A gold plating contact cleaner and method of use

Abstract

The application provides a gold-plated polished contact cleaning agent and a use method thereof, and the cleaning agent comprises the following components in percentage by mass: C3-C6 dihydric alcohol ether modified alcohol solvent 60-75%; non-ionic surfactant with HLB 10-12 and sulfonation degree <10 ppm 0.5-2%; EDTA-2Na chelating agent with chloride ion ≤5 ppm 0.1-0.3%; benzotriazole corrosion inhibitor with sulfur content ≤3 ppm 0.05-0.2%; and the balance is 18 MΩ.cm electronic grade deionized water. The gold-plated polished contact cleaning agent has the advantages of low conductivity, zero corrosion to the gold-plated layer, and less ion residues, and can meet the requirement of high reliability of the precision contact. The conductivity of the 10% diluent of the gold-plated polished contact cleaning agent is ≤30 muS / cm at 25 DEG C, which is reduced by more than 40% compared with the commercially available neutral cleaning agent.

Description

Technical Field

[0001] This invention relates to the field of surface cleaning technology for precision electronic components, specifically to a gold-plated polishing contact cleaning agent and its application method. Background Technology

[0002] Riveted electrical contact materials are widely used in various relays, circuit breakers, contactors, and temperature controllers, and are crucial core components affecting the reliability of switching electrical contact systems. Existing acidic or alkaline cleaning agents easily leave residual ions on the gold plating surface, leading to increased conductivity, contact resistance drift, and even pitting corrosion. Commercially available neutral cleaning agents are mostly designed for stainless steel / plastic casings and lack quantitative verification of "gold plating weight loss and contact resistance ΔR"; conductivity indicators are generally missing. Patents such as CN105525318A and CN222778505U only provide the structure of the polishing solution or cleaning device before electroplating, failing to address the technical requirement of "conductivity ≤30 μS / cm and ΔR ≤0.5 mΩ after final cleaning." Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and provide a fast-drying gold-plated polishing contact cleaner with a working fluid conductivity ≤30 μS / cm (25 °C), zero corrosion to the gold plating layer, contact resistance increment ΔR ≤0.5 mΩ after cleaning, compatibility with graphene / silver / copper substrates, and meeting the high reliability requirements of precision contacts.

[0004] The technical solution adopted in this invention is as follows: The first aspect of the present invention provides a gold-plated polishing contact cleaner, comprising, by weight percentage: C3-C6 diol ether modified alcohol solvent 60–75%; HLB 10–12, 0.5–2% of nonionic surfactants with sulfonation degree <10 ppm; EDTA-2Na chelating agent with chloride ion concentration ≤5 ppm: 0.1–0.3%; 0.05–0.2% of benzotriazole corrosion inhibitor with a sulfur content ≤3 ppm; The remainder is deionized water.

[0005] Preferably, the C3-C6 diol ether modified alcohol solvent is selected from at least one of ethylene glycol butyl ether (BCS / EB), diethylene glycol butyl ether (DB), propylene glycol methyl ether (PM), dipropylene glycol methyl ether (DPM), and dipropylene glycol butyl ether (DPNB).

[0006] Preferably, the nonionic surfactant is selected from at least one of fatty alcohol polyoxyethylene ether (AEO-9), isomeric alcohol polyoxyethylene ether (XL-90 / XL-100), and alkylphenol polyoxyethylene ether (OP-10).

[0007] Preferably, the deionized water is 18 MΩ·cm electronic grade deionized water.

[0008] A second aspect of the present invention provides a method for using a gold-plated polishing contact cleaning agent, comprising the following steps: Spray the above-mentioned cleaning agent onto the surface of the gold-plated polished contact or immerse the gold-plated polished contact in the above-mentioned cleaning agent for ultrasonic cleaning and then dry.

[0009] Preferably, the amount of cleaning agent used is 2–3 mL / 10 cm³. 2 .

[0010] Preferably, the ultrasonic cleaning frequency is 28–40 kHz.

[0011] Preferably, the ultrasonic cleaning temperature is 35–45 °C and the ultrasonic cleaning time is 60–120 s.

[0012] The beneficial effects of this invention are as follows: The gold-plated polishing contact cleaning agent provided by this invention has the advantages of low conductivity, zero corrosion to the gold plating layer, and low ion residue, which can meet the high reliability requirements of precision contacts.

[0013] Specifically, its 10% diluted solution has a conductivity of ≤30 μS / cm at 25°C, which is more than 40% lower than that of commercially available neutral cleaning agents. After cleaning, the residual ion content on the contact surface is less than 0.1 μg / cm². This ultra-low ion residual environment effectively avoids leakage current, thereby ensuring the integrity and reliability of high-frequency signal transmission. After cleaning with the cleaning agent of this invention, the contact resistance increment ΔR of the gold-plated contacts is ≤0.5 mΩ. This means that in applications such as precision relays and connectors, the contacts can maintain extremely low on-resistance without secondary adjustment, significantly improving the assembly yield and long-term service life of electronic components. The benzotriazole (BTA) corrosion inhibitor selected in the formula has undergone desulfurization treatment and, combined with a weakly alkaline alcohol ether solvent system, will not cause any chemical attack on the gold plating layer during the cleaning process. Weight loss test data showed that the gold plating layer quality remained unchanged after cleaning (weight loss was 0 mg / cm²). Furthermore, the formula exhibited excellent compatibility with the underlying silver, copper, and graphene coatings, avoiding plating peeling or increased contact resistance caused by underlying corrosion. Additionally, the cleaning agent of this invention uses C3-C6 diol ether solvents, possessing a suitable evaporation rate. Combined with ultrasonic-assisted cleaning at 35-45°C, it can be completely dried within 30 seconds. This fast-drying characteristic not only improves production efficiency but also avoids the risk of "water stains" or secondary oxidation caused by residual moisture, perfectly adapting to the automated production line operations of modern electronics manufacturing. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0015] Example 1 This embodiment provides a gold-plated polishing contact cleaning agent and its application method. The gold-plated polishing contact cleaning agent comprises, by weight percentage: C3-C6 diol ether modified alcohol solvent: 60%, HLB 10–12, nonionic surfactant with sulfonation degree <10 ppm: 0.5%, EDTA-2Na chelating agent with chloride ions ≤5 ppm: 0.1%, Benzotriazole corrosion inhibitor with sulfur content ≤3 ppm: 0.05%, The balance is 18 MΩ·cm electronic-grade deionized water.

[0016] Specifically, the diethylene glycol ether modified alcohol solvent is diethylene glycol butyl ether (DB, electronic grade from Jiangsu Tianyin Chemical Co., Ltd., metal ion content ≤10 ppb), the nonionic surfactant is fatty alcohol polyoxyethylene ether AEO-9 (HLB 12, Jiangsu Haian Petrochemical Plant, sulfonation degree <10 ppm), the EDTA-2Na chelating agent is low-chlorine grade EDTA-2Na (chloride ≤0.01%) produced by Hebei Chengxin Group and Qingdao Chuanyang Chemical Co., Ltd., and is used after recrystallization and purification with deionized water; the benzotriazole corrosion inhibitor is electronic grade benzotriazole (purity ≥99.5%) produced by Nanjing Shunhengxin Chemical Co., Ltd. and Wuhan Organic Industry Co., Ltd., which is further purified by vacuum distillation.

[0017] The method of using this gold-plated polishing contact cleaner includes the following steps: Spray the cleaner onto the surface of the rivet-type electrical contacts using a squeezing method. Cleaner dosage: 2 mL / 10 cm² 2 It also uses ultrasonic assistance, with a frequency set at 35 kHz, a temperature of 35°C, and a time of 60 seconds. After treatment, it is dried with a hair dryer for 25 seconds.

[0018] Example 2 This embodiment provides a gold-plated polishing contact cleaning agent and its application method. The gold-plated polishing contact cleaning agent comprises, by weight percentage: C3-C6 diol ether modified alcohol solvent: 75%, HLB 10–12, nonionic surfactant with sulfonation degree <10 ppm: 2%, EDTA-2Na chelating agent with chloride ion ≤5 ppm: 0.3%, Benzotriazole corrosion inhibitor with sulfur content ≤3 ppm: 0.2%, The balance is 18 MΩ·cm electronic-grade deionized water.

[0019] The specific selection of each component is the same as in Example 1.

[0020] The method of using this gold-plated polishing contact cleaner includes the following steps: Immerse the rivet-type electrical contacts in the cleaner for 2 minutes, using 3 mL / 10 cm² of the cleaner. 2 Furthermore, ultrasonic assistance was used with a frequency setting of 40 kHz, a temperature of 45 °C, and a time of 120 seconds. After treatment, the product was dried with a hair dryer for 30 seconds.

[0021] Example 3 This embodiment provides a gold-plated polishing contact cleaning agent and its application method. The gold-plated polishing contact cleaning agent comprises, by weight percentage: C3-C6 diol ether modified alcohol solvent: 68%, HLB 10–12, nonionic surfactant with sulfonation degree <10 ppm: 1.2%, EDTA-2Na chelating agent with chloride ion ≤5 ppm: 0.2%, Benzotriazole corrosion inhibitor with sulfur content ≤3 ppm: 0.1%, The balance is 18 MΩ·cm electronic-grade deionized water.

[0022] The specific selection of each component is the same as in Example 1.

[0023] The method of using this gold-plated polishing contact cleaner includes the following steps: The cleaner is sprayed onto the surface of the rivet-type electrical contacts using a squeezing method. The cleaning agent dosage is 2.5 mL / 10 cm². 2 It also uses ultrasonic assistance, with a frequency set at 32kHz, a temperature of 40°C, and a time of 90 seconds. After treatment, it is dried with a hair dryer for 28 seconds.

[0024] Comparative Example 1 This comparative example provides a conventional cleaning agent and its application method, wherein the conventional cleaning agent comprises, by weight percentage: Common alcohol solvent: 60%, Common nonionic surfactant: 0.5%, Common EDTA-2Na chelating agent: 0.1%, Ordinary benzotriazole corrosion inhibitor: 0.05%, The remainder is ordinary deionized water.

[0025] Specifically, the common alcohol solvent is ordinary ethylene glycol butyl ether (industrial grade, Guangzhou Chemical Reagent Factory); the common nonionic surfactant is ordinary nonionic surfactant (OP-10, industrial grade, Tianjin Beifang Tianpu Chemical Industry Co., Ltd., sulfonation degree not controlled); the common EDTA-2Na chelating agent is ordinary EDTA-2Na chelating agent (industrial grade, Hebei Chengxin Group Co., Ltd., chloride content approximately 0.05%, i.e., 500 ppm); and the benzotriazole corrosion inhibitor is ordinary benzotriazole corrosion inhibitor (industrial grade, Wuhan Organic Industry Co., Ltd., total sulfur content approximately 50 ppm).

[0026] The cleaning agent is used in the same way as in Example 1.

[0027] Comparative Example 2 This comparative example provides a conventional cleaning agent and its application method, wherein the conventional cleaning agent comprises, by weight percentage: Common alcohol solvent: 75%, Common nonionic surfactants: 2%, Common EDTA-2Na chelating agent: 0.3%, Common benzotriazole corrosion inhibitor: 0.2%, The remainder is ordinary deionized water.

[0028] The specific selection of each component is the same as in Comparative Example 1.

[0029] The method of using this cleaning agent is the same as in Example 2.

[0030] Comparative Example 3 This comparative example provides a conventional cleaning agent and its application method, wherein the conventional cleaning agent comprises, by weight percentage: Common alcohol solvent: 68%, Common nonionic surfactants: 1.2%, Common EDTA-2Na chelating agent: 0.2%, Common benzotriazole corrosion inhibitor: 0.1%, The remainder is ordinary deionized water.

[0031] The specific selection of each component is the same as in Comparative Example 1.

[0032] The cleaning agent is used in the same way as in Example 3.

[0033] The riveted electrical contacts cleaned using the cleaning agents and methods of Examples 1-3 and Comparative Examples 1-3 were tested, and the test methods are as follows: (1) Contact resistance increment (ΔR) test: The contact resistance of the gold-plated contacts was measured before and after cleaning using the four-probe method or micro-ohmmeter method, and the resistance increment ΔR was calculated.

[0034] (2) Conductivity test: Using a high-precision conductivity meter, the cleaning agent was diluted to a concentration of 10% and the temperature was controlled at 25°C to measure its conductivity value.

[0035] (3) Ion residue test: Ion chromatography (IC) or inductively coupled plasma mass spectrometry (ICP-MS) is used to ultrasonically treat the cleaned gold-plated contacts to dissolve the residual ions, inject them into the instrument to detect the ion concentration, and calculate the amount of ion residue per unit area.

[0036] (4) Weight loss test of gold plating layer: Using a high-precision electronic balance, weigh the mass of the gold plating contacts before and after cleaning, and calculate the mass difference as the weight loss of the gold plating layer.

[0037] (5) Drying time test: Use a stopwatch or high-precision timer to start timing from the moment the air drying begins until the gold-plated contact surface is completely dry and there is no liquid residue, and record the drying time.

[0038] (6) Cleaning effect verification: Visually inspect the surface of the gold-plated contacts for any residues or corrosion, and combine this with contact resistance testing to ensure that the contact resistance increment ΔR after cleaning meets the requirements.

[0039] The test results are as follows: Table 1 Test data of Examples 1-3 and Comparative Examples 1-3 The experimental data from the comparative examples show that the cleaning agent of the present invention is superior to the comparative example in terms of increased contact resistance of gold-plated contacts after cleaning, conductivity of the 10% diluted solution, ion residue, and weight loss of the gold plating layer. This indicates that the cleaning agent of the present invention has advantages such as low conductivity, zero corrosion to the gold plating layer, and low ion residue, which can meet the high reliability requirements of precision contacts.

[0040] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A cleaning agent for gold-plated polishing contacts, characterized in that, Included by mass percentage: C3-C6 diol ether modified alcohol solvent 60–75%; HLB 10–12, 0.5–2% of nonionic surfactants with sulfonation degree <10 ppm; EDTA-2Na chelating agent with chloride ion concentration ≤5 ppm: 0.1–0.3%; 0.05–0.2% of benzotriazole corrosion inhibitor with a sulfur content ≤3 ppm; The remainder is deionized water.

2. The gold-plated polishing contact cleaning agent according to claim 1, characterized in that: The C3-C6 diol ether modified alcohol solvent is selected from at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, and dipropylene glycol butyl ether.

3. The gold-plated polishing contact cleaning agent according to claim 1, characterized in that: The nonionic surfactant is selected from at least one of fatty alcohol polyoxyethylene ether, isomeric alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

4. The gold-plated polishing contact cleaning agent according to claim 1, characterized in that: The deionized water is 18 MΩ·cm electronic grade deionized water.

5. A method of using a gold-plated polishing contact cleaning agent, characterized in that, Includes the following steps: The cleaning agent according to any one of claims 1-4 is sprayed onto the surface of the gold-plated polished contact or the gold-plated polished contact is immersed in the cleaning agent according to any one of claims 1-4, ultrasonically cleaned, and then dried.

6. The method of using the gold-plated polishing contact cleaning agent according to claim 5, characterized in that: The cleaning agent dosage is 2–3 mL / 10 cm². 2 .

7. The method of using the gold-plated polishing contact cleaning agent according to claim 5, characterized in that: The ultrasonic cleaning frequency is 28–40 kHz.

8. The method of using the gold-plated polishing contact cleaning agent according to claim 5, characterized in that: The ultrasonic cleaning temperature is 35–45 °C, and the ultrasonic cleaning time is 60–120 s.

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