JP2739409B2 - Manufacturing method of corrosion and wear resistant multilayer metal coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a multilayered metal target film having a corrosion and wear resistance.

[0002]

2. Description of the Related Art Conventionally, in order to improve the wear resistance of a steel material, plating of a metal having high hardness (for example, hard chrome plating) has been performed on the surface. In addition, in order to improve the corrosion resistance of a steel material, a metal (zinc, aluminum, or the like) that corrodes preferentially over a base material, or a metal film that has better corrosion resistance than a base material and that shields the base material from the environment ( (Nickel, tin, etc.). When both corrosion resistance and wear resistance are required, first, nickel or nickel-phosphorus plating with good corrosion resistance is applied on the base material, and then hard chromium with wear resistance is provided on the upper surface thereof. Plating may be applied. Normally, fine defects such as pinholes are present in the plating layer. However, by performing heat treatment at a temperature near the melting point of the coating film, it is possible to reduce defects and improve adhesion to the base material. Further, in order to improve the adhesion of the film, a plating of another metal may be formed as an intermediate layer between the base material and the plating.

Japanese Patent Application Laid-Open No. 3-247779 discloses that a metal material is plated with a metal such as nickel, zinc, aluminum, or tin, and then the surface of the metal plating is blasted, followed by 18-8 stainless steel. A method for producing a corrosion-resistant and wear-resistant composite coating in which a wear-resistant sprayed coating of a metal such as 13Cr stainless steel or a ceramic material such as chromium oxide, chromium nitride, and tungsten carbide is described. Japanese Patent Application Laid-Open No. Sho 60-149762 describes a corrosion-resistant thermal spray coating method in which a thermal spray material made of a Ni-Cr alloy is thermally sprayed onto an iron-based alloy material to coat the material. JP-A-2-4950 discloses that Ni, Co, F
e, the first layer and the second layer are each sprayed as a second layer, and the steel sheet is heated at a temperature of 800 to 1300 ° C. to make the first layer a dense layer, and between the steel sheet and the dense layer. A method for producing a surface-treated steel sheet having excellent corrosion resistance and wear resistance in which a diffusion layer is formed between a dense layer and a second layer to improve the adhesion of a coating layer to a steel sheet is described. Japanese Patent Application Laid-Open No. Hei 4-26777 discloses that the surface of titanium or a titanium alloy is pickled, strike-plated with Cu or Ni, further electroplated with Ni or Ni-P alloy, and then heated in vacuum to activate the surface. After processing
A method is described in which a heat-resistant abrasion-resistant film is formed and the surface is roughened to form a fixed lubricating film to improve heat resistance, abrasion resistance, and sliding resistance.

[0004]

However, for example, under a use condition in which a high surface pressure is applied in a highly corrosive environment such as seawater, in addition to the corrosion resistance and abrasion resistance of the coating film itself, the adhesion is also reduced. Is also required to be excellent. Chromium plating, which has excellent wear resistance, has excellent corrosion resistance of the film itself, but is susceptible to corrosion of the base material due to the presence of defects in the film. However, the hardness of chromium plating decreases when heated to a high temperature, so that the film cannot be densified by heat treatment. Therefore, it is necessary to form a corrosion-resistant plating layer between the chromium plating and the base material. However, a nickel or nickel-phosphorous plating layer, which is a typical corrosion-resistant plating, generally has insufficient adhesion with the chromium plating layer. The chromium plating layer is easily peeled off by friction. In addition, in the case of using a jack for a shield excavator, a plating damage accident is likely to occur as the size of the jack increases, and it is necessary to prevent the accident.

The method described in Japanese Patent Application Laid-Open No. 3-247779 does not perform heat treatment, so that the adhesion of the plating layer is insufficient and the corrosion resistance is not sufficient. JP-A-60-1
The methods described in JP-A-49-762 and JP-A-2-4950 perform heat treatment at a high temperature. However, since the hardness of chromium plating decreases when heated to a high temperature, the abrasion resistance is not sufficient. The method described in Japanese Patent Application Laid-Open No. Hei 4-26777 is for plating the surface of titanium or a titanium alloy, and cannot be directly applied to the method for producing a multilayer metal film used in the present invention. The present invention has been made in view of the above points, the corrosion resistance is relatively good as the intermediate layer, and by using a metal plating having a low melting point,
Even for thin coatings, heat treatment improves corrosion resistance and adhesion to the base material, while keeping the heat treatment temperature low near the melting point of low-melting metals prevents a decrease in the hardness of the chromium plating layer and increases wear resistance. and its object is to provide a method for manufacturing a multilayer metal target membrane with.

[0006]

[0007]

Means for Solving the Problems To achieve the above object,
As shown in FIGS. 1 and 2, the method for manufacturing a corrosion-resistant and wear-resistant multilayer metal coating according to the present invention includes the steps of, as shown in FIGS. Abrasion-resistant hard chromium plating layer 3 is formed on the upper surface, and heat treatment is performed at 200 to 400 ° C., which is a temperature near the melting point of the low-melting metal, to improve corrosion resistance and adhesion without lowering the hardness of the chromium plating. It is characterized by having Further, the method for producing a corrosion-resistant and wear-resistant multilayer metal coating of the present invention comprises a corrosion-resistant nickel-plated layer or a corrosion-resistant and wear-resistant nickel-phosphorus plated layer on a metal base material 1 as shown in FIGS. After applying the corrosion-resistant and abrasion-resistant nickel-based plating layer 6, the low-melting-point metal plating layer 2 is formed on the upper surface of the corrosion-resistant and abrasion-resistant nickel-based plating layer 6. After forming the wear-resistant hard chromium plating layer 3 on the substrate, the temperature is about 200 to 400 which is a temperature near the melting point of the low melting point metal.
It is characterized by improving the corrosion resistance and adhesion without reducing the hardness of chromium plating by heat treatment at ℃.

If the heat treatment temperature is lower than 200 ° C., the low melting point metal does not melt, so that the crack 4 cannot be filled. on the other hand,
If the heat treatment temperature exceeds 400 ° C., there is a problem that the hardness of the chromium plating layer decreases. Low melting point metals include tin (melting point: 232 ° C) and lead (melting point: 327 ° C)
Are used.

[0009]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and the present invention may be practiced by appropriately changing the gist of the invention. Is possible. Example 1 FIGS. 1 and 2 show the corrosion resistance and the corrosion resistance produced by the method of the present invention.
1 shows an example of a wear-resistant multilayer metal coating. In this embodiment,
The case where an iron base material is used as a metal base material and tin is used as a low melting point metal is shown. A tin plating layer 2 having a thickness of about 5 μm was formed on the surface of the iron-based base material 1 by electrolytic plating. Next, a hard chromium plating layer 3 was formed on the tin plating layer 2 to a thickness of about 50 μm (see FIG. 1).
This is heated in an electric furnace at a melting point of tin (23
2 ° C) for a certain period of time to reduce minute defects such as pinholes in the tin plating layer 2 and
Cracks 4 in hard chromium plating layer 3 were also closed with molten tin. In order to prevent a decrease in the hardness of the chromium plating, the heating and holding temperature was set to 400 ° C. or less at the maximum. As a result, as shown in FIG. 2, the molten tin 5 flowed into the crack 4 and closed the crack 4.

Example 2 FIGS. 3 and 4 show corrosion-resistant and anti-corrosion products produced by the method of the present invention.
5 shows another example of a wear-resistant multilayer metal coating. This embodiment shows a case where a corrosion-resistant nickel plating layer formed on an upper surface of an iron-based base material is used as a metal base material and tin is used as a low-melting-point metal. On the surface of the iron-based base material 1, a corrosion-resistant nickel plating layer 6 was formed with a thickness of about 30 μm, and on the upper surface of the corrosion-resistant nickel plating layer 6, a tin plating layer 2 was formed with a thickness of about 5 μm by electrolytic plating. . Then, the hard chromium plating layer 3 was coated on the tin plating layer 2 by about 50 μm.
(See FIG. 3). This in an electric furnace, low
Keeping the temperature near the melting point (232 ° C.) of tin as a melting point metal for a certain period of time to reduce minute defects such as pinholes in the tin plating layer 2 and to reduce the hard chromium plating layer 3
Crack 4 inside was also closed with molten tin. In order to prevent a decrease in the hardness of the chromium plating, the heating and holding temperature was set to 400 ° C. or less at the maximum. As a result, as shown in FIG. 4, the molten tin 5 flowed into the crack 4 and closed the crack 4.

[0011]

As described above, the present invention has the following effects. (1) By using a metal film with low melting point and good corrosion resistance in combination with chromium plating and performing heat treatment at a low temperature near the melting point of the low melting point metal, corrosion resistance and adhesion can be maintained while maintaining the hardness of the chromium plating. Can be improved, and the wear resistance is also improved. (2) Since plating is not damaged, its durability can be improved by using it for a thrust jack for a tunnel excavator. (3) Corrosion- and wear-resistant nickel on a metal base material
-After applying a phosphorous plating layer,
And a wear-resistant hard chromium plating layer
In this case, the corrosion resistance and the wear resistance are further improved.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing an example of a corrosion-resistant and wear-resistant multilayer metal coating produced by the method of the present invention.

FIG. 2 is an explanatory cross-sectional view showing a state in which a low melting point metal flows into a crack in FIG.

FIG. 3 is an explanatory cross-sectional view showing another example of the corrosion-resistant and abrasion-resistant multilayer metal coating manufactured by the method of the present invention.

FIG. 4 is an explanatory cross-sectional view showing a state in which a low melting point metal flows into a crack in FIG. 3;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 metal base material 2 low melting point metal plating layer 3 hard chromium plating layer 4 cracked part (crack) 5 molten low melting point metal flowing into crack 6 corrosion and wear resistant nickel-based plating layer

Continuation of front page (72) Inventor Shozo Okazaki 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Akashi factory (56) References JP-A-5-263208 (JP, A) JP-A-1 -230794 (JP, A) JP-A-57-67196 (JP, A) JP-A-57-23091 (JP, A) JP-A-4-325690 (JP, A)

Claims (2)

(57) [Claims] After a low melting point metal plating is applied to a metal base material (1), a wear resistant hard chromium plating layer (3) is formed on an upper surface of the low melting point metal plating layer (2). A method for producing a corrosion-resistant and abrasion-resistant multi-layer metal coating, which comprises performing a heat treatment at 200 to 400 ° C., which is a temperature near the melting point, to improve the corrosion resistance and adhesion without lowering the hardness of chromium plating. 2. After applying a corrosion-resistant and wear-resistant nickel-based plating layer (6) comprising a corrosion-resistant nickel plating layer or a corrosion- and wear-resistant nickel-phosphorus plating layer on a metal base material (1), A low-melting metal plating layer (2) is formed on the upper surface of the wear-resistant nickel-based plating layer (6), and a wear-resistant hard chrome plating layer (3) is further formed on the upper surface of the low-melting metal plating layer (2). After formation, heat treatment is performed at 200 to 400 ° C., which is a temperature near the melting point of the low-melting metal, to improve corrosion resistance and adhesion without reducing the hardness of chromium plating. A method for producing a multilayer metal coating.