Insulation checking method

Abstract

To provide an insulation confirming method for detecting the presence or absence of an insulation defect due to the existence of innumerable conductive parts in an insulation film on a base material by a simple method.SOLUTION: In the insulation confirmation method, a conductive fluid is applied between an electric resistance layer 50 whose surface of a metal base material 10 is subjected to chemical conversion treatment and which forms a conductive layer 60 and a planar contactor 70, and a measuring device having a first electrode 72 for applying a negative or positive DC voltage to the planar contactor 70 and a second electrode for applying a negative or positive DC voltage to a part other than the electric resistance layer 50 of the metal base material 10 is used. The electric resistance value of the range of the contact surface where the planar contactor 74 is brought into contact with the electric resistance layer 50 is measured, and the presence or absence of the generation of a conductive part due to the existence of a fine conductive part in the range of the contact surface is determined from the electric resistance value to confirm the level of insulation of the electric resistance layer.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to an insulation checking method for checking the insulation of an electrical resistance layer formed on the surface of a base material. [Background technology]

[0002] Conventionally, multilayer printed wiring boards formed by alternately laminating conductor layers and insulating layers have been proposed (see, for example, Patent Document 1). The insulating layer of this multilayer printed wiring board is formed by stacking a thermosetting resin layer and a liquid crystal polymer resin layer.

[0003] Also, a thin metal package has been proposed in which an insulating layer is formed by directly changing the surface of the base metal constituting the base member through a chemical reaction, and pattern electrodes are formed on the insulating layer (see, for example, Patent Document 2). The insulating layer here is made of insulating metal compounds such as metal oxides and metal hydroxides generated directly from the base metal, and is an anodic oxide film or the like formed by anodizing the base member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-216841 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-128037 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional insulating layers have various problems. For example, insulating layers made of resin have a different thermal expansion coefficient from that of the conductor layer, which can lead to problems such as peeling of the insulating layer from the conductor layer and cracking. Furthermore, resin insulating layers lack sufficient heat resistance and weather resistance, and therefore deteriorate quickly due to repeated thermal expansion, contraction, wetting, and drying in high-temperature, humid, and other environments, which can lead to problems such as peeling of the insulating layer from the conductor layer and cracking.

[0006] Furthermore, when an insulating film is formed by chemically reacting the surface of a base metal, as in Patent Document 2, problems such as peeling and cracking due to differences in thermal expansion coefficients, and peeling and cracking that can occur due to heat resistance or weather resistance, can be prevented to a certain extent. However, the thickness of the insulating film is uneven, and insulation breakdown is likely to occur in thin parts.

[0007] Furthermore, insulating films contain many so-called pinholes, which are conductive areas along with thin areas. Although only a very small current can flow through each of these conductive areas individually, the total amount of current passing through the insulating film as a whole is the sum of the small currents because there are so many of them. Therefore, if a conductive layer or conductive pattern is formed on an insulating film with such defects, electrons will flow between the conductive layer and the conductive base material, causing current to flow and preventing normal circuit function. Therefore, despite being an insulating film, a relatively large current will flow through it, making it very difficult to use as an insulating film.

[0008] The present invention was made through intensive research by the inventors in view of the above problems, and aims to provide a simple method for checking insulation properties that can detect the presence or absence of insulation defects caused by the presence of countless conductive parts in an insulating film on a base material. [Means for solving the problem]

[0009] One embodiment of the insulation confirmation method of the present invention is a method for confirming the insulation of an electrical resistance layer in which the surface of a metal base material is chemically treated to form a conductive layer, characterized in that a conductive fluid is applied between the electrical resistance layer and a planar contact, the planar contactor covers the electrical resistance layer over an area of ​​a predetermined size or more to bring the electrical resistance layer into planar contact, and the electrical resistance value of the range of contact surface where the planar contactor comes into contact with the electrical resistance layer is measured using a measuring device having a first electrode that applies a negative or positive DC voltage to the planar contactor and a second electrode that applies a negative or positive DC voltage to a location of the metal base material other than the electrical resistance layer, and the presence or absence of conductive locations due to the presence of fine conductive parts within the range is determined from the electrical resistance value to confirm the level of insulation of the electrical resistance layer.

[0010] The insulation checking method is also characterized in that the electrical resistance layer is formed by phosphate treatment of the surface of the metal base material, and the electrical resistance value of the phosphate layer is measured.

[0011] The method for checking insulation properties is characterized in that the fluid that does not cause an oxidation or dissolution reaction is applied to the metal base material.

[0012] The method for checking insulation properties is characterized in that the fluid selected from water, salt water, silver paste, and ionic liquid is applied.

[0013] The insulation checking method is characterized in that a needle-shaped probe, which is the first electrode, is inserted into a hole in the block body, which is the planar contactor, and the tip of the probe is brought into contact with the bottom part of the block body, which is the metal surface, to electrically connect them.

[0014] The insulation checking method is characterized in that it detects thin layer portions or a large number of so-called pinhole-like minute conductive portions.

[0015] The insulation checking method is also characterized in that the conductive layer is a conductive pattern formed on the electrical resistance layer. [Effects of the Invention]

[0016] According to the present invention, a simple method for checking insulation properties can be provided that detects the presence or absence of insulation defects due to the presence of numerous conductive portions in an insulating film on a base material. Furthermore, when the insulating film has thin portions or numerous conductive portions such as pinholes, the method for checking insulation properties of the present invention can eliminate the conductive portions by stacking insulating layers, thereby detecting and selecting a defect-free insulating layer that has high insulation properties, including high electrical resistance and high voltage resistance. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing a base material to which an insulating layer forming method according to an embodiment of the present invention is applied; [Figure 2] FIG. 2 is a diagram showing a base material after a second step in the insulating layer forming method according to the embodiment. [Figure 3] FIG. 10 is a diagram showing the base material after a third step in the insulating layer forming method according to the embodiment. [Figure 4] FIG. 10 is a diagram showing a phosphate layer when oxidation treatment is performed in the third step. [Figure 5] FIG. 10 is a diagram showing a base material on which a metal plating portion is formed in a preliminary step. [Figure 6] FIG. 10 is a diagram showing a conductive portion that exists after the third step. [Figure 7] FIG. 10 shows the formation of a phosphate layer when the second and third steps are carried out again. [Figure 8] FIG. 1 is a view showing an iron-plated portion formed by dry plating. [Figure 9] FIG. 1 is a diagram showing a phosphate layer formed on an iron-plated portion. [Figure 10] FIG. 10 is a diagram showing a conductive layer formed on an insulating layer. [Figure 11] FIG. 2 is a diagram showing a measurement block. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following describes an example of an embodiment of the method for forming an insulating layer according to the present invention, which is a method for forming an insulating layer by self-selective blocking of fine conductive portions. In this embodiment, the base material on which the insulating layer is formed is a metal that is a good conductor, but the present invention is not limited to this and can also be applied to an electrically resistive base material or an electrically insulating base material.

[0019] The insulating layer forming method of the present invention includes a first step of forming a high-resistance layer on a base material by surface treatment, a second step of forming a metal plating portion capable of forming the high-resistance layer on the base material that has undergone the first step, and then a further step of forming the high-resistance layer. Conventionally, simply forming a high-resistance layer on a base material inevitably results in the formation of fine conductive portions, such as so-called pinholes that allow electricity to pass through, thin portions of the high-resistance layer, and portions in the high-resistance layer where fine conductors are present continuously or intermittently and may conduct electricity when a voltage is applied, resulting in insufficient insulation. However, the present invention reduces the fine conductive portions by sealing the fine conductive portions with metal plating and then further treating the portions to form a high-resistance layer, thereby achieving high insulation.

[0020] The first step of the present invention is to form a high-resistivity layer on the base material. Examples of the step of forming a high-resistivity layer include chemical conversion treatment and phosphate conversion treatment, which form a metal oxide layer on the surface of the base material using a rust accelerator and / or rust-inducing agent containing an acidic liquid such as hydrochloric acid or salt water.

[0021] The method for forming an insulating layer using a phosphate conversion treatment comprises at least three steps. Specifically, the method comprises a first step of performing a phosphate conversion treatment on a base material; a second step of selectively forming a metal plating on the fine conductive portions present in the phosphate conversion layer formed in the first step to block them; and a third step of insulating the metal plating by performing a phosphate conversion treatment on the metal plating. In the second step, iron is precipitated mainly around the conductive portions (fine conductive portions) remaining in the phosphate conversion layer (described below), preferably only in the conductive portions. As a result, the iron plating is formed selectively only in the conductive portions of the phosphate conversion layer, which is referred to as self-selective blocking of fine conductive portions by the iron plating.

[0022] Furthermore, since the base material is subjected to phosphate chemical treatment, the base material here is a metal that can be subjected to phosphate chemical treatment, such as iron or an iron alloy, tin or a tin alloy, zinc or a zinc alloy, nickel or a nickel alloy, or aluminum or an aluminum alloy.

[0023] 1 shows a base material 10 to which the insulating layer forming method according to this embodiment is applied, with (a) showing the base material before the first step and (b) showing the base material after the first step. The first step is a phosphate conversion treatment to form a high-resistivity layer (insulating layer) with high electrical resistivity on the base material 10. The phosphate conversion treatment to form the insulating layer uses a phosphate conversion treatment solution that generates phosphates such as zinc phosphate, manganese phosphate, or zinc manganese phosphate on the surface of the base material.

[0024] The first step may include a degreasing step, a water washing step, a water washing step after the phosphate chemical treatment step, a pure water washing step, a drying step, etc., in addition to the phosphate chemical treatment step, and these steps are carried out by using known methods.

[0025] In the phosphate chemical treatment step, the surface of the base material is brought into contact with the phosphate chemical treatment solution by spraying or immersion, thereby forming a phosphate layer 20 on the surface of the base material 10 as shown in FIG.

[0026] The phosphate chemical treatment can be carried out by, for example, immersing the material in a phosphate chemical treatment solution, in which case the solution temperature is preferably 95°C or higher. Another method is cathodic electrolysis in the phosphate chemical treatment solution. In this case, the current density is 1 to 100 A / dm 2 It is preferable that the liquid temperature is 90°C or less. 2 If the current is less than 100 A / dm, crystals (called phosphate crystals) that form an appropriate phosphate chloride layer will not be produced. 2 If the current density exceeds this value, hydrogen gas is generated intensively on the surface of the base material 10 during the cathodic electrolysis treatment, making it difficult for a phosphate layer to grow on the surface of the base material 10. In either case, the treatment time is preferably 5 to 60 minutes, and more preferably 10 to 20 minutes.

[0027] The phosphate conversion treatment solution contains phosphate ions as an essential component and at least one metal ion selected from the group consisting of magnesium ions, aluminum ions, calcium ions, manganese ions, iron ions, cobalt ions, nickel ions, copper ions, and zinc ions. The phosphate ion concentration in the phosphate conversion treatment solution is preferably 3 to 50 g / L. If the concentration is less than 3 g / L, the rate of formation of the phosphate layer slows down. If the concentration exceeds 50 g / L, the phosphate ion concentration becomes too high, resulting in the disadvantage of increased carryover.

[0028] Nitrate ions may be added to the phosphate chemical treatment solution to improve its stability and promote polarization in cathodic electrolysis, and nitrite ions, hydrogen peroxide, or chlorate ions may be added as oxidation promoters. Electrodes used in electrolysis may be made of carbon, stainless steel, platinum, titanium alloys, or titanium-platinum coated alloys.

[0029] A surface conditioning step may be performed before the phosphate chemical conversion treatment step, which activates the base material surface and creates nuclei for phosphate crystal precipitation. The surface conditioner used in the surface conditioning step is selected appropriately depending on the phosphate and may be a liquid, gel, fluid, or the like. For example, the surface conditioning step causes components that serve as nuclei for phosphate crystals to adhere to the surface of the base material 10. Therefore, phosphate crystals are generated and grow from the nuclei. Furthermore, by performing the surface conditioning step, the phosphate crystals become dense crystals, making it easier for the chemical conversion reaction to occur. Therefore, the processing time for the chemical conversion treatment step is shortened compared to when the surface conditioning step is not performed.

[0030] The phosphate layer 20 formed on the surface of the base material 10 has many conductive parts 22 through which extremely small currents flow, such as thin parts that are minute conductive parts and pinholes, similar to the insulating layer formed by chemically reacting the surface of the base metal in Patent Document 2. These conductive parts 22 are filled with the phosphate layer and insulated by carrying out the second and third steps described below.

[0031] Next, the second step performed after the first step will be described. Fig. 2 is a diagram showing the base material 10 after the second step in the method for forming an insulating layer according to this embodiment. The second step is a step of forming an iron-plated portion as an upper layer of the phosphate layer 20. Here, the description will be made assuming that an iron-plated portion is formed, but this is not limited thereto. Any metal-plated portion may be used as long as it has good adhesion to a phosphate layer such as a zinc-plated portion, a tin-plated portion, or a nickel-plated portion, and is primarily composed of a material that can be subjected to the phosphate chemical conversion treatment in the third step described below.

[0032] The iron-plated portion may be any plating containing at least iron as a main component, such as a pure iron-plated portion, an iron-carbon alloy-plated portion, or an iron-based alloy-plated portion (Fe-W, Fe-Ni, Fe-P, Fe-Zn, Fe-Ni-Mo, Fe-Co, Fe-Cr, Fe-Cr-Ni, etc.).

[0033] Such iron-plated portions can be produced by various plating methods, such as dry plating methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD), hot-dip plating, and thermal spraying, but it is preferable to use wet plating methods such as electrolytic plating and electroless plating, which will be described later.

[0034] Formation of the iron-plated portion by electrolytic plating can be carried out by a known method, such as a sulfate bath or a borofluoride bath. When electrolytic plating is carried out, an anode is immersed in a plating solution, and at the same time, a base material 10 (cathode) is immersed so as to face the anode with a gap therebetween.

[0035] The anode is an iron metal plate. For example, two anodes may be prepared and immersed in the plating solution so that they face each other with a gap between them. In this case, the base material 10 is preferably immersed in the plating solution between the two anodes so that it faces each anode with a gap between them.

[0036] The temperature of the plating solution is preferably in the range of 20°C to 38°C when a sulfate bath is used. While maintaining the temperature of the plating solution within a predetermined range, electroplating is performed at a constant current to form an iron-plated portion. The current density is, for example, 2.5 to 10 A / dm when a sulfate bath is used. 2 That would be good.

[0037] By performing electroplating using the above method, iron is deposited on conductive portions 22 in the phosphate layer 20, forming iron-plated portions 30, as shown in Figure 2. That is, since electroplating forms plating on electrically conductive portions, iron-plated portions 30 are formed around conductive portions 22 through which current flows in minute conductive portions in the insulating phosphate layer 20 (for example, pinholes or portions where the layer is thin and insulation breakdown is likely to occur).

[0038] Next, the third step will be described. Fig. 3 is a diagram showing the base material 10 after the third step in the method for forming an insulating layer according to this embodiment. The third step is a step of forming a second phosphate layer 40 on the iron-plated portion 30.

[0039] The second phosphate layer 40 can be formed by performing a phosphate conversion treatment similar to that in the first step. The second phosphate layer 40 is formed as an upper layer on the iron-plated portion 30. In other words, the phosphate conversion treatment is almost ineffective against the already formed phosphate layer 20, and almost no phosphate crystals precipitate. In contrast, the phosphate conversion treatment is effective against the iron-plated portion 30, and as shown in Figure 3(a), phosphate crystals precipitate on the surface of the area where the iron-plated portion 30 is formed. As the phosphate conversion treatment progresses, the second phosphate layer 40 is formed, covering the area where the iron-plated portion 30 was formed, as shown in Figure 3(b).

[0040] Therefore, phosphate crystals are precipitated in the areas that were conductive portions 22 of the phosphate layer 20 formed in the first step and where the iron-plated portions 30 are formed, and a second phosphate layer 40 is formed so as to spontaneously and selectively fill in the areas that were conductive portions 22 of the phosphate layer 20 formed in the first step. As a result, the conductive portions 22 of the phosphate layer 20 are blocked by the second phosphate layer 40, and as a result, the entire surface of the base material 10 can be covered with an insulating layer made up of a substantially uniform phosphate layer with almost no conductive portions 22.

[0041] The insulating layer of the present invention has almost no conductive portions 22, and therefore can be said to be a surface insulating layer in which the phosphate layer is insulated throughout.

[0042] The second phosphate layer 40 does not necessarily have to be the same as the phosphate chemical treatment in the first step, but may be a different phosphate chemical treatment. For example, the first step may be a phosphate chemical treatment to form a manganese phosphate layer, and the third step may be a phosphate chemical treatment to form a zinc-manganese phosphate layer.

[0043] As described above, according to the method for forming an insulating layer of this embodiment, the base material is subjected to surface treatment in the following order: phosphate conversion treatment, electroplating to form an iron-plated portion, and phosphate conversion treatment. This allows the phosphate layer to fill (seal) pinholes and thin conductive areas that occur in the initially formed phosphate layer. This allows the formation of an insulating layer with significantly higher insulating properties, thereby providing a highly insulating surface for the base material. Furthermore, because this insulating layer is not made of resin, it prevents peeling or cracking of the insulating layer due to differences in the thermal expansion coefficients of the base material and the insulating layer, and suppresses strength loss due to deterioration in high-temperature, high-humidity environments.

[0044] In the second step, the iron-plated portion may be formed by electroless plating. In this case, an autocatalytic (reduction) electroless plating solution is used, and the temperature of the plating solution is set to 70 to 100°C, preferably 85 to 95°C. This method also allows the iron-plated portion to be formed in the conductive portion that has become a pinhole. If a third step is then performed, the conductive portion that has become a pinhole can be sealed with a phosphate layer, and the surface of the base material can be covered with a phosphate layer that acts as an insulating layer.

[0045] Furthermore, it is desirable to set the thickness of the iron plating to be equal to or less than the limit of the thickness that the phosphate layer formed in the subsequent third step can achieve, because if the iron plating is too thick, iron molecules in the iron plating that exceed the thickness that the phosphate layer can achieve in the third step will remain without being phosphated, and the remaining iron molecules may form fine conductive portions.

[0046] Of course, the thickness of this iron plating can be adjusted by time control. The iron plating time is, for example, 1 to 60 minutes, preferably 2 to 10 minutes. However, the optimum iron plating time can vary depending on the size and number of fine conductive portions formed in the phosphate layer formed in the first step.

[0047] Furthermore, in the above-described embodiment, phosphate conversion treatment is performed in the first and third steps. However, oxidation treatment may also be used if it is possible to form a high-resistance layer. That is, phosphate conversion treatment is performed in the first step, and oxidation treatment is performed in the third step. Figure 4 shows the phosphate layer after oxidation treatment in the third step. When conductive portions 22 containing iron-plated portions 30 are scattered throughout the phosphate layer 20 as shown in Figure 4(a), the iron-plated portions 30 are oxidized by oxidation treatment. As a result, as shown in Figure 4(b), the iron-plated portions become metal oxides 42, which correspond to high-resistance layers, like the phosphate layer. Therefore, the surface of the iron-plated portions formed in the second step is oxidized to form metal oxides 42, thereby insulating the conductive portions 22.

[0048] In the third step, an oxidation treatment may be further performed after the phosphate chemical conversion treatment. The oxidation treatment may be performed by any of a variety of methods, such as by subjecting the base material 10 to an anodized layer formation treatment, by heating the base material 10 in a high-concentration oxygen atmosphere, or by immersing the base material 10 in an oxidation (accelerated) treatment solution.

[0049] Furthermore, since phosphate conversion treatment is performed in the first and third steps, the base material is a metal that can be phosphate converted. However, if the base material is a metal that is difficult to phosphate convert (e.g., copper or some stainless steels), a pre-processing step prior to the first step may be performed to form a metal plating portion 15 on the base material 10 that is effective against phosphate conversion treatment, as shown in FIG. 5(a). By performing the first process in this manner, a phosphate layer 20 can be formed on the metal plating portion 15, as shown in FIG. 5(b). Then, by performing the second process, an iron plating portion 30 can be formed on the phosphate layer 20, as shown in FIG. 5(c). Then, by performing the third process, a phosphate layer 40 can be formed as an upper layer on the iron plating portion 30, as shown in FIG. 5(d). As a result, even if the base material 10 is difficult to phosphate convert, an insulating layer can be formed by the first to third processes described above by forming a metal plating portion 15 directly on the base material 10. Of course, the base material is not limited to metal, but may be resin, ceramic, glass, or the like. In this case, a layer that can be subjected to conductive surface modification, treatment, plating, etc., i.e., phosphate chemical conversion treatment, is formed in advance on the surface of the base material.

[0050] Therefore, the method for forming an insulating layer according to the present invention can be applied even to base materials that are difficult to treat with phosphate chemical conversion treatment. The metal-plated portion to be applied in the preliminary step can be, for example, an iron-plated portion, a tin-plated portion, a zinc-plated portion, or the like, and can be appropriately selected.

[0051] Furthermore, the plating method in the preliminary step is not particularly limited and can be selected as appropriate from dry plating, wet plating, hot-dip plating, etc., but it is preferable to use a method that can form a metal plating portion over the entire base material, such as physical vapor deposition, chemical vapor deposition, or electroless plating using an ionic liquid.

[0052] Furthermore, in the above-described embodiment, the second and third steps may be repeated after the third step. In this way, if a conductive portion 22 still exists after the third step, as shown in Fig. 6, a metal plating portion can be formed on the conductive portion 22 by performing the second step again. The metal plating portion here is an iron plating portion, as in the initial second step, but of course it may be a different metal plating portion, such as a tin plating portion, a zinc plating portion, or a nickel plating portion.

[0053] That is, when the second step is performed again after the third step, iron-plated portions 35 are formed on the remaining conductive portions, as shown in Fig. 7(a). When the third step is performed again, the iron-plated portions 35 dissolve and phosphate layers 45 are formed, as shown in Fig. 7(b). As a result, phosphate layers 45 are formed on the conductive portions 22, allowing the formation of an insulating layer with higher insulating properties. Note that the number of times the second and third steps are repeated is not particularly limited, but by increasing the number of times, the conductive portions 22 can be reduced and the thickness of the layer formed on the base material can also be increased.

[0054] It goes without saying that the iron-plated portion in the second step may be formed by dry plating, in which case the iron-plated portion is formed over the entire base material so as to cover almost the entire phosphate layer including the conductive portion 22, as shown in FIG.

[0055] Next, when the third step is carried out, the surface of the iron-plated portion dissolves, phosphate crystals are precipitated, and a phosphate layer is formed, as shown in Figure 9. At this time, the iron-plated portion may not completely dissolve, but may remain on top of the original phosphate layer, and a new phosphate layer may be formed on top of that. In other words, a state may arise in which phosphate layers are locally stacked on either side of the iron-plated portion.

[0056] Furthermore, although fine conductive portions may also be formed in the phosphate layer formed by the third step, the likelihood of these fine conductive portions communicating with the fine conductive portions of the phosphate layer formed by the first step is low. This is because if the thickness of the iron-plated portion is set to be equal to or less than the maximum thickness of the phosphate layer that can be formed by the subsequent phosphate conversion treatment, most of the iron components generated on the phosphate layer previously formed by the iron plating will be replaced by the phosphate layer, and most of the conductive iron components will disappear. In other words, by stacking the phosphate layer through multiple iron plating steps, the likelihood of the formation of fine conductive portions that could communicate with the base material can be significantly reduced.

[0057] Furthermore, even in the above-mentioned wet plating, if the base material is immersed in the plating solution for a long time, the iron-plated portion formed around the conductive portion can cover the entire phosphate layer, and as a result, as in the case of dry plating, an iron-plated portion can be formed over the entire base material so as to cover almost the entire phosphate layer including the conductive portion 22.

[0058] In this way, when a phosphate layer is formed over the entire base material, the thickness of the phosphate layer formed can eliminate conductive areas caused by thinness, and conductive areas caused by pinholes can also be eliminated, resulting in an insulating layer with high insulation properties that not only has high electrical resistance but also high voltage resistance. Furthermore, peeling and cracking of the insulating layer due to differences in the thermal expansion coefficients of the base material and the insulating layer can be prevented, and deterioration under high temperature, high humidity, and other environments can be suppressed.

[0059] Although the insulating layer is formed by completing the third step described above, it is also possible to form a conductive layer, conductive pattern, electronic element, etc., through subsequent processing. For example, a conductive layer 60 having electrical conductivity may be disposed on the insulating layer 50 (which is an insulating layer including the phosphate layer 20 and the second phosphate layer 40) shown in FIG. 10. Such a conductive layer 60 can be formed directly on the insulating layer 50 by, for example, lamination printing using a conductive paste, pad printing, painting, plating, inkjet printing, sputtering, spray coating, hot-dip plating, thermal spraying, or the like.

[0060] The conductive layer 60 may be formed in various shapes, such as a planar, linear, mesh, geometric pattern, dotted, or combinations thereof. Therefore, the conductive layer may be formed linearly to form a conductive pattern. Alternatively, the conductive layer may be formed planar and then patterned to form a conductive pattern. In this case, the patterning process may be, for example, etching, cutting, laser processing, or masking, as long as it removes unnecessary portions.

[0061] In addition, an electric element may be formed at the same time as forming the conductive layer. For example, a coil may be formed by forming a linear conductive layer in a spiral shape along the outer peripheral surface of the base material, or a resistive portion with high electrical resistance may be formed by narrowing the line width or thickness of the linear conductive layer. Furthermore, since an insulating layer exists between the base material and the conductive layer, a capacitor may also be formed. Needless to say, a capacitor may also be formed by alternately forming insulating layers and conductive layers on the conductive layer.

[0062] Furthermore, a protective layer may be formed on the conductive layer. For example, the material for the protective layer may be an ionizing radiation curable resin that is cured by light or an electron beam, a thermosetting resin that is cured by heat, or a photosensitive resin that is cured by ultraviolet light. Alternatively, a resin layer serving as the protective layer may be formed by a method such as painting, dipping, or spraying.

[0063] The target components on which an insulating layer is formed include buildings such as residential houses, apartment buildings, and office buildings, bridges, steel towers, railways, pipelines, plants, power plants, wind power generation equipment, and solar power generation equipment (hereinafter, buildings and structures will be collectively referred to as structures), various components such as building materials and structural materials used therein, industrial machinery such as construction machinery and machine tools, and other mechanical devices, as well as consumables such as fastening members, gears, blades, and holding members that make up these devices, or elemental parts such as springs, bearings, and linear guides, various means of transportation such as rockets, aircraft, submarines, ships, trains, buses, trucks, passenger cars, motorcycles, bicycles, and elevators, as well as components used in a variety of situations such as office and home appliances and daily necessities.

[0064] In addition, the insulating layer in each of the above-described embodiments may be provided on the entire surface of the component, or may be provided on only a part of the surface of the component. For example, when the above-described patterning is performed, the insulating layer may be formed on the patterned portion and its surroundings, and the range in which the insulating layer is formed is set appropriately.

[0065] [Example] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0066] In the examples and comparative examples, the treatment procedures of the first to third steps, the measurement of insulation properties, the measurement of voltage resistance, and the evaluation of rust prevention properties were carried out as follows.

[0067] [Base material] An SPCC plate with a thickness of 0.475 mm, a width of 30 mm, and a length of 100 mm was used as the base material for forming the insulating layer.

[0068] [First step] An SPCC plate was formed with one of the following phosphate chloride layers: a manganese phosphate layer, a zinc manganese phosphate layer, or a zinc phosphate layer. When forming the manganese phosphate layer, the SPCC plate was immersed in a manganese phosphate treatment solution at 95°C for 11 minutes. The manganese phosphate treatment solution used contained phosphoric acid, a manganese compound, and a nickel compound (manufactured by Chemicoat Co., Ltd., under the trade name Chemicoat No. 618 bath make-up agent). After immersion in the manganese phosphate treatment solution, the SPCC plate was rinsed with water.

[0069] [Second process] First, the SPCC plate was immersed in an electroless iron plating solution at 90°C for 4 minutes. The electroless iron plating solution contained 158.66 g / L of ferrous sulfate (heptahydrate), 120 g / L of sodium hypophosphite, 60 g / L of sodium citrate, and 60 g / L of sodium acetate.

[0070] [Third step] In the third step, the SPCC plate was subjected to the same treatment as in the first step (immersion in the manganese phosphate treatment solution). That is, the plate was immersed in the same treatment solution as in the first step at 95°C for 11 minutes. After immersion in the manganese phosphate treatment solution, the SPCC plate was rinsed with water.

[0071] [Insulation measurement] [Needle contact] Resistance measurements were carried out to confirm the insulation of the surface of the SPCC board. Specifically, the resistance of the manganese phosphate layer was measured using a digital multi-tester (TDB-401) (simply referred to as the tester) manufactured by Ohm Electric Co., Ltd. The probe (contactor) positions were also interchanged when measuring the resistance. That is, the anode probe was placed on the manganese phosphate layer, and the cathode probe was placed on the conductive part of the SPCC board, which is a good conductor, as a line terminal, and resistance measurements were carried out for both cases.

[0072] [Surface contact] Measurements were also carried out using planar contact, which is different from needle contact. Planar contact here means that a metal surface (planar contactor) is brought into contact with the manganese phosphate layer. Measurements using planar contact involve indirect contact of the anode probe of the tester with the manganese phosphate layer so that electrical conduction can be achieved via the metal surface.

[0073] Therefore, the anode probe was attached to the measuring block 74 (see Figure 11) by inserting it into the measuring block 74, which served as a planar contact. The tip of the negative probe was in contact with a conductive area of ​​good conductivity other than the manganese phosphate layer of the SPCC plate. Note that the planar contactor here is a block-shaped measuring block 74 separate from the probe, but it goes without saying that it does not necessarily have to be separate, and the probe itself may be the planar contactor.

[0074] As shown in Figure 11(a), the measuring block 74 has a bottom 76 that forms a metal surface. The bottom 76 is in planar contact with the manganese phosphate layer, and the probe 72 is inserted into a hole 78 in the measuring block 74 and the tip is brought into contact with the bottom 76, so that the probe 72 indirectly contacts the manganese phosphate layer via the bottom 76. Note that the measuring block 74 does not necessarily need to have a hole 78, and it is sufficient if the measuring block 74 is provided integrally with the probe 72 so that the probe 72 is in planar contact. In this example, the bottom 76 of the measuring block 74 is circular with a diameter of 10 mm and an area of ​​approximately 78 mm 2 The following was used.

[0075] While resistance is typically measured by needle contact, the inventors used a commercially available measurement probe and found that different resistance values ​​were measured depending on the location of the probe's contact. That is, when the probe contacted the conductive portion of the manganese phosphate layer, a low resistance value was measured, but when the probe contacted a location away from the conductive portion, a high resistance value was measured. Therefore, in this example, measurements were performed by surface contact to more objectively confirm whether insulation was present or not compared to conventional methods.

[0076] Although the other probe was brought into direct contact with the SPCC plate, it goes without saying that it may be electrically connected to the SPCC plate via the measurement block 74. Also, although the bottom 76 of the measurement block 74 has been described as being in planar contact with the manganese phosphate layer, the present invention is not limited to this.

[0077] For example, bottom 76 may be configured to cover the manganese phosphate layer over a predetermined area or more and to be in point contact with the manganese phosphate layer at multiple locations. That is, bottom 76 may have multiple protruding portions on the surface facing the manganese phosphate layer that can be in point contact with the manganese phosphate layer. Needless to say, bottom 76 may also have a shape that has both a portion in planar contact with the manganese phosphate layer and protruding portions that make point contact with the manganese phosphate layer.

[0078] [Water + surface contact] Since the surface of a typical manganese phosphate layer is non-uniform in thickness and has many fine conductive parts, in addition to measuring the resistance value described above, conductive water was applied as a conductive fluid between the measurement block 74 and the manganese phosphate layer, and the conductive parts were filled with the fluid, and then the resistance value was measured.

[0079] [Voltage resistance test] Using a digital insulation resistance meter (MY600 manufactured by Yokogawa Measurement Co., Ltd.) as a voltage withstand meter, the electrodes were placed in contact with the SPCC plate and a voltage was applied. The resistance value was measured while gradually increasing the applied voltage in the order of 5 [V], 50 [V], 125 [V], 250 [V], 500 [V], and 1000 [V].

[0080] The effective maximum display value of the resistance value of a voltmeter is 100 [MΩ] when the applied voltage is 50 [V], 250 [MΩ] when the applied voltage is 125 [V], 500 [MΩ] when the applied voltage is 250 [V], 2000 [MΩ] when the applied voltage is 500 [V], and 4000 [MΩ] when the applied voltage is 1000 [V].

[0081] The applied voltage when a resistance value below a predetermined value was measured was defined as the breakdown voltage (upper limit of withstand voltage). In the withstand voltage test, both the needle contact and surface contact measurement methods were used. Furthermore, measurements were also performed with the anode and cathode probes swapped.

[0082] [Evaluation of rust prevention] To confirm rust prevention, a saltwater immersion experiment was conducted in which the SPCC plate was immersed in a 5 wt% NaCl solution. In the saltwater immersion experiment, the immersion time from immersion in saltwater until rust appeared on the SPCC plate was measured.

[0083] [Comparative Examples 1 and 2, Examples 1 to 9] By the treatments in the first to third steps described above, SPCC plates having manganese phosphate layers with the number of layers shown in Tables 1 and 2 were obtained. The SPCC plate of Comparative Example 1 had no manganese phosphate layers that had not been treated in the first to third steps. The SPCC plate of Comparative Example 2 had one manganese phosphate layer that had only been treated in the first step.

[0084] The SPCC plates of Examples 1 to 9 were treated in the first to third steps to form any one of 2 to 10 manganese phosphate layers. [Table 1] [Table 2]

[0085] The conductive points (+) in Tables 1 and 2 indicate the measurement results when the anode probe was in contact with a conductive point (such as the surface of the base material of the SPCC plate) and the cathode probe was in contact with the manganese phosphate layer. The conductive points (-) indicate the measurement results when the anode probe was in contact with the manganese phosphate layer and the cathode probe was in contact with a conductive point.

[0086] The results obtained in each comparative example and each example are shown in Tables 1 and 2. The thickness of the SPCC plates in Comparative Example 2 and Examples 1 to 9 was almost constant regardless of the number of manganese phosphate layers. The tester measurement results in Table 1 are listed as OL because they exceeded the resistance value of 40 MΩ, which is measurable with a tester. Furthermore, the resistance values ​​listed as breakdown in Table 2 indicate that breakdown occurred when the corresponding voltage was applied. Therefore, the breakdown voltage does not necessarily correspond to the applied voltage.

[0087] Specifically, in the results shown in Table 2 for the conductive point (+) of needle contact in Example 1, breakdown occurred at an applied voltage of 500 V. This is because when the applied voltage was set to 250 V, the resistance value exceeded 50 MΩ, making it impossible to measure. The next time the applied voltage was set to 500 V, breakdown occurred. In such cases, the resistance value was recorded as breakdown and the applied voltage was recorded as 500 V. Therefore, the actual breakdown voltage is thought to be an applied voltage in the range of more than 250 V but less than 500 V.

[0088] It can be seen that Examples 1 to 9 had higher resistance values ​​measured by a tester and significantly improved insulation properties compared to Comparative Examples 1 and 2. This is thought to be because iron-plated portions were formed in the conductive portions of the manganese phosphate layer formed in the first step, and a manganese phosphate layer was further formed on the iron-plated portions, blocking the areas that were previously conductive.

[0089] Furthermore, in Comparative Example 2, needle contact resulted in an unmeasurable resistance (OL: 40 MΩ or higher), whereas area-based contact yielded values ​​in the range of several kΩ to several MΩ. This clearly indicates that the manganese phosphate layer (phosphate chloride layer) itself contains numerous conductive portions, which affect conductivity (insulation) and withstand voltage. Therefore, area-based contact measurement can detect conductivity that could not be detected in electrical resistance measurements using a needle probe because the contact area with the object being measured is too small and the total number of micro-conductive portions is small. That is, in area-based contact measurements, the contact surface of the measurement block 74 is significantly larger than the tip of the needle probe, significantly increasing the total number of micro-conductive portions within this contact surface, thereby enabling conductivity to be detected through the measurement block 74. As a result, this area effect allows for more accurate measurement of the electrical resistance of layers such as insulating layers, enabling accurate determination of the presence or absence of micro-conductive portions and accurate confirmation of the level of insulation.

[0090] Furthermore, Examples 1 to 9 have improved withstand voltage compared to Comparative Example 2. Furthermore, an increase in the number of layers tends to further improve the withstand voltage. This is thought to be because the withstand voltage is improved by blocking the conductive portions of the manganese phosphate layers. Furthermore, it is thought that the more times the second and third steps are performed, i.e., the more the number of manganese phosphate layers increases, the more the conductive portions of the manganese phosphate layers are blocked, resulting in a decrease in the total number of conductive portions, and thus an improvement in the withstand voltage.

[0091] Furthermore, in the evaluation of rust prevention, when the number of manganese phosphate layers was 10, no rust was observed even after 240 hours, which suggests that there are almost no fine conductive parts on the surface of the manganese phosphate layer. This also suggests that the total number of conductive parts in the manganese phosphate layer decreases as the number of times the second and third steps are repeated increases, i.e., as the number of manganese phosphate layers increases.

[0092] Furthermore, in each of the examples, the insulating layer formed on the SPCC plate has a withstand voltage performance of at least 250 V. This means that when the conductive layer 60 described above is used as an electric element and the power source connected to the conductive layer 60 is a lithium-ion secondary battery, the voltage of the lithium-ion secondary battery is 3.7 V, so the insulating layer has a withstand voltage performance of several tens of times the voltage of the power source. Of course, the insulating layer also has a withstand voltage performance equal to or greater than that of primary batteries such as manganese dry batteries, nickel batteries, and lithium batteries, and secondary batteries such as nickel-cadmium batteries and nickel-metal hydride batteries.

[0093] Although not shown in the table, it has been confirmed that even when a zinc phosphate layer or a zinc manganese phosphate layer is formed as the insulating layer instead of a manganese phosphate layer, the withstand voltage tends to improve as the number of layers (which may be considered as the number of times the second and third steps are repeated) increases.

[0094] Furthermore, it is clear that in each example, the resistance value differs significantly depending on the positions of the anode probe and the cathode probe. Specifically, the resistance value was significantly higher when the anode probe was in contact with the manganese phosphate layer (when the cathode probe was in contact with the conductive portion with good conductivity) than when the anode probe was in contact with the manganese phosphate layer (when the cathode probe was in contact with the conductive portion with good conductivity). From this, it is considered that the member with an insulating layer of the present invention, in which a phosphate layer is formed on the base material, as in the present invention, has a rectifying effect that makes it easier for current to flow from the metal base material side to the phosphate layer, which is the insulating layer.

[0095] Therefore, by utilizing the rectifying effect, a member in which the phosphate layer 20 is formed on the base material 10 can be used as a rectifying element. That is, a rectifying element is formed by joining the base material 10 as a metal with the phosphate layer 20, and a terminal is provided directly or indirectly on the base material 10, and a terminal is provided directly or indirectly on the phosphate layer 20. The direction of the voltage applied to the rectifying element is not particularly limited, and the terminal provided on the base material 10 may serve as either the anode or the cathode.

[0096] The conductive fluid used in the above-mentioned insulation measurement is not limited to conductive water, but may be, for example, salt water, silver paste, ionic liquid, etc., but it is preferable to select a conductive fluid that does not cause reactions such as oxidation or dissolution with the base material (SPCC plate).

[0097] The size of the measuring block 74 used for planar contact is not particularly limited. However, as shown in FIG. 11(b), the bottom 76 may be miniaturized so that the area of ​​the surface of the bottom 76 facing the manganese phosphate layer is smaller than the area of ​​the bottom 76 in FIG. 11(a). In particular, miniaturizing the bottom 76 makes it easier to fill the gap between the measuring block 74 and the manganese phosphate layer with a conductive fluid. It is desirable to insulate the side surfaces of the planar contactor, i.e., the measuring block 74, so that the conductive fluid interposed between the measuring block 74 and the surface of the manganese phosphate layer (the measurement target area) does not become conductive even if it spills out from between the measuring block 74 and the manganese phosphate layer and comes into contact with the side surfaces of the measuring block 74.

[0098] The present invention includes the following features.

[0099] The insulating layer forming method of the present invention includes a first step of subjecting a base material to a high-resistivity layer forming treatment having high electrical resistivity by surface treatment, a second step of subjecting the base material that has undergone the first step to a metal plating portion forming treatment capable of forming a high-resistivity layer, and a third step of subjecting the base material that has undergone the second step to a high-resistivity layer forming treatment.

[0100] In the insulating layer forming method of the present invention, the second step forms a metal plating on the fine conductive portions of the high resistance layer formed in the first step.

[0101] In addition, in the insulating layer forming method of the present invention, the high-resistance layer is a phosphate layer formed by phosphate chemical treatment, and the metal-plated portion is mainly composed of a metal that can be phosphate chemical treatment and / or oxidized.

[0102] In the insulating layer forming method of the present invention, the high-resistance layer in the third step is formed by phosphate chemical conversion treatment and / or oxidation treatment.

[0103] Furthermore, the insulating layer forming method of the present invention is a method for forming an insulating layer having high electrical insulation properties on a base material on which a high-resistance layer cannot be directly formed, and includes a preliminary step of forming a metal plating portion in a layered form on the base material, a first step of forming a high-resistance layer having high electrical resistivity on the metal plating portion by surface treatment, a second step of forming a metal plating portion capable of forming a high-resistance layer on the base material that has undergone the first step, and a third step of forming a high-resistance layer on the metal plating portion formed in the second step by subjecting the base material that has undergone the second step to a treatment for forming a high-resistance layer.

[0104] Furthermore, in the insulating layer forming method of the present invention, the high-resistance layer is a phosphate layer formed by phosphate chemical treatment, and the metal-plated portion is mainly composed of a metal that can be subjected to phosphate chemical treatment and / or oxidation treatment.

[0105] In the insulating layer forming method of the present invention, the high-resistance layer in the third step is formed by phosphate chemical conversion treatment and / or oxidation treatment.

[0106] In the insulating layer forming method of the present invention, the second step and the third step are alternately repeated.

[0107] In the second step of the insulating layer forming method of the present invention, the metal plating portion is formed by wet plating.

[0108] In the method for forming an insulating layer of the present invention, the metal plating portion contains iron, tin, zinc or nickel as a main component.

[0109] The insulating layer forming method of the present invention also includes a forming step of forming a conductive layer on the outermost high-resistance layer.

[0110] Furthermore, in the method for forming an insulating layer of the present invention, the conductive layer has a planar, linear, mesh, geometric pattern and / or dotted shape, or a combination thereof.

[0111] In the insulating layer forming method of the present invention, the conductive layer forms a conductive pattern.

[0112] In the insulating layer forming method of the present invention, the width, thickness and direction of the conductive layer provided on the high resistance layer are set so as to form an electronic element.

[0113] In addition, the insulating layer-attached member of the present invention has a phosphate layer formed on the surface of the base material, and a conductive liquid is applied to the surface of the phosphate layer. The anode probe is brought into contact with the conductive portion, and the cathode probe is brought into contact with the phosphate layer. 2 The resistance value measured with the surface probe is 190KΩ or more.

[0114] Furthermore, the member with an insulation layer of the present invention has an insulation layer made up of a substantially uniform phosphate layer on the surface of the base material.

[0115] Furthermore, the member with an insulating layer of the present invention is a surface insulating layer in which the insulating layer is insulated throughout the entire surface formed by the insulating layer.

[0116] The member with an insulation layer of the present invention has an insulation layer mainly composed of a phosphate layer on the surface of the base material, and metal oxides are scattered in the insulation layer.

[0117] The member with an insulating layer of the present invention has a conductive layer on the insulating layer.

[0118] Furthermore, in the member with an insulating layer of the present invention, the conductive layer has a configuration consisting of a surface, a line, a mesh, a geometric pattern and / or a dot, or a combination thereof.

[0119] In the member with an insulating layer of the present invention, the conductive layer forms a conductive pattern.

[0120] In the member with an insulating layer of the present invention, the width, thickness, and direction of the conductive layer provided on the high-resistance layer are set so as to form an electronic element.

[0121] Furthermore, in the member with an insulating layer of the present invention, the insulating layer has a withstand voltage performance that exceeds the voltage applied to the conductive layer.

[0122] In addition, the resistance measurement method of the present invention is a resistance measurement method for measuring the resistance value of a high-resistance layer formed on a component, and measures the resistance of the high-resistance layer using a measuring device that covers the high-resistance layer over an area of ​​a predetermined size or more and has a first contactor that makes point contact and / or planar contact with multiple locations on the high-resistance layer, and a second contactor that makes contact with the surface of the component other than the locations where the first contactor makes contact.

[0123] In the resistance measuring method of the present invention, the member has good conductivity, and the second contactor comes into contact with a portion of the member having good conductivity.

[0124] In the resistance measuring method of the present invention, the member is covered with a high resistance layer, and the second contactor is brought into contact with the surface covered with the high resistance layer.

[0125] In addition, in the resistance measurement method of the present invention, the first contactor is a member that is separate from the measuring device and that makes point contact with multiple locations on the high resistance layer and / or makes planar contact with the high resistance layer, and the contactor of the measuring device indirectly makes contact with the high resistance layer via the first contactor.

[0126] In addition, in the resistance measuring method of the present invention, a conductive fluid is placed between the high resistance layer and the first contact.

[0127] The junction rectifying element of the present invention is a junction rectifying element formed by joining a metal and a phosphate, and has an anode terminal provided directly or indirectly on the metal, and a cathode terminal provided directly or indirectly on the phosphate.

[0128] Furthermore, the junction rectifying element of the present invention is a junction rectifying element formed by joining a metal and a phosphate, and has a cathode terminal provided directly or indirectly on the metal and an anode terminal provided directly or indirectly on the phosphate.

[0129] Furthermore, in the junction rectifying element of the present invention, the metal is mainly composed of iron, which can be subjected to a phosphate chemical conversion treatment.

[0130] In the junction rectifying element of the present invention, the phosphate is a phosphate chloride layer. [Explanation of symbols]

[0131] 10... Base material (metal base material), 20, 40, 45, 50... Phosphate layer (insulating layer / electrically resistive layer), 22... Conductive portion (fine conductive portion), 60... Conductive layer, 72... Probe (first electrode), 74... Measuring block (surface contact), 76... Bottom, 78... Hole

Claims

1. A method for verifying the insulation of an electrical resistance layer in which a conductive layer is formed by chemically treating the surface of a metal base material, comprising: Applying a conductive fluid between the electrical resistance layer and the sheet contact, The planar contactor covers the electrical resistance layer over a predetermined area or more to form planar contact therewith, measuring the electrical resistance value of the range of the contact surface where the sheet contactor comes into contact with the electrical resistance layer using a measuring device having a first electrode that applies a negative or positive DC voltage to the sheet contactor and a second electrode that applies a negative or positive DC voltage to a location of the metal base material other than the electrical resistance layer; An insulation confirmation method characterized by determining whether or not conductive points due to the presence of fine conductive parts within the above range are present from the above electrical resistance value, and confirming the level of insulation of the above electrical resistance layer.

2. 2. The method for checking insulation according to claim 1, wherein the electrical resistance layer is a phosphate layer formed by phosphate treating the surface of the metal base material, and the electrical resistance value of the phosphate layer is measured.

3. 3. The method for checking insulation properties according to claim 1, wherein the fluid that does not cause an oxidation or dissolution reaction is applied to the metal base material.

4. 4. The method for checking insulation properties according to claim 1, wherein the fluid is water, salt water, silver paste, or an ionic liquid.

5. 5. The insulation checking method according to claim 1, wherein a needle-shaped probe serving as the first electrode is inserted into a hole in a block body serving as the planar contactor, and a tip of the probe is brought into contact with a bottom portion of the block body that forms a metal surface, thereby electrically connecting the probe to the block body.

6. 6. The method for checking insulation according to claim 1, wherein the minute conductive portions are detected as thin portions or as a large number of so-called pinhole-like fine conductive portions.

7. 7. The insulation checking method according to claim 1, wherein the conductive layer is a conductive pattern formed on the electrical resistance layer.

Images