JPH05163562A - Formation of metal member and composite coating film - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a metal member having a composite coating having high wear resistance and excellent non-adhesiveness, and a method for forming the composite coating. The metal member 1 of the present invention comprises a metal film 4 formed on the surface of a base metal material 3, and a large number of irregular holes having a depth of 50 μm or more formed by etching the film 4 chemically or by melting. It is characterized in that it has a metal / fluorine resin composite film 2 consisting of a fluorine resin 5 embedded in 4a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal member having a composite coating film comprising a metal coating film and a fluororesin formed on the surface thereof, which is excellent in wear resistance and non-adhesiveness, and a method for forming the composite coating film. .. INDUSTRIAL APPLICABILITY The metal member and the method for forming a composite film of the present invention are used, for example, in the manufacture of papermaking or filmmaking rolls.

[0002]

2. Description of the Related Art Conventionally, as a roll for paper making or film forming,
Hard chrome plating film, ceramic sprayed film,
A metal roll having a metal spray coating is used.
Since these coatings have good wear resistance, they are often used when a doctor blade is applied to the roll surface. However, since these coatings are inferior in non-adhesiveness, it is necessary to perform frequent cleaning operations on the roll surface, and if the blade linear pressure is increased to enhance the scraping action of adhering materials by the doctor blade, scratches will occur on the roll surface. However, there is a problem in that the amount of deposits increases.

In order to improve non-tackiness, coating with a fluororesin is generally effective. However, since the fluororesin film has a low film hardness, the film surface easily wears,
It is easily scratched. Further, since the adhesive strength to the roll surface is weak, there is a problem of peeling by a doctor knife.

As a solution to the above-mentioned problems, there is a conventional one disclosed in Japanese Patent Laid-Open No. 1-142071. In this conventional technique, a composite coating is formed on the roll surface by applying a non-adhesive fluororesin coating on the surface of a ceramic sprayed coating having abrasion resistance.

[0005]

However, in the composite coating according to the above-mentioned conventional method, sufficient adhesion cannot be obtained between the thermal spray coating and the fluororesin, so that the fluororesin peels off during use and the fluororesin is removed. In some cases, the characteristics possessed by may not be obtained. When the fluororesin layer is worn by the doctor blade, a composite layer in which the resin remains appears in the irregularities of the sprayed layer. However, since the thickness of the remaining fluororesin is small, there is a problem that the period for obtaining the characteristics as the composite layer is short.

The present invention has been made in view of the above problems, and an object thereof is to provide a metal member having a composite coating having high abrasion resistance and excellent non-adhesiveness, and a method for forming the composite coating. I am trying.

[0007]

Means for Solving the Problems The present inventors have studied the problems in the above-mentioned conventional composite coating and obtained the following findings. Generally, it is desirable that the thermal spray coating of ceramics or metal be as dense as possible and have few voids. Otherwise, the film will have weak mechanical strength and will be easily chipped or peeled off. On the other hand, a dense spray coating with few pores
It has a smooth surface with a surface roughness of 40 μm Rmax. In the above-mentioned conventional composite coating, since the smooth coating surface is coated with the fluororesin as it is, the adhesive force between the two is low, and therefore it is considered that they peel off during use. Further, since the surface unevenness is small, the thickness of the resin present in the unevenness is small, and it is considered that the period for obtaining the characteristics as the composite layer is short as described above. If the thermal spray coating is formed under the thermal spraying conditions in which the unevenness becomes large, the adhesiveness of the resin layer is increased, but the denseness of the coating is reduced, the number of pores is increased, and the mechanical strength of the thermal spray coating is reduced as described above. The conflicting problems of doing so arise.

Therefore, the present inventors have found that if the thermal spray coating is as dense as possible and has no pores to ensure its mechanical strength, and if artificially deep holes are formed on the surface of the thermal spray coating. The present invention has been completed on the idea that the above problems can be solved.

The first aspect of the present invention provides a metal coating formed on the surface of a base metal material, and a large number of irregular pores having a depth of 50 μm or more formed by etching the coating by chemical or electrochemical dissolution. Metal consisting of fluororesin embedded inside
A metal member having a fluororesin composite coating. The invention of claim 2 is characterized in that the metal film has a thickness of 100 μm or more, and the invention of claim 3 is
The feature is that the irregular-shaped hole has a small diameter of 5 mm or less. Here, the metal film in the present invention includes both a film made of only metal and a film made of a composite of metal and ceramics.

A fourth aspect of the present invention is a method for forming a composite coating on a metal member as described above, wherein a metal coating is formed on the surface of the base metal material by thermal spraying, and the metal coating is chemically or electrochemically dissolved. A large number of irregular shaped holes with a depth of 50 μm or more are formed by etching, and a fluororesin primer is applied to the irregular shaped holes and baked, and then a fluororesin is embedded to form a metal / fluorine resin composite film on the surface of the base metal material. It is characterized by

[0011]

According to the metal member and the method for forming a composite coating according to the present invention, both the metal layer and the fluororesin layer are present in the obtained composite coating, so that the metal layer has abrasion resistance. Moreover, non-adhesiveness is obtained by the fluororesin layer. In forming this composite film, the metal film itself is dense and has no pores, and since many deep holes are artificially formed in the metal film, the mechanical strength of the metal film is ensured and the resin layer is formed. It is possible to increase the adhesive strength of the resin layer and increase the thickness of the resin layer. As a result, both abrasion resistance and non-adhesiveness can be improved, and the period of functioning as a composite film can be extended by the amount that the thickness of the resin remaining in the metal film can be increased.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 are views for explaining one embodiment of the present invention, FIGS. 1 and 2 are views showing a composite coating layer portion of a metal member, FIG. 3 is a view showing an experimental method, and FIG. It is a figure which shows an experimental result.

In the figure, reference numeral 1 denotes a metal member of this embodiment, on the surface of which a composite film 2 is formed.
The composite film 2 is composed of a metal film 4 formed on the surface of the base metal 3 and a fluororesin layer 5 embedded in a large number of irregularly shaped holes 4a artificially formed in the film 4. ing.

Next, a method of forming the composite film 2 will be described. The base metal 3 may be iron-based, Al-based, Ni-based, Co-based, or the like. Further, the shape is not limited, and anything such as a flat plate or a roll may be used. The surface of the base metal 3 is roughened by a mechanical method such as grid blasting.

On the surface of the roughened base metal 2, a mixed powder composed of one kind or two or more kinds of metal powder such as Ni alloy, Fe alloy, Co alloy and Al alloy,
Alternatively, a composite powder, or alumina to the above metal powder,
Non-metal powders such as zirconia and titania are further mixed or a composite powder is sprayed. In this case, the spraying conditions are set so that the obtained sprayed coating is dense and only extremely fine pores are produced.

Since the thermal spray coating obtained as described above has a low surface roughness, the intended composite coating cannot be obtained even if the fluororesin coating is performed as it is. Therefore, on the surface of the thermal spray coating, the pore diameter is 5 mm or less and the depth is 50 μm.
A large number of the above irregular shaped holes are formed. As a method of forming the irregular pores, a method of chemically treating with a sulfate or the like, a method of performing electrochemical dissolution, and a method of performing laser irradiation can be adopted.

In the case of chemical treatment with sulfate or electrolysis,
As a result, the inner surface of the fine pores existing on the surface of the thermal spray coating 4 is attacked, and the pore diameter increases and the depth increases. Further, the electrochemically base portion is attacked by the noble portion to form an irregular hole. In this case, by applying a material that is not attacked by the treatment liquid to the region A portion of FIG. 2 in the form of rectangular dots and masking it, the depressions of the grid-shaped portion B of the thermal spray coating that directly contacts the treatment liquid can be made even larger. it can.

Further, in the case of the method of irradiating the thermal spray coating with a laser, the irradiated portion is rapidly melted and reaches a high temperature. Since the molten metal that has reached a high temperature has a low viscosity, the bead end portion rises due to the shield gas, or the bead center portion disappears due to evaporation, so that a large depression can be formed.

An appropriate amount of a silane coupling agent having an amino group is applied to the surface of the sprayed coating having irregularities of 100 μm or more formed by the above method. By applying this coupling agent, the adhesion between the thermal spray coating and the fluororesin can be greatly improved. The above coupling agent is disclosed in JP-A-3-4971, 21379. Then, a fluororesin primer is further applied to the surface of the metal film having the irregular pores, and then a fluororesin is applied and heated / baked to form a composite film.

The composite film formed as described above has excellent non-adhesiveness even when used as it is, and also has excellent adhesiveness between the fluororesin and the base metal, but as shown in FIG. By subjecting the surface to grinding until 4 is exposed, a composite film more suitable for the purpose of the present invention can be obtained. That is, the fluororesin layer 5 can maintain the non-adhesiveness, and the metal coating 4 can provide the composite coating 2 having abrasion resistance at the same time.

Example 1 In this example, in order to satisfy both the abrasion resistance and the non-adhesiveness of the above composite coating, the abundance ratio of the sprayed metal coating 4 and the fluororesin layer 5 of the above composite coating 2 was determined. The following experiment was conducted to determine what range should be.

Ni-based self-fluxing alloy is sprayed on a mild steel plate having a thickness of 20 mm × 100 mm × 5 mm, and a fluororesin layer is formed on the mild steel plate with an area ratio of 2%, 12%, 46%, 64%, 100%. Was adjusted so that Cellophane tape was attached to the upper surface of each of these test pieces, and a peeling test was performed by setting the tape in a peeling tester shown in FIG. 3 to evaluate the tensile strength. The results obtained are shown in Table 1.

[0023]

[Table 1]

Next, an abrasion resistance test was conducted on the above test piece. In this abrasion resistance test, the amount of abrasion loss was measured using a JISK7204 Taber tester. The result is shown in FIG.

As a result of the above peeling test and abrasion resistance test, it was found that the fluororesin layer should be 10% or more of the total surface layer in order to secure both abrasion resistance and non-adhesiveness. ..

Example 2 After blasting the surface of an iron-based material, Ni alloy 30
Plasma sprayed to a thickness of 0 μm. Next, using a sulfate electrolyte solution, the sprayed coating side was made to face the cathode in the electrolyte solution using the positive electrode of the DC power supply as a positive electrode, and a current of 40 A / dm ^{2 was applied} , whereby the surface of the sprayed coating was electrochemically dissolved. As a result, the micropores on the surface of the thermal spray coating and in the vicinity of the surface become large,
Asperities were formed up to a maximum depth of 100 μm. A silane coupling agent containing an amino group was applied onto the sprayed coating having such large irregularities, dried, and then a fluororesin primer and a fluororesin cover coat were sequentially applied.

The adhesion of the composite coating thus produced was applied with a fluororesin only by blasting the surface of the base material (Comparative Example 1), and the fluororesin was applied as it was after forming the sprayed coating (Comparative Example 2). Compared to the adhesive strength of. As a result, the adhesion of the coating of this example increased 2.5 times and 2.0 times, respectively, as compared with Comparative Examples 1 and 2 above.

The wear resistance, non-adhesiveness, and durability of the composite coating of this example coating were tested. First,
The wear rate was examined for wear resistance. The wear rate after the fluororesin coating layer disappeared to the interface of the sprayed coating by grinding was reduced to about 1/30 as compared with the case of the fluororesin coating layer alone. This is because the thermal spray coating reduces wear. On the other hand, non-stickiness is
Since the fluororesin remained in the film recesses, it did not decrease.

Next, the durability of the composite coating depends on the surface of the composite coating.
Starting from the point where the metal layer was exposed by 10 μm grinding and the metal layer was exposed, the non-adhesiveness of the paper powder when 20 μm was ground from this point was compared with the samples of the above comparative examples. In the case of only the blasting treatment and the thermal spraying as it was, the adhesion was deteriorated after grinding by 40 μm, whereas in the case of the present invention, there was almost no deterioration even by grinding by 80 μm. . At this time, 20% of the fluororesin remained on the surface.

Example 3 Ni-based self-fluxing alloy powder was used as a thermal spray material and plasma sprayed on the surface of a blasted base metal. This was irradiated with carbon dioxide gas laser at an output of 3 kW at intervals of 500 μm. Then, the part irradiated with the laser rapidly melted and reached a high temperature.
Since the temperature of the molten metal reached a high temperature, the viscosity of the molten metal was low, and the bead edge was bulged by the shield gas and the bead center disappeared due to evaporation, resulting in the formation of irregularities with a maximum depth of 150 μm. A silane coupling agent containing an amino group was applied on the sprayed coating having such large irregularities and dried, and then a fluororesin primer and a fluororesin cover coat were sequentially applied.

The adhesion, abrasion resistance, non-adhesiveness, and durability of the thus-prepared composite coating were evaluated according to the above-mentioned examples.
The survey was conducted in the same manner as 1,2. Adhesion is better than that of the one coated with fluororesin just by blasting the surface of the base material, and the one coated with fluororesin as it is after forming the sprayed coating.
It increased 2.5 times and 2.0 times, respectively.

The wear resistance rate is as follows: When the fluororesin coating layer is removed by grinding to the boundary surface of the sprayed coating,
It was reduced to about 1/30 as compared with the case where only the fluororesin coating layer was used. On the other hand, the non-tackiness did not decrease. In addition, the durability of the composite coating is only blasted, while the as-sprayed material is 40 μm, the adhesiveness deteriorates.
The material of the present invention showed almost no deterioration even at 120 μm.

[0033]

As described above, according to the method for forming a metal member and a composite film thereof according to the present invention, the metal film itself is dense and has no pores, and the metal film has an artificially deep amorphous shape. Since a large number of holes are formed, the mechanical strength of the metal film is secured and the adhesion of the resin layer is increased,
The thickness of the resin layer in the metal coating can be increased, and as a result, both abrasion resistance and non-adhesiveness can be improved, and the period of functioning as a composite coating can be extended.

[Brief description of drawings]

FIG. 1 is a sectional side view of a metal member according to an embodiment of the present invention.

FIG. 2 is a view for explaining a method of etching the metal member of the above-mentioned embodiment.

FIG. 3 is a diagram showing a peeling test state.

FIG. 4 is a cumulative rotation speed-cumulative weight loss characteristic chart showing the results of an abrasion resistance test.

[Explanation of symbols]

 1 Metal Member 2 Composite Film 3 Base Metal 4 Metal Film 4a Amorphous Hole 5 Resin Layer

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Akira Yamamoto Akira Yamamoto 2-15-8-105 Fujigaoka, Fujisawa City, Kanagawa Prefecture (72) Koichi Wada 1-478 Wakihamacho, Chuo-ku, Kobe City Kobe Steel Pantech Co., Ltd. (72) Inventor Masayuki Okitsu 4-13-4 Fukaekita-cho, Higashinada-ku, Kobe-shi Tokaro Co., Ltd.

Claims (4)

[Claims] 1. A metal film formed on the surface of a base metal material, and fluorine embedded in a large number of amorphous holes having a depth of 50 μm or more formed by etching the film by chemical or electrochemical dissolution. A metal member having a metal / fluorine resin composite coating made of a resin. 2. The metal film according to claim 1, wherein the metal film has a thickness of 100 μm.
A metal member having the above thickness. 3. The metal member according to claim 1, wherein the irregularly shaped hole has a small diameter of 5 mm or less. 4. A metal film is formed on the surface of a base metal material by thermal spraying, and a large number of amorphous holes having a depth of 50 μm or more are formed in the metal film by etching by chemical or electrochemical dissolution. A method for forming a composite coating, which comprises forming a metal / fluororesin composite coating on the surface of a base metal material by applying a fluororesin primer to the holes, baking the coating, and then burying the fluororesin.