U.S. patent application number 13/215682 was filed with the patent office on 2012-10-04 for device housing and method for making the same.
This patent application is currently assigned to HON HAI PRECISION INDUSTRY CO., LTD.. Invention is credited to HSIN-PEI CHANG, CHENG-SHI CHEN, WEN-RONG CHEN, HUANN-WU CHIANG, NAN MA.
Application Number | 20120251746 13/215682 |
Document ID | / |
Family ID | 46927616 |
Filed Date | 2012-10-04 |
United States Patent
Application |
20120251746 |
Kind Code |
A1 |
CHANG; HSIN-PEI ; et
al. |
October 4, 2012 |
DEVICE HOUSING AND METHOD FOR MAKING THE SAME
Abstract
A device housing is described. The device housing includes an
aluminum alloy substrate and a compound corrosion resistant layer
formed on the substrate. The compound corrosion resistant layer
includes two crystalline films and a non-crystalline film formed
between the crystalline films. One of the crystalline films is
formed on the substrate. The crystalline film is a
chromium-oxygen-nitrogen film or an aluminum-oxygen-nitrogen film.
The non-crystalline film is an aluminum oxide film or a silicon
dioxide film. A method for making the device housing is also
described.
Inventors: |
CHANG; HSIN-PEI; (Tu-Cheng,
TW) ; CHEN; WEN-RONG; (Tu-Cheng, TW) ; CHIANG;
HUANN-WU; (Tu-Cheng, TW) ; CHEN; CHENG-SHI;
(Tu-Cheng, TW) ; MA; NAN; (Shenzhen City,
CN) |
Assignee: |
HON HAI PRECISION INDUSTRY CO.,
LTD.
Tu-Cheng
TW
HONG FU JIN PRECISION INDUSTRY (ShenZhen) CO., LTD.
Shenzhen City
CN
|
Family ID: |
46927616 |
Appl. No.: |
13/215682 |
Filed: |
August 23, 2011 |
Current U.S.
Class: |
428/34.6 ;
204/192.1; 204/192.15 |
Current CPC
Class: |
C23C 14/0036 20130101;
C23C 14/0676 20130101; Y10T 428/1317 20150115; Y10T 428/12667
20150115 |
Class at
Publication: |
428/34.6 ;
204/192.1; 204/192.15 |
International
Class: |
B32B 1/02 20060101
B32B001/02; C23C 14/35 20060101 C23C014/35; C23C 14/08 20060101
C23C014/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2011 |
CN |
201110081194.9 |
Claims
1. A device housing, comprising: an aluminum alloy substrate; and a
compound corrosion resistant layer formed on the substrate, the
compound corrosion resistant layer comprising two crystalline films
and a non-crystalline film formed between the crystalline films,
one of the crystalline films being formed on the substrate; the
crystalline film being a chromium-oxygen-nitrogen film or an
aluminum-oxygen-nitrogen film, the non-crystalline film being an
aluminum oxide film or a silicon dioxide film.
2. The device housing as claimed in claim 1, wherein each
crystalline film has a thickness of about 300 nm-800 nm.
3. The device housing as claimed in claim 1, wherein the
non-crystalline film has a thickness of about 300 nm-600 nm.
4. The device housing as claimed in claim 1, wherein the
crystalline films contain columnar crystals having a plurality of
inter-crystal pores.
5. The device housing as claimed in claim 1, wherein the
crystalline films contain Cr--O and Cr--N crystalline phases, or
Al--O and Al--N crystalline phases.
6. The device housing as claimed in claim 1, wherein the
non-crystalline film has an internal disorder structure.
7. A method for making a device housing, comprising: providing an
aluminum alloy substrate; and forming a compound corrosion
resistant layer on the substrate by vacuum sputtering, the compound
corrosion resistant layer comprising two crystalline films and a
non-crystalline film formed between the crystalline films, one of
the crystalline films being formed on the substrate; the
crystalline film being a chromium-oxygen-nitrogen film or an
aluminum-oxygen-nitrogen film, the non-crystalline film being an
aluminum oxide film or a silicon dioxide film.
8. The method as claimed in claim 7, wherein forming the compound
corrosion resistant layer comprising steps of vacuum sputtering one
of the crystalline films on the substrate, vacuum sputtering the
non-crystalline film on the crystalline film, and vacuum sputtering
the other crystalline film on the non-crystalline film.
9. The method as claimed in claim 8, wherein vacuum sputtering the
crystalline films uses a magnetron sputtering process, uses
nitrogen and oxygen as reaction gases, the nitrogen and oxygen have
a flow rate of about 20 sccm-40 sccm and 40 sccm-60 sccm
respectively; uses argon as a working gas, the argon has a flow
rate of about 130 sccm-200 sccm; ratios of partial pressure of the
nitrogen and the oxygen are about 5%-20% and about 15%-40%
respectively with regards to total of the nitrogen, oxygen, and
argon; uses a target made of aluminum or chromium, the target is
applied with a power of about 5 KW-8 KW; magnetron sputtering of
the crystalline film is conducted at a temperature of about
100.degree. C.-150.degree. C. and takes about 30 min-150 min.
10. The method as claimed in claim 9, wherein the substrate has a
bias voltage of about -100V to about -200V during sputtering of the
crystalline film.
11. The method as claimed in claim 8, wherein vacuum sputtering the
non-crystalline film uses a magnetron sputtering process, uses
oxygen as a reaction gas, the oxygen has a flow rate of about 50
sccm-150 sccm; uses argon as a working gas, the argon has a flow
rate of about 130 sccm-200 sccm; ratio of partial pressure of the
oxygen is about 30%-90% with regards to total of the oxygen and
argon; uses a target made of silicon or aluminum, the target is
applied with a power of about 6 KW-8 KW; magnetron sputtering of
the non-crystalline film is conducted at a temperature of about
100.degree. C.-150.degree. C. and takes about 20 min-70 min.
12. The method as claimed in claim 11, wherein the substrate has a
bias voltage of about -100V to about -200V during sputtering of the
non-crystalline film.
13. The method as claimed in claim 7, further comprising a step of
pre-treating the substrate before forming the compound corrosion
resistant layer.
14. The method as claimed in claim 13, wherein the pre-treating
process comprising ultrasonic cleaning the substrate and plasma
cleaning the substrate.
15. The method as claimed in claim 14, wherein plasma cleaning of
the substrate uses argon as a working gas, the argon has a flow
rate of about 500 sccm; the substrate has a bias voltage of about
-500 V to about -800 V; plasma cleaning of the substrate takes
about 5 min-10 min.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure relates to device housings,
particularly to a device housing having a corrosion resistance
property and a method for making the device housing.
[0003] 2. Description of Related Art
[0004] Aluminum alloy is widely used for its excellent properties.
To protect the aluminum alloy from corrosion, protective layers may
be formed on the aluminum alloy by anodizing, painting, or vacuum
depositing. However, the anodizing and painting processes are not
environmentally friendly, and protective layers formed by vacuum
depositing may have pinholes and cracks formed therein. These
pinholes and cracks allow corrosives to permeate the layers, which
causes a galvanic corrosion to the layers and the underlying
aluminum alloy.
[0005] Therefore, there is room for improvement within the art.
BRIEF DESCRIPTION OF THE FIGURES
[0006] Many aspects of the disclosure can be better understood with
reference to the following figures. The components in the figures
are not necessarily drawn to scale, the emphasis instead being
placed upon clearly illustrating the principles of the disclosure.
Moreover, in the drawings like reference numerals designate
corresponding parts throughout the several views.
[0007] FIG. 1 is a cross-sectional view of an exemplary embodiment
of a device housing.
[0008] FIG. 2 is an overhead view of an exemplary embodiment of a
vacuum sputtering device.
DETAILED DESCRIPTION
[0009] FIG. 1 shows a device housing 10 according to an exemplary
embodiment. The device housing 10 includes an aluminum alloy
substrate 11, and a compound corrosion resistant layer 13 formed on
a surface of the substrate 11.
[0010] The compound corrosion resistant layer 13 includes two
crystalline films 131 and a non-crystalline film 133 formed between
the two crystalline films 131. One of the crystalline films 131 is
directly formed on the substrate 11.
[0011] Each crystalline film 131 may be a chromium-oxygen-nitrogen
(Cr--O--N) film or an aluminum-oxygen-nitrogen (Al--O--N) film in
which columnar crystals having a plurality of inter-crystal pores
(not shown) are formed. The crystalline film 131 contains Cr--O and
Cr--N crystalline phases, or Al--O and Al--N crystalline phases.
Each phase inhibits the growth of the other phase, so the size of
the crystalline grains in the crystalline film 13 is reduced and
the density of the crystalline film 131 is enhanced, which enables
the device housing 10 to have a good corrosion resistance property.
Each crystalline film 131 has a thickness of about 300 nm-800
nm.
[0012] The non-crystalline film 133 may be an aluminum oxide
(Al.sub.2O.sub.3) film or a silicon dioxide (SiO.sub.2) film. The
non-crystalline film 133 has a thickness of about 300 .mu.m-500
.mu.m. The non-crystalline film 133 has an internal disorder
structure. The non-crystalline film 133 is also a hard coating,
which has a high hardness.
[0013] As mentioned above, the non-crystalline film 133 having an
internal disorder structure obstructs the inter-crystal pores of
the two crystalline films 131 from connection. This prevents
corrosives from permeating the films 131 and 133 and affecting the
substrate 11, thus reducing the corrosion in the device housing 10
and achieves an excellent corrosion resistance property.
[0014] The crystalline films 131 and the non-crystalline film 133
may be all formed by vacuum deposition, such as vacuum sputtering
or evaporation deposition.
[0015] A method for making the device housing 10 may include the
following steps:
[0016] The substrate 11 is pre-treated. The pre-treating process
may include the following steps:
[0017] The substrate 11 is cleaned in an ultrasonic cleaning device
(not shown) filled with ethanol or acetone.
[0018] The substrate 11 is plasma cleaned. Referring to FIG. 2, the
substrate 11 may be positioned in a coating chamber 21 of a vacuum
sputtering device 20. The coating chamber 21 is fixed with first
targets 23 and second targets 24 therein. The first targets 23 are
made of chromium or aluminum, the second targets 24 are made of
silicon or aluminum. The coating chamber 21 is then evacuated to
about 8.0.times.10.sup.-3 Pa. Argon (Ar) gas having a purity of
about 99.999% may be used as a working gas and is fed into the
coating chamber 21 at a flow rate of about 500 standard-state cubic
centimeters per minute (sccm). The substrate 11 may have a bias
voltage of about -500 V to about -800 V, then high-frequency
voltage is produced in the coating chamber 21 and the argon gas is
ionized to plasma. The plasma then strikes the surface of the
substrate 11 to clean the surface of the substrate 11. Plasma
cleaning the substrate 11 may take about 5 minutes (min) to about
10 min. The plasma cleaning process enhances the bond between the
substrate 11 and the compound corrosion resistant layer 13. The
first targets 23 and the second targets 24 are unaffected by the
pre-cleaning process.
[0019] One of the crystalline films 131 may be magnetron sputtered
on the pretreated substrate 11 by using the first targets 23.
Magnetron sputtering of the crystalline film 131 is implemented in
the coating chamber 21. The internal temperature of the coating
chamber 21 may be heated to about 100.degree. C.-150.degree. C.
Nitrogen (N.sub.2) and oxygen (O.sub.2) may be used as reaction
gases and are fed into the coating chamber 21 at a flow rate of
about 20 sccm-40 sccm and about 40 sccm-60 sccm respectively. Argon
gas may be used as a working gas and is fed into the coating
chamber 21 at a flow rate of about 130 sccm-200 sccm. The ratio of
partial pressure of the nitrogen may be about 5%-20% with regards
to the total gases in the coating chamber 21, the ratio of partial
pressure of the oxygen may be about 15%-40% with regards to the
total gases in the coating chamber 21. A power of about 5 kilowatt
(KW)-8 KW is applied on the first targets 23, and then aluminum
atoms or chromium atoms are sputtered off from the first targets
23. The aluminum or chromium atoms, nitrogen atoms, and oxygen
atoms are then ionized in an electrical field in the coating
chamber 21. The ionized aluminum or chromium chemically reacts with
the ionized nitrogen and oxygen and deposits on the substrate 11 to
form the crystalline film 131. During the depositing process, the
substrate 11 may have a bias voltage of about -100 V to about -200
V. Depositing of the crystalline film 131 may take about 30 min-150
min.
[0020] The non-crystalline film 133 may be magnetron sputtered on
the crystalline film 131 by using the second targets 24. Magnetron
sputtering of the non-crystalline film 133 is implemented in the
coating chamber 21. The internal temperature of the coating chamber
21 may be maintained at about 100.degree. C.-150.degree. C. Oxygen
(O.sub.2) may be used as a reaction gas and is fed into the coating
chamber 21 at a flow rate of about 50 sccm-150 sccm. Argon gas may
be used as a working gas and is fed into the coating chamber 21 at
a flow rate of about 130 sccm-200 sccm. The ratio of partial
pressure of the oxygen may be about 30%-90% with regards to the
total gases in the coating chamber 21. A power of about 6 KW-8 KW
is applied on the second targets 24, and then silicon atoms or
aluminum atoms are sputtered off from the second targets 24. The
silicon or aluminum atoms and oxygen atoms are then ionized in an
electrical field in the coating chamber 21. The ionized silicon or
aluminum chemically reacts with the ionized oxygen and deposits on
the crystalline film 131 to form the non-crystalline film 133.
During the depositing process, the substrate 11 may have a bias
voltage of about -100 V to about -200 V. Depositing of the
non-crystalline film 133 may take about 20 min-70 min.
[0021] The step of magnetron sputtering the crystalline film 131 is
repeated to form the other crystalline film 131 on the
non-crystalline film 133 and forms the compound corrosion resistant
layer 13.
[0022] Specific examples of making the device housing 10 are
described below. The ultrasonic cleaning in these specific examples
may be substantially the same as described above so it is not
described here again. Additionally, the process of magnetron
sputtering the compound corrosion resistant layer 13 in the
specific examples is substantially the same as described above, and
the specific examples mainly emphasize the different process
parameters of making the device housing 10.
Example 1
[0023] The substrate 11 is made of 6061 or 6063 aluminum alloy.
[0024] Plasma cleaning the substrate 11: the flow rate of argon gas
is 500 sccm; the substrate 11 has a bias voltage of -500 V; plasma
cleaning of the substrate 11 takes 8 min.
[0025] Sputtering to form a crystalline film 131 on the substrate
11: the flow rate of argon gas is 180 sccm, the flow rate of
nitrogen is 20 sccm, the flow rate of oxygen is 40 sccm; the ratio
of partial pressure of nitrogen is 7%, the ratio of partial
pressure of oxygen is 17%; the substrate 11 has a bias voltage of
-170 V; the first targets 23 are made of chromium and are applied
with a power of 6 KW; the internal temperature of the coating
chamber 21 is 120.degree. C.; sputtering of the crystalline film
131 takes 60 min; the crystalline film 131 has a thickness of 500
nm.
[0026] Sputtering to form non-crystalline film 133 on the
crystalline film 131: the flow rate of argon gas is 180 sccm, the
flow rate of oxygen is 80 sccm; the ratio of partial pressure of
oxygen is 30%; the substrate 11 has a bias voltage of -150 V; the
second targets 24 are made of silicon and are applied with a power
of 6 KW; the internal temperature of the coating chamber 21 is
120.degree. C.; sputtering of the non-crystalline film 133 takes 70
min; the non-crystalline film 133 has a thickness of 400 nm.
[0027] Repeats the step of sputtering the crystalline film 131 to
form another crystalline film 131 on the non-crystalline film
133.
Example 2
[0028] The substrate 11 is made of 5052 aluminum alloy.
[0029] Plasma cleaning the substrate 11: the flow rate of argon gas
is 500 sccm; the substrate 11 has a bias voltage of -600 V; plasma
cleaning of the substrate 11 takes 5 min.
[0030] Sputtering to form a crystalline film 131 on the substrate
11: the flow rate of argon gas is 150 sccm, the flow rate of
nitrogen is 30 sccm, the flow rate of oxygen is 60 sccm; the ratio
of partial pressure of nitrogen is 12.5%, the ratio of partial
pressure of oxygen is 25%; the substrate 11 has a bias voltage of
-200 V; the first targets 23 are made of aluminum and are applied
with a power of 8 KW; the internal temperature of the coating
chamber 21 is 150.degree. C.; sputtering of the crystalline film
131 takes 90 min; the crystalline film 131 has a thickness of 300
nm.
[0031] Sputtering to form non-crystalline film 133 on the
crystalline film 131: the flow rate of argon gas is 150 sccm, the
flow rate of oxygen is 100 sccm; the ratio of partial pressure of
oxygen is 40%; the substrate 11 has a bias voltage of -150 V; the
second targets 24 are made of silicon and are applied with a power
of 8 KW; the internal temperature of the coating chamber 21 is
150.degree. C.; sputtering of the non-crystalline film 133 takes 60
min; the non-crystalline film 133 has a thickness of 350 nm.
[0032] Repeats the step of sputtering the crystalline film 131 to
form another crystalline film 131 on the non-crystalline film
133.
[0033] A salt spray test has been performed on the device housings
10 described in the above examples 1-2. The salt spray test used a
sodium chloride (NaCl) solution having a mass concentration of 5%
at a temperature of 35.degree. C. The test indicated that the
corrosion resistance property of the device housing 10 lasted
longer than 96 hours. Thus, the device housing 10 has an excellent
corrosion resistance property.
[0034] It is believed that the exemplary embodiment and its
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 disclosure or
sacrificing all of its advantages, the examples hereinbefore
described merely being preferred or exemplary embodiment of the
disclosure.
* * * * *