U.S. patent application number 12/416248 was filed with the patent office on 2009-10-15 for method for surface treating a substrate.
This patent application is currently assigned to SHENZHEN FUTAIHONG PRECISION INDUSTRY CO., LTD.. Invention is credited to CHENG-SHIN CHEN, CHUAN-LONG CHEN, RUN-YI CHEN, YUEH-FENG LEE, JONG-YI SU, REN-NING WANG.
Application Number | 20090255824 12/416248 |
Document ID | / |
Family ID | 40933601 |
Filed Date | 2009-10-15 |
United States Patent
Application |
20090255824 |
Kind Code |
A1 |
SU; JONG-YI ; et
al. |
October 15, 2009 |
METHOD FOR SURFACE TREATING A SUBSTRATE
Abstract
A method for surface treating a substrate includes following
steps. Firstly, a substrate including a metallic surface capable of
being electroplated with a metal coating is provided. Secondly, a
first metal coating is electroplated onto the metallic surface of
the substrate. Thirdly, an oxidized metal film is formed to cover
the first metal coating. The first metal coating of substrate is
blasted using quartz sand. The oxidized metal film is removed from
the first metal coating. The second metal coating is electroplated
onto the first metal coating.
Inventors: |
SU; JONG-YI; (Shindian,
TW) ; CHEN; CHENG-SHIN; (Shindian, TW) ; LEE;
YUEH-FENG; (Shindian, TW) ; CHEN; CHUAN-LONG;
(Shindian, TW) ; WANG; REN-NING; (Shenzhen City,
CN) ; CHEN; RUN-YI; (Shenzhen City, CN) |
Correspondence
Address: |
PCE INDUSTRY, INC.;ATT. Steven Reiss
288 SOUTH MAYO AVENUE
CITY OF INDUSTRY
CA
91789
US
|
Assignee: |
SHENZHEN FUTAIHONG PRECISION
INDUSTRY CO., LTD.
ShenZhen City
CN
FIH (HONG KONG) LIMITED
Kowloon
HK
|
Family ID: |
40933601 |
Appl. No.: |
12/416248 |
Filed: |
April 1, 2009 |
Current U.S.
Class: |
205/182 |
Current CPC
Class: |
C25D 5/48 20130101; C25D
5/34 20130101; C25D 5/10 20130101; C25D 3/38 20130101 |
Class at
Publication: |
205/182 |
International
Class: |
C25D 5/10 20060101
C25D005/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 11, 2008 |
CN |
200810301065.4 |
Claims
1. A method for surface treating a substrate, comprising the steps
of: providing a substrate including a metallic surface capable of
being electroplated with a metal coating; electroplating a first
metal coating onto the metallic surface of the substrate;
passivating the first metal coating by immersing the substrate into
an oxidizing agent to forming an oxidized metal film covering the
first metal coating; sand blasting the first metal coating of
substrate; activating the first metal coating by removing the
oxidized metal film from the first metal coating; and
electroplating a second metal coating onto the first metal
coating.
2. The method as claimed in claim 1, wherein the substrate is made
of plastic, the substrate being metalized by wet chemical
deposition.
3. The method as claimed in claim 2, wherein the metallization of
the substrate comprises steps of forming a noble metal coating on
the substrate and plating a copper layer onto the noble metal
coating in a copper electrolyte containing copper salt and sulfuric
acid.
4. The method as claimed in claim 2, wherein the substrate is made
of plastic selected from a group consisting of acrylonitrile
butadiene styrene, poly methyl methacrylate, and polycarbonate.
5. The method as claimed in claim 1, wherein the substrate is made
of metal selected from a group consisting of steel, aluminum,
titanium, magnesium, and alloys thereof.
6. The method as claimed in claim 1, wherein the first metal
coating is made of copper.
7. The method as claimed in claim 1, wherein the thickness of the
first metal coating is in a range from about 10 to about 50
microns.
8. The method as claimed in claim 1, wherein the oxidizing agent
includes one of chromic acid and chromate salt.
9. The method as claimed in claim 1, wherein the step of sand
blasting the first metal coating is carried out using a mixture of
quartz sand and water in an air sand blower to strike the first
metal coating, to put a plurality of dispersed and distributed
dents in the first metal coating.
10. The method as claimed in claim 1, further comprising a step of
repeatedly passivating the first metal coating by immersing the
substrate into the oxidizing agent after the sand blasting.
11. The method as claimed in claim 9, further comprising a step of
immersing the substrate into hydrofluoric acid to remove residual
quartz sand particles from the first metal coating.
12. The method as claimed in claim 1, wherein the second metal
coating is made of copper and has a thickness less than that of the
first metal coating.
13. The method as claimed in claim 1, wherein the thickness of the
second metal coating is in a range from about 2 to about 8
microns.
14. The method as claimed in claim 1, wherein the second metal
coating is coated with a decorative coating made of chrome, which
has a thickness less than that of the second metal coating.
15. The method as claimed in claim 14, wherein the decorative
coating is in a range from about 0.1 to about 2 microns.
16. A method for surface treating a substrate, comprising the steps
of: providing a substrate including a metallic surface capable of
being electroplated with a metal coating; electroplating a first
metal coating onto the metallic surface of the substrate; forming
an oxidized metal film covering the first metal coating; sand
blasting the first metal coating of substrate; removing the
oxidized metal film from the first metal coating; and
electroplating a second metal coating onto the first metal
coating.
17. The method as claimed in claim 16, wherein the first metal
coating is made of copper and has a thickness in a range from about
10 to about 50 microns.
18. The method as claimed in claim 16, wherein the second metal
coating is made of copper and has a thickness less than that of the
first metal coating.
19. The method as claimed in claim 18, wherein the thickness of the
second metal coating is in a range from about 2 to about 8
microns.
20. The method as claimed in claim 16, wherein the second metal
coating is coated with a decorative coating made of chrome, which
has a thickness in a range from about 0.1 to about 2 microns less
than that of the second metal coating.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates to a method for surface
treating a substrate.
[0003] 2. Discussion of the Related Art
[0004] Mobile devices, such as mobile telephones, personal digital
assistants, or MP3 players, enable consumers to enjoy the
convenience of high technology services, almost anytime and at
virtually any location. These mobile devices often employ a variety
of decorative housings to attract consumers. Electroplating is an
attractive and effective process for improving corrosion resistance
and metallic appearance of the housings. Many housings for mobile
devices are processed to form metal coatings on surfaces thereof by
electroplating.
[0005] However, electroplated housings can be excessively bright
and cause discomfort to the users.
[0006] Therefore, there is room for improvement within the art.
BRIEF DESCRIPTION OF THE DRAWING
[0007] Many aspects of the method for surface treating a substrate
can be better understood with reference to the following drawing.
The components in the drawing are not necessarily to scale, the
emphasis instead being placed upon clearly illustrating the
principles of the method for surface treating a substrate.
[0008] The FIGURE is a flow chart of an exemplary embodiment of a
method for surface treating a substrate.
DETAILED DESCRIPTION OF EMBODIMENTS
[0009] Referring to the FIGURE, a method for surface treating a
substrate may include the steps S100 to S600.
[0010] In step S100, a substrate is provided. The substrate
includes a metallic surface capable of being electroplated with a
metal coating.
[0011] According to the exemplary embodiment, the substrate is made
of plastic selected from a group consisting of acrylonitrile
butadiene styrene (ABS), poly methyl methacrylate (PMMA), and
polycarbonate (PC). The substrate is metalized by wet chemical
deposition. During wet chemical deposition, a surface of the
substrate to be metalized is firstly etched so that the surface is
roughened. The etching of the substrate allows an activating layer
in a subsequent process to be attached to the roughened surface.
The etching process may be carried out, for example, in chromic
acid, chromosulfuric acid, or potassium permanganate etching
solution. An associated cleaning step is then carried out for
cleaning the substrate. Subsequently, the surface of the substrate
is activated in such manner that active metal particles, i.e.,
noble metal particles, are deposited on the surface of the
substrate when being immersed into an activating solution
containing hydrochloric acid, polyamide acid, and noble metal salt.
During activation, the noble metal particles are separated out from
the activating solution, dispersed, and deposited on the surface of
the substrate. The noble metal salt may include palladium salt.
After being activated, the substrate is rinsed with water and then
metalized with chemical plating in a copper electrolyte containing
copper salt and sulfuric acid, thereby depositing a chemical copper
coating on the substrate. As such, the surface of the substrate is
metalized. It should be understood that the substrate can instead
be made of metal selected from a group consisting of steel,
aluminum, titanium, magnesium, and alloys thereof.
[0012] In step S200, a first electroplated metal coating is
deposited onto the metalized surface of the plastic substrate by
electroplating. The first electroplated metal coating may include
copper. The electroplating may be carried out by immersing the
substrate into an electrolyte including at least one of copper
sulfate and copper pyrophosphate, with the metalized surface of the
plastic substrate being a cathode, and a copper anode being
provided and immersed in the electrolyte. The thickness of the
first electroplated metal coating is in a range from about 10 to
about 50 microns.
[0013] In step S300, the first electroplated metal coating is
passivated (i.e., has its chemical reactivity reduced) in an
oxidizing agent containing chromic acid or chromate salt. That is,
the first electroplated metal coating is oxidized to form an
oxidized metal film coated thereon, which may protect the first
electroplated metal coating from moisture corrosion.
[0014] In step S400, the passiviated first electroplated metal
coating then undergoes sand blasting. During the sand blasting
process, a mixture of quartz sand and water in an air sand blower
strike the passiviated first electroplated metal coating, to put a
plurality of dispersed and distributed dents in the passiviated
first electroplated metal coating. The dents cause the first
electroplated metal coating to possess a dull frosted appearance,
which may be more attractive to consumers. The oxidized metal film
is partially struck away from the first electroplated metal coating
by sand blasting, thereby partially exposing the first
electroplated metal coating.
[0015] In step S500, the first electroplated metal coating is
repeatedly passivated in the oxidizing agent so as to passiviate
the exposed portion thereof.
[0016] In step S600, the first electroplated metal coating is
activated to remove the oxidized metal film that covers the first
electroplated metal coating. The activation is carried out in an
electrolyte including sodium hydroxide by an electric current.
[0017] In step S700, the substrate is immersed into hydrofluoric
acid to remove the residual quartz sand on the first electroplated
metal coating.
[0018] In step S800, a second electroplated metal coating is
electroplated onto the first electroplated metal coating. The
second electroplated metal coating may be made one of palladium and
alloys of tin and copper. The thickness of the second electroplated
metal coating is in a range from about 2 to about 8 microns and
less than that of the first electroplated metal coating. It should
be understood that, the second electroplated metal coating can be
further coated with a decorative coating made of chrome, which has
a thickness in a range from about 0.1 to about 2 microns and less
than that of the second electroplated metal coating. The first
electroplated metal coating and the second electroplated metal
coating may give the substrate a dull frosted appearance attractive
to consumers.
[0019] It is believed that the present embodiments and their
advantages will be understood from the foregoing description, and
it will be apparent that various changes may be made thereto
without departing from the spirit and scope of the invention or
sacrificing all of its material advantages, the examples
hereinbefore described merely being preferred or exemplary
embodiments of the invention.
* * * * *