Method for manufacturing metal mesh, method for modifying surface of metal mesh, and metal mesh

Abstract

To provide a method, etc., for manufacturing a metal mesh excellent in durability.SOLUTION: There is provided a method for manufacturing a metal mesh including a metal wire. The method comprises a step of subjecting the metal wire including iron based metal or nickel based metal to gas nitriding or gas carburizing. In the step of subjecting the metal wire to the gas nitriding or gas carburizing, formed is, on the surface of the metal wire, a processing layer having a surface nitrogen concentration of 2.5 wt.% or more or a surface carbon concentration of 1.0 wt.% or more, and 60% or less of the ratio of the thickness of the metal wire to the radius thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a metal mesh, a method for surface modification of a metal mesh, and a metal mesh.

Background Art

[0002] Conventionally, metal meshes have been used as sieves, filters, cushioning materials, etc. Technologies for improving the durability of such metal meshes have been proposed.

[0003] For example, Patent Document 1 discloses a surface treatment method for a mesh filter, which comprises spraying and colliding injection particles on the surface of a wire forming the mesh filter to process the surface roughness of the wire within a specific range.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the technology described in Patent Document 1 has room for improvement from the viewpoint of durability.

[0006] The main object of the present disclosure is to provide a method for manufacturing a metal mesh excellent in durability.

Means for Solving the Problems

[0007] Aspects of the present disclosure for solving the above problems are as follows.

[0008] [1] A method for manufacturing a metal mesh including a metal wire, comprising a step of performing gas nitriding treatment or gas carburizing treatment on the metal wire containing an iron-based metal or a nickel-based metal. including a step of performing gas nitriding treatment or gas carburizing treatment on the metal wire containing an iron-based metal or a nickel-based metal. In the step of performing the gas nitriding treatment or the gas carburizing treatment, a treatment layer having a surface nitrogen concentration of 2.5% by weight or more or a surface carbon concentration of 1.0% by weight or more and a ratio of the thickness to the radius of the metal wire of 60% or less is formed on the surface of the metal wire. A method for manufacturing a metal mesh. [2] The method for manufacturing a metal mesh according to [1], wherein the gas nitriding treatment or the gas carburizing treatment is performed under a reduced pressure atmosphere. [3] The method for manufacturing a metal mesh according to [1] or [2], including a step of performing a blasting treatment on the metal wire before or after the step of performing the gas nitriding treatment or the gas carburizing treatment. [4] The method for manufacturing a metal mesh according to any one of [1] to [3], including a halogenation treatment step of heating and holding the metal wire in a halogen-based gas atmosphere before the step of performing the gas nitriding treatment or the gas carburizing treatment. [5] A method for surface modification of a metal mesh including a metal wire, including a step of performing a gas nitriding treatment or a gas carburizing treatment on the metal wire containing an iron-based metal or a nickel-based metal, In the step of performing the gas nitriding treatment or the gas carburizing treatment, a treatment layer having a surface nitrogen concentration of 2.5% by weight or more or a surface carbon concentration of 1.0% by weight or more and a ratio of the thickness to the radius of the metal wire of 60% or less is formed on the surface of the metal wire. A method for surface modification of a metal mesh. [6] A metal wire including an iron-based metal or a nickel-based metal, and a treatment layer formed on the surface of the metal wire, wherein the treatment layer has a surface nitrogen concentration of 2.5% by weight or more or a surface carbon concentration of 1.0% by weight or more, and a ratio of the thickness of the treatment layer to the radius of the metal wire is 60% or less. A metal mesh. [7] The metal wire includes vertical wires and horizontal wires that intersect each other, The metal mesh according to [6], wherein the treatment layer is formed over the entire circumference of the cross-sections of the vertical wire and the horizontal wire at the intersection of the vertical wire and the horizontal wire. [8] The treatment layer has a surface nitrogen concentration of 2.5 wt% or more and 10.0 wt% or less, or a surface carbon concentration of 1.0 wt% or more and 7.0 wt% or less, and the ratio of the thickness of the treatment layer to the radius of the metal wire is 1% or more and 60% or less. The metal mesh according to [6] or [7].

Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a method for manufacturing a metal mesh excellent in durability, etc.

Brief Description of the Drawings

[0010]

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[0011] Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The elements listed below can be arbitrarily combined, and the scope of the present invention is intended to include all modifications within the scope of the claims and the scope equivalent to the claims. Also, in this specification, the upper limit value and the lower limit value exemplified for the numerical range can be arbitrarily combined to form a new numerical range. For example, when "A or more and B or less" and "C or more and D or less" are described, the ranges of "A or more and D or less" and "C or more and B or less" can also be included in the numerical range.

[0012] [Metal Mesh] FIG. 1 is a schematic partial plan view showing an example of the metal mesh 1 of the present embodiment, and FIG. 2 is a schematic partial cross-sectional view taken along line II-II in FIG. 1. The metal mesh 1 includes a plurality of metal wires 2. The metal wire 2 includes a warp (vertical wire) 21 and a weft (horizontal wire) 22. The metal mesh 1 is woven and formed such that the warp 21 and the weft 22 intersect each other. A treatment layer 3 is formed on the surface of the metal wire 2 as a base material.

[0013] The metal wire 2 contains an iron-based metal or a nickel-based metal. The iron-based metal or nickel-based metal is not particularly limited as long as it is a material capable of being subjected to gas nitriding or gas carburizing treatment described later. Examples thereof include carbon steel, alloy steel, piano wire, stainless steel, nickel-based alloys, etc. The metal wire 2 is preferably stainless steel, and more preferably austenitic stainless steel (for example, SUS304, SUS316, etc.) from the viewpoints of durability, easy adjustment of the nitrogen or carbon concentration in the treatment layer 3, corrosion resistance, etc.

[0014] The cross-sectional shape in the cross-section orthogonal to the spool of the metal wire 2 is not particularly limited, and may be, for example, circular, elliptical, square, rectangular, etc.

[0015] The wire diameter of the metal mesh 1 is preferably 2 μm or more, more preferably 5 μm or more, and still more preferably 10 μm or more from the viewpoints of durability and easy adjustment of the thickness of the treatment layer 3. The upper limit of the wire diameter of the metal mesh is not particularly limited, but can be, for example, 2 mm or less from the viewpoint of easy formation of the treatment layer 3.

[0016] The mesh opening of the metal mesh 1 is not particularly limited and may be appropriately set according to the intended use. The mesh opening of the metal mesh 1 is, for example, 10 μm or more and 12 mm or less.

[0017] In FIGS. 1 and 2, an example is shown in which the metal mesh 1 is formed by plain weaving the warp 21 and the weft 22. However, the configuration and weaving mode of the warp 21 and the weft 22 are not particularly limited as long as they are formed bodies woven so that the warp 21 and the weft 22 cross each other. Other weaving methods include, for example, twill weaving, plain tuck weaving, crimp netting, welded wire mesh, etc.

[0018] As described above, the metal mesh 1 of the embodiment includes a treatment layer 3 formed on the surface of the metal wire 2. The treatment layer 3 is formed on the surface of the metal wire 2 by performing gas nitriding treatment or gas carburizing treatment described later on the metal wire 2 as a base material. The treatment layer 3 is a layer in which nitrogen and / or carbon has diffused and penetrated into the metal wire 2 and includes a compound layer containing nitrogen and / or carbon.

[0019] The metal mesh 1 of the embodiment is provided with a treatment layer 3 containing nitrogen and / or carbon, so that its hardness is significantly improved compared with the base material, realizing excellent durability and exhibiting excellent strength and wear resistance. Furthermore, by forming the treatment layer 3 by gas nitriding treatment or gas carburizing treatment, a treatment layer 3 having irregularities caused by expansion of metal crystals or the like on the surface can be obtained. By providing the treatment layer 3 having irregularities, for example, when the metal mesh 1 is used as a sieve or a filter for powdery or granular materials, the fluidity of the material can be improved, and the adhesion of the material to the surface of the metal wire 2 can be favorably suppressed. Furthermore, by forming high-hardness irregularities on the surface of the metal wire 2, the durability can be improved and the duration of the adhesion suppression effect can be extended, reducing the frequency of replacement and maintenance, leading to an improvement in productivity.

[0020] The treatment layer 3 is preferably formed over the entire circumference of the cross-sections of the warp 21 and the weft 22, respectively, at the intersection portion 4 where the warp 21 and the weft 22 intersect, on the surfaces of the warp 21 and the weft 22 as the metal wires 2. More preferably, the treatment layer 3 is formed on substantially the entire surface of each of the warp 21 and the weft 22, and even more preferably, it is formed on the entire surface of each of the warp 21 and the weft 22. Note that the intersection portion 4 of the warp 21 and the weft 22 may be in a mode where the warp 21 and the weft 22 are in contact, or may be in a mode where there is a gap between the warp 21 and the weft 22.

[0021] When the treatment layer 3 is formed on substantially the entire surface of the metal wire 2, the formation region of the treatment layer 3 is preferably 95% or more, more preferably 97% or more, and even more preferably 99% or more of the total surface area of the metal wire 2.

[0022] In the metal mesh 1 of the embodiment, in order to diffuse and infiltrate nitrogen and / or carbon into the metal wire 2 by using a gas nitriding treatment or a gas carburizing treatment method, the treatment layer 3 can be uniformly formed over the entire surface of the metal wire 2. For example, in a plasma nitriding treatment method that generates glow discharge between the furnace wall, it is difficult to generate discharge evenly on the product to be treated, and there is a problem that the nitriding treatment effect cannot be obtained in the shaded part. Also, in a method of plating or coating, a film is not formed at the portion where the warp and the weft are in contact. By using a gas nitriding treatment or a gas carburizing treatment method, even in a portion where the warp 21 and the weft 22 are in contact or in a portion where there is only a slight gap between the warp 21 and the weft 22, the treatment layer 3 can be formed over the entire circumference of the cross section in the above portion. Thereby, even in an environment where a high tension is applied during use, the occurrence of breakage such as tearing of the mesh and elongation can be suppressed, and long-term use becomes possible.

[0023] In the metal mesh 1 of the embodiment, the treatment layer 3 has a surface nitrogen concentration of 2.5 wt% or more or a surface carbon concentration of 1.0 wt% or more, and the ratio of the thickness of the treatment layer 3 to the radius of the metal wire 2 (thickness of the treatment layer 3 / radius of the metal wire 2) is 60% or less.

[0024] In the metal mesh 1 of the embodiment, as described above, the treatment layer 3 has a surface nitrogen concentration of 2.5 wt% or more or a surface carbon concentration of 1.0 wt% or more. When the surface nitrogen concentration or the surface carbon concentration of the treatment layer 3 is within the above range, it is excellent in durability and adhesion suppression, and can maintain its effect for a longer time. The treatment layer 3 preferably has a surface nitrogen concentration of 4.0 wt% or more or a surface carbon concentration of 2.0 wt% or more, more preferably a surface nitrogen concentration of 6.0 wt% or more or a surface carbon concentration of 3.0 wt% or more. The upper limit of the surface nitrogen concentration and the surface carbon concentration of the treatment layer 3 is not particularly limited and can be appropriately set according to the material of the base material. The treatment layer 3 has, for example, a surface nitrogen concentration of 10.0 wt% or less, preferably 9.0 wt% or less, or, for example, a surface carbon concentration of 7.0 wt% or less, more preferably 6.0 wt% or less. When the upper limit of the surface nitrogen concentration is within the above range, embrittlement can be well suppressed. Also, when the upper limit of the surface carbon concentration is within the above range, adhesion of soot can be well suppressed.

[0025] The surface nitrogen concentration or the surface carbon concentration of the treatment layer 3 can be adjusted to the target value by adjusting treatment conditions such as the treatment temperature, treatment time, gas concentration, and atmospheric pressure in the gas nitriding treatment or the gas carburizing treatment.

[0026] In the metal mesh 1 of the embodiment, the ratio of the thickness of the treatment layer 3 to the radius of the metal wire 2 (thickness of the treatment layer 3 / radius of the metal wire 2) is 60% or less, preferably 1% or more and 60% or less. When the ratio of the thickness of the treatment layer 3 to the radius of the metal wire 2 is within the above range, it is excellent in durability and adhesion suppression, and embrittlement can be suppressed. The ratio of the thickness of the treatment layer 3 to the radius of the metal wire 2 is more preferably 5% or more and 50% or less, still more preferably 10% or more and 40% or less, and most preferably 18% or more and 37% or less.

[0027] In the metal mesh 1 of the embodiment, the thickness of the treatment layer 3 is appropriately adjusted in consideration of the material of the material to which the metal mesh 1 is applied, the pressure applied, etc., so that the ratio of the thickness of the treatment layer 3 to the radius of the metal wire 2 is within the above range. The thickness of the treatment layer 3 is preferably 0.5 μm or more and 600 μm or less from the viewpoints of durability, adhesion suppression, and embrittlement suppression.

[0028] The thickness of the treatment layer 3 and the ratio of the thickness of the treatment layer 3 to the radius of the metal wire 2 can be adjusted to target values by adjusting treatment conditions such as treatment temperature, treatment time, gas concentration, and atmospheric pressure in the gas nitriding treatment or gas carburizing treatment.

[0029] The surface roughness (arithmetic mean roughness Ra) of the metal wire 2 in the metal mesh 1 is preferably 0.1 μm or more and 1.0 μm or less, more preferably 0.25 μm or more and 1.0 μm or less, from the viewpoint of adhesion suppression.

[0030] The surface hardness of the metal wire 2 in the metal mesh 1 is preferably 650 Hv or more, more preferably 700 Hv or more, in terms of Vickers hardness, from the viewpoints of durability and wear resistance.

[0031] The surface roughness and surface hardness of the metal wire 2 can be adjusted to target values by adjusting treatment conditions such as treatment temperature, treatment time, gas concentration, and atmospheric pressure in the gas nitriding treatment or gas carburizing treatment. When performing the blasting treatment described later in addition to the gas nitriding treatment or gas carburizing treatment, the surface roughness can be adjusted by adjusting the treatment conditions in the gas nitriding treatment or gas carburizing treatment and the blasting treatment.

[0032] Since the metal mesh 1 of the embodiment is excellent in durability and adhesion suppression, it can be suitably used as a contact member with which powder particles such as edible powder particles and pharmaceutical powder particles come into contact. Examples of such contact members include sieves, filters, cooking utensils, etc. The metal mesh 1 can also be suitably used for mechanical appliances used in fields that handle foods, drugs, glass, ceramics, electricity, electronics, battery materials, etc.

[0033] [Method for manufacturing a metal mesh] The manufacturing method of the metal mesh 1 of the embodiment includes a step of performing gas nitriding treatment or gas carburizing treatment on the metal wire 2 containing the above-described iron-based metal or nickel-based metal. By the gas nitriding treatment or gas carburizing treatment, a treatment layer 3 containing nitrogen and / or carbon and having irregularities due to expansion of metal crystals or the like can be formed on the surface of the metal wire 2. Thereby, a metal mesh excellent in durability and excellent in adhesion suppression can be obtained.

[0034] In the gas nitriding treatment, nitrogen is diffused and penetrated into the surface of the metal wire 2 by holding the metal wire 2 as a base material in a heated state in an atmosphere containing a nitriding source gas. As the gas nitriding treatment, any of the methods of gas nitriding treatment, gas soft nitriding treatment, and vacuum nitriding treatment can be applied.

[0035] The gas nitriding treatment and gas soft nitriding treatment are performed by heating and holding the metal wire 2 as a base material in a gas atmosphere for nitriding or soft nitriding, that is, an atmosphere in which NH3 is used as a nitrogen source and N2, H2, CO, CO2, etc. are mixed as necessary. The vacuum nitriding treatment can be performed by heating and holding the metal wire 2 in a reduced-pressure atmosphere for nitriding or soft nitriding, that is, an atmosphere in which NH3 is used as a nitrogen source and N2, H2, CO, CO2, etc. are mixed as necessary.

[0036] In the gas carburizing treatment, carbon is diffused and penetrated into the surface of the metal wire 2 by holding the metal wire 2 as a base material in a heated state in an atmosphere containing a carburizing source gas. As the gas carburizing treatment, any of the methods of gas carburizing treatment and vacuum carburizing treatment can be applied.

[0037] The gas carburizing treatment can be carried out by heating and holding the metal wire 2 in a carburizing gas atmosphere, that is, an atmosphere in which CO or C2H2, etc. is used as the carburizing source and N2, H2, CO, CO2, etc. are mixed as required. The vacuum carburizing treatment can be carried out by heating and holding the metal wire 2 in a reduced-pressure carburizing atmosphere, that is, an atmosphere in which CO or C2H2, etc. is used as the carburizing source and N2, H2, CO, CO2, etc. are mixed as required.

[0038] The treatment temperatures (atmosphere temperatures) of the gas nitriding treatment and the gas carburizing treatment can be appropriately determined according to the material of the metal wire 2 and the characteristics of the target treatment layer 3. The temperatures of the gas nitriding treatment and the gas carburizing treatment have a correlation with the diffusion rates of nitrogen and carbon and affect the thickness and surface hardness of the treatment layer 3. If the treatment temperature is too low, the diffusion rates of nitrogen and carbon are small, and the thickness of the treatment layer 3 becomes small. If the treatment temperature is too high, the thickness of the treatment layer 3 becomes excessive, and the economy deteriorates. The treatment temperature of the gas nitriding treatment is, for example, 350°C or higher and 900°C or lower, preferably 430°C or higher and 650°C or lower. The treatment temperature of the gas carburizing treatment is, for example, 350°C or higher and 1050°C or lower, preferably 350°C or higher and 950°C or lower.

[0039] The treatment times (holding times) of the gas nitriding treatment and the gas carburizing treatment can be appropriately determined according to the material of the metal wire 2 and the characteristics of the target treatment layer 3. The treatment times of the gas nitriding treatment and the gas carburizing treatment have a correlation with the diffusion rates of nitrogen and carbon and affect the thickness and surface hardness of the treatment layer 3. If the treatment time is too short, the diffusion of nitrogen and carbon becomes insufficient, and the thickness of the treatment layer 3 becomes small. If the treatment time is too long, the thickness of the treatment layer 3 becomes excessive, and the economy deteriorates. The treatment time of the gas nitriding treatment is, for example, 10 minutes or more and 50 hours or less, preferably 20 minutes or more and 30 hours or less. The treatment time of the gas carburizing treatment is, for example, 10 minutes or more and 50 hours or less, preferably 20 minutes or more and 30 hours or less.

[0040] In the method for manufacturing the metal mesh 1 of the embodiment, it is preferable that the above-described gas nitriding treatment or gas carburizing treatment is performed in a reduced-pressure atmosphere. By performing the treatment in a reduced-pressure atmosphere, it becomes easy for the nitriding source gas or carburizing source gas to reach the fine parts of the metal wire 2. Therefore, for example, even in a portion where the warp 21 and the weft 22 are in contact with each other, or a portion where there is only a slight gap between the warp 21 and the weft 22, the treatment layer 3 can be uniformly formed. Further, even when the metal meshes 1 are stacked, the treatment layer 3 can be formed on the surface of each metal wire 2, and the productivity is improved.

[0041] The pressure of the reduced-pressure atmosphere is preferably 0.1 kPa or more and 50 kPa or less, more preferably 1 kPa or more and 40 kPa or less. When the pressure is less than 0.1 kPa, the concentration of the treatment gas is low, and the surface nitrogen concentration or surface carbon concentration of the obtained treatment layer 3 tends to be low. When the pressure exceeds 50 kPa, there is a possibility that the treatment gas does not sufficiently reach the metal wire 2.

[0042] In the method for manufacturing the metal mesh 1 of the embodiment, in the gas nitriding treatment or gas soft nitriding treatment, the surface nitrogen concentration of the treatment layer 3 is 2.5% by weight or more or the surface carbon concentration is 1.0% by weight or more, and the ratio of the thickness of the treatment layer 3 to the radius of the metal wire 2 (thickness of the treatment layer 3 / radius of the metal wire 2) is 60% or less, so as to form the treatment layer 3. The thickness, surface nitrogen concentration or surface carbon concentration of the treatment layer 3 can be adjusted to the target value by adjusting the treatment temperature, treatment time, gas concentration, atmospheric pressure, etc. in the gas nitriding treatment or gas carburizing treatment as described above.

[0043] In the method for manufacturing the metal mesh 1 of the embodiment, it is preferable to include a halogenation treatment step of heating and holding the metal wire 2 in a halogen-based gas atmosphere before the step of performing the above-described gas nitriding treatment or gas carburizing treatment.

[0044] By performing a halogenation treatment before a gas nitriding treatment or a gas carburizing treatment, the passive film formed on the surface of the metal wire 2 containing an iron-based metal or a nickel-based metal can be replaced with a halogenated film that facilitates the penetration of nitrogen or carbon, facilitating the formation of the subsequent treatment layer 3.

[0045] In the halogenation treatment, a heating furnace whose atmosphere can be controlled is used, and the metal wire 2 as a base material is held in a heated state in an atmosphere gas containing a halogen. Thereby, the surface of the metal wire 2 is activated.

[0046] As the halogen used for the atmosphere gas, a halogen-based gas (for example, F2, Cl2, etc.) or a halogen compound gas (for example, HCl, NF3, etc.) can be used, and preferably NF3. The halogen may be used alone or in combination of two or more.

[0047] The above atmosphere gas may be a mixed gas of a halogen-based gas or a halogen compound gas and a nitrogen gas or an inert gas. The concentration of the halogen-based gas or the halogen compound gas in the mixed gas can be, for example, 0.5% by volume or more and 20% by volume or less.

[0048] The treatment temperature and treatment time of the halogenation treatment can be appropriately determined according to the material of the metal wire 2 and the characteristics of the target treatment layer 3. The treatment temperature of the halogenation treatment is, for example, 200°C or higher and 550°C or lower, preferably 300°C or higher and 450°C or lower. The treatment time of the halogenation treatment is, for example, 10 minutes or more and 3 hours or less, preferably 30 minutes or more and 2 hours or less.

[0049] In the method for manufacturing the metal mesh 1 of the embodiment, it is preferable to further include a step of performing a blasting treatment. The blasting treatment is a treatment in which abrasive grains are sprayed onto the surface of the metal wire 2. By performing the blasting treatment, the surface roughness of the metal wire 2 can be adjusted, and fine irregularities can be formed on the surface of the metal wire 2. Thereby, the adhesion suppression property can be further improved. In addition, unnecessary substances adhering to the surface of the metal wire 2 can be removed.

[0050] The blasting treatment may be performed either before or after the step of performing the above-described gas nitriding treatment or gas carburizing treatment. When the halogenation treatment is performed before the gas nitriding treatment or gas carburizing treatment, it is preferable to perform the halogenation treatment and the gas nitriding treatment or gas carburizing treatment after the blasting treatment. From the viewpoints of adhesion suppression and cleaning properties, the blasting treatment is preferably performed after the step of performing the gas nitriding treatment or gas carburizing treatment.

[0051] Examples of the method of the blasting treatment include air blasting treatment, wet blasting treatment, etc., and wet blasting treatment is preferable.

[0052] Examples of the material of the abrasive grains used in the blasting treatment include hard particles such as glass, various ceramics, and stainless steel. The average particle size of the abrasive grains used in the blasting treatment is preferably 1 μm or more and 50 μm or less. The discharge pressure in the blasting treatment can be appropriately adjusted according to the particle size of the abrasive grains, etc., and may be, for example, 0.1 to 1 MPa.

[0053] The surface roughness of the unevenness formed on the metal wire 2 by the blasting treatment can be adjusted to the target value by adjusting the average particle size of the abrasive grains, the discharge pressure, etc. in the blasting treatment.

[0054] [Method for surface modification of metal mesh] In the present embodiment, a method for surface modification of the metal mesh 1 including the metal wire 2 can be provided. The method for surface modification of the metal mesh 1 according to the embodiment includes a step of performing a gas nitriding treatment or a gas carburizing treatment on the metal wire 2 containing an iron-based metal or a nickel-based metal in a reduced-pressure atmosphere. In the step of performing the gas nitriding treatment or gas carburizing treatment, a treatment layer having a surface nitrogen concentration of 2.5% by weight or more or a surface carbon concentration of 1.0% by weight or more and a ratio of the thickness to the radius of the metal wire of 60% or less is formed on the surface of the metal wire. According to the above method for surface modification of the metal mesh, the durability of the metal mesh can be improved and the adhesion suppression property can be improved.

Example

[0055] Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not intended to be limited to these examples.

[0056] (Manufacture of Metal Mesh) [Example 1] A mesh (SUS304) with a wire diameter of 10 μm and a mesh number of 600 was cut out into a circle with a diameter of 280 mm. The cut-out mesh was subjected to a fluorination treatment (halogenation treatment) by holding it at 350 °C for 1 hour in an atmosphere of 10% by volume of NF3 and 90% by volume of N2. Then, the mesh was subjected to a gas nitriding treatment by holding it at 380 °C for 3 hours in an atmosphere containing a mixed gas with a ratio of NH3:N2 = 50:50 (by volume%) to obtain the metal mesh of Example 1.

[0057] [Examples 2 to 8, Comparative Examples 1 to 3] Metal meshes of Examples 2 to 7 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1, except that the material, wire diameter, mesh number of the mesh, and various treatment conditions were as shown in Table 1. Note that in Examples 3, Comparative Examples 1 and 3, the halogenation treatment was not carried out. In Examples 7 and 8, after vacuum nitriding treatment or vacuum carburizing treatment, subsequent blasting treatment was performed. In Comparative Examples 1 and 3, plasma nitriding treatment was carried out by applying a DC voltage between the furnace wall to generate glow discharge in a vacuum atmosphere containing a mixed gas of nitrogen and hydrogen at 1 kPa or less. Also, in Examples 5 to 8, the halogenation treatment and nitriding or carburizing treatment were carried out with 5 metal meshes stacked, and in Comparative Example 3, the nitriding treatment was carried out with 5 metal meshes stacked.

[0058] In Table 1, RX is a modified gas obtained by reacting a hydrocarbon-based gas with air, and is a mixed gas of N2, H2, CO, and CO2 having carburizing properties. Also, in any of Examples 1, 2, 4 to 8 and Comparative Example 2 where a halogenation treatment was carried out, the atmosphere condition was 10% by volume of NF3 + 90% by volume of N2. After the halogenation treatment, a nitriding treatment or a carburizing treatment was subsequently carried out. In Examples 6 to 8, a vacuum nitriding treatment or a vacuum carburizing treatment was carried out under the atmospheric pressure shown in Table 1, that is, in a reduced pressure state. In Examples 7 and 8, as the blasting treatment, in both cases, a wet blasting treatment was carried out using a manual wet blasting device with abrasive grains being ceramics (center particle size of 5 μm or less) and a discharge pressure of 0.4 MPa.

[0059] [Measurement and Evaluation Methods] For the metal meshes of each example and comparative example, the characteristic values were measured by the following method, and the durability, adhesion suppression property, and layer thickness uniformity were evaluated. In Examples 5 to 8 and Comparative Example 3, the measurement and evaluation were carried out on the central metal mesh among those manufactured in a stack of five. The measurement results and evaluation results are shown in Table 2.

[0060] (Surface Hardness) The surface hardness (Hv) was measured using a micro Vickers hardness tester with a load of 25 g. The surface hardness is the average value of the hardness measured at five arbitrary points on the surface of the metal mesh.

[0061] (Treatment Layer Thickness) The treatment layer thickness was measured by observing each metal mesh using a digital microscope having a length measuring function. The treatment layer thickness is the average value of the treatment layer thickness measured at three arbitrary points on the cross-section of the metal mesh.

[0062] (Surface Nitrogen Concentration and Surface Carbon Concentration) The surface nitrogen concentration and the surface carbon concentration were measured for the surface of the metal mesh by energy dispersive X-ray spectroscopy (EDX). The surface nitrogen concentration and the surface carbon concentration are the average values of the concentrations measured at three arbitrary points on the surface of the metal mesh.

[0063] (Surface roughness Ra) For the metal plates corresponding to Example 1, Example 2, and Comparative Example 1, the surface roughness Ra of the metal plates was measured using a scanning confocal laser microscope. The surface roughness Ra is the average value of the surface roughness measured at three points on the surface of the metal plate. Note that the metal plates corresponding to Example 1, Example 2, and Comparative Example 1 were produced by performing each treatment on a plate material of the same material as the metal mesh of each example and comparative example under the same treatment conditions as each example and comparative example. Although the measurement was performed using a plate-shaped test piece to accurately measure the surface roughness, it has been confirmed that the same unevenness as that of the plate shape occurs even in the case of the mesh shape. The surface roughness Ra before treatment in the metal plates corresponding to Example 1 and Comparative Example 1 was 0.12 μm.

[0064] (Durability) Using a gravity suction type air blast device, glass beads (average particle diameter of 45 μm or less) were collided at a discharge pressure of 0.4 MPa for 5 minutes in a range of about 10 mm in diameter on each metal mesh installed at a position about 100 mm from the nozzle tip. After the shot blasting was completed, the appearance of the metal mesh was observed, and the presence or absence of breakage was visually confirmed. If there was no breakage, it was determined that the durability was good.

[0065] (Adhesion suppression property) Using a gravity-attraction type air blast device, glass beads (average particle size of 45 μm or less) were made to collide for 1 minute at a discharge pressure of 0.4 MPa within a range of approximately 10 mm in diameter on each metal mesh installed at a position about 100 mm from the nozzle tip. After the shot blasting was completed, each metal mesh was attached to a circular vibrating sieve machine, and 500 g of alumina powder (average particle size 0.3 μm) was sieved at 25 Hz for 3 minutes. Then, using a digital microscope, the surface of the metal mesh was photographed from directly above at a magnification of 139 times, and for a 2 mm × 2 mm field of view (5 locations) of the obtained observation photos, using image processing software (Image J), the surface area of the metal mesh and the area of the alumina powder adhering portion were measured. The ratio of the obtained surface area of the metal mesh to the area of the alumina powder adhering portion (area of the powder adhering portion / surface area of the metal mesh) was calculated and evaluated according to the following criteria. In the cases of ◎ and ○, it was determined that the adhesion suppression property was good. Note that for the metal meshes of Comparative Examples 1 and 2, since tearing occurred in the durability test, the adhesion suppression property was not evaluated. (Evaluation Criteria) ◎: Less than 5% ○: 5% or more and less than 15% ×: 15% or more

[0066] (Layer Thickness Uniformity) For each metal mesh, by observing the cross-section using a digital microscope, the thickness of the treatment layer was confirmed and evaluated according to the following criteria. In the cases of ◎ and ○, it was determined that the layer thickness uniformity was good. (Evaluation Criteria) ◎: The treatment layer is formed on the entire surface of the wire rod, and no portion where the treatment layer thickness at the intersection of the wire rods is clearly thinner than the treatment layer thickness at the non-intersecting portion (the treatment layer thickness is less than 50% of the treatment layer thickness at the non-intersecting portion) is confirmed. ○: The treatment layer is formed on the entire surface of the wire rod, but a portion where the treatment layer thickness at the intersection of the wire rods is clearly thinner than the treatment layer thickness at the non-intersecting portion (the treatment layer thickness is less than 50% of the treatment layer thickness at the non-intersecting portion) is confirmed. ×: A portion where the treatment layer is hardly formed on the surface of the wire rod is confirmed.

[0067] Figure 3 is a cross-sectional microscopic photograph of the metal mesh of Comparative Example 1. Figure 4 is a cross-sectional microscopic photograph of the metal mesh of Example 1. Figure 5 is a cross-sectional microscopic photograph of the metal mesh of Comparative Example 2. Figure 6 is a surface microscopic photograph of the metal plate before treatment corresponding to Example 1 and Comparative Example 1. Figure 7 is a surface microscopic photograph of the metal plate after treatment corresponding to Comparative Example 1. Figure 8 is a surface microscopic photograph of the metal plate after treatment corresponding to Example 1. Figure 9 is a surface microscopic photograph of the metal plate after treatment corresponding to Example 2.

[0068] Figure 10 is a cross-sectional microscopic photograph of the metal mesh of Example 5. Figure 11 is a cross-sectional microscopic photograph of the metal mesh of Example 6. Figure 12 is a cross-sectional microscopic photograph of the metal mesh of Example 7. Figure 13 is a photograph of the appearance after the shot blast test related to the durability evaluation of the metal meshes of Comparative Example 3 and Example 7. In Figure 13, the region surrounded by the dashed line represents the region to be treated by shot blasting. Figure 13A shows the metal mesh of Comparative Example 3, and Figure 13B shows the metal mesh of Example 7.

[0069] Figure 14 is a photograph of the appearance after the shot blast test and alumina powder screening test related to the adhesion suppression evaluation of the metal mesh of Comparative Example 3. Figure 15 is a photograph of the appearance after the shot blast test and alumina powder screening test related to the adhesion suppression evaluation of the metal mesh of Example 6. Figure 16 is a photograph of the appearance after the shot blast test and alumina powder screening test related to the adhesion suppression evaluation of the metal mesh of Example 7. Figure 17 is a photograph of the appearance after the shot blast test and alumina powder screening test related to the adhesion suppression evaluation of the metal mesh of Example 8.

[0070] [Table 1]

[0071] [Table 2]

[0072] As shown in Table 2 and FIGS. 3 to 17, in each example where gas nitriding treatment or gas carburizing treatment was performed to form a treatment layer in which the surface nitrogen concentration or the surface carbon concentration and the ratio of the thickness to the radius of the metal wire are within a specific range, it was confirmed that the metal mesh is excellent in durability and excellent in adhesion suppression.

[0073] As shown in Table 2 and FIGS. 3 to 4, in Example 1 where fluorination treatment and gas nitriding treatment were performed, a substantially uniform nitriding layer of about 2 μm was formed over the entire circumference of the metal wire. On the other hand, in Comparative Example 1 where plasma nitriding treatment was performed, there were portions on the surface of the metal wire where no nitriding layer was formed, and the thickness of the formed nitriding layer was non-uniform. The surface nitrogen concentration of Example 1 is 3.0% by weight, which is much higher than the surface nitrogen concentration of 0.8% by weight of Comparative Example 1, and it is considered that the strength of the metal mesh has been greatly improved.

[0074] From Example 1 and Comparative Example 2 shown in Table 2 and FIGS. 4 to 5, it can be seen that when the thickness of the treatment layer is too large with respect to the wire diameter of the metal wire, cracks are likely to occur in the treatment layer, and as a result, the durability is poor. The occurrence of cracks is presumably due to the fact that the expansion of the treatment layer due to the infiltration of nitrogen or the like cannot be sufficiently relaxed by the flexibility of the base material.

[0075] As shown in Table 2 and FIGS. 6 to 9, in Example 1 where gas nitriding treatment was performed and in Example 2 where gas carburizing treatment was performed, the surface roughness is significantly increased compared to Comparative Example 1 where plasma nitriding treatment was performed, and it can be seen that unevenness is well formed on the surface of the metal mesh.

[0076] As shown in Table 2, in Example 3, it was confirmed that a 6-μm-thick carbonitriding layer with a total surface nitrogen concentration and surface carbon concentration of 6.0% by weight was formed on the entire surface of the metal wire. Also in Example 3, the same surface unevenness as in Example 1 was confirmed. In Example 4, it was confirmed that a 7-μm-thick carbonitriding layer with a total surface nitrogen concentration and surface carbon concentration of 4.5% by weight was formed on the entire surface of the metal wire, and the same surface unevenness as in Example 1 was confirmed.

[0077] As shown in Table 2 and Figures 10 to 12, in any of Examples 5 to 8 where the mesh was laminated and processed, it was confirmed that the processing layer was formed on the entire surface of the metal wire. From Figures 11 and 12, in Examples 6 and 7 where gas nitriding treatment was performed in a reduced-pressure atmosphere, it can be seen that a nitride layer with a thickness that does not significantly differ from that of the non-crossing part (non-contact part) is uniformly formed even in the details including the vicinity of the crossing part (contact part) of the metal wire. The resistance to breakage and elongation when tension is applied to the metal mesh can be increased, and the durability can be further improved.

[0078] As shown in Table 2 and Figure 13, in Comparative Example 3, holes were open in the mesh, whereas in Example 6, the mesh shape was maintained, and it was confirmed that the durability was significantly improved.

[0079] As shown in Table 2 and Figures 14 to 17, in Comparative Example 3, in addition to the thinning of the wire diameter (widening of the mesh opening), there was a large amount of powder adhesion. In contrast, in Example 6, no thinning of the wire diameter was confirmed, and it was confirmed that the amount of powder adhesion had decreased. Also in Examples 7 and 8, no thinning of the wire diameter was confirmed, and it was confirmed that the amount of powder adhesion had significantly decreased. In the evaluation of the adhesion suppression property, the ratio of the surface area of the metal mesh measured by the above method to the area of the alumina powder adhesion part (area of the powder adhesion part / surface area of the metal mesh) was 18.2% in Comparative Example 3, 6.0% in Example 6, 1.4% in Example 7, and 3.3% in Example 8.

Explanation of Reference Numerals

[0080] 1 Metal mesh 2 Metal wire 21 Vertical yarn 22 Horizontal yarn 3 Processing layer 4 Crossing part

Claims

1. A method for manufacturing a metal mesh comprising a metal wire, comprising: a step of performing gas nitriding treatment or gas carburizing treatment on the metal wire containing an iron-based metal or a nickel-based metal; In the step of performing the gas nitriding treatment or gas carburizing treatment, a treatment layer having a surface nitrogen concentration of 2.5 wt% or more or a surface carbon concentration of 1.0 wt% or more and a ratio of the thickness to the radius of the metal wire of 60% or less is formed on the surface of the metal wire. A method for manufacturing a metal mesh.

2. The method for manufacturing a metal mesh according to claim 1, wherein the gas nitriding treatment or gas carburizing treatment is performed in a reduced-pressure atmosphere.

3. The method for manufacturing a metal mesh according to claim 1 or claim 2, comprising a step of performing a blasting treatment on the metal wire before or after the step of performing the gas nitriding treatment or gas carburizing treatment.

4. The method for manufacturing a metal mesh according to claim 1 or claim 2, comprising a halogenation treatment step of heating and holding the metal wire in a halogen-based gas atmosphere before the step of performing the gas nitriding treatment or gas carburizing treatment.

5. A method for surface modification of a metal mesh comprising a metal wire, comprising: a step of performing gas nitriding treatment or gas carburizing treatment on the metal wire containing an iron-based metal or a nickel-based metal; In the step of performing the gas nitriding treatment or gas carburizing treatment, a treatment layer having a surface nitrogen concentration of 2.5 wt% or more or a surface carbon concentration of 1.0 wt% or more and a ratio of the thickness to the radius of the metal wire of 60% or less is formed on the surface of the metal wire. A method for surface modification of a metal mesh.

6. A metal wire containing an iron-based metal or a nickel-based metal; and a treatment layer formed on the surface of the metal wire, The treatment layer has a surface nitrogen concentration of 2.5 wt% or more or a surface carbon concentration of 1.0 wt% or more, and a ratio of the thickness of the treatment layer to the radius of the metal wire is 60% or less. A metal mesh.

7. The metal wires include vertical wires and horizontal wires that intersect each other, The metal mesh according to claim 6, wherein the treatment layer is formed over the entire circumference of the cross-sections of the vertical wire and the horizontal wire at the intersection of the vertical wire and the horizontal wire.

8. The treatment layer has a surface nitrogen concentration of 2.5 wt% or more and 10.0 wt% or less or a surface carbon concentration of 1.0 wt% or more and 7.0 wt% or less, The metal mesh according to claim 6 or claim 7, wherein a ratio of a thickness of the treatment layer to a radius of the metal wire is 1% or more and 60% or less.

Images