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CN-122000719-A - Corrosion-resistant terminal and manufacturing method thereof

CN122000719ACN 122000719 ACN122000719 ACN 122000719ACN-122000719-A

Abstract

The invention provides a corrosion-resistant terminal and a manufacturing method thereof, and belongs to the technical field of electric connectors. The invention ensures that a plating system forms a synergistic effect in structure and function by arranging the copper-based porous anchoring layer and the nickel-phosphorus compact barrier layer between the copper alloy matrix and the outer contact layer. The copper-based multi-Kong Maogu layer has the advantages that the mechanical bonding strength between the coating and the matrix is improved through the controlled micropore structure, the interfacial stress concentration caused by thermal circulation and mechanical load is relieved, so that the cracking and stripping risks of the coating are reduced, the nickel-phosphorus compact barrier layer has excellent compactness and barrier property, the penetration of corrosive media to the matrix along micro defects is effectively inhibited, the corrosion occurrence probability is remarkably reduced, the non-penetrating pore structure of the copper-based composite porous anchoring layer avoids the rapid penetration of the corrosive media, and the synergistic effect of the two layers of structures remarkably reduces the occurrence risks of pitting corrosion and corrosion under the interface.

Inventors

  • YANG CHUANLIANG
  • WANG JIACHENG

Assignees

  • 合肥仁邦电子科技有限公司

Dates

Publication Date
20260508
Application Date
20260306

Claims (10)

  1. 1. The corrosion-resistant terminal is characterized by comprising a base body formed by copper alloy, wherein a copper-based Kong Maogu layer, a nickel-phosphorus compact barrier layer and a noble metal contact layer are sequentially arranged on the surface of the base body from inside to outside; Wherein, micropores taking non-through holes or low communication holes as main parts are arranged in the copper-based Kong Maogu layers, the microporosity is 3-6%, the micropore communication rate is less than or equal to 5%, the porosity of the nickel-phosphorus compact barrier layer is less than or equal to 0.5%, and the pinhole rate is less than or equal to 0.3 pinholes/cm 2 .
  2. 2. The corrosion resistant terminal of claim 1, wherein the copper-based Kong Maogu layer has a thickness of 5-15 μm, the nickel-phosphorus dense barrier layer has a thickness of 8-20 μm, the noble metal contact layer is a gold layer or a silver layer, the gold layer has a thickness of 0.3-1.0 μm, and the silver layer has a thickness of 1.0-3.0 μm.
  3. 3. The corrosion resistant terminal of claim 1, wherein the plating bond of the terminal meets a cross-hatch test of 4B or more and a contact resistance of 5mΩ or less.
  4. 4. A method of manufacturing the corrosion-resistant terminal according to any one of claims 1 to 3, comprising the steps of: s1, preprocessing the surface of a substrate; S2, depositing a copper-based multi-Kong Maogu layer on the surface of the pretreated substrate in a composite electrodeposition mode, introducing copper-tin alloy powder into an electrodeposition liquid in the composite electrodeposition process, and performing deposition by matching with pulse current or pulse reversal current to form micropores with a non-through hole or low communication hole structure in the copper-based multi-Kong Maogu layer; s3, depositing a nickel-phosphorus compact barrier layer on the surface of the copper-based Kong Maogu layer by adopting an electroless plating process; s4, depositing a gold layer or a silver layer on the surface of the nickel-phosphorus compact barrier layer in an electroplating mode to form a noble metal contact layer.
  5. 5. The method according to claim 4, wherein the pretreatment comprises degreasing and cleaning, removing oxide film, and activating the surface of the substrate in this order in step S1.
  6. 6. The method according to claim 4, wherein in the step S2, the electrodeposition liquid contains 200-250g/L of copper sulfate, 50-80g/L of sulfuric acid, 50-100mg/L of chloride ions, and 1-3mL/L of brightening agent, the concentration of the copper-tin alloy powder in the electrodeposition liquid is 8-15g/L, and the tin content in the copper-tin alloy powder is 10% -15%.
  7. 7. The method according to claim 4, wherein the pulse current has a current density of 1-3A/dm 2 , a pulse frequency of 500-2000Hz, a duty cycle of 30-60%, a deposition temperature of 25-40 ℃ and a deposition time of 15-40min; The pulse reverse current parameters are that the forward current density is 2-4A/dm 2 , the reverse current density is 0.5-1A/dm 2 , the pulse frequency is 500-1000Hz, the duty ratio is 30-50%, the reverse period is 5-10s, the deposition temperature is 25-35 ℃, and the deposition time is 15-30min.
  8. 8. The method according to claim 4, wherein in step S3, the electroless plating solution comprises 20-30g/L of nickel sulfate, 30-40g/L of sodium hypophosphite, 15-25g/L of sodium citrate, 10-15g/L of sodium acetate, and 0.5-1mg/L of stabilizer (thiourea).
  9. 9. The method according to claim 4, wherein the electroless plating is performed at a plating solution temperature of 85-90deg.C and a pH of 4.8-5.2 for a deposition time of 20-40min with continuous stirring, and after the deposition, the solution is rinsed 3 times with deionized water and incubated at 120-150deg.C for 30min.
  10. 10. The method according to claim 4, wherein in step S4, when the gold layer is deposited, an electroplating process is adopted, the plating solution system is a sulfite system, and the composition comprises 2-5g/L of potassium aurous cyanide, 50-80g/L of sodium sulfite, 20-30g/L of trisodium citrate, 0.5-1A/dm 2 of current density, 40-50 ℃ of temperature and 5-15min of deposition time are adopted, so that a soft gold layer with the thickness of 0.3-1.0 μm is obtained; When the silver layer is deposited, adopting an electroless plating process, wherein a plating solution system is a thiosulfate system, and the silver layer with the thickness of 1.0-3.0 mu m is obtained by adopting the composition of 10-15g/L of silver nitrate, 80-120g/L of sodium thiosulfate, 5-10mL/L of ammonia water, 0.1-0.3g/L of stabilizer, 1-2A/dm 2 of current density, 25-35 ℃ and 10-30min of deposition time.

Description

Corrosion-resistant terminal and manufacturing method thereof Technical Field The invention relates to the technical field of electric connectors, in particular to a corrosion-resistant terminal and a manufacturing method thereof. Background The terminal used as a precise electric conductive part is widely applied to the fields of electronic equipment, automobiles, aerospace and the like, and the performance of the terminal directly influences the reliability and stability of electric connection. At present, the terminal type electric connection member generally uses copper or copper alloy as a base material, because the copper alloy has excellent conductivity and mechanical strength, and can meet the dual requirements of electric transmission and structural support. In the actual service process, the terminal is exposed to a complex environment for a long time, and is easy to face serious corrosion problems. Under the working conditions of a humid environment and a corrosive medium, the copper alloy matrix is easy to generate oxidation reaction to form an oxide layer, and meanwhile, local corrosion phenomena such as pitting corrosion, crevice corrosion and the like can also occur, and can lead to the contact resistance of the terminal to be obviously increased, and even lead to electrical connection failure in serious cases. At present, in order to improve the corrosion resistance of the terminal, the prior art often pursues to improve the compactness of a plating layer, but the mode is difficult to achieve the corrosion resistance, the interface bonding reliability and the long-term service stability. If the density of the coating is reduced for relieving the stress, the corrosion medium cannot be effectively blocked, and the corrosion resistance is difficult to meet the requirement. Therefore, there is a need to develop a novel terminal that effectively improves the corrosion resistance and structural reliability of the terminal without sacrificing the electrical conductivity and the contact performance. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide a corrosion-resistant terminal, which realizes the cooperative improvement of corrosion resistance, interface bonding reliability and electrical contact performance by constructing a multi-layer composite plating structure, and is used for solving the problems of easy corrosion and easy peeling of the plating layer in the prior art under complex working conditions, and simultaneously, the present invention also provides a manufacturing method of the corrosion-resistant terminal. To achieve the above and other related objects, the present invention provides the following technical solutions: In a first aspect of the invention, a corrosion-resistant terminal is provided, comprising a base body formed by copper alloy, wherein the surface of the base body is sequentially provided with a copper-based Kong Maogu layer, a nickel-phosphorus compact barrier layer and a noble metal contact layer from inside to outside. Further, the base body is made of brass, red copper or tin bronze, and is preferably made of C1100 red copper or QSn6.5-0.1 tin bronze. Furthermore, the surface roughness of the substrate needs to be controlled to be Ra0.1-0.3 mu m so as to ensure the bonding effect of the subsequent coating. Furthermore, the copper-based Kong Maogu layer is formed on the surface of the copper alloy terminal substrate through composite electrodeposition, and the inside of the copper-based Kong Maogu layer is provided with a micropore structure which is distributed in a controlled manner, and micropores are mainly non-through holes (blind holes) or low communication holes. Furthermore, the thickness of the copper-based Kong Maogu layer is 5-15 mu m, the microporosity is 3% -6%, and the micropore communication rate is less than or equal to 5%. If the microporosity is less than 3%, the mechanical interlocking effect with the nickel-phosphorus layer cannot be ensured, and if the microporosity is more than 6%, the strength of the anchoring layer is reduced, and the pores are easily filled with corrosive media. Wherein the microporosity refers to the percentage of the area of the holes of the copper-based Kong Maogu layer in the metallographic section to the area of the section of the anchoring layer. Preferably, a metallographic section is prepared by taking a terminal sample along the thickness direction of a coating, after embedding, grinding and polishing, at least 5 view fields are randomly selected under a 500-2000 times microscope or scanning electron microscope, binarization image segmentation is carried out on a hole area, the area fraction is calculated, and the average value is taken as the microporosity. The micropore communication rate refers to the percentage of the area of the holes capable of forming communication channels to the total area of the holes in the sectional image, wherein th