Stress regulator of palladium or palladium alloy coating and application of stress regulator

Abstract

The invention belongs to the technical field of palladium or palladium alloy coatings, and particularly relates to a stress regulator for a palladium or palladium alloy coating and application of the stress regulator. The stress regulator for the palladium or palladium alloy coating is composed of a component A and a component B, the component A is selected from inorganic salt with reducibility, and the component B is selected from a compound shown in a molecular formula I. The invention further discloses a preparation method of the stress regulator for the palladium or palladium alloy coating. The invention further provides a palladium or palladium alloy electroplating solution which comprises the stress regulator for the palladium or palladium alloy coating. The technical scheme provided by the invention has an obvious stress adjusting effect on the palladium and palladium alloy coating, and especially under the condition that the coating is relatively thick, a qualified coating without warping and cracks can be obtained. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of palladium or palladium alloy plating, and in particular relates to a stress regulator for palladium or palladium alloy plating and application thereof. Background Art

[0002] Electrochemical deposition of palladium or palladium alloys on metal substrates has a variety of decorative and technical applications. It has excellent corrosion resistance, wear resistance, electrical properties and brightness, and is a key material for manufacturing circuit contacts and connectors.

[0003] Electrodeposited palladium usually has no adhesion, so the coating is often porous due to hydrogen absorption, prone to cracks and very brittle. When the coating thickness is large, the palladium or palladium alloy coating with poor flexibility will produce large internal stress due to hydrogen absorption, internal particle unevenness and other reasons. The existence of internal stress will directly lead to cracking and warping of the coating, and even cause its adhesion to the underlying metal to deteriorate and be easily peeled off. Therefore, only by effectively reducing the internal stress of the coating can the quality of the palladium or palladium alloy coating and the stability of the manufactured electrical devices be guaranteed.

[0004] However, little is known about the mechanism of internal stress generation, and there are only a handful of studies on stress agents for palladium or palladium alloy electroplating. Only a few foreign patents mention stress regulation in palladium or palladium alloy electroplating. For example, JP6663335B2 mentions that the internal stress of palladium-nickel coating can be affected by adjusting the nickel salt concentration in the plating solution, and sodium benzenesulfonate, sodium chromate, and benzoic acid have a regulating effect on stress. US8900436B2 mentions that iminodisuccinic acid, aminosulfonic acid, and sodium saccharin can be used as reagents to reduce the internal stress of palladium or palladium alloys. Considering that the stress regulation effect of the same stress agent in different plating solutions generally varies greatly, the number of available stress agents is too small to meet the diverse manufacturing needs of thick palladium and thick palladium alloy coatings. The development of stress agents is crucial to expanding the application range of palladium or palladium alloys and reducing the manufacturing cost of coatings. Summary of the invention

[0005] The invention provides a stress regulator for palladium or palladium alloy coating and application thereof, so as to solve the problem that the stress regulating effect of the current stress regulator is insufficient, especially the problem that the stress of the coating is too high when the palladium or palladium alloy coating is thick.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: the stress regulator for palladium or palladium alloy plating is composed of component A and component B, the component A is selected from inorganic salts with reducing properties, and the component B is selected from the compound shown in molecular formula I;

[0007]

[0008] wherein A1, A2, A3, A4 and A5 are each independently selected from -H, -CH=CH2, -COCH3, -CHO, -COOM2 or -SO3M3;

[0009] The M1, M2 and M3 are each independently selected from hydrogen ions or metal ions.

[0010] Optionally, the A component is selected from one or more of phosphites, hypophosphites, metaphosphates, nitrites, sulfites and selenites.

[0011] Optionally, the metal ion is a sodium ion, a potassium ion, a magnesium ion or a calcium ion.

[0012] Optionally, the compound of formula I is or its salts, or its salts, or its salts, 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.

[0013] Optionally, the ratio of component A to component B of the stress regulator for palladium or palladium alloy plating is (0.05-20):1, preferably (0.1-10):1, in parts by weight.

[0014] Optionally, the palladium or palladium alloy coating has a thickness of 0.01-50 μm.

[0015] The present invention also provides a palladium or palladium alloy electroplating solution, which comprises the stress regulator for palladium or palladium alloy plating.

[0016] Optionally, the concentration of the stress regulator is 0.1 to 50 g / L, preferably 0.2 to 30 g / L, and more preferably 0.5 to 10 g / L.

[0017] Optionally, the metal deposited in the palladium alloy in alloy form with palladium is selected from one or more of nickel, cobalt, iron, copper, indium, gold, silver and tin, preferably nickel and / or cobalt.

[0018] Optionally, the metal other than palladium in the palladium alloy electroplating solution exists in the plating solution in the form of its soluble salt, and the soluble salt is selected from one or more of halogen salts, sulfates, nitrates, carbonates, hydroxides, oxides, phosphates, aminosulfonates, pyrophosphates, oxalates, acetates and alkyl sulfonates.

[0019] Optionally, the concentration of the alloy metal salt in the palladium alloy electroplating solution is 1-100 g / L, preferably 2-60 g / L, more preferably 4-20 g / L.

[0020] Optionally, the metallic palladium in the palladium or palladium alloy electroplating solution exists in the form of a palladium salt, and 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, ammonia palladium nitrite, ammonia palladium nitrate and diamminepalladium oxalate.

[0021] Optionally, the concentration of the palladium salt in the palladium or palladium alloy electroplating solution is in the range of 2-250 g / L, preferably 4-100 g / L, and more preferably 10-40 g / L.

[0022] Optionally, the palladium alloy electroplating solution further includes a complexing agent, and the complexing agent is selected from one or more of formates, acetates, propionates, aminosulfonates, aminoacetates, citrates, acrylates, tartrates and malates.

[0023] Optionally, the concentration of the complexing agent ranges from 1 to 500 g / L, preferably from 10 to 300 g / L, and more preferably from 20 to 100 g / L.

[0024] The technical solution provided by the present invention has an obvious stress regulating effect on palladium and palladium alloy coatings, and the prepared coatings are free of warping, especially when the coatings are thicker, and are also free of warping and cracks. DETAILED DESCRIPTION

[0025] For ease of understanding, the stress regulator for palladium or palladium alloy plating and its 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. The technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0026] Unless otherwise specified, the reagents used in this example are all commercially available conventional products.

[0027] Example 1-9 Preparation of plating solution

[0028] In this embodiment, the method of preparing 1L of electroplating solution is taken as an example:

[0029] 1) Weigh the required palladium salt, alloy metal salt, complexing agent and stress agent according to the ratio;

[0030] 2) Dissolve in deionized water and stir until clear;

[0031] 3) The volume was adjusted to 1 L to obtain the plating solution.

[0032] Table 1 shows the selection of components and specific usage amounts for preparing 1L of electroplating solution in Examples 1-9.

[0033]

[0034]

[0035] Comparative Examples 1-5

[0036] The difference from the embodiment is mainly in the composition of the plating solution. Table 2 shows the selection of components and specific usage amounts of 1L of plating solution in the comparative example.

[0037] Table 2

[0038]

[0039]

[0040] Performance Experiment

[0041] The plating solutions prepared in Examples 1-9 and Comparative Examples 1-5 were subjected to stress testing experiments: the anode was a platinum-titanium plate, and the 1194UDF test piece produced by SPECIALTY TESTING&DEVELOPMENT COMPANY was used to perform stress analysis on the coating. The test piece was cleaned with a mild non-alkaline detergent before use, 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. Stirring with a magnetic bar, the plating solution temperature was 40-50°C, the current density was 1ASD, the stress bar opening angle was measured, and the stress value was calculated based on the coating thickness.

[0042] A 5 mm × 20 mm, 0.1 mm thick copper sheet was used as the cathode, and a thick palladium or palladium alloy coating was prepared using the plating solution prepared in Examples 1-9 and the plating solution prepared in Comparative Examples 1-5, with magnetic stirring, a plating temperature of 40-50° C., a current density of 1 ASD, and an electroplating time of 3 hours. After electroplating, the thin copper sheet was removed, and the palladium or palladium alloy coating was checked under a microscope for cracking, and the distance between the highest and lowest points of the warping was measured using the focus of the microscope.

[0043] Test results: as shown in Table 3.

[0044] Table 3

[0045]

[0046]

[0047] According to Table 3, it can be found that the coating stress of Examples 1 to 9 is between -15Mpa and 18Mpa, among which, the coating stress of Examples 1, 5, and 7 is 0 under the test conditions. In Comparative Examples 1-5, when the stress regulator contains only component A (Comparative Example 5) or only component B (Comparative Example 1 and Comparative Example 4), or component A is combined with other stress regulators (Comparative Example 2), or component B is combined with other stress regulators (Comparative Example 4), the coating stress is greater than 60MPa. This shows that the stress regulator scheme proposed in the present invention has a very outstanding stress regulating effect on palladium and palladium alloy coatings.

[0048] 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 stress regulator for palladium or palladium alloy plating, characterized in that: It consists of component A and component B, wherein the component A is selected from inorganic salts with reducing properties, and the component B is selected from the compound shown in molecular formula I; wherein A1, A2, A3, A4 and A5 are each independently selected from -H, -CH=CH2, -COCH3, -CHO, -COOM2 or -SO3M3; The M1, M2 and M3 are each independently selected from hydrogen ions or metal ions.

2. The stress regulator for palladium or palladium alloy plating according to claim 1, characterized in that: The component A is selected from one or more of phosphites, hypophosphites, metaphosphates, nitrites, sulfites and selenites.

3. The stress regulator for palladium or palladium alloy plating according to claim 1, characterized in that: The metal ion is a sodium ion, a potassium ion, a magnesium ion or a calcium ion.

4. The stress regulator for palladium or palladium alloy plating according to claim 1, characterized in that: The compound of formula I is or its salts, or its salts, or its salts, 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.

5. The stress regulator for palladium or palladium alloy plating according to claim 1, characterized in that: The stress regulator for palladium or palladium alloy plating has a weight ratio of component A to component B of (0.05-20):1, preferably (0.1-10):

1.

6. The stress regulator for palladium or palladium alloy plating according to claim 1, characterized in that: The thickness of the palladium or palladium alloy coating is 0.01-50 μm.

7. A palladium or palladium alloy electroplating solution, characterized in that: The invention comprises the stress regulator for palladium or palladium alloy plating as claimed in any one of claims 1 to 6.

8. The palladium or palladium alloy electroplating solution according to claim 7, characterized in that: The concentration of the stress regulator is 0.1 to 50 g / L, preferably 0.2 to 30 g / L, and more preferably 0.5 to 10 g / L.

9. The palladium or palladium alloy electroplating solution according to claim 7, characterized in that: The concentration of the palladium salt in the palladium or palladium alloy electroplating solution is in the range of 2-250 g / L, preferably 4-100 g / L, and more preferably 10-40 g / L.

10. The palladium or palladium alloy electroplating solution according to claim 7, characterized in that: The metal palladium in the palladium or palladium alloy electroplating solution exists in the form of palladium salt, and 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, ammonia palladium nitrite, ammonia palladium nitrate and diamminepalladium oxalate.

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