WO2016178675A1

WO2016178675A1 - Electroplating and electrophoretic deposition over surfaces of metal substrate

Info

Publication number: WO2016178675A1
Application number: PCT/US2015/029383
Authority: WO
Inventors: Chalam Kashyap; Kuan-Ting Wu; Tony C. KANG
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2015-05-06
Filing date: 2015-05-06
Publication date: 2016-11-10
Also published as: US20180305822A1

Abstract

Various examples described herein provide for a substrate, or a method for preparing a substrate, including a first electroplated layer disposed over a metal substrate, a second electroplated layer disposed under the metal substrate, and an electrophoretic deposition layer disposed over the first electroplated layer.

Description

ELECTROPLATING AND ELECTROPHORETIC DEPOSITION

OVER SURFACES OF METAL SUBSTRATE

BACKGROUND

[1] Various electronic products, such as laptops, tablets, media players, and smartphones, and the like, have a set of external surfaces having a metallic finish. In addition to providing aesthetic appeal, a metallic-finish surface can strengthen the housing of the electronic products.

BRIEF DESCRIPTION OF THE DRAWINGS

[2] Certain examples are described in the following detailed description in reference to the following drawings.

[3] FIGs. 1-6 are flowcharts illustrating example methods for preparing a substrate according to the present disclosure.

[4] FIGs. 7-10 are block diagrams illustrating example substrates according to the present disclosure.

DETAILED DESCRIPTION

[5] Various examples described herein provide for substrates or methods for preparing substrates that include electroplated layers, at least one eiectrophoretic deposition layer, and a metal substrate. Substrates described herein may be utilized as part of an electronic device, such as a laptop, tablet, media player, or a cellular telephone. The substrates may be part of a housing of an electronic device, which may support or house a number of components of the electronic device.

[6] According to some examples, a first electroplated layer is formed over a first exterior surface of a metal substrate, a second electroplated layer is formed over a second exterior surface of the metal substrate, and an eiectrophoretic deposition layer is formed over an exterior surface of the first electroplated layer. For some examples, a functional coating is disposed over the exterior surface of the eiectrophoretic deposition layer, the second electroplated layer, or both. [7] According to additional exampies, a first electroplated layer is formed over a first exterior surface of a metal substrate, a second electroplated layer is formed over a second exterior surface of the metal substrate, a first eiectrophoretic deposition layer is formed over an exterior surface of the first electroplated layer, and a second eiectrophoretic deposition layer is formed over an exterior surface of the second electroplated layer. For some examples, a functional coating is disposed over the exterior surface of the first eiectrophoretic deposition layer, the second eiectrophoretic deposition layer, or both.

[8] In some examples, a metal substrate is produced by way of a milling process, a forging process, or some combination thereof. The milling process may involves a computer numerical control (CNC) milling machine, and the forging process may involve extrusion, plate, a sand cast or a die cast. Subsequently, the exterior surfaces of the metal substrate may be electroplated to produce electroplated layers. Before electropiating an exterior surface of the metal substrate, the exterior surface may be activated by way of a surface treatment (e.g., cleaning and polishing the surfaces), which can remove oxides, hydroxides, or excess lubricant from the exterior surfaces. Eventually, an eiectrophoretic deposition layer is formed over at least one electroplated layer. The exterior surface of the electroplated layers receiving an eiectrophoretic deposition layer may also be activated by way of a surface treatment (e.g., cleaning and polishing the surfaces). Thereafter, a functionai coating may be disposed on the exterior surface of at least one eiectrophoretic deposition layer.

[9] For various examples, the prepared substrate possesses a desirable metallic luster, a desirable metaliic appearance, or both. Some examples include a metal substrate that comprises magnesium or a magnesium alloy (e.g., MgLi alloy) and that possesses a desirable metallic luster. Conventionally, fabricating metallic luster on magnesium and magnesium alloys is difficult, as the magnesium/ magnesium alloys tend to naturally oxidize on the surface. Some substrates described herein experience less coating layer peeling in comparison to coating layers on a bare-metal surface. Additionally, the use of eiectrophoretic deposition in preparing the substrate can provide a short processing cycle time for high productivity, can improve production yield rate for the substrate, and can permit substrates described herein to take more shapes.

[10] As used herein, the terms "over," "under," "between," and "on" refer to a relative position of one layer with respect to other layers. As such, for example, one layer formed over or under another layer may be directly in contact with the other layer or may have a set of intervening layers. Moreover, one layer disposed between two layers may be directly in contact with the two layers or may have a set of intervening layers, in contrast, a first layer "on" a second layer is in contact with that second layer. Additionally, the relative position of one layer with respect to other layers is provided assuming operations are performed relative to a substrate without consideration of the absolute orientation of the substrate.

[11] As also used herein, an "exterior surface" of a particular element (e.g., substrate, layer, coating, etc.) can refer to a surface exposed on the particular element after the particular element has been formed.

[12] FfG. 1 is a flowchart illustrating an example method 100 for preparing a substrate according to the present disclosure. The method 100 may be implemented in the form of executable instructions stored on a non-transitory computer-readable medium or in the form of electronic circuitry, which may cause a set of machines to prepare a substrate according to the example described in connection with FIG. 1. The sequence of operations described in connection with the method 100 is not intended to be limiting, and an example consistent with FIG. 1 need not perform the sequence of operations in the particular order depicted.

[13] As shown, the method 100 may begin at block 102 by forming a first electroplated layer over a metal substrate. Forming the first electroplated layer may involve an electroplating process that includes aluminum, zinc, copper, chromium, or nickel electroplating. For some examples, forming the first electroplated layer comprises electroplating an exterior surface of the metal substrate (e.g., an exterior surface on the upper-side of the metal substrate), thereby forming the first electroplated layer on that exterior surface, in particular, forming the first electroplated layer over the metal substrate may comprise activating an upper-side exterior surface of the metal substrate and then electroplating the activated upper-side exterior surface. As described herein, activating the upper-side exterior surface of the metal substrate may comprise applying a surface treatment to the upper-side exterior surface, which can remove oxides, hydroxides, or excess lubricant from the upper-side exterior surface. As also described herein, example surface treatments can include, without limitation, cleaning and polishing.

[14] Depending on the example, the metal substrate may be a multi-layer metal. Additionally, depending on the example, the metal substrate may comprise aluminum, magnesium, lithium, zinc, titanium, niobium, stainless steel, cooper, or an alloy thereof. For instance, the metal substrate may comprise a magnesium alloy, such as AZ91 (which includes magnesium, aluminum, and zinc) and LZ91 (which includes magnesium, lithium, and zinc). As described herein, the metal substrate may be created by way of a milling process (e.g., by a computer numerical control [CNC] milling machine), a forging process (e.g., by a sand cast or a die cast), or some combination thereof.

[15] The method 100 may continue to block 104 by forming a second electroplated layer under a metal substrate. Forming the second electroplated layer may involve an electroplating process that includes aluminum, zinc, copper, chromium, or nickel electroplating. For some examples, forming the second electroplated layer comprises electroplating an exterior surface of the metal substrate (e.g., an exterior surface on the underside of the metal substrate), thereby forming the second electroplated layer on that exterior surface. As described herein, the second electroplated layer may be formed by performing an electroplating process on the second exterior surface of the metal substrate, thereby forming the second electroplated layer on the second exterior surface of the metal substrate. In particular, forming the second electroplated layer under the metal substrate may comprise activating the underside exterior surface of the metal substrate and then electroplating the activated underside exterior surface. As described herein, activating the underside exterior surface of the metal substrate may comprise applying a surface treatment to the underside exterior surface, which can remove oxides, hydroxides, or excess lubricant from the underside exterior surface.

[16] The method 100 may continue to block 106 by forming an electrophoretic deposition layer over the first electroplated layer formed at block 102. For various examples, the electrophoretic deposition layer comprises a polyacrylic polymer, an epoxy polymer, inorganic particles, or a metal, which may include aluminum, magnesium, lithium, zinc, titanium, niobium, stainless steel, copper, or an alloys thereof. The electrophoretic deposition layer may have a thickness from about 0.5 microns to about 100 microns and, in particular examples, has a thickness from about 3 microns to about 30 microns. The electrophoretic deposition layer may be formed by an electrophoretic deposition process, which may involve an electrophoretic deposition coating bath and a precursor, such as colloidal particles. The electrophoretic deposition process may be performed on an exterior surface of the first electroplated layer, thereby forming the electrophoretic deposition layer on the exterior surface of the first electroplated layer. In particular, forming the electrophoretic deposition layer over the first electroplated layer may comprise activating the exterior surface of the first electroplated layer and then performing electrophoretic deposition on the activated exterior surface. As described herein, activating the exterior surface of the first electroplated layer may comprise applying a surface treatment to the exterior surface, which can remove oxides, hydroxides, or excess lubricant from the exterior surface.

[17] FIG. 2 is a flowchart illustrating an example method 200 for preparing a substrate according to the present disclosure. The method 200 may be implemented in the form of executable instructions stored on a non-transitory computer-readable medium or in the form of electronic circuitry, which may cause a set of machines to prepare a substrate according to the example described in connection with FIG. 2. The sequence of operations described in connection with the method 200 is not intended to be limiting, and an example consistent with FIG. 2 need not perform the sequence of operations in the particular order depicted. [18] As shown, the method 200 may begin with blocks 202, 204, and 206, which may be respectively similar to blocks 102, 104, and 106 of the method 100 as described above with respect to FIG. 1.

[19] The method 200 may continue to block 208 by disposing a functional coating over the electrophoretic deposition layer formed at block 206. For some examples, the functional coating comprises a conformal coating, an ultraviolet (UV) coating, an anti-finger print coating, a soft touch coating, an anti-bacterial coating, an anti-smudge coating or an insulation coating. In some examples, the functionai coating is disposed on the exterior surface of the electrophoretic deposition layer.

[20] FIG. 3 is a flowchart illustrating an example method 300 for preparing a substrate according to the present disclosure. The method 300 may be implemented in the form of executable instructions stored on a non-transitory computer-readable medium or in the form of electronic circuitry, which may cause a set of machines to prepare a substrate according to the example described in connection with FIG. 3. The sequence of operations described in connection with the method 300 is not intended to be limiting, and an example consistent with FIG. 3 need not perform the sequence of operations in the particular order depicted.

[21] As shown, the method 300 may begin with blocks 302, 304, and 306, which may be respectively similar to blocks 102, 104, and 106 of the method 100 as described above with respect to FIG. 1.

[22] The method 300 may continue to block 308 by disposing a functional coating under the second electroplated layer formed at block 304. As described herein, the functional coating may comprise a conformal coating, an ultraviolet (UV) coating, an anti-finger print coating, a soft touch coating, an anti-bacterial coating, an anti-smudge coating or an insulation coating. In some examples, the functional coating is disposed on the exterior surface of the second electroplated layer.

[23] FIG. 4 is a flowchart illustrating an example method 400 for preparing a substrate according to the present disclosure. The method 400 may be implemented in the form of executable instructions stored on a non-transitory computer-readabie medium or in the form of electronic circuitry, which may cause a set of machines to prepare a substrate according to the example described in connection with FIG. 4. The sequence of operations described in connection with the method 400 is not intended to be limiting, and an example consistent with FIG. 4 need not perform the sequence of operations in the particular order depicted.

[24] As shown, the method 400 may begin with blocks 402 and 404, which may be respectively similar to blocks 102 and 104 of the method 100 as described above with respect to FIG. 1.

[25] The method 400 may continue to block 406 by forming a first electrophoretic deposition layer over the first electroplated layer formed at block 402. As described herein, the first electrophoretic deposition layer may comprise a polyacryiic polymer, an epoxy polymer, inorganic particles, or a metal, which may include aluminum, magnesium, lithium, zinc, titanium, niobium, stainless steel, copper, or an alloys thereof. Additionally, the first electrophoretic deposition layer may be formed by an electrophoretic deposition process, which may involve an electrophoretic deposition coating bath and a precursor, such as colloidal particles. The electrophoretic deposition process may be performed on an exterior surface of the first electroplated layer, thereby forming the first electrophoretic deposition layer on the exterior surface of the first electroplated layer. The first electrophoretic deposition layer may have a thickness from about 0.5 microns to about 100 microns and, in particular examples, has a thickness from about 3 microns to about 30 microns.

[26] The method 400 may continue to block 408 by forming a second electrophoretic deposition layer under the second electroplated layer formed at block 404. The second electrophoretic deposition layer may be similar in composition to the first electrophoretic deposition layer. Likewise, the second electrophoretic deposition layer may be formed by an electrophoretic deposition process, and this electrophoretic deposition process may be performed on an exterior surface of the second electroplated layer, thereby forming the second electrophoretic deposition layer on the exterior surface of the second electroplated layer. The second electrophoretic deposition layer may have a thickness from about 0.5 microns to about 100 microns and, in particular examples, has a thickness from about 3 microns to about 30 microns.

[27] The method 400 may continue to block 410 by disposing a first functional coating over the first eiectrophoretic deposition layer formed at block 406. As described herein, the first functional coating may comprise a conformal coating, an ultraviolet (UV) coating, an anti-finger print coating, a soft touch coating, an anti-bacterial coating, an anti-smudge coating or an insulation coating. In some examples, the first functional coating is disposed on the exterior surface of the first eiectrophoretic deposition layer.

[28] The method 400 may continue to block 412 by disposing a second functional coating under the second eiectrophoretic deposition layer formed at block 406. As described herein, the second functional coating may comprise a conformal coating, an ultraviolet (UV) coating, an anti-finger print coating, a soft touch coating, an anti-bacterial coating, an anti-smudge coating or an insulation coating, in some examples, the second functional coating is disposed on the exterior surface of the second eiectrophoretic deposition layer.

[29] FfG. 5 is a flowchart illustrating an example method 500 for preparing a substrate according to the present disclosure. The method 500 may be implemented in the form of executable instructions stored on a non-transitory computer-readable medium or in the form of electronic circuitry, which may cause a set of machines to prepare a substrate according to the example described in connection with FIG. 5. The sequence of operations described in connection with the method 500 is not intended to be limiting, and an example consistent with FIG. 5 need not perform the sequence of operations in the particular order depicted.

[30] As shown, the method 500 may begin at block 502 by electroplating a first exterior surface of a metal substrate. The method 500 may continue to block 504 by electroplating a second exterior surface of the metal substrate. For some examples, the second exterior surface of the metal substrate is opposite the first exterior surface of the metal substrate. For instance, the first exterior surface may be on the upper-side of the metal substrate and the second exterior surface may be on the underside of the metal substrate. The method 500 may continue to block 506 by performing eiectrophoretic deposition on the electroplated first exterior surface resulting from block 502.

[31] FIG. 6 is a flowchart illustrating an example method 600 for preparing a substrate according to the present disclosure. The method 600 may be implemented in the form of executable instructions stored on a non-transitory computer-readable medium or in the form of electronic circuitry, which may cause a set of machines to prepare a substrate according to the example described in connection with FIG. 6. The sequence of operations described in connection with the method 600 is not intended to be limiting, and an example consistent with FIG. 6 need not perform the sequence of operations in the particular order depicted.

[32] As shown, the method 600 may begin with blocks 602, 604, and 606, which may be respectively similar to blocks 502, 504, and 506 of the method 500 as described above with respect to FIG. 5. The method 600 may continue to block 608 by performing eiectrophoretic deposition on the electroplated second exterior surface resulting from block 604.

[33] FfG. 7 is a block diagram illustrating an example substrate 700 according to the present disclosure. As shown, the substrate 700 comprises an eiectrophoretic deposition layer 702, a first electroplated layer 704, a metal substrate 706, and a second electroplated layer 708. As also shown, the metal substrate 706 is disposed over the second electroplated layer 708, the first electroplated layer 704 is disposed over the metal substrate 706, and the eiectrophoretic deposition layer 702 is disposed over the first electroplated layer 704. Though FIG. 7 illustrates elements (e.g., layers, coatings, etc.) of the substrate 700 as being in contact with one another, for some examples, a set of other elements (e.g., layers, coating, etc.) may be present between two elements of the substrate 700.

[34] FIG. 8 is a block diagram illustrating an example substrate 800 according to the present disclosure. As shown, the substrate 800 comprises a first eiectrophoretic deposition layer 802, a first electroplated layer 804, a metal substrate 806, a second electroplated layer 808, and a second eiectrophoretic deposition layer 810. As also shown, the second electroplated layer 808 is disposed over the second eiectrophoretic deposition layer 810, the metal substrate 806 is disposed over the second electroplated layer 808, the first electroplated layer 804 is disposed over the metal substrate 806, and the first eiectrophoretic deposition layer 802 is disposed over the first electroplated layer 804. Though FIG. 8 illustrates elements (e.g., layers, coatings, etc.) of the substrate 800 as being in contact with one another, for some examples, a set of other elements (e.g., layers, coating, etc.) may be present between two elements of the substrate 800.

[35] FIG. 9 is a block diagram illustrating an example substrate 900 according to the present disclosure. As shown, the substrate 900 comprises a first functional coating 902, a first eiectrophoretic deposition layer 904, a first electroplated layer 906, a metal substrate 908, a second electroplated layer 910, and a second functional coating 912. As also shown, the second electroplated layer 910 is disposed over the second functional coating 912, the metal substrate 908 is disposed over the second electroplated layer 910, the first electroplated layer 906 is disposed over the metal substrate 908, the first eiectrophoretic deposition layer 904 is disposed over the first electroplated layer 906, and the first functional coating 902 is disposed over the first eiectrophoretic deposition layer 904. Though FIG. 9 illustrates elements (e.g., layers, coatings, etc.) of the substrate 900 as being in contact with one another, for some examples, a set of other elements (e.g., layers, coating, etc.) may be present between two elements of the substrate 900.

[36] FIG. 10 is a block diagram illustrating an example substrate 1000 according to the present disclosure. As shown, the substrate 1000 comprises a first functional coating 1002, a first eiectrophoretic deposition layer 1004, a first electroplated layer 1006, a metal substrate 1008, a second electroplated layer 1010, a second eiectrophoretic deposition layer 1012, and a second functional coating 1014. As also shown, the second eiectrophoretic deposition layer 1012 is disposed over the second functional coating 1014, the metal substrate 1008 is disposed over the second eiectrophoretic deposition layer 1012, the first electroplated layer 1006 is disposed over the metal substrate 1008, the first eiectrophoretic deposition layer 1004 is disposed over the first electroplated layer 1006, and the first functional coating 1002 is disposed over the first eiectrophoretic deposition layer 1004. Though FIG. 10 illustrates elements (e.g., layers, coatings, etc.) of the substrate 1000 as being in contact with one another, for some examples, a set of other elements {e.g., layers, coating, etc.) may be present between two elements of the substrate 1000.

[37] In the foregoing description, numerous details are set forth to provide an understanding of the subject disclosed herein. However, various examples may be practiced without some or all of these details. Some examples may include modifications and variations from the details discussed above. It is intended that the appended claims cover such modifications and variations.

Claims

1. A method, comprising:

forming a first electroplated layer over a metal substrate;

forming a second electroplated layer under the metal substrate; and forming an electrophoretic deposition layer over the first electroplated layer.

2. The method of claim 1 , comprising disposing a functional coating over the electrophoretic deposition layer.

3. The method of claim 1 , comprising disposing a functional coating under the second electroplated layer.

4. The method of claim 1 , comprising forming a second electrophoretic deposition layer over the second electroplated layer.

5. The method of claim 4, comprising disposing a functional coating over the second electrophoretic deposition layer.

6. The method of claim 1 , wherein forming the electrophoretic deposition layer over the first electroplated layer comprises:

activating an exterior surface of the first electroplated layer; and performing electrophoretic deposition on the activated exterior surface of the first electroplated layer to form the electrophoretic deposition layer.

7. The method of claim 1 , wherein forming the first electroplated layer over the metal substrate comprises:

activating an upper-side exterior surface of the metal substrate to produce an activated upper-side exterior surface; and

electroplating the activated upper-side exterior surface to form the first electroplated layer.

8. The method of claim 1 , wherein forming the second electroplated layer under the metal substrate comprises: activating an underside exterior surface of the metal substrate to produce an activated underside exterior surface; and

electroplating the activated underside exterior surface to form the second electroplated layer.

9. A method, comprising:

electroplating a first exterior surface of a metal substrate;

electroplating a second exterior surface of the metal substrate, the second exterior surface being opposite the first exterior surface; and

performing electrophoretic deposition on the electroplated first exterior surface.

10. The method of claim 9, performing electrophoretic deposition on the electroplated second exterior surface.

11. A substrate, comprising:

an electrophoretic deposition layer disposed over a first electroplated layer;

the first electroplated layer disposed over a metal substrate;

the metal substrate disposed over a second electroplated layer; and the second electroplated layer.

12. The substrate of claim 11 , comprising a functional coating disposed over the electrophoretic deposition layer.

13. The substrate of claim 11 , comprising a functional coating disposed under the second electroplated layer.

14. The substrate of claim 11 , comprising a second electrophoretic deposition layer disposed under the second electroplated layer.

15. The substrate of claim 14, comprising a functional coating disposed under the second electrophoretic deposition layer.