-250ml/L sulfuric acid chemical polishing solution at 90-95°C for 5-20s.

According to the preparation method of the aluminum alloy shell of the present invention, the anodic oxidation method can use an anodic oxidation method known in the art, preferably, the anodic oxidation can include using 190-200g/L sulfuric acid to convert the aluminum alloy shell The surface of the body matrix is oxidized at an anode voltage of 13-17V and 10-21°C for 15-50min.

According to the preparation method of the aluminum alloy shell of the present invention, the electrophoretic decoration layer is formed on the surface of the aluminum alloy shell base through the first electrophoresis and/or the second electrophoresis, which can effectively protect and decorate the aluminum alloy shell. The first electrophoresis and/or the second electrophoresis may include electrophoresis using an electrophoresis solution with a pH value of 7-9 at a temperature of 28-32° C. and a voltage of 140-200 V for 1-3 minutes. As long as the electrophoretic liquid can form an electrophoretic decorative layer on the surface of the aluminum alloy shell substrate, the electrophoretic liquid used in this field can be used, for example, the matte paint (WNO-1) made by Nippon Shimizu Co., Ltd. and Nippon Shimizu Co., Ltd. can be used. The company's varnish (NNO-4) is an electrophoretic fluid mixed with a weight ratio of 7:3 (the solid content of the electrophoretic fluid is 8-14% by weight). The varnish (NNO-4) in the electrophoretic fluid solvent contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6% by weight of other components; matte paint (WNO -1) Contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

According to the preparation method of the aluminum alloy shell of the present invention, various conventional radium engraving methods in the field can be used to engrave the texture pattern on the surface of the aluminum alloy shell base by the method of radium engraving, for example, a laser radium engraving machine is used for engraving , exposing the aluminum alloy substrate on the surface of the aluminum alloy shell base to form a texture pattern with a depth of 0.1 mm.

According to the method for preparing an aluminum alloy shell of the present invention, preferably, the hard anodizing may include using a hard anodizing solution to oxidize at 5-12° C. for 25-50 min. More preferably, the hard anodizing solution may contain 170-270 g/L of sulfuric acid and 8-20 g/L of oxalic acid. The electrical parameters of the hard anodizing include: the pulse type is a forward square wave pulse, the duty cycle is 60-80%, the frequency is 500-1000Hz, and the current density is 3-7A/dm ² .

According to the method for preparing an aluminum alloy shell of the present invention, preferably, the micro-arc oxidation may include oxidation at 20-30° C. for 40-100 min using a micro-arc oxidation electrolyte. More preferably, the micro-arc oxidation electrolyte may contain 0.02-0.05 mol/L sodium silicate and 0.03-0.07 mol/L sodium hydroxide. The oxidation forward voltage of micro-arc oxidation can be 400-600V.

Example

The preparation method of the aluminum alloy casing of the present invention will be further described by enumerating examples below. However, the present invention is not limited to the examples listed below.

Example 1

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 15°C, in a concentration of 250ml/L After neutralizing in nitric acid for 10s, wash it twice with deionized water; then, at 90°C, polish it in a chemical polishing solution containing 650ml/L phosphoric acid and 350ml/L sulfuric acid for 10s, then wash it with deionized water for 2 times then, at 15°C, neutralize in 250ml/L nitric acid for 10s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.05mm.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 15°C, in a concentration of 250ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components. The aluminum alloy casing of the present invention is obtained.

Example 2

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 70°C, the base material of the aluminum alloy shell was etched for 20s in an aqueous solution of sodium hydroxide with a concentration of 60g/L, and then washed twice with deionized water; then, at 20°C, at a concentration of 300ml/L After neutralizing in nitric acid for 20s, wash it twice with deionized water; then, at 93°C, polish it in a polishing solution containing 700ml/L phosphoric acid and 300ml/L sulfuric acid for 10s, then wash it with deionized water for 2 then, at 20°C, neutralize in 300ml/L nitric acid for 20s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 195g/L as the bath solution, the anode voltage is 17V, the temperature is 10°C, and the oxidation time is 50min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 32°C, voltage is 200V, time is 1min, and pH is 7; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.2mm.

At 70°C, the base material of the aluminum alloy shell was etched for 20s in an aqueous solution of sodium hydroxide with a concentration of 60g/L, and then washed twice with deionized water; then, at 25°C, at a concentration of 300ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 32°C, voltage is 200V, time is 1min, and pH is 7; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components. The aluminum alloy casing of the present invention is obtained.

Example 3

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After neutralizing in nitric acid for 10s, wash it twice with deionized water; then, at 95°C, polish it in a chemical polishing solution containing 650ml/L phosphoric acid and 350ml/L sulfuric acid for 10s, then wash it with deionized water for 2 times then, at 25°C, neutralize in 250ml/L nitric acid for 10s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.1 mm.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min. The aluminum alloy casing of the present invention is obtained.

Example 4

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After neutralizing in nitric acid for 10s, wash it twice with deionized water; then, at 95°C, polish it in a chemical polishing solution containing 650ml/L phosphoric acid and 350ml/L sulfuric acid for 10s, then wash it with deionized water for 2 times then, at 25°C, neutralize in 250ml/L nitric acid for 10s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.1 mm.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

The aluminum alloy casing substrate was oxidized at 10° C. for 25 minutes using a hard anodizing solution containing 200 g/L sulfuric acid and 15 g/L oxalic acid. The electrical parameters of the hard anodizing include: the pulse type is a positive square wave pulse, the duty cycle is 70%, the frequency is 800Hz, and the current density is 5A/dm ² . The aluminum alloy casing of the present invention is obtained.

Example 5

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After neutralizing in nitric acid for 10s, wash it twice with deionized water; then, at 95°C, polish it in a chemical polishing solution containing 650ml/L phosphoric acid and 350ml/L sulfuric acid for 10s, then wash it with deionized water for 2 times then, at 25°C, neutralize in 250ml/L nitric acid for 10s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.1 mm.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

The aluminum alloy casing substrate was oxidized at 5° C. for 30 min using a hard anodizing solution containing 170 g/L sulfuric acid and 20 g/L oxalic acid. The electrical parameters of the hard anodizing include: the pulse waveform is a positive square wave pulse, the duty cycle is 80%, the frequency is 500Hz, and the current density is 3A/dm ² . The aluminum alloy casing of the present invention is obtained.

Example 6

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After neutralizing in nitric acid for 10s, wash it twice with deionized water; then, at 95°C, polish it in a chemical polishing solution containing 650ml/L phosphoric acid and 350ml/L sulfuric acid for 10s, then wash it with deionized water for 2 times then, at 25°C, neutralize in 250ml/L nitric acid for 10s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.1mm.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

The aluminum alloy casing substrate was oxidized at 12° C. for 25 minutes using a hard anodizing solution containing 270 g/L sulfuric acid and 20 g/L oxalic acid. The electrical parameters of the hard anodizing include: the pulse type is a positive square wave pulse, the duty ratio is 60%, the frequency is 1000Hz, and the current density is 7A/dm ² . The aluminum alloy casing of the present invention is obtained.

Example 7

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After neutralizing in nitric acid for 10s, wash it twice with deionized water; then, at 95°C, polish it in a chemical polishing solution containing 650ml/L phosphoric acid and 350ml/L sulfuric acid for 10s, then wash it with deionized water for 2 times then, at 25°C, neutralize in 250ml/L nitric acid for 10s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.1mm.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

The aluminum alloy shell substrate was oxidized for 40 min at 25° C. with an oxidation forward voltage of 500 V using a micro-arc oxidation electrolyte containing 0.03 mol/L sodium silicate and 0.05 mol/L sodium hydroxide. The aluminum alloy casing of the present invention is obtained.

Example 8

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After neutralizing in nitric acid for 10s, wash it twice with deionized water; then, at 95°C, polish it in a chemical polishing solution containing 650ml/L phosphoric acid and 350ml/L sulfuric acid for 10s, then wash it with deionized water for 2 times then, at 25°C, neutralize in 250ml/L nitric acid for 10s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.1mm.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

The aluminum alloy shell substrate was oxidized at 30° C. with an oxidation forward voltage of 400 V for 100 min using a micro-arc oxidation electrolyte containing 0.02 mol/L sodium silicate and 0.07 mol/L sodium hydroxide. The aluminum alloy casing of the present invention is obtained.

Example 9

This embodiment is used to illustrate the aluminum alloy shell of the present invention and its preparation method

A die-casting aluminum alloy back shell base material for a P8 mobile phone (purchased from BYD Co., Ltd.) was used as the aluminum alloy shell base material in this embodiment.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After neutralizing in nitric acid for 10s, wash it twice with deionized water; then, at 95°C, polish it in a chemical polishing solution containing 650ml/L phosphoric acid and 350ml/L sulfuric acid for 10s, then wash it with deionized water for 2 times then, at 25°C, neutralize in 250ml/L nitric acid for 10s, and then wash twice with deionized water; Aluminum alloy shell base material.

An anodic film is formed on the surface of the aluminum alloy shell base material by anodic oxidation. The conditions are: use sulfuric acid with a concentration of 190g/L as the bath solution, the anode voltage is 15V, the temperature is 19°C, and the oxidation time is 5min.

An electrophoretic decorative layer is formed on the surface of the aluminum alloy shell base material by electrophoresis. The conditions of the electrophoresis are: temperature is 30°C, voltage is 160V, time is 2min, and pH is 7.8; Paint (WNO-1) and Nippon Shimizu Co., Ltd.'s varnish (NNO-4) are mixed in a weight ratio of 7:3 electrophoretic fluid (the solid content of the electrophoretic fluid is 13% by weight), and the electrophoretic fluid solvent is varnish. Lacquer (NNO-4) contains: 50% by weight of acrylic resin, 6% by weight of ethylene glycol monobutyl ether, 20% by weight of ethylene glycol monoisobutyl ether, 18% by weight of diethylene glycol butyraldehyde, and 6 other components % by weight; matt paint (WNO-1) contains: 50% by weight of acrylic resin, 10% by weight of ethylene glycol monobutyl ether, and 40% by weight of other components.

Use a mechanical polishing machine to polish the film layer on the surface of the aluminum alloy shell base, so that the overall thickness of the film layer is reduced by about 2 μm, so that the film surface presents a bright and reflective effect.

A laser engraving machine is used for engraving, so that the surface of the aluminum alloy shell substrate is exposed to the aluminum alloy substrate, forming a texture pattern with a depth of 0.1mm.

At 50°C, the base material of the aluminum alloy shell was etched for 10s in an aqueous solution of sodium hydroxide with a concentration of 55g/L, and then washed twice with deionized water; then, at 25°C, in a concentration of 250ml/L After being neutralized in nitric acid for 4 min, it was washed twice with deionized water.

The aluminum alloy shell substrate was oxidized for 60 min at 20° C. with an oxidation forward voltage of 600 V using a micro-arc oxidation electrolyte containing 0.05 mol/L sodium silicate and 0.03 mol/L sodium hydroxide. The aluminum alloy casing of the present invention is obtained.

Performance Testing

The performances of the aluminum alloy casings with clear convex-concave patterns prepared in Examples 1-9 were tested according to the following methods, and the test results are shown in Table 1.

Gloss test

The glossiness of the surface of the aluminum alloy casing prepared in Examples 1-9 was tested with a glossmeter (BKY micro-glossmeter A-4460, Germany), and the results are shown in Table 1.

Scratch Resistance Test

Using a Mitsubishi (UNI) pencil with a hardness of 2H, apply 800 grams of force on the sample in a 45° direction, 10 mm stroke, and draw 3 lines at different positions to observe whether there are obvious scratches on the appearance of the sample. If there are no obvious scratches, it means The sample is qualified.

High temperature resistance test

Put the sample into a precision high-temperature test chamber (Hongling HRHL45), heat it at 85°C for 240 hours, then place it at room temperature for 2 hours, observe whether the appearance of the sample has peeling, deformation, cracks and color changes, if there is no peeling, Deformation, cracks, and color changes are acceptable samples.

Low temperature resistance test

Put the sample into a constant temperature and humidity testing machine (Taiwan Qingsheng, THS-2001), place it at -40°C for 240 hours, and then place it at room temperature for 2 hours, and observe whether the appearance of the sample has peeling, deformation, cracks and color Changes, if there is no shedding, deformation, cracks and color changes, the sample is qualified.

Humidity Test

Put the sample into a constant temperature and humidity testing machine (Taiwan Qingsheng, HTS-400) with a humidity of 90% and a temperature of 60°C for 96 hours, and then place it at room temperature for 2 hours to observe whether the appearance of the sample is shedding, deformed, Cracks and color changes, if there is no peeling, deformation, cracks and color changes, the sample is qualified.

Temperature Shock Test

Put the sample into the thermal shock testing machine (Hongling HTS-400), first place it at -40°C for 1 hour, then switch the temperature to 85°C, place it for 1 hour, and the conversion time is 15 seconds. 12 cycles (24 hours). Observe whether the appearance of the sample has peeling, deformation, cracks and color changes. If there is no peeling, deformation, cracks and color changes, the sample is qualified.

Salt spray test

Place the sample in a test chamber (HOLINK H-SST-90 salt spray tester) with a temperature of 30°C and a humidity of ≥85%, and spray it continuously for 48 Take it out after an hour; rinse it with clean water at room temperature for 5 minutes and dry it with a hair dryer, and place it at room temperature for 1 hour to observe whether the appearance of the sample has peeling, deformation, cracks and color changes. If there is no peeling, deformation, cracks and color changes, it means the sample qualified.

Table 1

It can be seen from the above table that the surface of the aluminum alloy shell provided by the present invention is not easy to wear and tear, and the surface layer is not easy to fall off, which improves the durability of the aluminum alloy shell, and has a convex and concave texture pattern to endow the aluminum alloy shell with an excellent appearance effect, with layers The distinct convex-concave three-dimensional texture makes the aluminum alloy casing provided by the present invention have the advantages of aesthetics and durability. In addition, the aluminum alloy casings obtained in Examples 1-9 are mechanically polished so that the surface also has highlight and non-highlight effects.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way if there is no contradiction. The combination method will not be described separately.

In addition, various combinations of different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

Claims (12)

1. a kind of Al-alloy casing, it is characterised in that the outer surface of the Al-alloy casing have convex portion and Recess, is sequentially formed with convex portion oxide-film and convex portion electrophoresis decorative layer, the recess tool on the convex portion There are recess oxide-film or recess electrophoresis decorative layer, the surface of the convex portion electrophoresis decorative layer has 90-105 Glossiness, the glossiness or the recess electrophoresis that the surface of the recess oxide-film has 5-25 decorate The surface of layer has the glossiness of 0.5-5.

2. Al-alloy casing according to claim 1, it is characterised in that the convex portion and described The difference in height of recess is 0.05-0.2mm.

3. Al-alloy casing according to claim 1 and 2, it is characterised in that the convex portion oxygen Changing film and the recess oxide-film has different colors.

4. a kind of preparation method of Al-alloy casing, it is characterised in that the preparation method includes successively：

Step a, first anode oxidation is carried out to Al-alloy casing matrix surface,

Step b, by the first electrophoresis Al-alloy casing matrix surface formed electrophoresis decorative layer,

Step c, Al-alloy casing matrix surface after the first electrophoresis is mechanically polished,

Step d, textured pattern is carved out on Al-alloy casing matrix surface by the method for laser carving,

Step e, the second electrophoresis or second are carried out to the grain pattern portion on Al-alloy casing matrix surface Anodic oxidation or hard anodizing or differential arc oxidation.

5. preparation method according to claim 4, it is characterised in that the first anode oxidation And/or second plate is aoxidized after including being pre-processed Al-alloy casing matrix surface by anodic oxidation Form anode film.

6. preparation method according to claim 5, it is characterised in that the pretreatment includes： Alkaline etching 3-20s is carried out at 50-70 DEG C using the NaOH of 50-60g/L, uses 200-300ml/L's Nitric acid carries out neutralization 10-20s at 15-25 DEG C, and, using the phosphoric acid containing 650-750ml/L and The change of the sulfuric acid of 350-250ml/L is thrown liquid and chemical polishing 5-20s is carried out at 90-95 DEG C.

7. preparation method according to claim 5, it is characterised in that the anodic oxidation includes Using 190-200g/L sulfuric acid by Al-alloy casing matrix surface 13-17V anode voltage, 5-50min is aoxidized at 10-21 DEG C.

8. preparation method according to claim 4, it is characterised in that first electrophoresis and/or Second electrophoresis is included using the electrophoresis liquid that pH value is 7-9 in 28-32 DEG C of temperature, the electricity of 140-200V Pressure carries out electrophoresis 1-3min.

9. preparation method according to claim 4, it is characterised in that the hard anodizing Including aoxidizing 25-50min at 5-12 DEG C using hard anodizing liquid.

10. preparation method according to claim 9, it is characterised in that the hard anodizing Liquid contains the sulfuric acid of 170-270g/L and the oxalic acid of 8-20g/L.

11. preparation methods according to claim 4, it is characterised in that the differential arc oxidation includes Using micro-arc oxidation electrolyte 40-100min is aoxidized at 20-30 DEG C.

12. preparation methods according to claim 11, it is characterised in that the differential arc oxidation electricity Solution liquid contains the sodium metasilicate of 0.02-0.05mol/L and the NaOH of 0.03-0.07mol/L.