U.S. patent application number 13/720136 was filed with the patent office on 2014-02-06 for electrolyte for removing metal-carbide/nitride coatings or metal-carbide-nitride coatings and removing method using same.
This patent application is currently assigned to FIH (HONG KONG) LIMITED. The applicant listed for this patent is FIH (HONG KONG) LIMITED, SHENZHEN FUTAIHONG PRECISION INDUSTRY CO., LTD.. Invention is credited to DA-HUA CAO, TING DING.
Application Number | 20140034514 13/720136 |
Document ID | / |
Family ID | 50024409 |
Filed Date | 2014-02-06 |
United States Patent
Application |
20140034514 |
Kind Code |
A1 |
CAO; DA-HUA ; et
al. |
February 6, 2014 |
ELECTROLYTE FOR REMOVING METAL-CARBIDE/NITRIDE COATINGS OR
METAL-CARBIDE-NITRIDE COATINGS AND REMOVING METHOD USING SAME
Abstract
An electrolyte for removing metal-carbide/nitride coatings or
metal-carbide-nitride coatings from substrates, the electrolyte
includes an acid, an inhibiter and a complexant. The acid is a
mixture of a sulfuric acid and a weak acid. The inhibiter is an
organic compound containing hydrophilic group, lipophilic group,
and at least one polar group selected from nitrogen-containing
group, sulfur-containing group, and hydroxyl group. The complexant
is capable of complexing with Fe.sup.3+. A method for removing the
metal-carbide/nitride coatings or metal-carbide-nitride coatings
using the electrolyte is also provided.
Inventors: |
CAO; DA-HUA; (Shenzhen,
CN) ; DING; TING; (Shenzhen, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHENZHEN FUTAIHONG PRECISION INDUSTRY CO., LTD.
FIH (HONG KONG) LIMITED |
Shenzhen
Kowloon |
|
CN
HK |
|
|
Assignee: |
FIH (HONG KONG) LIMITED
Kowloon
HK
SHENZHEN FUTAIHONG PRECISION INDUSTRY CO., LTD.
Shenzhen
CN
|
Family ID: |
50024409 |
Appl. No.: |
13/720136 |
Filed: |
December 19, 2012 |
Current U.S.
Class: |
205/714 ;
205/766 |
Current CPC
Class: |
C25F 5/00 20130101; C25F
1/00 20130101 |
Class at
Publication: |
205/714 ;
205/766 |
International
Class: |
C25F 1/00 20060101
C25F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 2, 2012 |
CN |
2012102733188 |
Claims
1. An electrolyte for removing metal-carbide/nitride coatings or
metal-carbide-nitride coatings from substrates, the electrolyte
comprising: an acid, the acid being a mixture of a sulfuric acid
and a weak acid; an inhibiter, the inhibiter being an organic
compound containing hydrophilic group, lipophilic group, and at
least one polar group selected from nitrogen-containing group,
sulfur-containing group, and hydroxyl group; and a complexant being
capable of complexing with Fe.sup.3+.
2. The electrolyte as claimed in claim 1, wherein the acid is a
mixture of sulfuric acid and oxalic acid.
3. The electrolyte as claimed in claim 2, wherein in the
electrolyte, the mass percentage of the oxalic acid is about 3% to
about 5%.
4. The electrolyte as claimed in claim 1, wherein the acid is a
mixture of sulfuric acid and acetic acid.
5. The electrolyte as claimed in claim 4, wherein in the
electrolyte, the mass percentage of the acetic acid is about
1%-3%.
6. The electrolyte as claimed in claim 1, wherein the inhibiter is
at least one selected from nicotinamide, (N,N-methylenebis
N'-1-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl))-urea, and
thiourea.
7. The electrolyte as claimed in claim 1, wherein in the
electrolyte, the concentration of the nicotinamide is about 0.1
g/l-0.3 g/l.
8. The electrolyte as claimed in claim 6, wherein in the
electrolyte, the concentration of the (N,N-methylenebis
N'-1-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl))-urea is about 0.1
g/l to about 0.3 g/l.
9. The electrolyte as claimed in claim 1, wherein the complexant is
edetic acid.
10. The electrolyte as claimed in claim 9, wherein in the
electrolyte, the concentration of edetic acid is about 0.1 g/l to
about 0.2 g/l.
11. The electrolyte as claimed in claim 1, wherein the electrolyte
further comprises accelerant, the accelerant is sodium dodecyl
sulphonate.
12. The electrolyte as claimed in claim 11, wherein in the
electrolyte, the concentration of sodium dodecyl sulphonate is
about 0.1 g/l to about 0.2 g/l.
13. A method for removing metal-carbide/nitride coatings or
metal-carbide-nitride coatings comprising: providing a substrate
having at least one coating formed thereon, the at least one
coating being a metal-carbide coating, a metal-nitride coating, or
a metal-carbide-nitride coating; manufacturing an electrolyte, the
electrolyte comprising acid, inhibiter and complexant; immersing
the substrate in the electrolyte to perform an electrolysis to
remove the coating, the substrate being an anode; wherein the acid
is a mixture of a sulfuric acid and a weak acid, the inhibiter
being an organic compound containing hydrophilic group, lipophilic
group, and at least one polar group selected from
nitrogen-containing group, sulfur-containing group, and hydroxyl
group; and the complexant is capable of complexing with
Fe.sup.3+.
14. The method as claimed in claim 13, wherein the substrate is
made of stainless steel or ferric-based alloy.
15. The method as claimed in claim 13, wherein the temperature of
the electrolyte during electrolysis is room temperature.
16. The method as claimed in claim 13, wherein during the
electrolysis process, the current density is about 0.8 A/dm.sup.2
to about 2 A/dm.sup.2, the voltage is about 1 V to about 5 V, the
electrolysis process takes about 2 min to about 8 min.
17. The method as claimed in claim 13, wherein the acid is a
mixture of sulfuric acid and oxalic acid.
18. The method as claimed in claim 13, wherein the acid is a
mixture of sulfuric acid and acetic acid.
19. The method as claimed in claim 13, wherein the inhibiter is at
least one selected from nicotinamide, (N,N-methylenebis
N'-1-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl))-urea, and
thiourea.
20. The method as claimed in claim 13, wherein the complexant is
edetic acid.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The exemplary disclosure relates to an electrolyte for
removing metal-carbide/nitride coatings or metal-carbide-nitride
coatings and removing method using the electrolyte.
[0003] 2. Description of Related Art
[0004] Hard coatings, such as metal-carbide/nitride coatings or
metal-carbide-nitride coatings, impart specific properties to
workpieces such as machining tools, die core-pins, and high
temperature devices. These hard coatings resist wear, abrasion,
oxidation, and corrosion, and reduce susceptibility to chemical
reactions with the workpieces to which they are applied. These
coatings, however, can fail locally during manufacture or use.
[0005] When the coatings fail, the entire die or tool component is
discarded even if the underlying substrate shows no damage, at
considerable cost. For this reason, the ability to recycle the
underlying substrate by removing a failed coating and replacing it
with a new coating is economically preferable.
[0006] Therefore, there is room for improvement within the art.
DETAILED DESCRIPTION
[0007] The present disclosure relates to an electrolyte and a
related method for removing metal-carbide/nitride coatings or
metal-carbide-nitride coatings formed on the surfaces of
substrates. The substrate may be made of stainless steel or
ferric-based alloy.
[0008] The electrolyte is an aqueous solution containing acid,
inhibiter, complexant, and accelerant.
[0009] The acid is a mixture of a sulfuric acid and a weak acid.
The acid provides an acid condition for changing the metal elements
contained in the coatings into metal ions during electrolysis
process. In the embodiment, the weak acid is oxalic acid or acetic
acid. In the electrolyte, the mass percentage of the oxalic acid is
about 3% to about 5%, the mass percentage of the acetic acid is
about 1% to about 3%.
[0010] The inhibiter is an organic compound containing hydrophilic
group, lipophilic group, and at least one polar group selected from
nitrogen-containing group, sulfur-containing group, and hydroxyl
group. The inhibiter is at least one selected from nicotinamide
(C.sub.6H.sub.6N.sub.2O), (N,N-methylenebis
N'-1-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl))-urea
(C.sub.11H.sub.16N.sub.2O.sub.8), and thiourea (H.sub.4N).sub.2S).
In the exemplary embodiment, a combination of
C.sub.6H.sub.6N.sub.2O and C.sub.11H.sub.16N.sub.8O.sub.8 may be
selected. In the electrolyte, the concentration of the nicotinamide
is about 0.1 g/l to about 0.3 g/l, and the concentration of the
C.sub.11H.sub.16N.sub.8O.sub.8 is about 0.1 g/l to about 0.3 g/l.
The inhibiter protects the substrate from being etched or damaged
by the acid.
[0011] During the removing method, the inhibiter reduces the
surface energy of the substrate, and enhances the activation energy
for reaction, thus slowing down the corrosion rate of the
electrolyte to the substrate. Furthermore, the polar group of the
inhibiter can be electrostatic adsorbed onto the surface of the
substrate to form a lipophilic layer on the surface of the
substrate, which protects the substrate from being etched or
damaged by the acid.
[0012] The complexant is capable of complexing with Fe.sup.3+,
which inhibits the corrosion reaction that may exist on the surface
of the substrate. The complexant is edetic acid (EDTA). In the
electrolyte, the concentration of EDTA is about 0.1 g/l to about
0.2 g/l.
[0013] The accelerant is sodium dodecyl sulphonate (OP-10). In the
electrolyte, the concentration of the OP-10 is about 0.1 g/l-0.2
g/l.
[0014] The electrolyte may be manufactured by dissolving the acid,
inhibiter, complexant, and accelerant in water.
[0015] A method for removing the metal-carbide/nitride coatings or
metal-carbide-nitride coatings using the electrolyte may at least
include the following steps:
[0016] A substrate is provided. The substrate may be made of
stainless steel or ferric-based alloy. At least one coating is
formed on the substrate. The coating may be a metal-carbide
coating, a metal-nitride coating, or a metal-carbide-nitride
coating, metal-carbide/nitride coatings or metal-carbide-nitride
coatings.
[0017] The electrolyte is provided. The substrate having the
coating is immersed in the electrolyte and used as an anode, and
carbon material may be provided and used as a cathode. The
temperature of the electrolyte during electrolysis is room
temperature. The current density is about 0.8 A/dm.sup.2-2
A/dm.sup.2, the voltage is about 1 V-5 V. The electrolysis takes
about 2 min-8 min. Then, the substrate is taken out of the
electrolyte and rinsed with water and then dried.
[0018] After electrolysis, the coating can be effectively removed
from the substrate and the underlying substrate is free from damage
for the protection of the inhibiter and the accelerant.
EXAMPLES
[0019] Experimental examples of the present disclosure follow:
Example 1
[0020] 0.1 g C.sub.6H.sub.6N.sub.2O, 0.3 g
C.sub.11H.sub.16N.sub.8O.sub.8, 0.1 g EDTA, 0.2 g OP-10, 5 ml
oxalic acid, and 2 ml sulfuric acid were added to deionized water
to produce 1000 ml of electrolyte.
[0021] Samples of stainless steel substrate were provided. The
stainless steel substrate samples had chromium nitride coatings
formed thereon. The samples, being anodes, were completely immersed
in the electrolyte for about 4 min at an electric current density
of about 1.4 A/dm.sup.2 and an electrolysis voltage of about 3 V.
After electrolysis, the samples were taken out of the electrolyte
and were dried after being rinsed with water. There was no damage
to the stainless steel substrate.
Example 2
[0022] 0.3 g C.sub.6H.sub.6N.sub.2O, 0.1 g
C.sub.11H.sub.16N.sub.8O.sub.8, 0.2 g EDTA, 0.2 g OP-10, 5 ml
oxalic acid, and 2 ml sulfuric acid were added to deionized water
to produce 1000 ml of electrolyte.
[0023] Samples of stainless steel substrate were provided. The
stainless steel substrate samples had chromium carbide coatings
formed thereon. The samples, being anodes, were completely immersed
in the electrolyte for about 4 min at an electric current density
of about 1.4 A/dm.sup.2 and an electrolysis voltage of about 3 V.
After electrolysis, the samples were taken out of the electrolyte
and were dried after being rinsed with water. There was no damage
to the stainless steel substrate.
Example 3
[0024] 0.3 g C.sub.6H.sub.6N.sub.2O, 0.1 g
C.sub.11H.sub.16N.sub.8O.sub.8, 0.2 g EDTA, 0.2 g OP-10, 5 ml
acetic acid, and 2 ml sulfuric acid were added to deionized water
to produce 1000 ml of electrolyte.
[0025] Samples of stainless steel substrate were provided. The
stainless steel substrate samples had chromium carbide coatings
formed thereon. The samples, being anodes, were completely immersed
in the electrolyte for about 2 min at an electric current density
of about 2 A/dm.sup.2 and an electrolysis voltage of about 4V.
After electrolysis, the samples were taken out of the electrolyte
and were dried after being rinsed with water. There was no damage
to the stainless steel substrate.
[0026] It is to be understood, however, that even through numerous
characteristics and advantages of the exemplary disclosure have
been set forth in the foregoing description, together with details
of the system and function of the disclosure, the disclosure is
illustrative only, and changes may be made in detail, especially in
the matters of shape, size, and arrangement of parts within the
principles of the disclosure to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
* * * * *