JP3320965B2 - Hard film peeling method and recoated member obtained by the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is provided on the surface of a high-speed cutting tool steel, Fe-based metal base material such as SNCM or SCM, or a cemented carbide base material for the purpose of improving wear resistance and life. The present invention relates to a method for removing a hard film, specifically, by chemically removing only a hard film on the surface without deteriorating the base material and enabling re-use of the base material by performing re-coating. The present invention relates to a method for removing a hard film and a re-coated member obtained by using the method. The “hard metal” of the present invention means a hard metal represented by a WC-based hard metal containing WC as a main component and one or more of Fe-based metals as a binder phase forming component. .

[0002]

2. Description of the Related Art Members requiring wear resistance, such as cutting tools, dies, and bearings, are often coated with a hard film made of nitride, carbide, or carbonitride of Ti, Al, or Cr. . Since this hard coating has excellent wear resistance and corrosion resistance, it is effective in extending the life of the above members.

[0003] These hard films are generally coated by a CVD method, a PVD method or the like, but depending on the conditions at the time of coating, defects may occur in the film,
Expected wear resistance and corrosion resistance may not be obtained due to partial peeling. A member coated with a hard film has a longer service life than an uncoated member. However, the hard film suffers from abrasion damage due to long-time use, and eventually becomes unusable.

Attempts have been made to remove a hard film having such a defect or a hard film which has reached the end of its life from a substrate. That is, after removing the unnecessary hard film from the base material,
If a new hard film is coated, the member can be used repeatedly, which contributes to efficient use of resources and cost reduction.

There are two known methods for removing a hard film: a physical removal method such as grinding, and a chemical removal method using an aqueous hydrogen peroxide solution. However, in the physical removal method,
It is impossible to grind only a very thin hard film without damaging the base material, and even if such precision grinding is possible, the cost will increase, and the purpose of "cost reduction" Would be contrary.

On the other hand, in the chemical removal method, it is known that an aqueous solution of hydrogen peroxide can be used. For example, U.S. Pat. No. 4,554,049 discloses the use of a solution containing a hydrogen peroxide solution, but it cannot be removed at all depending on the type of hard film, or it takes a long time to remove it. There was a problem that the wood itself was eroded. Japanese Patent Application Laid-Open No. 5-503320 discloses a method for removing a hard film using an aqueous solution containing a hydrogen peroxide solution, an acid, and an alkali source of hydroxyl ions as a stripping solution. However, this method is applicable because the base material is a steel material having excellent corrosion resistance such as superalloy, stainless steel or alloy steel, and in other general Fe-based metal members and cemented carbide materials,
After all it is eroded. In addition, since the hard film that could not be removed remains on the base material or the base material surface is contaminated by the stripping solution, even if re-coating is performed, the adhesion with the re-coated film is impaired. As a result, there is also a problem that excellent abrasion resistance characteristics as in the case of a new article cannot be obtained.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been developed so that a member after recoating can have the same wear resistance and corrosion resistance as a new member. An object of the present invention is to provide a method for quickly removing a hard film on the surface of a substrate while suppressing chemical erosion on the substrate, and an inexpensive recoating member using the method.

[0008]

Means for Solving the Problems A first method of the present invention which can solve the above-mentioned problems is a method of peeling a hard film from a wear-resistant member having a hard film coated on a substrate surface. This is a method for stripping a hard film, which has a gist in immersing the member in an aqueous solution containing a permanganate ion and / or a dichromate ion and having a pH of 10 or more. The concentration of permanganate ion is 0.05 mol / l or more,
It is a preferred embodiment of the first method that the concentration of dichromate ion is 0.03 mol / l or more and that the temperature of the aqueous solution is maintained at 40 to 90 ° C.

On the other hand, a second method is a method of peeling the hard film from a wear-resistant member having a hard film coated on the surface of a base material, while immersing the member in an alkaline solution having a pH of 8 or more. The gist lies in that the electrolytic treatment is performed using the member as an anode. The temperature of the alkaline solution is 40-90 ° C
Is also a preferred embodiment in the second method.

In the first and second methods of the present invention, the hard film is preferably made of any one of nitrides, carbides, and carbonitrides of at least one element selected from the group consisting of IVa, Va, VIa group elements and Al. It is preferable to apply when.

[0011] The present invention also includes a recoated member in which a hard film is newly coated after the hard film is peeled off by the peeling method of either the first method or the second method. The peeling method of the present invention can be preferably used when the substrate is an Fe-based metal substrate or a cemented carbide substrate, and the substrate of the recoating member is preferably an Fe-based metal or a cemented carbide substrate. . Further, when the base material contains V and / or W, a compound derived from V and / or W is eluted at the time of peeling the hard film, and fine pores effective for improving the adhesion to the recoating film are obtained. Was found to occur innumerably on the substrate surface. Therefore, the composition of V and / or W on the surface of the substrate is 0.1 to 0.1% of the composition of V and / or W inside the substrate.
When one or both of the following two conditions are satisfied: 9 times, and a large number of holes having a diameter of 0.2 to 8 μm are present on the substrate surface after peeling the hard film.
The above two conditions are the most preferable embodiments of the recoating member of the present invention, since the recoating film has extremely good adhesion and a recoating member like a new one can be obtained.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A hard coating film provided for the purpose of improving wear resistance and corrosion resistance of a member is a single or composite nitride of at least one element selected from the group consisting of IVa, Va, VIa group elements and Al. , Carbides and carbonitrides. These compounds exhibit excellent corrosion resistance in acidic solutions, especially non-oxidizing solutions, but decompose in oxidizing environments. The oxidizing stripper disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-503320 utilizes this effect. However, as a result of studies by the present inventors, metal ions resulting from oxidative decomposition are converted into oxides because the atmosphere is an oxidizing environment. Since the oxide was deposited on the surface of the hard film and this oxide covered the entire surface of the film, the decomposition and peeling of the hard film became difficult to proceed further, and it was found that a considerable time was required for the peeling. Furthermore, it was also clarified that since the film decomposed by the stripping solution had many cracks, the stripping solution eroded the base material itself from the cracks.

The inventors of the present invention have studied the creation of an oxidizing environment in which a hard film can be decomposed without forming a metal oxide film, and have found two useful peeling methods.
This will be described in detail below.

First, the first method of the present invention is a method for preparing a pH 1 containing permanganate ion and / or dichromate ion.
It is characterized in that the hard film-coated member is immersed in zero or more aqueous solutions. Permanganate ion and / or
Or the aqueous solution containing dichromate ion has strong oxidizing power,
Since almost no oxygen is generated during the oxidation-reduction reaction, there is an effect of suppressing the formation of a metal oxide film. Therefore, it is possible to remove the hard film in a shorter time than in a conventional stripping solution. However, if the pH of the aqueous solution for stripping is not 10 or more, even if these ions are present, a metal oxide film is formed, which hinders the progress of the dissolution and stripping reaction of the hard film.

Therefore, in the first method of the present invention, the pH 10
The above are defined as essential requirements. Since the higher the pH of the aqueous solution, the higher the dissolution reaction of the hard film is promoted, the preferred pH is 12 or more, and more preferably pH 14 or more. In order to adjust the pH of the aqueous solution for stripping, a compound which is soluble in water and shows alkalinity can be used without any particular limitation, but easily available and inexpensive sodium hydroxide and potassium hydroxide are preferably used.

On the other hand, the concentration of permanganate ion is 0.0
More than 5 mol / l is appropriate. If it is lower than 0.05 mol / l, the dissolution rate of the hard film is low, which is not practical. Preferably 0.1 mol / l or more, more preferably 0.3 mol / l
l or more, and it is recommended that the upper limit be lower than the saturation concentration in terms of cost. The concentration of dichromate ion is
0.03 mol / l or more is suitable. Preferably 0.1mo
l / l or more, more preferably 0.2 mol / l or more. It is recommended that the upper limit be lower than the saturation concentration as in the case of permanganate ion. These ions are
Although only one type may be present alone in the aqueous solution for stripping, it is preferable that both ions be present at the above concentrations in order to remove the hard film in a shorter time. In order for these ions to be present in the aqueous solution for stripping, a salt compound which dissociates in water to generate these ions may be used, and examples thereof include potassium permanganate and sodium dichromate.

In order to dissolve and peel off the hard film more quickly, it is preferable to heat the aqueous solution for peeling. Particularly, when the temperature is set to 40 ° C. or higher, the dissolution reaction remarkably proceeds. However, if the temperature is maintained at 90 ° C. or more, there is a risk of corrosion of the base material. More preferably 45 to 80
° C, more preferably 50-75 ° C.

The second peeling method of the present invention is characterized in that the hard film-coated member is immersed in an alkaline solution having a pH of 8 or more and electrolytic treatment is performed using the member as an anode. By using the alkaline solution as the electrolytic solution, metal ions generated by decomposition of the hard film do not form an oxide. In addition, even if an oxide is formed, it is dissolved and does not inhibit the progress of decomposition of the hard film. Therefore, even in this method, the hard film can be removed quickly and reliably as compared with the conventional peeling method. In the case of the second method, if the pH is 8 or more, generation of a metal oxide is prevented. The preferred pH is 10 or more, more preferably pH 12 or more. Also in the second stripping method, the alkali solution is preferably prepared using sodium hydroxide or potassium hydroxide. It is recommended that the temperature during electrolysis be in the range of 40 to 90 ° C. in order to promote the progress of the reaction as in the case of the first method. The voltage in the electrolytic treatment is not particularly limited, but in order to promote the progress of the reaction, the potential of the coating member as the anode is set to 800 mV.
vs. Ag / AgCl (silver / silver chloride reference electrode reference) or more is preferable.

In the first stripping method using a stripping aqueous solution of the present invention, the degree of dissolution and stripping of the hard film is determined by the concentration of permanganate ion and dichromate ion in the stripping aqueous solution,
H, the solution temperature and the immersion time, and in the second stripping method by electrolysis, it is determined by the pH and the set potential of the electrolytic solution, the solution temperature and the immersion electrolysis time. In order to obtain a desired dissolution / peeling state while minimizing erosion of the base material in each method, depending on the type of the hard film to be peeled and removed and the type of the base material coated with the hard film, May be set as appropriate.

In the above two methods of the present invention, the liquid for immersing the coated member is in an alkaline solution environment. In this environment, the Fe-based metal substrate corrodes in a very small amount, but no generation of corrosion products such as rust is observed. In addition, although corrosion may occur in the cemented carbide substrate, by precisely controlling the time of the peeling treatment, only the hard film can be dissolved and removed, thereby preventing erosion of the substrate. Therefore, the peeling method of the present invention can suitably select, as an application object, an Fe-based metal substrate or a cemented carbide substrate that could not be reused by being corroded by the conventional removal method. . Since these substrates are not subjected to chemical erosion by the peeling method of the present invention and the strength of the substrate hardly decreases, by coating the hard film again on the substrate after peeling the hard film, high performance abrasion resistance is obtained. It can be reused as a functional member.

Of course, it is needless to say that the method of the present invention is preferably applied to stainless steel having excellent corrosion resistance (containing about 20% of Cr) and high-speed tool steel having a wide range of uses. If the metal substrate is not likely to be severely eroded by either of the two peeling methods, Fe
The present invention is sufficiently applicable to other metal base materials other than base metals and cemented carbides.

The hard film peeled off by the method of the present invention is IVa
, Va, VIa or one or more elements selected from the group consisting of Al and single or complex nitrides, carbides and carbonitrides.

The base material from which the hard film has been removed by the two peeling methods of the present invention is coated with a new hard film, so that members requiring various wear resistance such as cutting tools, dies, bearings, etc. Can be used for Compared to the conventional peeling method, the peeling method of the present invention has little residual chemicals and contamination of the substrate and the unremoved peeling film,
This is because the adhesion of the recoating film is good, and a service life equivalent to that of a new product can be obtained. Accordingly, the present invention also includes a re-coated member in which the hard film is newly coated on the substrate from which the hard film has been removed by one of the two peeling methods. At this time, the type of the hard film to be removed and the type of the hard film to be newly coated may be the same or different.

According to the study of the present inventors, the peeling method of the present invention is applied to the removal of a hard film of a high speed tool steel or a cemented carbide member having V and / or W as an alloying element in a base material. In particular, it was found that the adhesion of the recoating film was excellent. FIG. 1 shows a scanning electron microscope (S) of the surface of a high-speed tool steel after the hard film was peeled and removed by the electrolytic peeling method.
EM) A photograph as a substitute for a drawing is shown, and it can be seen that fine holes are generated on one surface. FIG. 2 shows a conventional method (Japanese Unexamined Patent Publication No.
A photograph instead of a drawing of the surface when peeled off by the method using a peeling liquid disclosed in JP-A-503320 is shown, but no fine holes as shown in FIG. 1 are recognized.

Also, in the first stripping method of the present invention using the stripping aqueous solution, when V and / or W is contained in the substrate, fine holes as shown in FIG. 1 are generated. Was confirmed. Since this phenomenon of pore generation occurs only in the case of high-speed tool steel or cemented carbide base materials containing V and W, carbides of V and W contained in these base materials in relatively large amounts during electrolysis. It is considered to be a trace dissolved in

The present inventors have reported that the diameter of this hole is 0.2-8.
It was found that the adhesion of the recoating film was particularly excellent when the thickness was μm. The so-called "anchor effect" enhances the adhesion. Anchor effect cannot be expected with a hole smaller than 0.2 μm. Conversely, if a hole larger than 8 μm is formed, the flatness of the coated hard film is lost and the adhesion is reduced. It is preferable to control the peeling conditions so as to fall within the range.

Since V and W contained in the base material are eluted by the formation of such holes, it is considered that the alloy composition on the surface of the base material may be changed. If the composition of V and / or W on the surface of the substrate after the treatment is 0.1 to 0.9 times the composition inside the substrate, the effect of improving the adhesion of the subsequent recoating film is the strength of the substrate. Was found to exceed the degree of decrease. That is, for example, V
When a peeling treatment is performed using a base material containing as an additive element, a hardness exhibiting component such as VC elutes from the base material surface and the hardness of the base material is slightly lowered, but the above-described pores are formed. Therefore, the adhesion between the substrate and the recoating film is greatly improved, and as a result, a recoating wear-resistant member having excellent characteristics can be obtained. Since V and W are both carbides and are components that exhibit excellent hardness, in the present invention, V or W,
Alternatively, for both V and W, the composition on the substrate surface and the degree of change in the composition inside the substrate were set as described above.

At this time, V and / or W on the substrate surface
Of the composition of V and / or W inside the substrate is 0.
When an excessive release treatment is performed so as to be less than 1 time, V and W in the vicinity of the surface of the base material become too small, and the mechanical strength becomes inferior. I can't get it. On the other hand, the fact that V or W remains over 0.9 times the composition inside the substrate on the surface of the substrate after peeling off the hard film means that few holes capable of exhibiting the anchor effect are generated. This is not preferable because the effect of improving the adhesion is not exhibited. V and / or of substrate surface
Alternatively, the more preferable range of the composition of W is 0.15 to 0.5 times the composition of V and / or W inside the substrate, and the most preferable range is 0.2 to 0.4 times.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which do not limit the present invention.
Modifications and alterations that do not depart from the spirit described below are all included in the technical scope of the present invention.

Experimental Example 1 A high-speed tool steel was coated with a TiAlN hard film to a thickness of 4 μm by an ion plating method. 5 containing 0.1 mol / l of permanganate ion and 0.1 mol / l of dichromate ion
As shown in Table 1, the pH of the aqueous sodium hydroxide solution at 0 ° C. was changed to 8, 10, 12, and 14, and the time until the high-speed tool steel was immersed in each and the hard film was peeled off was changed. It was measured. The results are shown in Table 1.

[0031]

[Table 1]

As is clear from Table 1, when the pH is 8, the stripping time is as long as 10 hours, which is not practical, and the higher the pH, the shorter the time required for stripping. When the same experiment was performed by the conventional method disclosed in Japanese Patent Application Laid-Open No. 5-503320, it took as long as 20 hours to peel off the hard film.

Experimental Example 2 A peeling experiment was performed in the same manner as in Experimental Example 1 except that the pH was kept constant at 10 and the permanganate ion concentration was changed as shown in Table 2. Table 2 shows the results.

[0034]

[Table 2]

As is clear from Table 2, the higher the permanganate ion concentration, the shorter the stripping time.
It was found that mol / l was considered impractical.

Experimental Example 3 The pH was kept constant at 10 and the concentration of dichromate ions was measured as shown in Table 3.
A peeling test was performed in the same manner as in Experimental Example 1 except that the test was changed as follows. Table 3 shows the results.

[0037]

[Table 3]

As is clear from Table 3, the higher the dichromate ion concentration, the shorter the stripping time,
It was found that l / l was considered impractical.

Experimental Example 4 A peeling experiment was conducted in the same manner as in Experimental Example 1 except that the pH was kept constant at 10 and the temperature of the stripping solution was changed as shown in Table 4. Table 4 shows the results.

[0040]

[Table 4]

As is clear from Table 4, the higher the solution temperature, the shorter the peeling time. In the case of high-speed tool steel, it is considered practical to set the solution temperature to 40 ° C. or higher. In the experiment at 100 ° C., although the peeling of the hard film was completed in 2 hours, erosion was observed on the surface of the high-speed tool steel, and it was confirmed that the solution temperature was preferably set to 90 ° C. or lower.

Experimental Example 5 In addition to the high-speed tool steel, a cemented carbide material mainly composed of WC,
A hard film was also coated on carbon steel and stainless steel in the same manner as in Experimental Example 1, and a peeling experiment was performed when the solution temperature was changed in the same manner as in Experimental Example 4. Table 5 shows the results. The results for the high-speed tool steel are again the results in Table 4.

[0043]

[Table 5]

As is clear from Table 5, 30 ° C. for carbon steel
It can be seen that erosion can be prevented by slowly peeling at a low temperature. Cemented carbide and stainless steel have the same degree of erosion as high-speed tool steel, and it was found that the peeling conditions for these members may be set to the same degree.

Experimental Example 6 Instead of TiAlN, Si ₃ N ₄ , ZrAlN, HfA
Using a high-speed tool steel coated with 1N of each hard film, the same peeling test as in Experimental Example 1 was performed except that the pH was kept constant at 10. Table 6 shows the results. The results for TiAlN are again the results for pH 10 in Table 1.

[0046]

[Table 6]

ZrAlN and HfAlN are almost TiAl
The stripping time was similar to that of the N film. 1 for Si ₃ N ₄
It turned out that it took as long as 5 hours. However, it took 40 hours to carry out a stripping test of the Si ₃ N ₄ film by the method of JP-A-5-503320, and it is clear that the stripping method of the present invention is excellent.

Experimental Example 7 Using the same sample as in Experimental Example 1, a hard film peeling test was performed by an electrolytic method. The electrolytic solution was an aqueous sodium hydroxide solution at 50 ° C., and the pH was changed as shown in Table 7. The anode is a hard film coating material, the cathode is a platinum plate, and the potential of the anode is 800 m.
V vs. Ag / AgCl (based on silver / silver chloride reference electrode)
, And the time required for stripping was measured. Table 7 shows the results.

[0049]

[Table 7]

As is clear from Table 7, when the pH is 6, the stripping time is as long as 12 hours, which is not practical, and the higher the pH, the shorter the time required for stripping. The drawing substitute photograph shown in FIG. 1 is a surface SEM photograph of the high-speed tool steel after electrolytic peeling at pH: 8.

Experimental Example 8 A high-speed tool steel from which a hard film was removed by the peeling method of the present invention having a pH of 8 in Experimental Example 7 and a conventional method (JP-A-5-50)
Each of the high-speed tool steel substrates obtained by stripping by the stripping solution shown in
The hard film was coated to a thickness of 4 μm by an ion plating method. A scratch test was performed on the obtained recoated high-speed tool steel, and a critical load when the coating was peeled was examined. Also, the time until the film peels off when a cutting test is performed with this recoated high-speed tool steel drill (durable life)
And the results are shown in Table 8.

[0052]

[Table 8]

As is clear from Table 8, the recoated member of the present invention has a large critical load for peeling and exhibits excellent film adhesion.
It was also found that the service life was long.

Experimental Example 9 The high-speed tool steel coated with TiAlN film used in Experimental Example 5, W
Using a cemented carbide material containing C as a main component, carbon steel, and stainless steel, the TiAlN film was peeled off and recoated in the same manner as in Experimental Example 8, and the critical load was measured. The results are shown in Table 9. The results for the high speed tool steel are again the results in Table 8.

[0055]

[Table 9]

From Table 9, it can be seen that, similarly to the high-speed tool steel, the cemented carbide material and the stainless steel also exhibit excellent adhesion of the recoating film. In the case of carbon steel which is easily eroded, it is considered that the peeling condition in Experimental Example 9 was slightly severe, and the critical load was 5
Although it was N, the value was much lower at 1N when peeled off by the conventional method, so that the superiority of the recoated member of the present invention could be confirmed.

Experimental Example 10 In Experimental Example 7, the pH was kept constant at 8, and the potential of the anode coating member was set to 100 mV to 2 V vs. 100 mV. Ag / AgCl
(Silver / silver chloride reference electrode reference), the diameter (maximum) of the substantially uniform fine holes shown in FIG. 1 after peeling was changed from 0.1 to 10 μm. Thereafter, the TiAlN film was re-coated and the critical load was measured. The results are shown in Table 10.

[0058]

[Table 10]

From Table 10, it was confirmed that a high critical load was obtained when the diameter of the pores was 0.2 to 8 μm, and excellent adhesion was exhibited. Further, a potential of 800 mV vs. potential. Ag / Ag
It was also found that if Cl was used, the diameter of the generated pore would be 0.2 to 8 μm.

Experimental Example 11 In Experimental Example 10, a hard film peeling experiment was performed by changing the pH in addition to the potential to 8 to 12. This is because the composition of V and W near the surface with respect to the composition of V and W inside the high-speed tool steel after hard film peeling is changed by 0.01 to 0.95 times. The surface hardness of the high-speed tool steel after peeling was measured with a load of 10 g.
f, a Vickers hardness test was performed and measured. The results are shown in Table 11. The high-speed tool steel after peeling is again
After coating the film, a scratch test was performed to measure a critical load when the film was peeled off. The results are shown in Table 12.

[0061]

[Table 11]

[0062]

[Table 12]

As is clear from Table 11, when the V composition on the surface of the base material is 0.01 times the V composition on the inside, the Vickers hardness is low irrespective of W, and the W composition on the surface is 0.0% of the W composition on the inside.
The same was true for 1-fold. Also, from Table 12, it was found that when the surface V composition was 0.95 times the internal V composition, the adhesion was inferior regardless of the W composition, and the same was true even when the surface W composition was 0.95 times the internal W composition. Therefore, when the peeling method of the present invention is applied to a substrate containing V or W, the composition of V and / or W on the surface is 0.1 to 0.1 or less of the composition of V and / or W inside.
When the peeling conditions were controlled so as to be 0.9 times, it was confirmed that a recoated member excellent in both the mechanical strength after the recoating and the adhesiveness of the recoated film was obtained.

EXPERIMENTAL EXAMPLE 12 A high-speed tool steel was coated with a TiAlN hard film to a thickness of 4 μm by an ion plating method, and constant-potential electrolysis was performed in the same manner as in Experimental Example 7 except that the pH was kept constant at 8. Was peeled off. Then, Si ₃ N ₄ , TiAlN, ZrAlN,
Each hard film of HfAlN was re-coated, and the critical load of the obtained member was measured. The results are shown in Table 13.

[0065]

[Table 13]

The members recoated with TiAlN, ZrAlN and HfAlN all exhibited excellent adhesion. However, when Si ₃ N ₄ was selected as the re-coated hard film, the critical load was slightly lower at 5 N, but when it was peeled off by the conventional method and re-coated, the critical load was even lower at 1 N. The superiority of the re-coated member of the invention was confirmed.

[0067]

As described above, the present invention is constructed as described above and succeeds in creating an oxidizing environment in which a hard film can be decomposed without forming a metal oxide film. For this reason, while minimizing chemical erosion of the substrate coated with the hard film,
Only the hard film can be quickly removed.
Further, even in the case of recoating the hard film after peeling, the coating can be performed with good adhesion since there is no erosion or contamination of the substrate. Furthermore, it has been found that when the base material contains V and / or W, formation of pores capable of exhibiting an anchor effect can provide more excellent adhesion.

According to the present invention, it is possible to obtain a re-coated member having a wear resistance characteristic close to that of a new article, and it is possible to effectively use the base material, that is, to save resources and energy and to reduce the cost. The peeling method of the present invention can be applied to various wear-resistant members coated with a hard film, such as cutting tools, dies, bearings, and the like, and the re-coated member of the present invention can also be used as these wear-resistant members. Can be used.

[Brief description of the drawings]

FIG. 1 is a drawing-substituting SEM photograph of a high-speed tool steel surface after a hard film is peeled off by the method of the present invention.

FIG. 2 is a drawing-substituting SEM photograph of the surface of a high-speed tool steel after a hard film is peeled off by a conventional method.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiki Sato 1-318 Wakihama-cho, Chuo-ku, Kobe City, Hyogo Prefecture Kobe Steel, Ltd. Kobe Head Office (72) Inventor Tatsuya Yasunaga Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture 1-5-5 Kobe Steel, Ltd.Kobe Research Institute (72) Inventor Masanori Cai 1-5-5 Takatsukadai, Nishi-ku, Kobe, Hyogo Prefecture Kobe Steel, Ltd.Kobe Research Institute (72 ) Inventor Kazuhisa Kawada 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Kobe Steel, Ltd.Kobe Research Institute (72) Inventor Yasuyuki Yamada 179-1 Kanegasaki Nishi-Oike, Uozumi-cho, Akashi-shi, Hyogo 1 Shares Kobe Steel, Ltd. Akashi Factory (72) Inventor Yusuke Tanaka 179 Kanegasaki Nishi-Oike, Uozumi-cho, Akashi-shi, Hyogo 1 Kobe Steel, Ltd. Akashi Factory (72) Inventor Yasunori Wada No. 179 Kanegasaki Nishi-Oike, Uozumi-cho, Akashi-shi, Hyogo 1 Inside the Akashi Works of Kobe Steel Ltd. (56) References JP-A-6-287775 (JP, A) JP-A-6-349978 ( JP, A) JP-A-3-150374 (JP, A) JP-A-60-107000 (JP, A) JP-A-6-299318 (JP, A) JP-A-58-130280 (JP, A) 50-50896 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23F 1/00 103 C23F 1/32 C23F 1/40 C25F 1/00

Claims (12)

(57) [Claims] 1. A method for peeling a hard film from a wear-resistant member having a hard film coated on a substrate surface, wherein the hard film has a pH of 1 containing permanganate ions and / or dichromate ions.
A method for removing a hard film, comprising immersing the member in an aqueous solution of zero or more. 2. The concentration of permanganate ion is 0.05 mol.
The peeling method according to claim 1, wherein the peeling rate is l / l or more. 3. The concentration of dichromate ion is 0.03 mol /
The peeling method according to claim 1, which is at least l. 4. The peeling method according to claim 1, wherein the temperature of the aqueous solution is maintained at 40 to 90 ° C. 5. A method for peeling a hard film from a wear-resistant member having a hard film coated on a substrate surface, wherein the member is used as an anode while immersing the member in an alkaline solution having a pH of 8 or more. A method for removing a hard film, comprising performing an electrolytic treatment. 6. The temperature of the alkaline solution is 40 to 90 ° C.
The peeling method according to claim 5, wherein 7. The hard film according to claim 1, wherein the hard film is any one of a nitride, a carbide and a carbonitride of at least one element selected from the group consisting of IVa, Va, Group VIa and Al. The stripping method as described. 8. A recoating member characterized in that an arbitrary hard film is newly coated after the hard film has been stripped by the stripping method according to any one of claims 1 to 7. 9. The recoated member according to claim 8, wherein the base material is an Fe-based metal. 10. The recoated member according to claim 8, wherein the base material is a cemented carbide. 11. The substrate contains V and / or W, and V and / or W on the surface of the substrate after peeling off the hard film.
Is 0.1% of the V and / or W composition inside the substrate.
The re-coated member according to any one of claims 8 to 10, wherein the ratio is 0.9 to 0.9. 12. A substrate having a diameter of 0.2 after the hard film is peeled off.
A large number of pores having a diameter of up to 8 µm.
12. The re-coated member according to any one of items 11.