TW202134480A - Palladium-nickel alloy coating film and manufacturing method thereof capable of reducing the palladium content in the palladium-nickel alloy coating film while maintaining corrosion resistance or preventing diffusion of the base metal material - Google Patents

Abstract

Provided is a palladium-nickel alloy coating film, in which the palladium content in the continuous palladium-nickel alloy coating film has a difference of more than 10 wt% in the thickness direction. The object of the present invention is to provide a palladium-nickel alloy coating film and a manufacturing method thereof. The aforementioned palladium-nickel alloy coating film reduces the palladium content in the palladium-nickel alloy coating film while maintaining corrosion resistance or preventing diffusion of the base metal material.

Description

Palladium-nickel alloy coating film and manufacturing method thereof

The present invention relates to a palladium-nickel alloy plating film useful as a constituent material of electrical, electronic, mechanical parts, etc., and a manufacturing method thereof.

Palladium and nickel alloy coating has excellent corrosion resistance and prevents the diffusion of base metal materials (barrier properties), so it is widely used in electronic parts, electroforming parts, decorations, medical fields, etc. As electronic parts, it is used in connectors or substrates. In connectors, a palladium-nickel alloy plating film is formed on the base metal material, and a hard gold plating film is formed on the outermost surface. Use palladium-nickel alloy coating as a material with less diffusion of base metal.

Moreover, in the medical field, precision filters and precision nozzles have been popularized. There are electroforming methods using palladium-nickel alloy plating solutions, and coating methods using palladium-nickel alloys only on the surface of the material. Regarding the latter, there are Known are a method of coating the entire surface and a coating method of coating only the parts that require corrosion resistance (for example, Patent Documents 1 and 2). Both the electroforming method and the coating method require materials with less metal elution in the parts in contact with corrosive liquids. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2017-192394 [Patent Document 2] JP 2018-113980 A

[The problem to be solved by the invention]

Palladium-nickel alloy materials are mostly used in the manufacture of the above-mentioned connectors, precision filters, or precision nozzles. By using palladium-nickel alloys, it is possible to strengthen the prevention of the diffusion of base metal materials and improve the corrosion resistance. In addition, at this time, the palladium content in the palladium-nickel alloy is preferably 50 wt% or more. When the palladium-nickel alloy is less than 50 wt%, the physical properties of nickel are superior, and the corrosion resistance or the anti-diffusion of the base metal material is hardly good.

When using palladium-nickel alloy plating to manufacture connectors, generally the thickness needs to be about 0.5 μm. In addition, when manufacturing precision filters, precision nozzles, etc., if electroforming is used, plating must be used. The coating thickness is about tens to hundreds of microns to maintain the strength of the film. If it is a coating method, it is not necessary to increase the film thickness to the level of the electroforming method, but in extremely thin coatings, pinholes may occur. Concerns, so the thickness of about sub-micron is still needed.

The higher the palladium content in the palladium-nickel alloy film, the better the function of preventing the diffusion of the base metal material or the corrosion resistance, but there is a problem that the higher the palladium content, the higher the cost. In particular, the thicker the film thickness of the palladium-nickel alloy film, the more the palladium content will increase, so that the cost issue becomes more significant. In order to reduce costs, attempts have been made to reduce the palladium content, but in terms of corrosion resistance or prevention of the diffusion of the base metal material, the current situation is that only coatings with a higher palladium content can be used.

The present invention was completed in view of the above problems, and its purpose is to provide a palladium-nickel alloy coating and a manufacturing method thereof. The above-mentioned palladium-nickel alloy coating reduces the palladium content in the palladium-nickel alloy coating on the one hand, and can maintain corrosion resistance on the other hand. The function of preventing the diffusion of base metal materials. [Technical means to solve the problem]

In order to solve the above-mentioned problems, the inventors of the present invention have made painstaking research and found that by changing the palladium content in the thickness direction of the palladium-nickel alloy coating, the corrosion resistance or the function of preventing the diffusion of the base metal material can be maintained and the palladium-nickel alloy coating can be reduced The total content of palladium, thus completing the present invention. The above-mentioned problems are solved by the present invention shown below.

1) A palladium-nickel alloy coating film in which the palladium content in the continuous palladium-nickel alloy coating film has a difference of more than 10 wt% in the thickness direction. 2) The palladium-nickel alloy coating described in 1), wherein the palladium content of the part with the highest palladium content in the continuous palladium-nickel alloy coating is 50 wt% or more. 3) The palladium-nickel alloy coating as described in 1) or 2), wherein the thickness of the continuous palladium-nickel alloy coating is 0.5 μm or more and 100 μm or less. 4) The palladium-nickel alloy coating described in any one of 1) to 3), wherein the continuous palladium-nickel alloy coating has a stress of -50 MPa or more and 100 MPa or less. 5) The palladium-nickel alloy coating according to any one of 1) to 4), wherein the Vickers hardness of the continuous palladium-nickel alloy coating is 200 Hv or more and 600 Hv or less. 6) A manufacturing method of palladium-nickel alloy coating, which is a method of manufacturing palladium-nickel alloy coating by electrolytic plating, and is characterized in that the palladium content in the coating is achieved by using two or more cathode current densities There is a difference of 10 wt% or more in the thickness direction. 7) The method for producing a palladium-nickel alloy coating as described in 6), wherein the cathode current density of the part with the lowest palladium content in the continuous palladium-nickel alloy coating when the coating is formed is set to the part with the highest palladium content. More than 2 times the cathode current density during coating. 8) The method for producing a palladium-nickel alloy coating as described in 6) or 7), wherein the cathode current density of the part with the highest palladium content when the coating is formed is set to 0.3-5.0 A/dm ² . 9) The method for producing a palladium-nickel alloy plating film as described in any one of 6) to 8), wherein the cathode current density of the part with the lowest palladium content when the plating film is formed is set to 1.5-15 A/dm ² . 10) The method for producing a palladium-nickel alloy coating film as described in any one of 6) to 9), wherein the current waveform during plating is a rectangular wave. [Effects of Invention]

According to the present invention, it is possible to adjust the palladium content in the thickness direction in the continuous palladium-nickel alloy plating film. Therefore, it has the excellent effect of increasing the palladium content in the plating film near the base metal or the outermost surface layer, thereby maintaining the prevention of the base metal The function of diffusion or corrosion resistance, and can reduce the content of palladium in other parts, thereby reducing the total content of palladium in the coating. In addition, the amount of palladium used can be reduced by this, so there is an excellent effect of being able to suppress the cost.

Generally speaking, in order to make the palladium-nickel alloy plating film have corrosion resistance, the palladium content is increased to 80 wt%, and the thickness is formed to 5 μm. However, most of the parts that require corrosion resistance are only the wetted part, that is, the outermost surface. Even considering pinholes, etc., a film with a palladium content of 80 wt% is about 1 μm, and the remaining 4 μm palladium-nickel alloy coating only needs to be To meet other physical properties, it is not necessary to set the palladium content to 80 wt%.

Therefore, by changing the palladium content in the film in the thickness direction during continuous palladium-nickel alloy plating, increasing the palladium content in the parts that require corrosion resistance or barrier properties, and reducing the palladium content in other parts, so that the entire coating can be made The content of palladium is reduced compared to the conventional one, so that the cost can be reduced.

The palladium-nickel alloy coating film of the embodiment of the present invention is characterized in that the palladium content in the continuous palladium-nickel alloy coating film has a difference of more than 10 wt% in the thickness direction. Here, the term "continuous" refers to a plating film produced by using one type of plating solution, and it will be explained by distinguishing it from a plating film with a multilayer structure produced by using multiple plating solutions.

In order to facilitate the understanding of the present invention, an example of this embodiment is shown in FIGS. 1 to 5. Figure 1 is an example of palladium-nickel alloy coating, where only the thicker part of the coating, that is, the outermost part, has a higher palladium content, while the other parts have reduced palladium content (conceptual diagram). Palladium is easily reduced, and nickel is more difficult to be reduced than palladium. Therefore, plating with a low current density can increase the proportion of palladium precipitation. On the other hand, plating with a high current density can relatively increase nickel precipitation. The ratio.

That is, by controlling the cathode current density during plating, the desired palladium content can be arbitrarily selected, and the palladium content can be changed in the thickness direction. Thereby, it is possible to manufacture a plating film that ensures corrosion resistance or barrier properties or both functions and reduces the palladium content. The difference in the palladium content in the coating film is more than 10 wt% in the thickness direction. More preferably, it is 25 wt% or more, and still more preferably 47 wt% or more. In the present invention, the so-called palladium content difference refers to the difference between the palladium content of the part with the highest palladium content and the palladium content of the part with the lowest palladium content.

In addition, in the continuous palladium-nickel alloy coating, the palladium content of the part with the highest palladium content is preferably 50 wt% or more. More preferably, it is 70 wt% or more, and still more preferably 80 wt% or more. The parts with the highest palladium content are mainly near the base metal (in terms of ensuring barrier properties) or/and the outermost surface (corrosion resistance). By adding to these parts, the barrier properties or corrosion resistance are effectively affected. The content of palladium can obtain the desired characteristics.

Figure 2 is an example of palladium-nickel alloy coating where only the thinner part of the coating, that is, the part near the base metal, has a higher palladium content, while the other parts have reduced palladium content (conceptual diagram). Figure 3 is on the outermost surface and An example where the palladium content is increased in the vicinity of the base metal, and the palladium content is decreased in the middle part. Figures 4 and 5 are examples of continuously increasing/decreasing the palladium content in the thickness direction.

In terms of corrosion resistance or the performance of preventing the diffusion of the base metal material (barrier property), the film thickness of the continuous palladium-nickel alloy coating is preferably set to 0.1 μm or more. More preferably, it is 0.5 μm or more. For example, when the thickness of the continuous plating film is set to 0.5 μm, in terms of ensuring corrosion resistance or barrier properties, the thickness of the part with a higher palladium content is set to about 0.2-0.3 μm. On the other hand, the thickness of the palladium The thickness of the part with the lower content is set to about 0.3-0.2 μm, which can reduce the palladium content in at least half of the plating film.

In addition, the more the thickness increases, the more the plated part with reduced palladium content will increase, so that compared with the prior art plating film containing a certain amount of palladium content, the corrosion resistance or barrier properties can be maintained (or improved) and the palladium The coating with less content is especially effective. On the other hand, if the thickness of the continuous palladium-nickel alloy coating exceeds 100 μm, discoloration, cracking, or voids are likely to occur, and it becomes difficult to control the appearance, and it is difficult to say that it is a practical manufacturing. Therefore, the film thickness is preferably 100 μm or less, and more preferably 60 μm or less. However, by appropriately controlling the type, concentration, and plating conditions of the doping components of the plating bath, it is possible to produce a plating film of 100 μm or more.

In this embodiment, the stress of the continuous palladium-nickel alloy coating is preferably -50 MPa or more and 100 MPa or less. The low-stress coating is not easy to crack or peel off, and it can maintain good adhesion to the substrate.

Regarding the hardness of the coating, the requirements vary according to the use of connectors, precision filters or precision nozzles. In the application of electroformed components where strength is particularly required, although the hardness of the coating film also depends on the product characteristics, it tends to be a harder coating film of 400 Hv to 600 Hv. On the other hand, for connectors, etc., if the coating is too hard, it will have a negative impact on the sliding properties. Therefore, about 200 Hv can fully meet the required specifications. The high hardness palladium-nickel alloy coating has excellent durability and wear resistance, and can maintain stable characteristics even if it is used for a long time without damaging its function. The hardness varies with the nickel content or plating conditions. If the nickel content increases, the plating film becomes hard, and if the cathode current density increases, the plating film becomes hard. In addition, in general, as the crystal grain size becomes smaller, the hardness increases.

In the plating conditions of continuous palladium-nickel alloy plating, two or more cathode current densities are used, that is, the cathode current density is changed in the middle of plating, thereby, as shown in Figures 1 to 5 above, the plating can be The palladium content changes step by step in the thickness direction, especially, it can make the palladium content in the coating film have a difference of more than 10 wt% in the thickness direction. At this time, it is preferable to set the cathode current density of the portion with the lowest palladium content in the continuous palladium-nickel alloy plating film when the plating film is formed to be more than twice the cathode current density of the portion with the highest palladium content when the plating film is formed.

The cathode current density is preferably 0.3 A/dm ² to 30 A/dm ² , more preferably 0.5 A/dm ² to 20 A/dm ² , and still more preferably 0.7 A/dm ² to 15 A/dm ² . If the cathode current density is higher than the above range, the coating film may fade or crack. In addition, it is necessary to increase the stirring speed and increase the metal concentration. In addition, if the cathode current density is lower than the above-mentioned range, there is a case where the plating film cannot be produced. In addition, it is preferable to set the cathode current density of the part with the highest palladium content during the formation of the plating film to 0.3 to 5.0 A/dm ² , and set the cathode current density of the part with the lowest palladium content during the formation of the plating film to 1.5-15 A/dm ² . Furthermore, the duty cycle and frequency can be set according to the desired palladium content.

Moreover, it is more desirable to use a shielding plate in the plating tank. Especially when the cathode current density is changed to control the palladium content as shown in the present invention, if the cathode is formed into a complicated shape, the theoretical cathode current density and actual cathode current density current distribution are quite different. Therefore, in order to obtain the desired palladium content, the current distribution of the cathode current density must be kept uniform to a certain extent by the shielding plate.

Hereinafter, the manufacturing method of the palladium-nickel alloy plating film of this embodiment is specifically shown. First, a palladium-nickel plating bath composed of the following components is taken as an example. Tetraammine palladium(II)chloride Nickel sulfamate Ammonium acetate Ammonium Chloride Saccharin Sodium Dihydrate Salicylic acid

The plating bath is made of palladium salt and nickel salt as main components, and additives and conductive salt are added. As the palladium salt, in addition to the above-mentioned dichlorotetraamine palladium, dibromotetraamine palladium ([Pd(NH ₃ ) ₄ ]Br ₂ ), diiodotetraamine palladium ([Pd(NH ₃ ) ₄ ]I ₂ ), tetraammonium palladium sulfate ([Pd(NH ₃ ) ₄ ]SO ₄ ) and other tetraammonium palladium compounds; dichlorodiamine palladium ([Pd(NH ₃ ) ₂ Cl ₂ ]), dibromodiamine palladium ( [Pd(NH ₃ ) ₂ Br ₂ ]), palladium diamine diamine ([Pd(NH ₃ ) ₂ I ₂ ]), palladium diamine sulfate ([Pd(NH ₃ ) ₂ (SO ₄ )]), etc. The two ammonia palladium compounds and so on.

In addition, as the nickel salt, in addition to the above-mentioned nickel sulfamate, nickel sulfate (II) hydrate, nickel acetate, nickel chloride, etc. can also be used, and the acid radical of the nickel salt is not particularly limited. Although the palladium content in the coating film can vary according to the difference in cathode current density, the initial concentration ratio of the palladium salt to the metal salt will also affect the palladium content in the coating film, so this point must be considered before determining the concentration.

As additives, benzoic acid, 3-aminopyridine-2-sulfonic acid, saccharin, thiourea, sodium benzenesulfonate, etc. can be used.

In addition, as the conductive salt, citric acid, tripotassium citrate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, boric acid, ammonium chloride, ammonium sulfate, ammonium nitrite, etc. can be used. In addition, plural kinds of them may be mixed. The conductivity salt is ideal to add 10～150 g/L. The conductivity salt of the plating solution can be selected to have a buffering effect near the pH of the general use, but the type of conductivity salt will affect the alloy ratio, so the desired characteristics must be considered Decide again.

Then, using the above-mentioned plating bath, electrolytic plating is performed under the following conditions, for example, to form a plating film. In addition, the following conditions are an example, and the present invention is not limited to these conditions. By using both DC wave, rectangular wave, DC wave, and rectangular wave as current waveforms for plating, plating can be performed with a wide range of current values, and palladium and nickel can be plated at a wide ratio. Cathode current density: 0.3～30 A/dm ² Duty ratio: 10～90% Frequency: 0.25～1000 Hz Bath volume: 3 L pH: 5.5～7.5 Temperature: 40℃～50℃ Cathode: copper (no substrate plating ) Anode: Titanium shielding plate coated with iridium oxide: Yes [Example]

Next, examples and comparative examples of the present invention will be described. Furthermore, the following embodiments are only representative examples, and the invention of this case need not be limited to these embodiments, and should be interpreted within the scope of the technical ideas described in the specification.

(Examples 1 to 9) The building bath is a palladium-nickel plating bath composed of the components described in Table 1 below, and plating is performed under the conditions described in the same table to form a palladium-nickel alloy plating film. Furthermore, in the case of plating with more than three types of cathode current densities, for example, plating condition 1, plating condition 2, and plating condition 1, but the third plating condition does not have to be plating condition 1. For coatings larger than 15 μm, the thickness is calculated from the weight of the coating, and the coating thickness of other coatings is measured using SFT9500 manufactured by SII.

[Table 1] Example 1 2 3 4 5 6 7 8 9 Palladium salt Palladium Dichlorotetraamine g/L (Pd amount conversion) 10 Nickel salt Nickel(II) sulfate hexahydrate g/L (conversion of Ni amount) 3 Nickel acetate g/L (conversion of Ni amount) 4 Conductivity salt Ammonium Chloride g/L 5 Ammonium Sulfate g/L 20 Ammonium Nitrite g/L 4 additive saccharin g/L 1 Sodium benzene sulfonate g/L 3 Plating condition 1 Current density A/dm ² 0.7 0.3 0.7 2.0 2.0 0.7 5.5 4.0 0.7 frequency Hz 5.0 6.3 3.8 6.7 6.7 3.8 13 6.3 5.0 Duty cycle % 50 50 50 50 50 50 100 50 50 pH 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 Bath temperature °C 45 45 45 45 45 45 45 45 45 Coating film obtained under plating condition 1 Palladium content wt% 97 98 97 85 85 97 67 75 97 Film thickness μm Hv 0.2 0.3 0.2 0.5 0.3 0.3 0.5 0.3 0.4 hardness 250 280 260 320 330 260 450 370 270 Plating condition 2 Current density A/dm ² 1.5 4.5 12 5 12 12 12 13 15 frequency Hz 12.5 12.5 50.0 20.0 62.5 100 100 100 100 Duty cycle % 50 50 50 80 50 50 50 50 50 pH 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 Bath temperature °C 45 45 45 45 45 45 45 45 45 Coating film obtained under plating condition 2 Palladium content wt% 87 74 50 73 55 50 50 50 50 Film thickness μm 0.3 50.7 100.8 101.5 0.2 50.7 51.5 100.7 0.1 hardness Hv 350 360 580 350 550 600 580 580 590 Coating film obtained under plating conditions 1 and 2 Film thickness (overall thickness of plating) μm 0.5 51 101 102 0.5 51 52 101 0.5 stress MPa -42 15 30 -18 80 -30 70 32 -59 Difference in palladium content wt% 10 ○ 24 ○ 47 ○ 12 ○ 25 ○ 47 ○ 10 ○ 25 ○ 47 ○

Because it is difficult to accurately measure the different palladium content in the coating, the plating is about 5-10 μm under each current condition, and the palladium content of each is measured. In addition, depending on the current conditions, the current value may be gradually increased. Therefore, in this case, the minimum current value and the maximum current value within the current conditions are respectively plated for about 5-10 μm under each current condition, and the measurement Palladium content of each. The palladium content was measured using the SFT3200 fluorescent X-ray device manufactured by SII.

The stress of the coating is measured by fixing the coating thickness at about 5 μm. For example, when the coating thickness is 100 μm and the coating with the higher palladium content is 10 μm, and the coating with the lower palladium content is 90 μm, the coating with the higher palladium content is set to 0.5 μm, and the coating with the lower palladium content is set to 0.5 μm. The coating is set to 4.5 μm, and the total stress value is 5 μm. The stress was measured using a strip electrodeposition stress tester manufactured by Specialty Testing and Development Company, and the stress was calculated based on the obtained film thickness based on the standard width and plating weight obtained by the measurement.

The hardness of the coating is measured by fixing the coating thickness at about 10 μm. For example, when the thickness of the coating is 50 μm and the coating with a higher palladium content is 5 μm, and the coating with a lower palladium content is 45 μm, the hardness of each coating is about 10 μm. When the plating film contains 3 different palladium contents, the hardness of the individual plating is about 10 μm. In addition, depending on the current conditions, it is possible to gradually increase the current value. Therefore, for example, when the plating thickness is 50 μm, the palladium content at the initial stage of plating is 70 wt%, and the palladium content after plating is 97 wt%. When the hardness is maintained at the same palladium content and the thickness of the coating is about 10 μm. The hardness was measured using a micro hardness tester HM-221 manufactured by Mitutoyo Co., Ltd. Regarding the test force, find the test force that is equal to or higher than the level 2 and use the larger value of the test force. In addition, regarding the hardness, the average value of the two measurements was obtained. Regarding the measurement conditions, the test time was set to load for 4 seconds, hold for 10 seconds, and unload for 4 seconds; the test force was arbitrarily changed according to the thickness.

Electrolytic plating was performed under the conditions disclosed in Table 1 to form a palladium-nickel alloy plating film to a specific film thickness. As a result, in any of Examples 1 to 9, by changing the plating conditions from a plating solution, a palladium-nickel alloy plating film with a difference in palladium content of 10 wt% or more was obtained. In addition, the stress and Vickers hardness of the coating are also within a specific numerical range.

(Comparative Examples 1 to 9) The build-up bath is a palladium-nickel plating bath composed of the same composition as in the examples, and is plated under the conditions described in Table 2 below to form a palladium-nickel alloy plating film. Furthermore, in Comparative Examples 1 to 9, the cathode current density of the "plating condition 2" was set to 1.5 times the cathode current density of the "plating condition 1". For the obtained palladium-nickel alloy coating film, the different palladium content in the coating film, the stress of the coating film, and the Vickers hardness of the coating film were measured in the same manner as the examples. As a result, if the cathode current density is 2 times or less, the difference in palladium content does not exceed 10 wt%.

[Table 2] Comparative example 1 2 3 4 5 6 7 8 9 Palladium salt Palladium Dichlorotetraamine g/L (Pd amount conversion) 10 Nickel salt Nickel(II) sulfate hexahydrate g/L (conversion of Ni amount) 3 Nickel acetate g/L (conversion of Ni amount) 4 Conductivity salt Ammonium Chloride g/L 5 Ammonium Sulfate g/L 20 Ammonium Nitrite g/L 4 additive saccharin g/L 1 Sodium benzene sulfonate g/L 3 Plating condition 1 Current density A/dm ² 0.7 0.3 0.7 2.5 2.5 0.7 5.5 4 0.7 frequency Hz 5.0 6.3 3.8 6.7 6.7 3.8 13 6.3 5.0 Duty cycle % 50 50 50 50 50 50 100 50 50 pH 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 Bath temperature °C 45 45 45 45 45 45 45 45 45 Coating film obtained under plating condition 1 Palladium content wt% 97 97 97 83 83 97 67 75 97 Film thickness μm 0.2 0.3 0.2 0.5 0.3 0.3 0.5 0.3 0.4 hardness Hv 250 280 260 320 330 260 450 370 270 Plating condition 2 Current density A/dm ² 1.1 0.5 1.1 3.8 3.8 1.1 8.3 6.0 1.1 frequency Hz 12.5 12.5 50.0 12.5 62.5 100.0 100.0 100.0 100.0 Duty cycle % 50 50 50 50 50 50 50 50 50 pH 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 Bath temperature °C 45 45 45 45 45 45 45 45 45 Coating film obtained under plating condition 2 Palladium content wt% 90 93 90 76 76 90 65 67 90 Film thickness μm 0.3 51.7 100.8 101.5 0.2 49.7 49.5 102.7 0.1 hardness Hv 270 260 270 320 320 270 470 450 270 Coating film obtained under plating conditions 1 and 2 Film thickness (overall thickness of plating) μm 0.5 52 101 102 0.5 50 50 103 0.5 stress MPa -42 15 30 -18 80 -30 98 32 -59 Difference in palladium content wt% 7 × 4 × 7 × 7 × 7 × 7 × 2 × 8 × 7 × [Industrial availability]

The present invention has the following excellent effects by adjusting the palladium content in the thickness direction in the continuous palladium-nickel alloy plating film, that is, it can increase the palladium content in the plating film near the base metal or the outermost surface layer, thereby maintaining barrier properties or corrosion resistance , And can reduce the palladium content in other parts, thereby reducing the total content of palladium in the coating. The present invention is useful as a palladium-nickel alloy coating used in connectors, substrates, etc., precision filters, precision nozzles, and the like.

without

[Figure 1] is a conceptual diagram of the palladium-nickel alloy coating of this embodiment (an example of a higher palladium content in the outermost surface layer). [Figure 2] is a conceptual diagram of the palladium-nickel alloy coating of this embodiment (an example of a higher palladium content near the substrate). [Figure 3] is a conceptual diagram of the palladium-nickel alloy coating of this embodiment (an example where the palladium content is higher in the outermost surface layer part and the part near the substrate). [Figure 4] is a conceptual diagram of the palladium-nickel alloy coating of this embodiment (an example where the palladium content gradually increases in the thickness direction). [Figure 5] is a conceptual diagram of the palladium-nickel alloy coating of this embodiment (an example where the palladium content gradually decreases in the thickness direction).

Claims (10)

A palladium-nickel alloy coating film in which the palladium content in the continuous palladium-nickel alloy coating film has a difference of more than 10 wt% in the thickness direction. For example, the palladium-nickel alloy coating of claim 1, wherein the palladium content of the part with the highest palladium content in the continuous palladium-nickel alloy coating is more than 50 wt%. For example, the palladium-nickel alloy coating of claim 1 or 2, wherein the film thickness of the continuous palladium-nickel alloy coating is 0.5 μm or more and 100 μm or less. Such as the palladium-nickel alloy coating of any one of claims 1 to 3, wherein the stress of the continuous palladium-nickel alloy coating is -50 MPa or more and 100 MPa or less. Such as the palladium-nickel alloy coating of any one of claims 1 to 4, wherein the Vickers hardness of the continuous palladium-nickel alloy coating is 200 Hv or more and 600 Hv or less. A method for manufacturing a palladium-nickel alloy coating film, which is a method of manufacturing a palladium-nickel alloy coating film by electrolytic plating, and is characterized in that the palladium content in the coating film is in the thickness by using two or more cathode current densities There is a difference of more than 10 wt% in direction. For example, the method for manufacturing a palladium-nickel alloy coating of claim 6, wherein the cathode current density of the part with the lowest palladium content in the continuous palladium-nickel alloy coating when the coating is formed is set to the part with the highest palladium content when the coating is formed More than 2 times the current density of the cathode. For example, the method for manufacturing a palladium-nickel alloy coating of claim 6 or 7, wherein the cathode current density of the part with the highest palladium content when the coating is formed is set to 0.3-5.0 A/dm ² . The method for manufacturing a palladium-nickel alloy coating film according to any one of claims 6 to 8, wherein the cathode current density of the part with the lowest palladium content when the coating film is formed is set to 1.5-15 A/dm ² . The method for manufacturing a palladium-nickel alloy coating film according to any one of claims 6 to 9, wherein the current waveform during plating is a rectangular wave.

Images