GB2127042A - Method for removing a titanium nitride film - Google Patents
Method for removing a titanium nitride film Download PDFInfo
- Publication number
- GB2127042A GB2127042A GB08323278A GB8323278A GB2127042A GB 2127042 A GB2127042 A GB 2127042A GB 08323278 A GB08323278 A GB 08323278A GB 8323278 A GB8323278 A GB 8323278A GB 2127042 A GB2127042 A GB 2127042A
- Authority
- GB
- United Kingdom
- Prior art keywords
- titanium nitride
- nitride film
- stainless steel
- nitric acid
- acid solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/085—Iron or steel solutions containing HNO3
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- ing And Chemical Polishing (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
This invention relates to a process for removing a titanium nitride film from the surface of a stainless steel article. Removing a titanium nitride film from stainless steel using conventional acid washes does not provide a satisfactory result. This invention provides removal of a titanium nitride film from stainless steel by immersing the stainless steel in a corrosive liquid which is an aqueous nitric acid solution heated to a temperature of greater than approximately 70 DEG C and having a concentration in the range of 15 to 30 percent by volume.
Description
3P ECIFICATION method for removing a titanium nitride film
This invention relates to a process for removing titanium nitride film applied to a surface of stainless steel.
It known conventionally to remove a titanium )xide film by dilute nitric acid or fluoric acid.
However, a titanium nitride film formed by ion blazing cannot be removed satisfactorily with the forementioned nitric acid orfluoric acid. In case f removal by dilute nitric acid, though the itanium nitride film is removed by being mmersed in a dilute nitric acid solution. The surface of the stock from which the film has been emoved undergoes discoloration and/or a colored film of an oxide is produced, so that this nethod is not useful. In case of removal by fluoric Icid, even the surface of the stainless steel naterial is dissolved.In particular, the foregoing :onventional method is not suitable in cases vhere the titanium nitride film is formed on a stainless steel material having an ornament ormed in advance and then the titanium nitride ilm is removed for producing a two-tone pattern :omposed of the finished stainless steel surface ind the unremoved titantium nitride film.
To elaborate, a titanium nitride film formed by Dn plating and consisting of TiNx is made for exhibiting the desired coloration by varying x in a value from about 0.2 to about 3. When x has a DW value, the titanium nitride film consisting of iNx has a pale yellow color. When x has a high tale, the film has a deep yellow color. In general,
TiNx film is formed by ion plating within a onstantly changing plasma. Therefore, the film onsists of mixed layers having various x values nd have a wide variety of crystal structures, hereby resulting in differing chemical resistance haracteristics of the films, respectively. With the onventional method, therefore, workmanships of he products are various.
According to the present invention, there is provided a method for removing a titanium nitride ilm which is applied to a stainless steel material, omprising the step of immersing said stainless teel material having said titanium nitride film in a orrosive liquid which is an aqueous nitric acid olution heated to a temperature of more than bout 70"C and having a concentration of 1 5 to 10 percent by volume.
In the accompanying drawings, in which:
Fig. 1 is a graph showing the relation between he temperature of an aqueous nitric acid solution nd the corrosion rate of a titanium nitride film;
Fig. 2 is a perspective view of a watch case in ccordance with the present invention;
Figs. 3(A) and (B) are photographs of the tainless steel surface before formation of the titanium nitride film and after the removal thereof, spectively; and
Fig. 4 is a photograph of a stainless steel urface according to the present invention.
The present invention is characterized by using 5 to 30 percent by volume of an aqueous nitric acid solution at a temperature of more than about 700C as the corrosive liquid for a titanium nitride film that has been applied to a stainless steel material.
As for the temperature of the aqueous nitric acid solution, it is well-known in the art to use nitric acid at room temperature, or nitric acid which is warm. However, in the present invention, nitric acid is heated to a temperature of more than about 700 C. Since a temperature of less than about 700C would greatly reduce the corrosion rate, the temperature of more than 700C is adopted. However, when the temperature approaches 1000C, the nitric acid solution becomes boiled and splash. Accordingly, it is preferred that the temperature be no higher than about 950C.
Fig. 1 is a graph showing the relation between the temperature of the aqueous nitric acid solution and the corrosion rate. It will be appreciated from the drawing that the corrosion rate changes suddenly at the boundary of about 700C.
The concentration of the aqueous nitric acid solution used ranges from 1 5 to 30 percent by volume. In case of concentration of less than 15% the corrosion becomes slow, therefore, the efficiency of the operation declines. In case of a concentration of greater than 30%, the corrosion rate also becomes slow, similar to the concentration of less than 15%. Further, in this case, owing to a black-colored film is produced on the surface of the stainless steel material, the finish of the surface is unsatisfactory.
In accordance with the process of the present invention, a titanium nitride film can be removed rapidly, without degrading a quality of the surface of the stainless steel material, by making the foregoing conditions.
Embodiments of the present invention will now be described in detail.
Example I
This example will now be described that a watch case made of stainless steel and having some portions exposed and other portions coated with a titanium nitride film is produced.
First, a stainless steel (SUS 304 in Japan
Industrial Standards) is shaped into a watch case.
The surface of the watch case is finished by a well-known machining method.
Next, the surface is coated with a titanium nitride film by an ion plating process. The thickness of the titanium nitride film is 1 ,um.
Then, an attractive pattern is formed on the titanium nitride film of the watch case by using a protective coating made of a nitric acid-resistant or epoxy resin. This patterning is carried out by a brush or by printing.
After the protective coating hardens, the watch case is immersed in an aqueous nitric acid solution under the following conditions:
aqueous nitric acid solution: 25 percent by
volume
immersion temperature and time: 800C, 48
hours
The aqueous nitric acid solution is stirred to maintain a distribution of a uniform temperature.
Also, the immersion time is variously set by depending upon the thickness of the titanium nitride film.
After 48 hours, the protective coating of the watch case is removed by a stripping agent to provide the completed watch case.
Fig. 2 is a perspective view of the completed watch case, and Figs. 3(A) and (B) are photographs of the stainless steel surface before formation of the titanium nitride film and after the removal thereof, respectively, in accordance with this example. Fig. 4 is a photograph of the stainless steel surface after removal of the titanium nitride film in accordance with this example. As shown in these photographs, by using the process of the present invention, the surface quality which prevailed prior to coating is maintained without the stainless steel surface experiencing sagging of the rugged pattern or discoloration, even though the titanium nitride film has been removed. It is thus possible to obtain a watch case having a two-tone pattern afforded by the combination of the gold colored titanium nitride and the white colored stainless steel, as shown in Fig. 2.
Example II
This example will now be described that a titanium nitride film applied to a watch case made of stainless steel is removed in its entirely.
As in Example I, a watch case made of stainless steel (SUS 304) is coated with a titanium nitride film by an ion plating process. The thickness of the titanium nitride film is 1.2 ym.
The watch case is immersed in an aqueous nitric acid solution under the following conditions:
aqueous nitric acid solution: 20 percent by
volume
immersion temperature and time: 95"C, 30
hours
After 30 hours, the watch case is withdrawn to complete the removal process. In the present embodiment, the stainless steel surface from which the film has been removed has a condition the same as that prior to coating.
Accordingly, if a titanium nitride film is not formed satisfactorily by the ion plating process, the titanium nitride film is removed by the process of the present example, and then ion plating can be carried again to produce the titanium nitride film.
Further, adding a surface-active agent to the aqueous nitric acid solution will have the effect of removing the titanium nitridr film uniformly.
Articles to which the process of the present invention can be applied include watch components and ornamental articles such as spectacle frames, lighters and tie pins. The method of the present invention is also applicable to mechanical components requiring corrosion, heat and acid resistance.
in accordance with the present invention as set forth hereinabove, a stainless steel surface coated with a titanium nitride film can have the film removed without any deterioration.
Claims (7)
1. A method for removing a titanium nitride film which is applied to a stainless steel material, comprising the step of:
immersing said stainless steel material having
said titanium nitride film is a corrosive liquid
which is an aqueous nitric acid solution
heated to a temperature of more than about 70CC and having a concentration of 1 5 to
30 percent by volume.
2. A method for removing a titanium nitride film according to claim 1, further comprising the step of providing a protective coating on a portion of said titanium nitride film for protecting said film from said corrosive liquid.
3. A method for removing a titanium nitride film according to claim 2, in which said protective coating is made of a nitric acid-resistant or epoxy resin.
4. A method for removing a titanium nitride film further comprising the step of removing said protective coating by using a stripping agent.
5. A method for removing a titanium nitride film according to claim 2, in which said step of immersing said stainless steel material is maintained for 48 hours.
6. A method for removing a titanium nitride film according to claim 1, in which said step of immersing said stainless steel material is maintained for 30 hours.
7. A method for removing a titanium nitride film, substantially as herein described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57151610A JPS5941479A (en) | 1982-08-31 | 1982-08-31 | Removal of titanium nitride film |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8323278D0 GB8323278D0 (en) | 1983-10-05 |
| GB2127042A true GB2127042A (en) | 1984-04-04 |
| GB2127042B GB2127042B (en) | 1985-12-04 |
Family
ID=15522292
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08323278A Expired GB2127042B (en) | 1982-08-31 | 1983-08-31 | Method for removing a titanium nitride film |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5941479A (en) |
| KR (1) | KR840006377A (en) |
| GB (1) | GB2127042B (en) |
| HK (1) | HK88190A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4101843C1 (en) * | 1991-01-23 | 1992-04-02 | Eifeler Werkzeuge Gmbh, 4000 Duesseldorf, De | Hard tool coating for economy - by stripping using tetra:sodium di:phosphate soln. and hydrogen peroxide |
| DE4110595C1 (en) * | 1991-04-02 | 1992-11-26 | Thyssen Edelstahlwerke Ag, 4000 Duesseldorf, De | Wet-chemical removal of hard coatings from workpiece surfaces - comprises using hydrogen peroxide soln. stabilised by complex former e.g. potassium-sodium tartrate-tetra:hydrate |
| EP0769570A1 (en) * | 1995-10-17 | 1997-04-23 | Ngk Insulators, Ltd. | Method of regenerating extrusion die for ceramic honeycomb structural bodies |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60187681A (en) * | 1984-03-06 | 1985-09-25 | Citizen Watch Co Ltd | Method for removing hard film |
| JP3264729B2 (en) * | 1993-04-23 | 2002-03-11 | シチズン時計株式会社 | Stripping method of plating film |
| CN108588728A (en) * | 2018-05-16 | 2018-09-28 | 深圳仕上电子科技有限公司 | The method for removing workpiece surface film using aqueous solution of nitric acid |
| JP2021065804A (en) * | 2019-10-17 | 2021-04-30 | 株式会社平和カーボン | Method for removing titanium nitride-containing lump |
| CN111534825B (en) * | 2020-05-14 | 2022-05-31 | 富乐德科技发展（大连）有限公司 | Process for removing titanium and titanium nitride deposited film of stainless steel part of semiconductor equipment |
-
1982
- 1982-08-31 JP JP57151610A patent/JPS5941479A/en active Pending
-
1983
- 1983-07-22 KR KR1019830003388A patent/KR840006377A/en not_active Application Discontinuation
- 1983-08-31 GB GB08323278A patent/GB2127042B/en not_active Expired
-
1990
- 1990-10-25 HK HK881/90A patent/HK88190A/en not_active IP Right Cessation
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4101843C1 (en) * | 1991-01-23 | 1992-04-02 | Eifeler Werkzeuge Gmbh, 4000 Duesseldorf, De | Hard tool coating for economy - by stripping using tetra:sodium di:phosphate soln. and hydrogen peroxide |
| DE4110595C1 (en) * | 1991-04-02 | 1992-11-26 | Thyssen Edelstahlwerke Ag, 4000 Duesseldorf, De | Wet-chemical removal of hard coatings from workpiece surfaces - comprises using hydrogen peroxide soln. stabilised by complex former e.g. potassium-sodium tartrate-tetra:hydrate |
| EP0769570A1 (en) * | 1995-10-17 | 1997-04-23 | Ngk Insulators, Ltd. | Method of regenerating extrusion die for ceramic honeycomb structural bodies |
| US5858463A (en) * | 1995-10-17 | 1999-01-12 | Ngk Insulators, Ltd. | Method of regenerating extrusion die for ceramic honeycomb structural bodies |
Also Published As
| Publication number | Publication date |
|---|---|
| HK88190A (en) | 1990-11-02 |
| JPS5941479A (en) | 1984-03-07 |
| KR840006377A (en) | 1984-11-29 |
| GB2127042B (en) | 1985-12-04 |
| GB8323278D0 (en) | 1983-10-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20000831 |