Palladium-cobalt alloy electroplating solution as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of electroplating, and particularly relates to palladium-cobalt alloy electroplating liquid as well as a preparation method and application thereof. The electroplating solution comprises a palladium salt, a cobalt salt, a component A, a component B, a component C, a complexing agent, a conductive salt, a surfactant, a pH regulator and water, the component A is one or more of benzenesulfonic acid and a benzenesulfonic acid derivative, and the derivative refers to at least one substituent group and / or corresponding salt on an aromatic ring; the component B is selected from one or more of compounds shown in the molecular formula I, and the component C is selected from inorganic salts with reducibility. According to the technical scheme provided by the invention, through the synergistic effect of the three added components, the palladium-cobalt alloy coating with low stress, high brightness and adjustable alloy ratio is obtained, and the technical blank is filled. R1-C is equivalent to C-R2 (I).

Description

Technical Field

[0001] The invention belongs to the technical field of electroplating, and in particular relates to a palladium-cobalt alloy electroplating solution and a preparation method and application thereof. Background Art

[0002] Palladium-cobalt alloy has the advantages of low price, high conductivity, high chemical stability, and no harm to the skin, and has been widely used in the decoration industry and the electronics industry. However, it is not easy to develop a palladium-cobalt alloy plating solution that can meet diverse needs. Decorative electroplating usually requires the coating to be bright, beautiful, dense and corrosion-resistant.

[0003] In addition, in the electronics industry, the coating thickness is usually greater than 1 micron, and the coating thickness required for micro-device manufacturing will exceed 10 microns. When the thickness is large, the palladium-cobalt alloy with poor flexibility will produce large internal stress due to hydrogen absorption, internal particle unevenness, etc. The existence of internal stress will directly lead to cracking and warping of the coating, and even cause its adhesion with the underlying metal to deteriorate and be easily peeled off.

[0004] There are few reports on the control of brightness and stress of palladium-cobalt plating solutions in the prior art. Summary of the invention

[0005] The invention provides a palladium-cobalt alloy electroplating solution and a preparation method and application thereof, which are used to solve the problems of large internal stress and low brightness of the plating layer of the current palladium-cobalt alloy electroplating solution.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: the palladium-cobalt alloy electroplating solution comprises palladium salt, cobalt salt, component A, component B, component C, complexing agent, conductive salt, surfactant, pH regulator and water;

[0007] The component A is one or more of benzenesulfonic acid and benzenesulfonic acid derivatives, wherein the derivatives refer to those containing at least one substituent and / or corresponding salt on the aromatic ring;

[0008] The B component is selected from one or more of the compounds shown in formula I;

[0009] R1-C≡C-R2 (I)

[0010] wherein R1 is selected from hydroxyl, alkyl substituted by at least one hydroxyl and / or amino group, alkoxy substituted by at least one hydroxyl, amino, amino substituted by at least one alkyl, amino substituted by at least one hydroxyl and one alkyl;

[0011] R2 is selected from hydrogen, alkyl, hydroxyl, alkyl substituted by at least one hydroxyl group, alkoxy substituted by at least one hydroxyl group;

[0012] The C component is selected from inorganic salts having reducing properties.

[0013] Optionally, the A component is selected from the compound shown in formula II;

[0014]

[0015] wherein A1, A2, A3, A4 and A5 are each independently selected from -H, -CHO, -COOM2 or -SO3M3;

[0016] The M1, M2 and M3 are each independently selected from hydrogen ions or metal ions.

[0017] Optionally, the compound of formula I is

[0018] Optionally, the C component is selected from one or more of phosphites, hypophosphites, metaphosphates, nitrites, sulfites and selenites.

[0019] Optionally, the compound of formula II is selected from or its salts, or its salts, or its salts, or its salts, or its salts, or its salts, or a salt thereof, or or a salt thereof.

[0020] Optionally, the palladium salt is selected from one or more of palladium chloride, palladium bromide, palladium iodide, palladium sulfate, palladium nitrate, palladium hydroxide, diamminepalladium dichloride, diamminepalladium tetrachloride, dibrominepalladium tetraamminepalladium, diiodinepalladium tetraamminepalladium, diamminepalladium sulfate, tetraamminepalladium sulfate, palladium nitrite, palladium nitrate and palladium diamminepalladium oxalate.

[0021] Optionally, the cobalt salt is selected from one or more of cobalt chloride, cobalt bromide, cobalt iodide, cobalt oxide, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt hydroxide, cobalt oxalate and cobalt acetate.

[0022] Optionally, the complexing agent is selected from one or more of formates, acetates, propionates, aminoacetates, citrates, acrylates, tartrates and malates.

[0023] Optionally, the conductive salt is selected from one or more of sulfate, phosphate, nitrate, formates, acetates and propionates.

[0024] Optionally, the surfactant is selected from one or more of sodium dodecyl sulfate, sodium hexadecyl sulfate, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, dodecylphenol polyoxyethylene ether and nonylphenol polyoxyethylene ether.

[0025] Optionally, the pH regulator is one or more of ammonia water, hydrochloric acid and sulfuric acid.

[0026] Optionally, the ratio of component A, component B and component C in parts by weight is (100-1000):(1-10):(100-1000), preferably (40-250):1:(4-200).

[0027] The present invention also provides a method for preparing the palladium-cobalt alloy electroplating solution, which comprises the following steps:

[0028] Step (1) Add half the volume of deionized water of the plating solution to a PP plating tank and heat to the plating temperature;

[0029] Step (2) adding weighed complexing agent, palladium salt and cobalt salt in sequence, stirring and ultrasonicating until completely dissolved;

[0030] Step (3) adding weighed component A, component B, component C, conductive salt and surfactant, stirring and ultrasonicating until completely dissolved;

[0031] Step (4) adjusting the volume of the prepared plating solution to the volume to be prepared;

[0032] In step (5), the pH is adjusted using one or more of aqueous ammonia, hydrochloric acid and sulfuric acid.

[0033] Optionally, the electroplating temperature is 30-60° C. and the pH value is 7-8.

[0034] The present invention also provides a metal part containing a palladium-cobalt alloy coating, wherein the palladium-cobalt alloy coating is formed by electroplating with the palladium-cobalt alloy electroplating solution.

[0035] Optionally, the method for electroplating the palladium-cobalt alloy electroplating solution on the surface of a metal part comprises the following steps:

[0036] Step (1) performing alkaline degreasing, plasma cleaning and / or acid activation treatment on the plated parts;

[0037] Step (2) placing the plated object and the anode plate in the plating solution facing each other, the anode plate having an area equivalent to that of the plated object, and the anode plate can be selected from a platinum plate, a platinum mesh, a platinum titanium plate or a platinum titanium mesh;

[0038] Step (3) connecting a power source, setting current parameters according to the electroplating area of ​​the plated part, setting the electroplating time according to the required coating thickness, and performing electroplating;

[0039] Step (4) After the electroplating is completed, the plated parts are cleaned with deionized water and the quality of the coating is checked.

[0040] The technical solution provided by the present invention obtains a palladium-cobalt alloy coating with low stress, high brightness and adjustable alloy ratio through the synergistic effect of three added components, thus filling the technical gap. DETAILED DESCRIPTION

[0041] For ease of understanding, the palladium-cobalt alloy electroplating solution and its preparation method and application are described below in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0042] Unless otherwise specified, the reagents used in this example are all commercially available conventional products.

[0043] The palladium-cobalt alloy electroplating solution comprises a palladium salt, a cobalt salt, a component A, a component B, a component C, a complexing agent, a conductive salt, a surfactant, a pH regulator and water. The method for preparing 1 L of the electroplating solution in Examples 1-7 is as follows:

[0044] Step (1) Add half the volume of the plating solution, i.e. 500 mL, of deionized water into a PP plating tank and heat to the plating temperature;

[0045] Step (2) adding weighed complexing agent, palladium salt and cobalt salt in sequence, stirring and ultrasonicating until completely dissolved;

[0046] Step (3) adding weighed component A, component B, component C, conductive salt and surfactant, stirring and ultrasonicating until completely dissolved;

[0047] Step (4) adjusting the volume of the prepared plating solution to 1 L;

[0048] Step (5) The pH is adjusted with aqueous ammonia.

[0049] The selection and specific usage of each component in Examples 1-7 are as follows:

[0050] Example 1

[0051] A palladium-cobalt alloy electroplating solution, measured by weight volume concentration, contains the following components:

[0052] Palladium salt: palladium chloride 20g / L;

[0053] Cobalt salt: cobalt chloride 6g / L;

[0054] Complexing agent: ammonium aminoacetate 20g / L;

[0055] Conductive salt: potassium sulfate 5g / L;

[0056] Surfactant: sodium dodecyl sulfate 0.02 g / L;

[0057] Component A: 4g / L;

[0058] Component B: 0.03g / L;

[0059] Component C: sodium phosphite 0.5g / L;

[0060] pH:7.

[0061] Example 2

[0062] A palladium-cobalt alloy electroplating solution, measured by weight volume concentration, contains the following components:

[0063] Palladium salt: palladium sulfate 30g / L;

[0064] Cobalt salt: cobalt sulfate 10g / L;

[0065] Complexing agent: ammonium acetate 100g / L;

[0066] Conductive salt: potassium sulfate 0.5g / L;

[0067] Surfactant: sodium hexadecyl sulfate, concentration 0.05 g / L;

[0068] Component A: 5g / L

[0069] Component B: 0.05g / LC component: potassium hypophosphite 0.2g / L;

[0070] pH:7.5.

[0071] Example 3

[0072] A palladium-cobalt alloy electroplating solution, measured by weight volume concentration, contains the following components:

[0073] Palladium salt: palladium nitrate 10g / L;

[0074] Cobalt salt: cobalt nitrate 2g / L;

[0075] Complexing agent: ammonium propionate 50g / L;

[0076] Conductive salt: sodium nitrate 1g / L;

[0077] Surfactant: dodecyltrimethylammonium chloride, concentration 0.01g / LA Components: 4g / LB Components: The concentrations were and 0.1 g / L;

[0078] Component C: metaphosphate 0.5 g / L;

[0079] pH:7.5.

[0080] Example 4

[0081] A palladium-cobalt alloy electroplating solution, measured by weight volume concentration, contains the following components:

[0082] Palladium salt: dichlorodiamminepalladium 14g / L;

[0083] Cobalt salt: cobalt chloride 4g / L;

[0084] Complexing agent: ammonium tartrate 40g / L;

[0085] Conductive salt: sodium phosphate 4g / L;

[0086] Surfactant: hexadecyltrimethylammonium chloride, concentration 0.08g / LA Components: 6g / LB component 0.1g / L;

[0087] Component C: Sodium nitrite 0.8g / L;

[0088] PH:8.

[0089] Example 5

[0090] A palladium-cobalt alloy electroplating solution, measured by weight volume concentration, contains the following components:

[0091] Palladium salt: dichlorotetraamminepalladium 16 g / L;

[0092] Cobalt salt: cobalt sulfate 6g / L;

[0093] Complexing agent: sodium citrate 30g / L;

[0094] Conductive salt: potassium propionate 6g / L;

[0095] Surfactant: dodecylphenol polyoxyethylene ether, concentration 0.1g / LA Components: 10g / LB Components: 0.1g / L;

[0096] Component C: sodium sulfite 1g / L;

[0097] PH:8.

[0098] Example 6

[0099] A palladium-cobalt alloy electroplating solution, measured by weight volume concentration, contains the following components:

[0100] Palladium salt: diammine palladium oxalate 25g / L;

[0101] Cobalt salt: cobalt oxalate 8g / L;

[0102] Complexing agent: sodium malate 20g / L;

[0103] Conductive salt: potassium formate 1g / L;

[0104] Surfactant: Sodium dodecyl sulfate 0.05g / L

[0105] Component A: 5g / L

[0106] Component B: 0.08g / LC component: sodium sulfite 1g / L;

[0107] pH:7.

[0108] Example 7

[0109] A palladium-cobalt alloy electroplating solution, measured by weight volume concentration, contains the following components:

[0110] Palladium salt: Tetraamminepalladium sulfate 18g / L;

[0111] Cobalt salt: cobalt acetate 4g / L;

[0112] Complexing agent: Ammonium aminoacetate 40g / L;

[0113] Conductive salt: potassium acetate 6g / L;

[0114] Surfactant: Nonylphenol polyoxyethylene ether 0.08g / LA Components: 2g / LB Components: 0.05g / L;

[0115] Component C: sodium selenite 0.2g / L;

[0116] pH:7.5.

[0117] Comparative Example 1

[0118] Measured by weight volume concentration, it contains the following components:

[0119] Palladium salt: palladium chloride 20g / L;

[0120] Cobalt salt: cobalt chloride 6g / L;

[0121] Complexing agent: ammonium aminoacetate 20g / L;

[0122] Conductive salt: potassium sulfate 5g / L;

[0123] Surfactant: Sodium dodecyl sulfate 0.02g / L; Component B: 0.03g / L; Component C: Sodium phosphite 1g / L;

[0124] pH:7.

[0125] Comparative Example 2

[0126] Measured by weight volume concentration, it contains the following components:

[0127] Palladium salt: palladium chloride 20g / L;

[0128] Cobalt salt: cobalt chloride 6g / L;

[0129] Complexing agent: ammonium aminoacetate 20g / L;

[0130] Conductive salt: potassium sulfate 5g / L;

[0131] Surfactant: Sodium dodecyl sulfate 0.02g / L; Component A: 4g / L;

[0132] Component C: sodium phosphite 1g / L;

[0133] pH:7.

[0134] Comparative Example 3

[0135] Measured by weight volume concentration, it contains the following components:

[0136] Palladium salt: palladium chloride 20g / L;

[0137] Cobalt salt: cobalt chloride 6g / L;

[0138] Complexing agent: ammonium aminoacetate 20g / L;

[0139] Conductive salt: potassium sulfate 5g / L;

[0140] Surfactant: sodium dodecyl sulfate 0.02 g / L;

[0141] Component A: 4g / L;

[0142] Component B: 0.03g / L;

[0143] pH:7.

[0144] Examples 8-14 and Comparative Examples 4-6

[0145] Pure copper metal parts are electroplated through the following steps:

[0146] Step (1) performing alkaline degreasing, plasma cleaning and / or acid activation treatment on the plated parts;

[0147] Step (2) placing the plated object and the anode plate in the plating solution facing each other, the anode plate having an area equivalent to that of the plated object, and the anode plate can be selected from a platinum plate, a platinum mesh, a platinum titanium plate or a platinum titanium mesh;

[0148] Step (3) connecting a power source, setting current parameters according to the electroplating area of ​​the plated part, setting the electroplating time according to the required coating thickness, and performing electroplating;

[0149] Step (4) After the electroplating is completed, the plated parts are cleaned with deionized water and the quality of the coating is checked.

[0150] The specific electroplating details and parameters are shown in Table 1:

[0151] Table 1

[0152]

[0153] Performance test: The metal coatings of Examples 8-14 and Comparative Examples 4-6 were tested as follows:

[0154] 1. Alloy ratio test: Use the energy dispersive spectrometer (EDS) of the scanning electron microscope (SEM) to characterize and analyze the composition of the coating.

[0155] 2. Roughness test: Use a 3D surface profiler to measure the surface roughness of the coating. The surface roughness is related to the scanning area. This test uses 100μm×100μm as the scanning area.

[0156] 3. Stress test: The anode is a platinum titanium plate, using SPECIALTY TESTING &

[0157] The 1194UDF test piece produced by DEVELOPMENT COMPANY was used for coating stress analysis. Before use, the test piece was cleaned with a mild non-alkaline detergent, then rinsed with water, immersed in a 10% sulfuric acid solution for 30 seconds, and finally rinsed with water. The test piece was fixed so that its two legs were parallel to the anode and the distance was equal. A magnetic stirrer was used during the electroplating process.

[0158] Test results: as shown in Table 2.

[0159] Table 2

[0160]

[0161] According to Table 2, it can be found that the palladium-cobalt alloy electroplating solutions of Examples 1 to 7 can all achieve co-deposition of palladium-cobalt alloy, and the roughness of the prepared coatings is less than 0.15 μm, the appearance is bright, and the stress value is between -16 MPa and 11 MPa, which meets the requirements of low-stress alloys. Compared with Example 8, Comparative Example 4 lacks component A. When electroplated with the same electroplating parameters, the coating becomes semi-bright, the coating roughness, stress value, and palladium / cobalt alloy ratio are significantly increased, and the coating thickness is significantly reduced, that is, the plating speed is reduced, indicating that component A plays multiple roles as an accelerator, brightener, and stress agent; Compared with Example 8, Example 5 lacks component B, and the coating becomes semi-bright, the roughness of the coating increases significantly, the palladium / cobalt alloy ratio and stress also increase, but the increase is not large compared with Comparative Example 4, indicating that component B mainly affects the bright performance of the coating, and only components A and C cannot make the coating reach a smaller roughness; Comparative Example 6 lacks component C compared with Example 8, and the roughness of the coating becomes slightly larger, but it is still bright, the palladium-cobalt ratio and plating speed do not change much, but the stress increases significantly, indicating that component C mainly affects the stress size, and only components A and B cannot control the stress within a smaller range. It can be seen that the three components A, B, and C are indispensable for achieving the brightness and stress control of palladium-cobalt alloy coatings.

[0162] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A palladium-cobalt alloy electroplating solution, characterized in that: It includes palladium salt, cobalt salt, component A, component B, component C, complexing agent, conductive salt, surfactant, pH regulator and water; The component A is one or more of benzenesulfonic acid and benzenesulfonic acid derivatives, wherein the derivatives refer to those containing at least one substituent and / or corresponding salt on the aromatic ring; The B component is selected from one or more of the compounds shown in Formula I; R1-C≡C-R2 (1) wherein R1 is selected from hydroxyl, alkyl substituted by at least one hydroxyl and / or amino group, alkoxy substituted by at least one hydroxyl, amino, amino substituted by at least one alkyl, amino substituted by at least one hydroxyl and one alkyl; R2 is selected from hydrogen, alkyl, hydroxyl, alkyl substituted by at least one hydroxyl group, alkoxy substituted by at least one hydroxyl group; The C component is selected from inorganic salts having reducing properties.

2. The palladium-cobalt alloy electroplating solution according to claim 1, characterized in that: The A component is selected from the compound shown in formula II; wherein A1, A2, A3, A4 and A5 are each independently selected from -H, -CHO, -COOM2 or -SO3M3; The M1, M2 and M3 are each independently selected from hydrogen ions or metal ions.

3. The palladium-cobalt alloy electroplating solution according to claim 2, characterized in that: The compound of formula II is selected from or its salts, or its salts, or its salts, or its salts, or its salts, or its salts, or a salt thereof, or or a salt thereof.

4. The palladium-cobalt alloy electroplating solution according to claim 1, characterized in that: The compound of formula I is 5. The palladium-cobalt alloy electroplating solution according to claim 1, characterized in that: The C component is selected from one or more of phosphites, hypophosphites, metaphosphates, nitrites, sulfites and selenites.

6. The palladium-cobalt alloy electroplating solution according to claim 1, characterized in that: The pH adjuster is one or more of ammonia water, hydrochloric acid and sulfuric acid.

7. The palladium-cobalt alloy electroplating solution according to claim 1, characterized in that: The ratio of component A, component B and component C in parts by weight is (100-1000):(1-10):(100-1000), preferably (40-250):1:(4-200).

8. The method for preparing the palladium-cobalt alloy electroplating solution according to any one of claims 1 to 7, characterized in that: The steps include: Step (1) Add half the volume of deionized water of the plating solution to a PP plating tank and heat to the plating temperature; Step (2) adding weighed complexing agent, palladium salt and cobalt salt in sequence, stirring and ultrasonicating until completely dissolved; Step (3) adding weighed component A, component B, component C, conductive salt and surfactant, stirring and ultrasonicating until completely dissolved; Step (4) adjusting the volume of the prepared plating solution to the volume to be prepared; In step (5), the pH is adjusted using one or more of aqueous ammonia, hydrochloric acid and sulfuric acid.

9. The preparation method according to claim 8, characterized in that: The electroplating temperature is 30-60° C., and the pH value is 7-8.

10. A metal part containing a palladium-cobalt alloy coating, characterized in that: The palladium-cobalt alloy plating layer is formed by electroplating using the palladium-cobalt alloy electroplating solution described in any one of claims 1-7.

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