JPH04193967A - Surface treated metallic material and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a black surface treated metallic material excellent in physical properties such as flawing resistance by coating the surface of a metallic material such as a steel sheet with a metallic oxide having oxygen content less than that in stoichiometry. CONSTITUTION:Hoop 1 in which the surface is cleaned is continuously passed in the direction of the arrow A in a vacuum vapor deposition chamber 2. In the vacuum chamber, an evaporating tank 3b charged with a metal 4a having high affinity with O2 and, on its downstream side, an evaporating tank 3b charged with a metal 4b for forming an oxide layer are arranged. Both metals 4a and 4b are heated to evaporate by electron beams from an electron gun 5 or the like to vapor-deposit the metal 4a on the surface of the steel sheet. Next, the oxide of the metal 4b is vapor-deposited by metallic vapor and oxygen ion beams 8, and, by the above metallic oxide and vapor deposited metal 4a, the steel sheet stoichiometrically deficient in O2 so as to be expressed by MxOn (where, at the time of defining the stoichiometric compsn. of the metallic oxide as MxOy, n<=0.8y is regulated) and in which black metallic oxide excellent in flawing resistance is formed into >=0.5mum thickness is stably and continuously manufactured.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a surface-treated metal material whose surface is strongly coated and protected with a black film made of a metal oxide, and a method for manufacturing the same. Metal materials are used for various electrical parts,
It is useful as household electrical appliances, building materials, etc.

The present invention relates to a metal material coated with a specific oxide that has an insufficient amount of oxygen relative to the stoichiometric amount, as will be made clear by the following explanation. Although there are no restrictions on the type or shape of the metal material, the following explanation will mainly be based on the case where the most common steel plate is used.

[Prior Art] When a steel plate is used as an outer panel of a household electrical appliance, etc., the surface may be colored black. The commonly used manufacturing method for black steel sheets is cold-rolled steel sheets or steel sheets that have been subjected to Zn-based plating to improve corrosion resistance, pre-coated steel sheets that have been subjected to chemical conversion treatments such as phosphate treatment, and black organic steel sheets. This method forms a black coating by applying an organic paint containing dyes and inorganic pigments.

However, the above method not only has the disadvantage that the precoating process is complicated and the processing cost is high;
Since the method for blackening the surface is to use an organic paint, it is easily damaged by external forces such as scratching, and furthermore, once scratched, it has the disadvantage of causing corrosion under the paint film and blistering of the paint film.

In addition, as a method for forming a black film other than the above, there is a method in which the surface of a stainless steel plate, A1 or A1 alloy plate, Ti or Ti alloy plate, etc. is colored by chemical treatment such as anodizing. This is extremely difficult compared to developing other colors, and processing costs are high. Moreover, there are only a limited number of metals that can be colored black, and all of them are more expensive than steel plates, so they lack versatility.

[Problems to be Solved by the Invention] The present invention has been made with attention to the above-mentioned circumstances, and its purpose is not limited at all to the type of material metal, and which has excellent physical properties such as scratch resistance. The present invention aims to provide a surface-treated metal material having a black film, and a method for manufacturing such a surface-treated metal material simply and at low cost.

[Means for Solving the Problems] The structure of the surface-treated metal material according to the present invention that can solve the above problems is that the top layer of the plating layer has a metal oxide layer with a thickness of 0.5 μm or more that satisfies the following conditions. The gist lies in the fact that layers are formed.

When the compositional formula of the metal oxide layer is MxOn and the stoichiometric composition of the metal oxide is MxOy (where M represents a metal), n≦0.8y. The cleaned metal material to be plated is introduced into a vacuum deposition chamber, where metals with high affinity for oxygen are evaporated first, metal oxide vapors are then generated, and each vapor is deposited on the surface of the metal material to be plated. and the top of the vapor-deposited plating layer has a thickness of 0 that satisfies the above conditions.
．． This can be obtained by forming a metal oxide layer with a thickness of 5 μm or more.

[Function] As mentioned above, in the present invention, there are no restrictions on the type of metal material to be plated on which the black film is formed, including high carbon steel,
All metal materials such as low oxygen steel, stainless steel, high alloy steel, A1 or A1 alloy, Ti or Ti alloy, copper or copper alloy can be used, and the shape can be plate, rod, wire, or tube. Although it can be applied to various shapes such as steel plates, the following description will focus on typical steel plates.

The present inventors have been conducting research on oxide-based ceramic coating using a vacuum deposition method as a method for improving the corrosion resistance of steel sheets. As part of this series of research, we investigated the atomic ratio of the oxide that makes up the coating layer, and found that if the atomic ratio of the metal elements and oxygen that make up the oxide deviates from the theoretical composition within a certain range, the oxidation It was discovered that a steel plate coated with a substance becomes black. That is, the composition of the oxide constituting the surface coating layer is MxOn (M represents a metal).
On the other hand, when the stoichiometric composition of the oxide is MxOy, an oxide with a degree of oxygen deficiency of n≦0.8yJ exhibits a black color, and is coated with a thickness of 0.5 μm or more. It has become clear that the steel sheet can be used as is as a black steel sheet.The reason why metal oxides take on a black color in the absence of oxygen has not been theoretically elucidated, but due to lack of oxygen, the oxide coating layer This is thought to be due to distortion of the crystal lattice within the crystal (in some cases, it becomes amorphous), which changes the visible light absorption characteristics.

By the way, even if there is a lack of oxygen, if the degree of the deficiency is rO, B yen, <y, the oxide will not be black but will be an interference color, brownish color, or almost colorless.
The purpose of the present invention cannot be achieved. However, if the amount of oxygen decreases too much, it becomes a metallic color and the black color becomes thinner, and the corrosion resistance also decreases, so it is better to set it to "0.3≦n", and more preferably ro, 43r≦n. ≦0
．． It is in the range of 73/J. In addition, if the thickness of the oxide is too thin, not only will parts with insufficient coating remain and corrosion resistance will deteriorate, but also parts with insufficient coloring will occur, resulting in uneven color tone, which will significantly reduce the commercial value. The layer thickness should be at least 0.5 μm, more preferably at least 1 μm. Although there is no particular upper limit to the thickness, making it thicker than necessary is not only economically disadvantageous, but also making it too thick may cause cracks in the oxide layer or powdering during processing such as press molding. Since this tends to occur, it is usually best to keep the thickness to about 20 μm or less, more preferably 10 μm or less.

The type of oxide constituting the oxide coating is not particularly limited,
Most of these oxides exhibit black color as long as they meet the above conditions, but when considering corrosion resistance and coating strength, typical oxides include Sin,..., At□0.
3-,, TiO2-,, Mg C++ -X, MOO
3-X, Ni0+-X, Cr203-X
, ' W O3-x , Z n O, -8 (however, 1
-x, 2-x, and 3-x are such that the oxygen content of each oxide satisfies the relationship of the above composition formula), and these can be used alone or in combination of two or more types. You can also.

By the way, there are no particular limitations on the method of forming an oxide film that satisfies the above requirements, but the following methods can be used, taking into consideration the uniformity of the oxide film, its adhesion to the base steel plate, productivity, processing cost, etc. The method is exemplified as an industrially advantageous method.

That is, in this method, a steel plate whose surface has been cleaned is introduced into a vacuum deposition chamber, a metal having a high affinity for oxygen is first vapor-deposited on the surface of the steel plate, and then a metal oxide is vapor-deposited thereon.

This method can be further embodied by methods (1) and (2) below.

(1) As shown in FIG. 1, a steel strip 1 whose surface has been cleaned in advance is continuously run through a vacuum deposition chamber 2.

Below the running trajectory of the strip steel plate 1 in the vacuum evaporation chamber 2, along the running direction A of the strip steel plate 1, there are two evaporation tanks 3a,
3b is arranged, and the upstream evaporation tank 3a is charged with a metal 4a having high affinity for oxygen, and the downstream evaporation tank 3b is
is charged with a metal 4b for forming an oxide layer, and is heated by any heating means such as electron beam heating, resistance heating, high frequency heating, laser beam heating (in the figure, an electron beam 6 using an electron gun 5 is used). An example using heating is shown) for each metal 4a.
, 4b is heated and evaporated. Then, while supplying oxygen and/or oxygen ion beam 8 toward the evaporation region of metal 4b, these vapors are deposited on steel plate 1. Then, the metal 4a having a high affinity for oxygen is first deposited on the steel plate 1, and then the oxide produced by the reaction between the metal 4b and oxygen is deposited thereon. In addition, 9 in the figure is a support roll, 10
indicates a vacuum exhaust port.

(2) As shown in FIG. 2, a steel strip 1 whose surface has been cleaned in advance is continuously run through a vacuum deposition chamber 2. Below the running trajectory of the strip steel plate 1 in the vacuum deposition chamber 2,
Two evaporation tanks 3a, 3 are installed along the running direction A of the strip steel plate 1.
b, and the upstream evaporation tank 3a is charged with a metal 4a having high affinity for oxygen, and the downstream evaporation tank 3b is charged with an oxide 7 that forms an oxide layer. The metal 4a and the oxide 7 are evaporated by heating them with an arbitrary heating means (same as above). Then, the metal 4a having a high affinity for oxygen is first deposited on the steel plate 1, and then the oxide 7 is deposited thereon.

For example, when vapor deposition plating is performed using the methods shown in (1) and (2) above, the metal 4a having a high affinity for oxygen is first vapor-deposited on the surface of the steel sheet 1, and then the metal 4a is deposited on the surface of the steel sheet 1.
and oxide vapor are deposited in a mixed state, and part of the oxygen constituting the oxide is taken away by the metal 4a, or part of the oxygen in the oxide after deposition is diffused to the metal 4a side. The amount of oxygen in the oxide layer becomes less than the amount of oxygen in the stoichiometric composition. Therefore, if the amount of evaporation of metals 4a, 4b or oxide 7 or the amount of oxygen or oxygen ions blown into the oxide layer is controlled so that the oxide in the oxide layer satisfies the above conditions, it is easy to form a black film made of an oxygen-deficient oxide. can be obtained. As the metal 4a having a high affinity for oxygen used here, for example, At, Mg, Ti, rare earth elements, etc. are preferably used.

As mentioned above, there are no restrictions on the heating source for evaporation, but electron beam heating is particularly easy to maintain, can be heated quickly by directly irradiating the evaporation source, and can easily adjust the heating energy. This is one of the most preferred heating methods because the amount of evaporation can be easily controlled.

In addition, the vapor deposition method employed in the present invention refers to a vacuum vapor deposition method in a broad sense, and includes ion blating methods, sputtering methods, CVD methods, etc. In particular, when ion blating methods are adopted, evaporated materials The diffusion and kinetic energy of the metal 4a are increased, and the reaction between the oxygen-affinity metal 4a and the oxide vapor or oxide layer is accelerated, which not only promotes the blackening of the surface layer but also improves the adhesion of the plating layer to the steel plate. This is preferable because it improves the quality and further reduces pinhole defects in the plating layer. In addition, the example in Figure 2 shows an example of evaporation using two evaporation tanks, but three or more evaporation tanks can be installed to combine two or more oxygen-affinity metals and oxides. Of course, it is also possible to form a composite oxide layer.

The thus obtained surface-treated steel sheet of the present invention has a strong black film with excellent scratch resistance, etc., has good adhesion between the plating layer and the base steel sheet, and has excellent corrosion resistance. It can be used as it is as a final product, but if necessary, it can be further treated with chromate treatment to further improve its corrosion resistance and appearance. Further, by applying a clear coat treatment, the gloss can be further enhanced, and by applying a matte type clear coat treatment, it is possible to obtain a deep black film, and it is naturally possible to perform these additional treatments according to the technical aspects of the present invention. It is included in the scope.

[Example I Example I A steel plate made of A1 quilt steel and stainless steel (SUS304) was used as the material to be plated, and a surface-treated steel plate exhibiting a black color was continuously coated using the apparatus shown in Fig. 1.2 under the following conditions. Manufactured in

Material to be plated: Pre-treatment of Al-killed steel plate or stainless steel plate plated material, introduced into vacuum after alkaline electrolytic degreasing, heating by electron beam irradiation and activation treatment of steel plate surface by Ar ion bombardment Temperature of plated material before plating =300~350℃ evaporation tank A
(corresponds to 38 in Figure 1.2) - Alumina ceramic evaporator Evaporator B (corresponds to 3b in Figure 1.2): Graphite evaporator Evaporation raw material A (4a in Figure 1.2) ): Al (purity 99% or more) Evaporation raw material B (corresponds to 7 in Figure 2): 5i02 (99% or more) Heating evaporation source of evaporation raw material: Pierce-type electron gun (maximum output 30
0 kW) Electron beam scanning method, etc.: Changing the electron beam using a magnetic field, scanning on the surface of the evaporation material, and jumping between the evaporation tanks Vacuum degree of the deposition chamber: 5 x 10-2 to 1 x 10-'
Pa Example 2 A surface-treated steel sheet exhibiting black color was produced in the same manner as in Example 1 except that the plating conditions were as follows.

Material to be plated: Pretreatment of material to be plated: Temperature of material to be plated before plating: Heating evaporation source of evaporation raw material: Vacuum degree of deposition chamber: The above is the same as in Example 1. A (corresponds to 3a in Figure 1.2): Graphite evaporator Evaporator B (corresponds to 3b in Figure 1.2): Alumina ceramic evaporator Evaporation raw material A (corresponds to 48 in Figure 1.2) ): Mg (purity 9
9.5% or more) Evaporation raw material B (corresponding to 7 in Figure 2): N1p (purity 99.5% or more) Each vapor-deposited steel plate obtained in Example 1.2 above was inspected visually and using a color difference meter. The brightness and color tone were measured to determine the degree of blackness.

The results are summarized in Table 1.

As is clear from the 'fS1 table, the blackness of the surface-treated steel sheets of the examples that meet the requirements stipulated by the present invention is very good, whereas the blackness of the surface-treated steel sheets of the examples that meet the requirements stipulated by the present invention is very good, whereas the blackness of the surface-treated steel sheets of the examples that meet the requirements stipulated by the present invention is The blackness of the surface-treated steel sheet in this example is poor.

[Effects of the Invention] The present invention is constructed as described above, and by forming an oxide film in an oxygen-deficient state on the top of the plating layer,
It is now possible to provide a surface-treated metal material that is black and exhibits excellent adhesion. In addition, this surface film has excellent corrosion resistance, exhibiting excellent corrosion resistance even in corrosive environments, and can be widely used in the various applications mentioned above.

[Brief explanation of the drawing]

FIG. 1.2 is a schematic vertical cross-sectional explanatory view showing the vacuum evaporation method employed in the example. 1. Steel plate 1. Vacuum deposition chambers 3a, 3b: Evaporation tanks 4a, 4b: Evaporation raw material 5/electron gun 6. Electron beam 7・Evaporation raw material (oxide) 8・Oxygen or oxygen ion beam 9: Support roll 10・Vacuum exhaust port

Claims (2)

[Claims] (1) A surface-treated metal material exhibiting a black color, characterized in that a metal oxide layer with a thickness of 0.5 μm or more that satisfies the following conditional expression is formed on the uppermost layer of the plating layer. When the compositional formula of the metal oxide layer is MxO_n and the stoichiometric composition of the metal oxide is MxOy (where M represents a metal), n≦0.8y (2) Introduce the surface-cleaned metal material to be plated into a vacuum evaporation chamber, first evaporate metals with high affinity for oxygen, then generate metal oxide vapor, and apply each vapor to the metal material to be plated. A surface-treated metal material exhibiting a black color, characterized by forming a metal oxide layer having a thickness of 0.5 μm or more that satisfies the conditional expression defined in claim (1) on the top of the vapor-deposited plating layer. manufacturing method.