Mobile phone rear cover and coating process thereof

Abstract

The invention relates to the technical field of film coating, in particular to a mobile phone rear cover and a film coating technology thereof.The film coating technology comprises the following steps that (1) the mobile phone rear cover with the cleaned surface is loaded into a film coating jig and placed into a film coating chamber, and the mobile phone rear cover comprises an area to be coated; (2) a pump is started for vacuumizing, a heating device is started for heating, three times of film coating are sequentially conducted on the area to be coated with the film through a physical vapor deposition method, and (3) the surface of a third film coating layer is coated with an AF film layer, and it is tested that the mobile phone rear cover obtained after film coating has excellent adhesive force, hardness, abrasion resistance and impact resistance, and the service life of the mobile phone rear cover is prolonged. And the coating also has excellent boiling resistance, temperature shock resistance, hand sweat resistance, cosmetic resistance, oil resistance, alcohol resistance, low-temperature storage, high-temperature storage, alternating temperature heat resistance, smudginess resistance, chemical reagent resistance and solar radiation resistance.

Description

Technical Field

[0001] The invention relates to the technical field of coating, and in particular to a mobile phone back cover and a coating process thereof. Background Art

[0002] As the mobile phone market continues to expand, competition in mobile phone back cover processing is also becoming increasingly fierce. Major mobile phone companies are constantly developing new processes, hoping to use new processes to reduce production costs and improve the company's market competitiveness.

[0003] In order to ensure the brightness of the back cover of the mobile phone, it is necessary to add an electroplating process to the printing process. The existing electroplating process for the back cover of the mobile phone generally uses magnetron sputtering technology. Under vacuum conditions, positively charged particles are bombarded on the surface of the negatively charged cathode target material, causing atoms or molecules to be sputtered from the surface of the target material. These particles sputtered from the surface of the target material are deposited on the substrate to form a thin film. This process is called magnetron sputtering coating.

[0004] The Chinese invention patent with application number 201910361306.2 discloses a color coating for the back cover of a mobile phone. The specific coating method of the color coating is as follows: set the parameters of the magnetron sputtering vacuum coating system, control the required color film system and film thickness ratio, and continuously sputter three layers of target sputtering materials, wherein the first layer is sputtered Nb2O5 target sputtering material, the second layer is sputtered SiO2 target sputtering material, and the third layer is sputtered Nb2O5 target sputtering material. After sputtering coating, screen-print black ink on the substrate of the back cover of the mobile phone after coating. The present invention can display different colors on the screen-printed black ink through different film thickness ratios, has simple ingredients, low cost, and can be mass-produced. However, the patent does not elaborate on the performance of the back cover of the mobile phone after coating. Summary of the invention

[0005] In order to overcome the shortcomings and deficiencies in the prior art, the present invention aims to provide a mobile phone back cover and a coating process thereof.

[0006] The purpose of the present invention is achieved through the following technical solution: A coating process for a mobile phone back cover comprises the following steps:

[0007] (1) placing the cleaned back cover of a mobile phone into a coating fixture and placing it in a coating chamber, wherein the back cover of the mobile phone includes an area to be coated;

[0008] (2) Turn on the vacuum pump and the heating device to heat, and perform three coating operations in sequence using the physical vapor deposition method on the area to be coated:

[0009] Ⅰ. Select a first coating material to perform a first coating in a reaction gas environment, and deposit a first coating layer in the area to be coated, wherein the first coating material is Si-TiO2N-Cr2O3, and the reaction gas is nitrogen;

[0010] Ⅱ. Select a second coating material and perform a second coating in a reaction gas environment to deposit the second coating layer on the surface of the first coating layer. The second coating material is Si-Cr2O3 and Si-TiO2N-Cr2O3, and the reaction gas is nitrogen.

[0011] III. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer. The third coating material is Si-TiO2N-Cr2O3 and the reaction gas is oxygen.

[0012] (3) An AF film layer is coated on the surface of the third coating layer.

[0013] Preferably, in the steps Ⅰ-Ⅲ, the mass content of Si in Si-TiO2N-Cr2O3 is 20%-40%, the mass content of TiO2N is 20%-30%, and the balance is Cr2O3. Silicon has high transparency and high substrate adhesion; titanium dioxide nitride has excellent optical properties; chromium oxide has high wear resistance and hardness as well as good chemical stability. The coating process of the present invention strictly controls the mass ratio of Si, TiO2N and Cr2O3 in Si-TiO2N-Cr2O3, so that the obtained coating layer has good wear resistance and good chemical stability, and the appearance color of the film layer can also be adjusted.

[0014] In step II, the mass content of Si in Si-Cr2O3 is 10%-20%, and the balance is Cr2O3. Indium has high transparency, high adhesion, high temperature resistance and corrosion resistance; silicon has high transparency and high substrate adhesion; chromium trioxide has high wear resistance and hardness as well as good chemical stability. The coating process of the present invention strictly controls the mass ratio of In, Si and Cr2O3 in In-Si-Cr2O3, and the obtained coating layer has good flexibility, wear resistance and good chemical stability.

[0015] In step II, Si-Cr2O3 and Si-TiO2N-Cr2O3 are mixed in a mass ratio of 0.1-1.0:0.1-1.0. The coating process of the present invention strictly controls the mass ratio of Si-Cr2O3 and Si-TiO2N-Cr2O3, and the obtained coating layer has good hardness, wear resistance and impact resistance.

[0016] In the steps I-II, the flow rate of nitrogen is 10-1000 sccm, and in the step III, the flow rate of oxygen is 10-1000 sccm. The coating process of the present invention can improve the color and optical transmittance of the film layer by strictly controlling the flow rate of the gas.

[0017] Preferably, in the steps I-III, the coating is performed by vacuum evaporation, vacuum ion plating or magnetron sputtering, and the gas pressure of the coating is 1.0*10 -4 -1.0*10 -2 Pa, power is 1-15kw, coating temperature is 80-160℃, single coating time is 1-10min, and total coating thickness is 1.5-15.0μm. More preferably, magnetron sputtering coating is used for coating. By bombarding the target material with ions, atoms on the surface of the target material are splashed onto the substrate to form a thin film. Sputtering coating has good film uniformity and adhesion, and is suitable for large-area coating. In a high vacuum environment, the impurity gas content is low, which is conducive to the formation of a high-purity film. The deposition temperature affects the crystallization quality and stress of the film, and a suitable temperature needs to be selected according to the material properties and process requirements. The coating process of the present invention strictly controls the process parameters of the coating, and the obtained film layer has good film uniformity and adhesion.

[0018] The object of the present invention can also be achieved by the following technical solution: A coating process for a mobile phone back cover comprises the following steps:

[0019] (1) placing the cleaned mobile phone back cover into a coating fixture and placing it in a coating chamber, wherein the mobile phone back cover includes a first coating area located on the inner side and a second coating area located on the outer side;

[0020] (2) Turn on the pump to evacuate and the heating device to heat, and perform four coating operations in sequence using physical vapor deposition on the area to be coated:

[0021] A. Select a first coating material and perform a first coating in a reaction gas environment to deposit a first coating layer in the area to be coated, wherein the first coating material is Si-Cr2O3 and the reaction gas is oxygen;

[0022] B. Select a second coating material and perform a second coating in a reaction gas environment to deposit the second coating layer on the surface of the first coating layer, wherein the second coating material is Si-Cr2O3 and the reaction gas is nitrogen;

[0023] C. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer, wherein the third coating material is In-Si-Cr2O3, and the reaction gas is nitrogen and oxygen;

[0024] D. Select a fourth coating material and perform a fourth coating in a reaction gas environment to deposit a fourth coating layer on the surface of the third coating layer, wherein the fourth coating material is Si-TiO2N-Cr2O3 and the reaction gas is oxygen;

[0025] (3) An AF film layer is coated on the surface of the fourth coating layer.

[0026] Preferably, in step AB, the mass content of Si in Si-Cr2O3 is 10%-20%, with the remainder being Cr2O3.

[0027] In step C, the mass content of In in In-Si-Cr2O3 is 15%-30%, the mass content of Si is 10%-20%, and the balance is Cr2O3. Indium has high transparency, high adhesion, high temperature resistance and corrosion resistance; silicon has high transparency and high substrate adhesion; chromium trioxide has high wear resistance and hardness as well as good chemical stability. The coating process of the present invention strictly controls the mass ratio of In, Si and Cr2O3 in In-Si-Cr2O3, so that the obtained coating layer has good flexibility, wear resistance and good chemical stability.

[0028] In step D, the mass content of Si in Si-TiO2N-Cr2O3 is 20%-40%, the mass content of TiO2N is 20%-30%, and the balance is Cr2O3. Silicon has high transparency and high substrate adhesion; titanium dioxide nitride has excellent optical properties; chromium oxide has high wear resistance and hardness as well as good chemical stability. The coating process of the present invention strictly controls the mass ratio of Si, TiO2N and Cr2O3 in Si-TiO2N-Cr2O3, so that the obtained coating layer has good wear resistance and good chemical stability, and the appearance color of the film layer can also be adjusted.

[0029] In the steps A and CD, the flow rate of oxygen is 10-1000 sccm, and in the step BC, the flow rate of nitrogen is 10-1000 sccm. The coating process of the present invention can improve the color and optical transmittance of the film layer by strictly controlling the flow rate of the gas.

[0030] Preferably, in the steps AD, the coating is performed by vacuum evaporation, vacuum ion plating or magnetron sputtering, and the gas pressure of the coating is 1.0*10 -4 -1.0*10 -2 Pa, power is 1-15kw, coating temperature is 80-160℃, single coating time is 1-10min, and total coating thickness is 1.5-15.0μm. More preferably, magnetron sputtering coating is used for coating. By bombarding the target material with ions, atoms on the surface of the target material are splashed onto the substrate to form a thin film. Sputtering coating has good film uniformity and adhesion, and is suitable for large-area coating. In a high vacuum environment, the impurity gas content is low, which is conducive to the formation of a high-purity film. The deposition temperature affects the crystallization quality and stress of the film, and a suitable temperature needs to be selected according to the material properties and process requirements. The coating process of the present invention strictly controls the process parameters of the coating, and the obtained film layer has good film uniformity and adhesion.

[0031] The object of the present invention can also be achieved by the following technical solution: A coating process for a mobile phone back cover comprises the following steps:

[0032] (1) placing the cleaned mobile phone back cover into a coating fixture and placing it in a coating chamber, wherein the mobile phone back cover includes a first coating area located on the inner side and a second coating area located on the outer side;

[0033] (2) Turn on the pump to evacuate and the heating device to heat, and perform four coating operations in sequence using physical vapor deposition on the area to be coated:

[0034] a. Select a first coating material and perform a first coating in an environment of working gas and reaction gas, and deposit a first coating layer in the area to be coated, wherein the first coating material is Si-Cr2O3 and Si-Cr2O3-CrN-CrC, the working gas is argon, and the reaction gas is oxygen;

[0035] b. Select a second coating material and perform a second coating in an environment of working gas to deposit the second coating layer on the surface of the first coating layer, wherein the second coating material is Si-Cr2O3-CrN-CrC and the working gas is argon;

[0036] c. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer, wherein the third coating material is Si-Cr2O3-CrN-CrC and the reaction gas is nitrogen;

[0037] d. Select a fourth coating material and perform a fourth coating in a reaction gas environment to deposit a fourth coating layer on the surface of the third coating layer, wherein the fourth coating material is Si-Cr2O3-CrN-CrC, and the reaction gas is oxygen;

[0038] (3) An AF film layer is coated on the surface of the fourth coating layer.

[0039] Preferably, in step a, the mass content of Si in Si-Cr2O3 is 10%-20%, and the balance is Cr2O3. Silicon has a high refractive index and a low absorption coefficient, and also has a high substrate adhesion; chromium trioxide has high wear resistance and hardness as well as good chemical stability. The coating process of the present invention strictly controls the mass ratio of Si and Cr2O3 in Si-Cr2O3, and the obtained coating layer has good hardness, wear resistance and impact resistance.

[0040] In the steps ad, the mass content of Si in Si-Cr2O3-CrN-CrC is 7%-15%, the mass content of Cr2O3 is 25%-40%, the mass content of CrN is 15%-25%, and the balance is CrC. Silicon has high transparency and high substrate adhesion; chromium trioxide has high wear resistance and hardness as well as good chemical stability; chromium nitride has high hardness and good wear resistance; chromium carbide has high hardness, wear resistance and corrosion resistance. The coating process of the present invention strictly controls the mass ratio of Si, Cr2O3, CrN and CrC in Si-Cr2O3-CrN-CrC, so that the obtained coating layer has good wear resistance, impact resistance and corrosion resistance.

[0041] In the steps ab, the flow rate of argon is 10-1000 sccm, in the steps a and d, the flow rate of oxygen is 10-1000 sccm, and in the step c, the flow rate of nitrogen is 10-1000 sccm. The coating process of the present invention can improve the color and optical transmittance of the film layer by strictly controlling the flow rate of the gas.

[0042] Preferably, in the steps ad, the coating is performed by vacuum evaporation, vacuum ion plating or magnetron sputtering, and the gas pressure of the coating is 1.0*10 -4 -1.0*10 -2 Pa, power is 1-15kw, coating temperature is 80-160℃, single coating time is 1-10min, and total coating thickness is 1.5-15.0μm. More preferably, magnetron sputtering coating is used for coating. By bombarding the target material with ions, atoms on the surface of the target material are splashed onto the substrate to form a thin film. Sputtering coating has good film uniformity and adhesion, and is suitable for large-area coating. In a high vacuum environment, the impurity gas content is low, which is conducive to the formation of a high-purity film. The deposition temperature affects the crystallization quality and stress of the film, and a suitable temperature needs to be selected according to the material properties and process requirements. The coating process of the present invention strictly controls the process parameters of the coating, and the obtained film layer has good film uniformity and adhesion.

[0043] Another object of the present invention is achieved through the following technical solution: a mobile phone back cover, the mobile phone back cover is made according to the above-mentioned preparation method.

[0044] The beneficial effects of the present invention are as follows: the mobile phone back cover of the present invention is coated with Si-TiO2N-Cr2O3 for the first time, coated with Si-Cr2O3 and Si-TiO2N-Cr2O3 for the second time, coated with Si-TiO2N-Cr2O3 for the third time, and then coated with AF film; or, the mobile phone back cover is coated with Si-Cr2O3 for the first time and the second time, coated with In-Si-Cr2O3 for the third time, coated with Si-TiO2N-Cr2O3 for the fourth time, Then AF film is coated; or, Si-Cr2O3 and Si-Cr2O3-CrN-CrC are used for the first coating, and Si-Cr2O3-CrN-CrC is used for the second, third and fourth coating, and then AF film is coated; after testing, the coated mobile phone back cover has excellent adhesion, hardness, wear resistance and impact resistance, and also has excellent resistance to boiling water, temperature shock, hand sweat, cosmetics, oil, alcohol, low temperature storage, high temperature storage, alternating warm and hot, dirt resistance, chemical reagent resistance and solar radiation resistance. DETAILED DESCRIPTION

[0045] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0046] Example 1

[0047] A coating process for a mobile phone back cover comprises the following steps:

[0048] (1) placing the cleaned back cover of a mobile phone into a coating fixture and placing it in a coating chamber, wherein the back cover of the mobile phone includes an area to be coated;

[0049] (2) Turn on the vacuum pump and the heating device to heat, and perform three coating operations in sequence using the physical vapor deposition method on the area to be coated:

[0050] Ⅰ. Select a first coating material to perform a first coating in a reaction gas environment, and deposit a first coating layer in the area to be coated, wherein the first coating material is Si-TiO2N-Cr2O3, and the reaction gas is nitrogen;

[0051] Ⅱ. Select a second coating material and perform a second coating in a reaction gas environment to deposit the second coating layer on the surface of the first coating layer. The second coating material is Si-Cr2O3 and Si-TiO2N-Cr2O3, and the reaction gas is nitrogen.

[0052] III. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer. The third coating material is Si-TiO2N-Cr2O3 and the reaction gas is oxygen.

[0053] (3) An AF film layer is coated on the surface of the third coating layer.

[0054] In the steps Ⅰ-Ⅲ, the mass content of Si in Si-TiO2N-Cr2O3 is 20%, the mass content of TiO2N is 20%, and the balance is Cr2O3; in the step Ⅱ, the mass content of Si in Si-Cr2O3 is 10%, and the balance is Cr2O3; in the step Ⅱ, Si-Cr2O3 and Si-TiO2N-Cr2O3 are mixed in a mass ratio of 0.2:0.8; in the steps Ⅰ-Ⅱ, the flow rate of nitrogen is 200sccm, and in the step Ⅲ, the flow rate of oxygen is 200sccm.

[0055] In the steps Ⅰ-Ⅲ, the coating is carried out by magnetron sputtering, and the gas pressure of the coating is 5.0*10 -4 Pa, power is 5kw, coating temperature is 100℃, single coating time is 5min, total coating thickness is 1.5μm (three layers, each layer is 500nm thick), in step (3), the thickness of AF film is 10nm.

[0056] A mobile phone back cover is prepared according to the above-mentioned preparation method.

[0057] Example 2

[0058] The difference between this embodiment and the above-mentioned embodiment 1 is that: in the steps Ⅰ-Ⅲ, the mass content of Si in Si-TiO2N-Cr2O3 is 30%, the mass content of TiO2N is 25%, and the balance is Cr2O3; in the step Ⅱ, the mass content of Si in Si-Cr2O3 is 15%, and the balance is Cr2O3; in the step Ⅱ, Si-Cr2O3 and Si-TiO2N-Cr2O3 are mixed in a mass ratio of 0.5:0.5; in the steps Ⅰ-Ⅱ, the flow rate of nitrogen is 250sccm, and in the step Ⅲ, the flow rate of oxygen is 250sccm.

[0059] In the steps Ⅰ-Ⅲ, the coating is carried out by magnetron sputtering, and the gas pressure of the coating is 5.0*10 -4 Pa, power is 5kw, coating temperature is 100℃, single coating time is 5min, total coating thickness is 2.4μm (three layers, each layer is 800nm ​​thick), in step (3), the thickness of AF film is 30nm.

[0060] Example 3

[0061] The difference between this embodiment and the above-mentioned embodiment 1 is that: in the steps Ⅰ-Ⅲ, the mass content of Si in Si-TiO2N-Cr2O3 is 40%, the mass content of TiO2N is 20%-30%, and the balance is Cr2O3; in the step Ⅱ, the mass content of Si in Si-Cr2O3 is 20%, and the balance is Cr2O3; in the step Ⅱ, Si-Cr2O3 and Si-TiO2N-Cr2O3 are mixed in a mass ratio of 0.8:0.2; in the steps Ⅰ-Ⅱ, the flow rate of nitrogen is 300sccm, and in the step Ⅲ, the flow rate of oxygen is 300sccm.

[0062] In the steps Ⅰ-Ⅲ, the coating is carried out by magnetron sputtering, and the gas pressure of the coating is 5.0*10 -4 Pa, power is 5kw, coating temperature is 100℃, single coating time is 5min, total coating thickness is 3.0μm (three layers, each layer is 1000nm thick), in step (3), the thickness of AF film is 50nm.

[0063] The performance test of the mobile phone back cover after coating of Example 1-3 is shown in the following table:

[0064]

[0065]

[0066]

[0067] The mobile phone back cover of the invention is coated with Si-TiO2N-Cr2O3 for the first time, Si-Cr2O3 and Si-TiO2N-Cr2O3 for the second time, Si-TiO2N-Cr2O3 for the third time, and then AF film is coated. The coated mobile phone back cover has excellent adhesion, hardness, wear resistance and impact resistance after testing, and also has excellent resistance to boiling water, temperature shock, hand sweat, cosmetics, oil, alcohol, low temperature storage, high temperature storage, alternating warm and hot, dirt resistance, chemical reagent resistance and solar radiation resistance.

[0068] Example 4

[0069] A coating process for a mobile phone back cover comprises the following steps:

[0070] (1) placing the cleaned mobile phone back cover into a coating fixture and placing it in a coating chamber, wherein the mobile phone back cover includes a first coating area located on the inner side and a second coating area located on the outer side;

[0071] (2) Turn on the pump to evacuate and the heating device to heat, and perform four coating operations in sequence using physical vapor deposition on the area to be coated:

[0072] A. Select a first coating material and perform a first coating in a reaction gas environment to deposit a first coating layer in the area to be coated, wherein the first coating material is Si-Cr2O3 and the reaction gas is oxygen;

[0073] B. Select a second coating material and perform a second coating in a reaction gas environment to deposit the second coating layer on the surface of the first coating layer, wherein the second coating material is Si-Cr2O3 and the reaction gas is nitrogen;

[0074] C. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer, wherein the third coating material is In-Si-Cr2O3, and the reaction gas is nitrogen and oxygen;

[0075] D. Select a fourth coating material and perform a fourth coating in a reaction gas environment to deposit a fourth coating layer on the surface of the third coating layer, wherein the fourth coating material is Si-TiO2N-Cr2O3 and the reaction gas is oxygen;

[0076] (3) An AF film layer is coated on the surface of the fourth coating layer.

[0077] In the steps AB, the mass content of Si in Si-Cr203 is 10%, with the remainder being Cr2O3; in the step C, the mass content of In in In-Si-Cr2O3 is 15%, the mass content of Si is 10%, with the remainder being Cr2O3; in the step D, the mass content of Si in Si-TiO2N-Cr2O3 is 20%, the mass content of TiO2N is 20%, with the remainder being Cr2O3; in the steps A and CD, the flow rate of oxygen is 200 sccm, and in the step BC, the flow rate of nitrogen is 200 sccm.

[0078] In the steps AD, the coating is performed by magnetron sputtering, and the gas pressure of the coating is 5.0*10 -4 Pa, power is 5kw, coating temperature is 100℃, single coating time is 5min, total coating thickness is 2.0μm (four layers in total, each layer is 500nm thick), in step (3), the thickness of AF film is 10nm.

[0079] A mobile phone back cover is prepared according to the above-mentioned preparation method.

[0080] Example 5

[0081] The difference between this embodiment and the above-mentioned embodiment 4 is that: in the step AB, the mass content of Si in Si-Cr2O3 is 15%, and the balance is Cr2O3; in the step C, the mass content of In in In-Si-Cr2O3 is 22%, the mass content of Si is 15%, and the balance is Cr2O3; in the step D, the mass content of Si in Si-TiO2N-Cr2O3 is 30%, the mass content of TiO2N is 25%, and the balance is Cr2O3; in the steps A and CD, the flow rate of oxygen is 250sccm, and in the step BC, the flow rate of nitrogen is 250sccm.

[0082] In the steps AD, the coating is performed by magnetron sputtering, and the gas pressure of the coating is 5.0*10 -3 Pa, power is 10kw, coating temperature is 120℃, single coating time is 8min, total coating thickness is 3.2μm (four layers in total, each layer is 800nm ​​thick), in step (3), the thickness of AF film is 30nm.

[0083] Example 6

[0084] The difference between this embodiment and the above-mentioned embodiment 4 is that: in the step AB, the mass content of Si in Si-Cr2O3 is 10%-20%, and the balance is Cr2O3; in the step C, the mass content of In in In-Si-Cr2O3 is 30%, the mass content of Si is 20%, and the balance is Cr2O3; in the step D, the mass content of Si in Si-Ti02N-Cr2O3 is 40%, the mass content of TiO2N is 30%, and the balance is Cr2O3; in the steps A and CD, the flow rate of oxygen is 300sccm, and in the step BC, the flow rate of nitrogen is 300sccm.

[0085] In the steps AD, the coating is performed by magnetron sputtering, and the gas pressure of the coating is 8.0*10 -3 Pa, power is 12kw, coating temperature is 140℃, single coating time is 10min, total coating thickness is 4.0μm (four layers in total, each layer is 1000nm thick), in step (3), the thickness of AF film is 50nm.

[0086] The performance test of the mobile phone back cover after coating of Example 4-6 is shown in the following table:

[0087]

[0088]

[0089]

[0090] The mobile phone back cover of the present invention adopts Si-Cr2O3 for the first coating and the second coating, adopts In-Si-Cr2O3 for the third coating, adopts Si-TiO2N-Cr2O3 for the fourth coating, and then coats the AF film. The coated mobile phone back cover has excellent adhesion, hardness, wear resistance and impact resistance after testing, and also has excellent resistance to boiling water, temperature shock, hand sweat, cosmetics, oil, alcohol, low temperature storage, high temperature storage, alternating warm and hot, dirt resistance, chemical reagent resistance and solar radiation resistance.

[0091] Example 7

[0092] A coating process for a mobile phone back cover comprises the following steps:

[0093] (1) placing the cleaned mobile phone back cover into a coating fixture and placing it in a coating chamber, wherein the mobile phone back cover includes a first coating area located on the inner side and a second coating area located on the outer side;

[0094] (2) Turn on the pump to evacuate and the heating device to heat, and perform four coating operations in sequence using physical vapor deposition on the area to be coated:

[0095] a. Select a first coating material and perform a first coating in an environment of working gas and reaction gas, and deposit a first coating layer in the area to be coated, wherein the first coating material is Si-Cr2O3 and Si-Cr203-CrN-CrC, the working gas is argon, and the reaction gas is oxygen;

[0096] b. Select a second coating material and perform a second coating in an environment of working gas to deposit the second coating layer on the surface of the first coating layer, wherein the second coating material is Si-Cr2O3-CrN-CrC and the working gas is argon;

[0097] c. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer, wherein the third coating material is Si-Cr2O3-CrN-CrC and the reaction gas is nitrogen;

[0098] d. Select a fourth coating material and perform a fourth coating in a reaction gas environment to deposit a fourth coating layer on the surface of the third coating layer, wherein the fourth coating material is Si-Cr2O3-CrN-CrC, and the reaction gas is oxygen;

[0099] (3) An AF film layer is coated on the surface of the fourth coating layer.

[0100] In the step a, the mass content of Si in Si-Cr2O3 is 10%, and the balance is Cr2O3; in the step ad, the mass content of Si in Si-Cr2O3-CrN-CrC is 7%, the mass content of Cr2O3 is 25%, the mass content of CrN is 15%, and the balance is CrC; in the steps ab, the flow rate of argon is 200sccm, in the steps a and d, the flow rate of oxygen is 200sccm, and in the step c, the flow rate of nitrogen is 200sccm.

[0101] In the steps ad, the coating is performed by magnetron sputtering, and the gas pressure of the coating is 5.0*10 -4 Pa, power is 5kw, coating temperature is 100℃, single coating time is 5min, total coating thickness is 2.0μm (four layers in total, each layer is 500nm thick), in step (3), the thickness of AF film is 10nm.

[0102] A mobile phone back cover is prepared according to the above-mentioned preparation method.

[0103] Example 8

[0104] The difference between this embodiment and the above-mentioned embodiment 7 is that: in the step a, the mass content of Si in Si-Cr2O3 is 15%, and the balance is Cr2O3; in the steps ad, the mass content of Si in Si-Cr2O3-CrN-CrC is 11%, the mass content of Cr2O3 is 32%, the mass content of CrN is 20%, and the balance is CrC; in the steps ab, the flow rate of argon is 250sccm, in the steps a and d, the flow rate of oxygen is 250sccm, and in the step c, the flow rate of nitrogen is 250sccm.

[0105] In the steps ad, the coating is performed by magnetron sputtering, and the gas pressure of the coating is 5.0*10 -3 Pa, power is 10kw, coating temperature is 120℃, single coating time is 8min, total coating thickness is 3.2μm (four layers in total, each layer is 800nm ​​thick), in step (3), the thickness of AF film is 30nm.

[0106] Example 9

[0107] The difference between this embodiment and the above-mentioned embodiment 7 is that: in the step a, the mass content of Si in Si-Cr2O3 is 20%, and the balance is Cr2O3; in the steps ad, the mass content of Si in Si-Cr2O3-CrN-CrC is 15%, the mass content of Cr2O3 is 40%, the mass content of CrN is 25%, and the balance is CrC; in the steps ab, the flow rate of argon is 300sccm, in the steps a and d, the flow rate of oxygen is 300sccm, and in the step c, the flow rate of nitrogen is 300sccm.

[0108] In the steps ad, the coating is performed by magnetron sputtering, and the gas pressure of the coating is 8.0*10 -3 Pa, power is 12kw, coating temperature is 140℃, single coating time is 10min, total coating thickness is 4.0μm (four layers in total, each layer is 1000nm thick), in step (3), the thickness of AF film is 50nm.

[0109] The performance test of the mobile phone back cover after coating of Examples 7-9 is shown in the following table:

[0110]

[0111]

[0112]

[0113] The mobile phone back cover of the present invention is coated with Si-Cr2O3 and Si-Cr2O3-CrN-CrC for the first time, and then coated with Si-Cr2O3-CrN-CrC for the second, third and fourth times, and then coated with an AF film. After being tested, the coated mobile phone back cover has excellent adhesion, hardness, wear resistance and impact resistance, and also has excellent resistance to boiling water, temperature shock, hand sweat, cosmetics, oil, alcohol, low-temperature storage, high-temperature storage, alternating warm and hot, dirt resistance, chemical reagent resistance and solar radiation resistance.

[0114] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A coating process for a mobile phone back cover, characterized in that: The steps include: (1) placing the cleaned back cover of a mobile phone into a coating fixture and placing it in a coating chamber, wherein the back cover of the mobile phone includes an area to be coated; (2) Turn on the vacuum pump and the heating device to heat, and perform three coating operations in sequence using the physical vapor deposition method on the area to be coated: Ⅰ. Select a first coating material to perform a first coating in a reaction gas environment, and deposit a first coating layer in the area to be coated, wherein the first coating material is Si-TiO2N-Cr2O3, and the reaction gas is nitrogen; Ⅱ. Select a second coating material and perform a second coating in a reaction gas environment to deposit the second coating layer on the surface of the first coating layer. The second coating material is Si-Cr2O3 and Si-TiO2N-Cr2O3, and the reaction gas is nitrogen. III. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer. The third coating material is Si-TiO2N-Cr2O3 and the reaction gas is oxygen. (3) An AF film layer is coated on the surface of the third coating layer.

2. The coating process for a mobile phone back cover according to claim 1, characterized in that: In the steps Ⅰ-Ⅲ, the mass content of Si in Si-TiO2N-Cr2O3 is 20%-40%, the mass content of TiO2N is 20%-30%, and the balance is Cr2O3; in the step Ⅱ, the mass content of Si in Si-Cr2O3 is 10%-20%, and the balance is Cr2O3; in the step Ⅱ, Si-Cr2O3 and Si-TiO2N-Cr2O3 are mixed in a mass ratio of 0.1-1.0:0.1-1.0; in the steps Ⅰ-Ⅱ, the flow rate of nitrogen is 10-1000sccm, and in the step Ⅲ, the flow rate of oxygen is 10-1000sccm.

3. The coating process for a mobile phone back cover according to claim 1, characterized in that: In the steps I-III, the coating is performed by vacuum evaporation, vacuum ion plating or magnetron sputtering, and the gas pressure of the coating is 1.0*10 -4 -1.0*10 -2 Pa, power is 1-15kw, coating temperature is 80-160℃, single coating time is 1-10min, and total coating thickness is 1.5-15.0μm.

4. A coating process for a mobile phone back cover, characterized in that: The steps include: (1) placing the cleaned mobile phone back cover into a coating fixture and placing it in a coating chamber, wherein the mobile phone back cover includes a first coating area located on the inner side and a second coating area located on the outer side; (2) Turn on the pump to evacuate and the heating device to heat, and perform four coating operations in sequence using physical vapor deposition on the area to be coated: A. Select a first coating material and perform a first coating in a reaction gas environment to deposit a first coating layer in the area to be coated, wherein the first coating material is Si-Cr2O3 and the reaction gas is oxygen; B. Select a second coating material and perform a second coating in a reaction gas environment to deposit the second coating layer on the surface of the first coating layer, wherein the second coating material is Si-Cr2O3 and the reaction gas is nitrogen; C. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer, wherein the third coating material is In-Si-Cr2O3, and the reaction gas is nitrogen and oxygen; D. Select a fourth coating material and perform a fourth coating in a reaction gas environment to deposit a fourth coating layer on the surface of the third coating layer, wherein the fourth coating material is Si-TiO2N-Cr2O3 and the reaction gas is oxygen; (3) An AF film layer is coated on the surface of the fourth coating layer.

5. The coating process for the back cover of a mobile phone according to claim 4, characterized in that: In the step AB, the mass content of Si in Si-Cr2O3 is 10%-20%, with the remainder being Cr2O3; in the step C, the mass content of In in In-Si-Cr2O3 is 15%-30%, the mass content of Si is 10%-20%, with the remainder being Cr2O3; in the step D, the mass content of Si in Si-TiO2N-Cr2O3 is 20%-40%, the mass content of TiO2N is 20%-30%, with the remainder being Cr2O3; in the steps A and CD, the flow rate of oxygen is 10-1000sccm, and in the step BC, the flow rate of nitrogen is 10-1000sccm.

6. The coating process for a mobile phone back cover according to claim 4, characterized in that: In the steps AD, the coating is performed by vacuum evaporation, vacuum ion plating or magnetron sputtering, and the gas pressure of the coating is 1.0*10 -4 -1.0*10 -2 Pa, power is 1-15kw, coating temperature is 80-160℃, single coating time is 1-10min, and total coating thickness is 1.5-15.0μm.

7. A coating process for a mobile phone back cover, characterized in that: The steps include: (1) placing the cleaned mobile phone back cover into a coating fixture and placing it in a coating chamber, wherein the mobile phone back cover includes a first coating area located on the inner side and a second coating area located on the outer side; (2) Turn on the pump to evacuate and the heating device to heat, and perform four coating operations in sequence using physical vapor deposition on the area to be coated: a. Select a first coating material and perform a first coating in an environment of working gas and reaction gas, and deposit a first coating layer in the area to be coated, wherein the first coating material is Si-Cr2O3 and Si-Cr2O3-CrN-CrC, the working gas is argon, and the reaction gas is oxygen; b. Select a second coating material and perform a second coating in an environment of working gas to deposit the second coating layer on the surface of the first coating layer, wherein the second coating material is Si-Cr2O3-CrN-CrC and the working gas is argon; c. Select a third coating material and perform a third coating in a reaction gas environment to deposit a third coating layer on the surface of the second coating layer, wherein the third coating material is Si-Cr2O3-CrN-CrC and the reaction gas is nitrogen; d. Select a fourth coating material and perform a fourth coating in a reaction gas environment to deposit a fourth coating layer on the surface of the third coating layer, wherein the fourth coating material is Si-Cr2O3-CrN-CrC, and the reaction gas is oxygen; (3) An AF film layer is coated on the surface of the fourth coating layer.

8. The coating process for the back cover of a mobile phone according to claim 7, characterized in that: In the step a, the mass content of Si in Si-Cr2O3 is 10%-20%, and the balance is Cr2O3; in the step ad, the mass content of Si in Si-Cr2O3-CrN-CrC is 7%-15%, the mass content of Cr2O3 is 25%-40%, the mass content of CrN is 15%-25%, and the balance is CrC; in the steps ab, the flow rate of argon is 10-1000sccm, in the steps a and d, the flow rate of oxygen is 10-1000sccm, and in the step c, the flow rate of nitrogen is 10-1000sccm.

9. The coating process for a mobile phone back cover according to claim 7, characterized in that: In the steps ad, the coating is performed by vacuum evaporation, vacuum ion plating or magnetron sputtering, and the gas pressure of the coating is 1.0*10 -4 -1.0*10 -2 Pa, power is 1-15kw, coating temperature is 80-160℃, single coating time is 1-10min, and total coating thickness is 1.5-15.0μm.

10. A mobile phone back cover, characterized in that: The mobile phone back cover is made according to the preparation method according to any one of claims 1-9.

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