JPH11256365A - Method for removing ti base coating film and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently removing a Ti-base coating film and a device therefor. SOLUTION: An agitator 3 for agitating and circulating a thermally insulated water 1, a heater 4 for heating the water 1 and a cooler 5 for cooling the water 1 to the temps. in a specified range are provided to a heat-insulating vessel 2 and a storage tank 6 for storing an aq. soln. 10 contg. hydrogen peroxide and further 5 wt.% alkali hyroxide such as potassium hydroxide and sodium hydroxide is provided in the vessel 2. An alkali hydroxide soln. feeder 7, an aq. hydrogen peroxide feeder 8 and an aq. soln. discharger 9 are connected respectively to the storage tank 6, a member 11 coated with a Ti-base coating film is put in the tank 6 and dipped in the aq. soln. 10, the devices 7 to 9 are operated to keep the concn. of the soln. 10 constant, the agitator 3 and the heater 4 and the cooler 5 are operated to keep the thermally insulated water 1 in a specified temp. range (60 to 80 deg.C) so that the Ti-base coating film is efficiently removed from the member 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing a Ti-based film, and is particularly effective when applied when removing a TiAlN film.

[0002]

2. Description of the Related Art Cutting tools obtained by coating a high-speed tool steel with a Ti-based coating have been widely used in recent years because of their excellent wear resistance. In such a cutting tool, as the coating is used, the coating on the blade part wears out faster than the coating on other parts. Therefore, after using for a predetermined time, all the coating is removed once and the blade part is ground. After re-adjustment, it is recycled by coating again. In the coating step, when the coated film deviates from the standard value, the film is completely removed and then coated again to be recycled.

[0003] In the removal of the Ti-based coating in such recycling, for example, Japanese Patent Application Laid-Open No. H5-
In Japanese Patent Publication No. 112885, a polymerized alkaline phosphate is used in an amount of 1 to 1.
20% by weight, 1 to 10% by weight of at least one alkali metal salt of a hydroxycarbonate organic acid, 2 to 15% by weight of an alkali salt of ethylenediamine / acetic acid, 0.1% by weight of an alkali hydroxide.
In a mixed aqueous solution containing 1 to 5% by weight and 3 to 7% by weight of hydrogen peroxide, a Ti-based coating (Ti
It discloses that a Ti-based coating can be removed by immersing (12 hours) a cutting tool coated with N, TiC, TiCN, and Ti) in a temperature range of 10 to 40 ° C.

[0004]

However, if the Ti-based film is removed by immersion in an aqueous solution as disclosed in Japanese Patent Application Laid-Open No. 5-112885, it takes a long time to remove the film. (Coating removal rate: 0.3
μm / h or less), and the processing efficiency was poor. In particular, TiAl
In the case of removing the N film, the film could not be removed even after immersion for 60 hours (film removal rate: less than 0.1 μm / h).

[0005] In view of the above, an object of the present invention is to provide a method and an apparatus for removing a Ti-based coating capable of efficiently removing the Ti-based coating.

[0006]

According to the present invention, there is provided a method for removing a Ti-based film, comprising the steps of: removing an aqueous solution containing hydrogen peroxide and containing more than 5% by weight of alkali hydroxide; Maintained at a temperature of 60-80 ° C.,
By immersing the member coated with the system coating in the aqueous solution, the Ti coating is removed from the member.

According to another aspect of the present invention, there is provided an apparatus for removing a Ti-based film, comprising: a storage tank for storing an aqueous solution containing hydrogen peroxide and containing alkali hydroxide in an amount exceeding 5% by weight; And the aqueous solution at 60 to 80 ° C.
And temperature maintaining means for maintaining the temperature at the temperature.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for removing a Ti-based film according to the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of the apparatus.

As shown in FIG. 1, a stirrer 3 for stirring and circulating the heat-retaining water 1 is provided in a heat-retention container 2 in which the heat-retaining water 1 is stored. A heater 4 for heating the warm water 1 is provided below the warm container 2. A cooler 5 for cooling the heat-retaining water 1 to a temperature within a predetermined range is connected to the heat-retaining container 2. In the present embodiment, the warm water 1, the warm container 2, the stirrer 3, the heater 4, the cooler 5, and the like constitute a temperature maintaining means in the present embodiment.

A storage tank 6 for storing an aqueous solution 10 containing hydrogen peroxide and containing more than 5% by weight of an alkali hydroxide such as potassium hydroxide or sodium hydroxide is provided in the heat insulating container 2. It is arranged. The storage tank 6 includes an alkali hydroxide solution supply device 7 serving as an alkali hydroxide supply unit that supplies a predetermined amount of an alkali hydroxide solution having a predetermined concentration into the storage tank 6 at predetermined time intervals. A hydrogen peroxide solution supply device 8 which is a hydrogen peroxide supply means for supplying a predetermined amount of hydrogen peroxide solution at predetermined intervals every predetermined time, and a predetermined amount of aqueous solution 10 in the storage tank 6 at predetermined intervals. An aqueous solution discharging device 9 which is an aqueous solution discharging means that discharges each one is in communication with each other.

A method for removing a Ti-based film using such a removing apparatus will be described below. The member 11 coated with the Ti-based coating is placed in the storage tank 6 and immersed in the aqueous solution 10, and the supply devices 7 and 8 are operated to supply a predetermined concentration of alkali hydroxide and hydrogen peroxide at predetermined time intervals. A predetermined amount is supplied into the storage tank 6 and the discharging device 9 is operated to discharge the aqueous solution 10 in the storage tank 6 by a predetermined amount at predetermined time intervals. While the concentration of alkali oxide and hydrogen peroxide is always kept constant (the concentration of alkali hydroxide exceeds at least 5% by weight), the stirrer 3 is operated to circulate the warm water 1, and the heater 4
Is operated to heat the water 1 and the cooler 5 is operated to cool and maintain the water 1 in a predetermined temperature range (60 to 80 ° C.). (About 10 to 60 hours, depending on the shape and film thickness).

Therefore, the time required for the process of removing the Ti-based coating from the member 11 can be greatly reduced, and the cost for the process can be reduced. In particular, Ti
In the case of the AlN film, it could not be removed conventionally, but it can be completely removed by the treatment described above.

If the concentration of the alkali hydroxide in the aqueous solution 10 is 5% by weight or less, the Ti-based coating cannot be removed efficiently.

If the temperature of the aqueous solution 10 is lower than 60 ° C., the film removal rate is reduced,
If the temperature exceeds 80 ° C., the concentration of the aqueous solution 10 changes rapidly due to the self-reaction of the aqueous solution 10, and the removal rate cannot be maintained.

The concentration of hydrogen peroxide in the aqueous solution 10 is as follows:
Although not particularly limited, it is preferable that it is in the range of 0.1 to 60%.

When potassium hydroxide is used as the alkali hydroxide, the surface of the base material is not roughened,
This is more preferable because it is possible to prevent a decrease in the adhesion of the Ti-based film to the base material during recoating.

Also, in the above-mentioned JP-A-5-112885, the concentration of alkali hydroxide in the aqueous solution is 5% by weight.
It is stated that the removal speed becomes slower and the surface of the base material becomes discolored black when the above is reached. However, when potassium hydroxide is used in the TiAlN coating, such a phenomenon does not occur, and a favorable The result can be obtained.

[0018]

EXAMPLES In order to confirm the effects of the method and apparatus for removing a Ti-based film according to the present invention, the following confirmation experiments were conducted based on the above-described embodiment.

[Confirmation experiment: Temperature of aqueous solution] <Experiment method> 40 ° C, 50 ° C, 60 ° C, 70 ° C, 80 ° C
A member coated with a Ti-based coating was immersed for 10 hours using aqueous solutions at a total of six temperatures of 90 ° C. and 90 ° C. Then, the member was taken out of the aqueous solution and the thickness of the Ti-based coating remaining on the member was examined. .

<Experimental conditions> Material / material: high speed tool steel Shape: flat plate Size: 20 × 20 × 5 mm Coating: TiAlN Film thickness: 5 μm ・ Aqueous solution-alkali hydroxide: 20% by weight (sodium hydroxide) Hydrogen: 3% by weight Capacity: 1 liter

<Experimental Results> The test results are shown in FIG. FIG.
As can be seen from the graph, in the temperature range of 60 to 80 ° C., the thickness of the remaining Ti-based film is 1.5 μm or less (film removal rate: 0.35 μm / h or more). It could be completely removed without remaining (removal rate: 0.5 μm / h or more). Therefore, it was confirmed that the Ti-based coating can be efficiently removed if the aqueous solution is maintained in the temperature range of 60 to 80 ° C.

Based on the results of the above-described confirmation experiments, the following tests were performed. [Test Example] While maintaining an aqueous solution (10 liters) containing 7.5% by weight of potassium hydroxide and 19% by weight of hydrogen peroxide in a temperature range of 70 ± 5 ° C., a TiAlN film was coated on a blade portion. Hobbed high-speed tool steel (outer diameter: 100 mm, length: 150 mm)
Was immersed for 60 hours.

As a result, the film could be completely removed from the hob without leaving the film on the hob (film removal speed: 0.5 μm / h or more).

[0024]

The method for removing a Ti-based coating according to the present invention comprises:
5% by weight of alkali hydroxide containing hydrogen peroxide
Is maintained at a temperature of 60 to 80 ° C., and the member coated with the Ti-based coating is immersed in the aqueous solution to remove the Ti-based coating from the member. Since the system-based coating can be efficiently removed, the time required for the process of removing the Ti-based film from the member can be significantly reduced, and the cost for the process can be reduced. In particular, TiAlN
In the case of a film, it could not be removed conventionally, but according to the method, it can be completely removed.

The apparatus for removing a Ti-based film according to the present invention comprises a storage tank for storing an aqueous solution containing hydrogen peroxide and containing alkali hydroxide in an amount exceeding 5% by weight; Temperature-holding means for holding the solution at a temperature of 2 ° C., so that the member coated with the Ti-based coating is placed in a storage tank and immersed in an aqueous solution, and the aqueous solution is held at a temperature of 60 to 80 ° C. by the temperature holding means. Then, since the Ti-based coating can be efficiently removed from the member, the time required for the removal processing of the Ti-based coating from the member can be significantly reduced, and the cost for the processing can be reduced. In particular, in the case of a TiAlN film, although it could not be removed conventionally, using the device,
It can be completely removed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of an apparatus for removing a Ti-based film according to the present invention.

FIG. 2 is a graph showing the results of a confirmation experiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulated water 2 Insulated container 3 Stirrer 4 Heater 5 Cooler 6 Storage tank 7 Alkali hydroxide solution supply device 8 Hydrogen peroxide solution supply device 9 Aqueous solution discharge device 10 Aqueous solution 11 Member

Claims (2)

[Claims] 1. An aqueous solution containing hydrogen peroxide and containing more than 5% by weight of alkali hydroxide at 60 to 80.degree.
And removing the Ti-based coating from the member by immersing the member coated with the Ti-based coating in the aqueous solution while maintaining the temperature. 2. A storage tank for storing an aqueous solution containing hydrogen peroxide and containing more than 5% by weight of an alkali hydroxide, and a temperature holding means for holding the aqueous solution at a temperature of 60 to 80 ° C. An apparatus for removing a Ti-based coating, comprising: