Local hard gold plating method of multi-core copper lead connector and connector

Abstract

The invention provides a local hard gold plating method for a multi-core copper lead connector and the connector, and belongs to the technical field of electronic packaging and surface treatment.The local hard gold plating method for the multi-core copper lead connector comprises the following steps that a sealing core and a patch plug in the connector are electrically connected into an electroplating hanger; the whole electroplating hanger connected with the connector is soaked in chemical oil removal liquid to be subjected to oil removal treatment; the connector after oil removal is wholly soaked in an acid solution for anode activation treatment, and the sealing core and the patch plug are both powered on; the connector after anode activation is soaked in a nickel plating solution; the plug and the sealing core are used for shunt conduction during electroplating, so that a nickel-plated layer of the sealing core is oxidized to a certain extent, the standard electrode potential of the surface of the nickel layer is improved, the nickel layer is prevented from being subjected to a replacement reaction with a gold solution, the surface of the prepared sealing core is the nickel layer, the surface of the plug is the gold layer, and local hard gold plating treatment of the connector is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic packaging and its surface treatment, and particularly relates to a method for locally plating hard gold on a multi-core copper lead connector and a connector. Background Art

[0002] With the development of aerospace technology, the deep space exploration project with a deeper and broader journey has become a new research direction for space activities. The deep space exploration system has put forward higher performance index requirements for detectors. The metal shell of the multi-core copper lead feedthrough structure (connector), as a key component of the detector, has the characteristics of low resistance, light weight, high integration, high reliability, etc., representing the development direction of the shell technology. The surface treatment and plating layer of the multi-core copper lead feedthrough structure (connector) have relatively high requirements. The plating layers on the surfaces of the multi-core copper lead and the sealing core need to have high protection performance to meet the corrosion resistance requirements. And usually, no gold plating layer is applied on the surface of the sealing core. The reasons are as follows: First, the sealing core is usually laser welded to the shell to ensure reliability. If the surface of the sealing core is gold plated, in the high-temperature environment of laser welding, gold is easily vaporized, and the gold vapor will form around the molten pool to interfere with the energy transfer and protective atmosphere during the welding process, resulting in a decrease in welding quality and affecting reliability. Second, gold undergoes an alloying reaction with the base metal during the laser welding process. This unexpected alloying changes the chemical composition of the welded joint and affects key performance indicators such as the mechanical properties and corrosion resistance of the joint. Third, gold is a precious metal. Especially now, the price of gold is soaring and is at a historical high value. Reducing the use of gold can greatly reduce the production cost.

[0003] Currently, there are several common methods for local gold plating in the field of electronic packaging: (1) Shielding method: For the parts that do not need to be gold plated, use shielding tooling, protective glue or tape, etc. to cover the parts that do not need to be gold plated. The method of using shielding tooling requires separate manufacturing of tooling appliances, and the fixtures for each model product are dedicated, resulting in a large amount of unnecessary waste; using methods such as protective glue and tape has problems of cumbersome process and poor environmental protection; (2) Removal method: Gold plate all parts of the product, and then remove the parts that do not need to be gold plated, such as removing by machining, soaking in a gold stripping solution after covering the area that needs gold, etc. This method not only causes waste of gold plating, but also increases many subsequent works. The production process is uncontrollable, increasing the risk of instability; (3) Adding additives to the gold plating solution: That is, adding an anti-displacement reagent to the electroplating gold solution to avoid the deposition of the gold layer in the areas that do not need to be gold plated. This method has many drawbacks: First, it is difficult to find a suitable special anti-displacement agent, and there are few reports in domestic and foreign patents; second, the gold plating solution system is relatively stable. Adding a reactive additive will cause the stability of the gold plating solution to deteriorate, and the reliability of the production process is difficult to control. If the addition is not properly controlled during continued replenishment, it will lead to the imbalance or even scrapping of the gold plating solution, resulting in a huge waste of production cost. Summary of the Invention

[0004] The present invention provides a method for locally electroplating hard gold on a multi-core copper lead connector and a connector. The sealing core of the connector prepared by the method of the present invention does not contain a gold layer, which meets the requirements of common laser welding of the connector and has high-reliability performance at the same time.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions: A method for locally electroplating hard gold on a multi-core copper lead connector, the method for locally electroplating hard gold comprising the following steps: The sealing core and the plug in the connector are respectively electrically connected to an electroplating fixture. The N point of the hook head in the electroplating fixture is connected to the plug, and the M point of the hook head is connected to the sealing core; The electroplating fixture connected with the connector is integrally immersed in a chemical degreasing solution for degreasing treatment; The connector after degreasing is integrally immersed in an acidic solution for anodic activation treatment, wherein both the sealing core and the plug are energized; The connector after anodic activation is immersed in a nickel plating solution, and both the sealing core and the plug are energized for overall nickel plating; The connector after nickel plating is integrally immersed in an anodic degreasing solution. The sealing core is energized and the plug is de-energized for anodic degreasing treatment of the nickel plating layer on the surface of the sealing core; The connector after anodic degreasing is immersed in an electroplating hard gold solution. The sealing core is de-energized and the plug is energized for hard gold plating treatment on the surface of the plug; The connector after local electroplating of hard gold is integrally immersed in a pickling solution for pickling treatment on the surface of the sealing core.

[0006] Preferably, the electroplating fixture includes two independently distributed conductive rods, an insulating rod arranged between the conductive rods, and mounting points arranged at the ends of the conductive rods. The mounting points are not electrically connected and are used for electrically connecting to the sealing core and the plug respectively.

[0007] Preferably, in the degreasing treatment step, the temperature of the degreasing solution is 80-90°C, the pH value is 14, and the immersion time of the connector is 10-30 min; The degreasing solution includes sodium hydroxide with a concentration of 50-80 g / L, sodium carbonate with a concentration of 20-50 g / L, trisodium phosphate with a concentration of 20-50 g / L, sodium silicate with a concentration of 5-30 g / L, and a surfactant with a concentration of 1-10 ml / L. Among them, the surfactant is one or several of sodium dodecylbenzenesulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

[0008] Preferably, in the anodic activation treatment step, both the sealing core and the plug are electrically connected to the positive pole of the power supply and are immersed in an acidic solution; the anodic current density is 1-20 A / dm2, and the anodic activation time is 0.5-5 min; Among them, the temperature of the acidic solution is room temperature, and the acidic solution is at least one of sulfuric acid at 10-40 ml / L, benzotriazole at 0.1-0.3 g / L, methylbenzotriazole at 0.1-0.5 g / L, aminotrimethylene phosphonic acid at 0.1-0.5 g / L, and hydroxyethylidene diphosphonic acid at 0.1-0.5 g / L.

[0009] Preferably, in the overall nickel plating step, both the sealing core and the connector are electrically connected to the negative electrode of the power supply. The nickel plating solution is nickel sulfamate, the solution temperature is 35-65°C, the pH value is 3.0-5.0, the nickel plating time is 20-50 min, and the cathode current density is set to 0.8-5 A / dm2; Among them, the nickel sulfamate solution contains: 250-500 g / L of nickel sulfamate, 5-50 g / L of nickel chloride, 20-60 g / L of boric acid, and the balance is deionized water.

[0010] Preferably, the anodic degreasing treatment includes the following steps: The mounting point M connected to the sealing core is connected to the positive electrode of the power supply, and the mounting point N connected to the connector is disconnected from the electrical connection; The negative electrode of the power supply is connected through a wire and placed in the anodic degreasing solution; Turn on the power supply, the sealing core is energized with the anode of the power supply, the anodic current density is set to 1-5 A / dm 2 , the anodic degreasing time is 0.5-5 min, and an electrochemical anodic activation occurs on the surface of the sealing core to form an oxide layer; Among them, the solution temperature of the anodic degreasing solution is 50-80°C, and the anodic degreasing solution contains: 50-80 g / L of sodium hydroxide, 20-50 g / L of sodium carbonate, 5-30 g / L of sodium silicate, and the balance is deionized water.

[0011] Preferably, the hard gold plating treatment includes the following steps: The mounting point N connected to the connector is connected to the negative electrode of the power supply, and the mounting point M connected to the sealing core is disconnected from the electrical connection; The positive electrode of the power supply is connected through a wire and placed in the hard gold solution; Turn on the power supply, the connector is energized with the cathode of the power supply, the cathode current density is set to 0.15-2 A / dm 2 , the gold plating time is 4-12 min, and cathodic electrochemical deposition of anions occurs on the surface of the connector to form a hard gold layer. Among them, the solution temperature of the hard gold solution is 50-80°C, the pH value is 3-5, and the electroplated hard gold solution is: 2-15 g / L of potassium gold cyanide, 20-90 g / L of citric acid, 30-100 g / L of potassium citrate, 0.5-5 g / L of cobalt sulfate, and the balance is deionized water.

[0012] Preferably, in the pickling treatment step, the connector after partial hard gold plating is immersed as a whole in a pickling solution, and is rinsed by swinging. The temperature of the pickling solution is at room temperature, the pH value is 3-5, and the pickling time is 1-5 minutes; Among them, the pickling solution is at least one of 50-200 g / L of sulfamic acid, 0.05-0.2 g / L of benzotriazole, and 0.05-0.2 g / L of methylbenzotriazole.

[0013] A connector is prepared by using the method for partial hard gold plating of the multi-core copper lead connector described above. The connector includes a sealing core, an insulator, and a plug.

[0014] From the above technical solutions, it can be seen that the present invention has the following beneficial effects: 1. In the present invention, it includes steps such as degreasing, anodic activation, nickel plating, anodic degreasing, partial hard gold plating, pickling, etc. During anodic degreasing and partial hard gold plating, the sealing core and the plug are used for shunt conduction. In this way, during anodic degreasing, the nickel plating layer on the sealing core can be oxidized to a certain extent, improving the standard electrode potential on the surface of the nickel layer, thereby preventing it from undergoing a displacement reaction with the gold solution during partial hard gold plating. In this way, the surface of the prepared sealing core is a nickel layer, and the surface of the plug is a gold layer, so as to achieve the purpose of partial hard gold plating treatment of the connector. In this way, the sealing core of the connector prepared by the method of the present invention does not contain a gold layer, meeting the requirements of common laser welding of the connector, and at the same time having high-reliability performance; in addition, the preparation process of the method for partial hard gold plating of the connector provided by the present invention is simple and environmentally friendly, greatly reducing the production and manufacturing cost, and having broad application prospects.

[0015] 2. In the present invention, the electroplating fixture includes a conductive rod and an insulating rod. The conductive rod is in a form of two independent distributions, and the conductive rod is used for electrically connecting with the sealing core and the plug. The insulating rod is arranged between the conductive rods, and at the same time, a mounting point is provided at the end of the conductive rod, and the mounting points are not electrically connected and conducted. In this way, the mounting points can be used to achieve electrical connection with the sealing core and the plug respectively, meeting the purpose of shunt conduction, so as to facilitate the smooth progress of the anodic degreasing and hard gold plating processes. Description of the Drawings

[0016] Figure 1 is a flowchart of the method for partial hard gold plating of the multi-core copper lead connector provided by the present invention; Figure 2 is a schematic structural diagram of the connector provided by the present invention; Figure 3 is a schematic structural diagram of the connector housing provided by the present invention; Figure 4 is a schematic structural diagram of the electroplating fixture.

[0017] In the figure: 10, sealing core; 20, insulator; 30, connector plug; 310, female head; 320, solid cylinder; 410, conductive rod; 420, insulating rod; 430, mounting point. Detailed implementation manners

[0018] The following is a detailed description of a preferred implementation manner of the present invention with reference to the accompanying drawings.

[0019] To achieve the above object, the embodiments of the present invention adopt the following technical solutions: Refer to Figure 1 , Figure 2 , a method for locally plating hard gold on a multi-core copper lead connector, the local hard gold plating method comprising the following steps: S10: Mounting: Electrically connect the sealing core and the connector plug in the connector to the electroplating fixture respectively.

[0020] Specifically, mount the connector using a "two-way conductive fixture", that is, electrically connect the sealing core and the connector plug to the electroplating fixture respectively. Specifically, the N point of the hook head in the electroplating fixture is connected to the connector plug, and the M point of the hook head is connected to the sealing core, so as to realize the electrical connection of the two hook heads in the fixture. This facilitates the separate energized connection of the sealing core or the connector plug during the electroplating process.

[0021] S20: Degreasing: Immerse the mounted connector as a whole in a chemical degreasing solution.

[0022] Specifically, immerse the mounted connector as a whole in a chemical degreasing solution to remove foreign matters such as oil stains, dirt, and dust on the surface, and clean and purify all surfaces of the connector.

[0023] S30: Anodic activation: Immerse the degreased connector as a whole in an acidic solution, wherein both the sealing core and the connector plug are energized.

[0024] Specifically, immerse the degreased and cleaned connector in an acidic solution, and energize both the sealing core and the connector plug to remove oxides or complex compounds formed on the surface of the metal material during sealing, so as to expose the fresh base material, facilitate the subsequent deposition of the electroplating layer, and improve the adhesion of the plating layer.

[0025] S40: Nickel plating: Immerse the anodically activated connector in a nickel plating solution, and energize both the sealing core and the connector plug for overall nickel plating.

[0026] Specifically, energize both the sealing core and the connector plug in the anodically activated connector for overall nickel plating to deposit an electroplated nickel layer.

[0027] S50: Anodic degreasing: Immerse the nickel-plated connector as a whole in an anodic degreasing solution, energize the sealing core, and cut off the power supply of the connector plug to perform anodic degreasing treatment on the nickel plating layer on the surface of the sealing core.

[0028] Specifically, the nickel-plated connector as a whole is immersed in an anodic degreasing solution. At this time, the plug is powered off and the sealing core is powered on to perform anodic degreasing on the nickel-plated layer on the surface of the sealing core to form an oxide layer to a certain extent.

[0029] S60: Local hard gold plating: Immerse the connector after anodic degreasing in an electroplating hard gold solution. The sealing core is powered off and the plug is powered on to perform hard gold plating on the surface of the plug.

[0030] Specifically, power off the sealing core in the connector after anodic degreasing and power on the plug to perform hard gold plating on the surface of the plug and deposit a hard gold layer. At this time, the sealing core is only immersed in the electroplating hard gold solution, and the nickel on its surface is prevented from undergoing a displacement reaction with gold ions due to the oxide layer.

[0031] S70: Pickling: Immerse the connector after local hard gold plating as a whole in a pickling solution to perform pickling treatment on the surface of the sealing core.

[0032] Specifically, immerse the connector after local hard gold plating as a whole in a pickling solution to clean and remove a certain extent of the oxide layer on the surface of the nickel layer of the sealing core to obtain a fresh nickel layer, and finally obtain a connector with a nickel layer on the surface of the sealing core and a hard gold layer on the surface of the plug.

[0033] The present invention includes process steps such as degreasing, anodic activation, nickel plating, anodic degreasing, local hard gold plating, pickling, etc. During electroplating, the plug and the sealing core are used for shunt conduction, so that the nickel-plated layer of the sealing core undergoes oxidation to a certain extent, improving the standard electrode potential of the nickel layer surface, thereby preventing it from undergoing a displacement reaction with the gold solution, and preparing a connector with a nickel layer on the surface of the sealing core and a gold layer on the surface of the plug to achieve local hard gold plating of the connector. In this way, the sealing core of the connector prepared by the method of the present invention does not contain a gold layer, meeting the requirements of common laser welding of the connector, and at the same time having high reliability performance. In addition, the preparation process of the local hard gold plating method for the connector provided by the present invention is simple and environmentally friendly, greatly reducing the production and manufacturing cost, and having broad application prospects.

[0034] Refer to Figure 4, As a preferred technical solution of this embodiment, the electroplating fixture includes a conductive rod 410, an insulating rod 420, and a mounting point 430. The conductive rod 410 is in a form of two independent distributions. Specifically in this embodiment, the two conductive rods 410 are arranged in parallel. The mounting point 430 is set at the end of the conductive rod, and the insulating rod 420 is arranged between the conductive rods. For easy distinction, the ends of the two conductive rods can be respectively named the mounting point M and the mounting point N. Among them, there is no electrical connection and conduction between the mounting point M and the mounting point N. These two mounting points are respectively electrically connected to the sealing core and the plug. During mounting, the sealing core 10 is separately electrically connected to the mounting point M of the fixture, and the plug is separately electrically connected to the mounting point N of the fixture; during the subsequent energization step, the sealing core or the plug can be energized separately as needed.

[0035] Further, in the degreasing treatment step, the temperature of the degreasing solution is 80 - 90 °C, the pH value is 14, and the soaking time of the connector is 10 - 30 min; The degreasing solution includes sodium hydroxide with a concentration of 50 - 80 g / L, sodium carbonate with a concentration of 20 - 50 g / L, trisodium phosphate with a concentration of 20 - 50 g / L, sodium silicate with a concentration of 5 - 30 g / L, and a surfactant with a concentration of 1 - 10 ml / L. Among them, the surfactant is one or several of sodium dodecylbenzenesulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

[0036] Further, in the anodic activation treatment step, both the sealing core and the plug are electrically connected to the positive electrode of the power supply and immersed in an acidic solution; the anodic current density is 1 - 20 A / dm 2 , and the anodic activation time is 0.5 - 5 min; Among them, the temperature of the acidic solution is at room temperature, and the acidic solution is at least one of sulfuric acid with a concentration of 10 - 40 ml / L, benzotriazole with a concentration of 0.1 - 0.3 g / L, methylbenzotriazole with a concentration of 0.1 - 0.5 g / L, aminotrimethylenephosphonic acid with a concentration of 0.1 - 0.5 g / L, and hydroxyethylidene diphosphonic acid with a concentration of 0.1 - 0.5 g / L.

[0037] Further, in the overall nickel plating step, both the sealing core and the plug are electrically connected to the negative electrode of the power supply. The nickel plating solution is nickel sulfamate, the solution temperature is 35 - 65 °C, the pH value is 3.0 - 5.0, the nickel plating time is 20 - 50 min, and the cathode current density is set to 0.8 - 5 A / dm 2 ; Among them, the nickel sulfamate solution contains: 250 - 500 g / L of nickel sulfamate, 5 - 50 g / L of nickel chloride, 20 - 60 g / L of boric acid, and the balance is deionized water.

[0038] Further, the anodic degreasing treatment includes the following steps: S510: Connect the mounting point M connected to the sealing core to the positive pole of the power supply, and disconnect the electrical connection of the mounting point N connected to the plug; S520: Connect the negative pole of the power supply to the anode degreasing solution through a wire; S530: Turn on the power supply, energize the sealing core and the anode of the power supply, and set the anode current density to 1 - 5 A / dm 2 , the anode degreasing time is 0.5 - 5 min, and electrochemical anodic activation occurs on the surface of the sealing core to form an oxide layer; wherein, the solution temperature of the anode degreasing solution is 50 - 80 °C, and the anode degreasing solution contains: 50 - 80 g / L of sodium hydroxide, 20 - 50 g / L of sodium carbonate, 5 - 30 g / L of sodium silicate, and the balance is deionized water.

[0039] Furthermore, the hard gold plating treatment includes the following steps: S610: Connect the mounting point N connected to the plug to the negative pole of the power supply, and disconnect the electrical connection of the mounting point M connected to the sealing core; S620: Connect the positive pole of the power supply to the hard gold solution through a wire; S630: Turn on the power supply, energize the plug and the cathode of the power supply, and set the cathode current density to 0.15 - 2 A / dm 2 , the gold plating time is 4 - 12 min, and cathodic electrochemical deposition of anions occurs on the surface of the plug to form a hard gold layer, wherein, the solution temperature of the hard gold solution is 50 - 80 °C, the pH value is 3 - 5, and the electroplating hard gold solution is: 2 - 15 g / L of potassium gold cyanide, 20 - 90 g / L of citric acid, 30 - 100 g / L of potassium citrate, 0.5 - 5 g / L of cobalt sulfate, and the balance is deionized water.

[0040] It should be noted that in this embodiment, during anode degreasing and local hard gold plating, the mounting points on the two conductive rods in the electroplating fixture are respectively connected to the sealing core and the plug. In each processing step, the polarity setting and electrical connection and disconnection of the sealing core and the plug can be independently realized, achieving shunt conduction of the sealing core and the plug. Finally, the surface of the prepared sealing core is a nickel layer, and the surface of the plug is a gold layer, realizing the purpose of local hard gold plating treatment of the connector.

[0041] This embodiment makes innovations in the process and the fixture through the anode degreasing and local hard gold plating processes, combined with a shunt-conducting electroplating fixture. The two complement each other and are efficiently combined to form a local gold plating solution for the connector. Compared with the existing conventional preparation methods, it has the characteristics of simple process and environmental friendliness, and at the same time can reduce the production and manufacturing costs, and has broad application prospects.

[0042] Further, in the pickling treatment step, the connector after partial hard gold plating is immersed entirely in a pickling solution and rinsed with a swinging motion. The temperature of the pickling solution is at room temperature, the pH value is 3 - 5, and the pickling time is 1 - 5 minutes. Among them, the pickling solution is at least one of 50 - 200 g / L of sulfamic acid, 0.05 - 0.2 g / L of benzotriazole, and 0.05 - 0.2 g / L of methylbenzotriazole.

[0043] Refer to Figure 2 , Figure 3 Furthermore, the present invention also provides a connector prepared by using the method for partial hard gold plating of the multi-core copper lead connector described above. Further, the connector includes a sealing core 10, an insulator 20, and a plug 30. The sealing core 10 is a stainless steel base containing pores, the insulator 20 is a glass bead made of quartz material, and the plug 30 is a plug lead with a female head 310 at one end and a solid cylinder 320 at the other end, and the material of the plug is a copper alloy material.

[0044] The beneficial effects of the connector prepared by using the method of the present application are verified through specific examples as follows: Example 1: A method for partial hard gold plating of a multi-core copper lead connector includes the following steps: Mounting: The sealing core and the plug in the connector are respectively electrically connected to an electroplating fixture. The N point of the hook head in the electroplating fixture is connected to the plug, and the M point of the hook head is connected to the sealing core. Degreasing: The electroplating fixture connected with the connector is immersed entirely in a chemical degreasing solution. Among them, the temperature of the degreasing solution is 80°C, the pH value is 14, and the immersion time is 10 minutes. Anodic activation: The connector after degreasing is immersed entirely in an acidic solution for anodic activation treatment. Both the sealing core and the plug are electrically connected to the positive pole of the power supply. The anodic current density is 1 A / dm 2 , and the anodic activation time is 0.5 minute. Nickel plating: The connector after anodic activation is immersed in a nickel plating solution. Both the sealing core and the plug are electrically connected to the negative pole of the power supply. The solution temperature is 35°C, the pH value is 4.0, the nickel plating time is 30 minutes, and the cathodic current density is set to 1 A / dm 2 ; Partial anodic degreasing: The connector after nickel plating is immersed entirely in an anodic degreasing solution. The sealing core is connected to the positive pole of the power supply, the plug is disconnected from the electrical connection, and the negative pole of the power supply is connected through a wire and placed in the anodic degreasing solution. The solution temperature is 60°C, the anodic degreasing time is 1 minute, and the anodic current density is set to 1 A / dm 2 , Partial hard gold plating: The connector after anode degreasing is immersed in the electroplating hard gold solution. The plug is connected to the negative pole of the power supply, the sealing core is disconnected from the electrical connection, and the positive pole of the power supply is connected to the hard gold solution through a wire. The solution temperature is 50 °C, the pH value is 4.0, the gold plating time is 4 min, and the cathode current density is set to 1.3 A / dm 2 ; Pickling: The connector after partial hard gold plating is immersed in the pickling solution as a whole. The pickling solution temperature is at room temperature, the pH value is 4.0, and the pickling time is 1 min.

[0045] Example 2: A method for partial hard gold plating of a multi-core copper lead connector, comprising the following steps: Mounting: The sealing core and the plug in the connector are respectively electrically connected to the electroplating fixture. The N point of the hook head in the electroplating fixture is connected to the plug, and the M point of the hook head is connected to the sealing core; Degreasing: The electroplating fixture connected with the connector is immersed in the chemical degreasing solution as a whole. Among them, the degreasing solution temperature is 80 °C, the pH value is 14, and the immersion time is 10 min; Anodic activation: The connector after degreasing is immersed in the acidic solution for anodic activation treatment. Both the sealing core box and the plug are electrically connected to the positive pole of the power supply. The anodic current density is 1 A / dm 2 , and the anodic activation time is 1 min; Nickel plating: The connector after anodic activation is immersed in the nickel plating solution. Both the sealing core and the plug are electrically connected to the negative pole of the power supply. The solution temperature is 35 °C, the pH value is 4.0, the nickel plating time is 40 min, and the cathode current density is set to 0.8 A / dm 2 ; Partial anodic degreasing: The connector after nickel plating is immersed in the anodic degreasing solution as a whole. The sealing core is connected to the positive pole of the power supply, the plug is disconnected from the electrical connection, and the negative pole of the power supply is connected to the anodic degreasing solution through a wire. The solution temperature is 60 °C, the anodic degreasing time is 1 min, and the anodic current density is set to 1 A / dm 2 , Partial hard gold plating: The connector after anodic degreasing is immersed in the electroplating hard gold solution. The plug is connected to the negative pole of the power supply, the sealing core is disconnected from the electrical connection, and the positive pole of the power supply is connected to the hard gold solution through a wire. The solution temperature is 50 °C, the pH value is 4.0, the gold plating time is 7 min, and the cathode current density is set to 0.8 A / dm 2 ; Pickling: The connector after partial hard gold plating is immersed in the pickling solution as a whole. The pickling solution temperature is at room temperature, the pH value is 4.0, and the pickling time is 1 min.

[0046] Comparative example 1: A method for partial hard gold plating of a multi-core copper lead connector, comprising the following steps: Mounting: The sealing core and the plug in the connector are respectively electrically connected to the electroplating fixture. In the electroplating fixture, the N point of the hook head is connected to the plug, and the M point of the hook head is connected to the sealing core; Degreasing: The electroplating fixture connected with the connector is immersed in the chemical degreasing solution as a whole. Among them, the temperature of the degreasing solution is 80 °C, the pH value is 14, and the immersion time is 10 min; Anodic activation: The connector after degreasing is immersed in an acidic solution for anodic activation treatment. Both the sealing core box and the plug are electrically connected to the positive pole of the power supply. The anodic current density is 1 A / dm 2 , and the anodic activation time is 0.5 min; Nickel plating: The connector after anodic activation is immersed in the nickel plating solution. Both the sealing core and the plug are electrically connected to the negative pole of the power supply. The solution temperature is 35 °C, the pH value is 4.0, the nickel plating time is 20 min, and the cathodic current density is set to 1 A / dm 2 ; Local anodic degreasing: The connector after nickel plating is immersed in the anodic degreasing solution as a whole. The sealing core is connected to the positive pole of the power supply, the plug is disconnected from the electrical connection, and the negative pole of the power supply is connected to the anode degreasing solution through a wire. The solution temperature is 60 °C, the anodic degreasing time is 0.1 min, and the anodic current density is set to 1 A / dm 2 , Local hard gold plating: The connector after anodic degreasing is immersed in the electroplating hard gold solution. The plug is connected to the negative pole of the power supply, the sealing core is disconnected from the electrical connection, and the positive pole of the power supply is connected to the hard gold solution through a wire. The solution temperature is 50 °C, the pH value is 4.0, the gold plating time is 4 min, and the cathodic current density is set to 1 A / dm 2 ; Pickling: The connector after local hard gold plating is immersed in the pickling solution as a whole. The temperature of the pickling solution is room temperature, the pH value is 4.0, and the pickling time is 1 min.

[0047] Comparative example 2: A method for local hard gold plating of a multi-core copper lead connector, comprising the following steps: Mounting: The sealing core and the plug in the connector are respectively electrically connected to the electroplating fixture. In the electroplating fixture, the N point of the hook head is connected to the plug, and the M point of the hook head is connected to the sealing core; Degreasing: The electroplating fixture connected with the connector is immersed in the chemical degreasing solution as a whole. Among them, the temperature of the degreasing solution is 80 °C, the pH value is 14, and the immersion time is 10 min; Nickel plating: The connector after degreasing is immersed in the nickel plating solution. Both the sealing core and the plug are electrically connected to the negative pole of the power supply. The solution temperature is 35 °C, the pH value is 4.0, the nickel plating time is 20 min, and the cathodic current density is set to 1 A / dm 2 ; Local anodic degreasing: The nickel-plated connector is immersed entirely in the anodic degreasing solution. The sealed core is connected to the positive pole of the power supply, and the plug is disconnected from the electrical connection. The negative pole of the power supply is connected through a wire and placed in the anodic degreasing solution. The solution temperature is 60 °C, the anodic degreasing time is 1 min, and the anodic current density is set at 1 A / dm 2 , Local hard gold plating: The connector after anodic degreasing is immersed in the electroplating hard gold solution. The plug is connected to the negative pole of the power supply, and the sealed core is disconnected from the electrical connection. The positive pole of the power supply is connected through a wire and placed in the hard gold solution. The solution temperature is 50 °C, the pH value is 4.0, the gold plating time is 4 min, and the cathodic current density is set at 1 A / dm 2 ; Pickling: The connector after local hard gold plating is immersed entirely in the pickling solution. The pickling solution temperature is at room temperature, the pH value is 4.0, and the pickling time is 1 min.

[0048] Perform relevant performance tests on the connector samples prepared in the above Examples 1, 2, Comparative Example 1, and Comparative Example 2. The test methods and results are as follows: I. Test methods: Sample appearance: Refer to Appendix A of "GJB 2440A-2006 General Specification for Hybrid Integrated Circuit Packages": Use a 10X optical microscope to inspect the appearance.

[0049] Coating thickness: Refer to "SJ 20129 Measuring Methods for Thickness of Metallic Coatings": Use a German FISCHER XDLM237 X-ray fluorescence coating thickness measuring material analyzer to measure the coating thickness of the plug and the sealed core respectively.

[0050] Solderability test: Refer to Method 2003 of "GJB 2440A-2006 General Specification for Hybrid Integrated Circuit Packages": Tinning test.

[0051] Coating quality test: Refer to the gold coating quality test method in Appendix B of "GJB 2440A-2006 General Specification for Hybrid Integrated Circuit Packages", and test under Condition A.

[0052] Insertion and extraction test: Refer to Clause 5.3.2 of "GB / T 15176 General Specification for Sockets and Accessories for Insertable Electronic Components": Insertion force and extraction force test.

[0053] Salt spray test: Refer to Method 1009 of "GJB 2440A-2006 General Specification for Hybrid Integrated Circuit Packages": Test Condition A.

[0054] II. Test results and analysis: Table 1 - Test results table of connectors prepared in Examples 1-2 and Comparative Examples 1-2

[0055] Note: The standard range of the plating thickness of electronic components is 2.54 - 8.9 μm As can be seen from Table 1 above, the product processed by the method of locally plating hard gold on a multi-core copper lead connector of the present invention meets the appearance requirements; the plating thickness meets the standard range of the plating thickness of electronic components, which is 2.54 - 8.9 μm; the solderability meets the requirement that the tinned area is ≥ 95%; the insertion and extraction forces meet the requirements: the insertion force is ≤ 4.5 Kgf; the extraction force is 1.0 - 4.0 Kgf; the salt spray test meets the test requirements of 24 h of neutral salt spray. At the same time, in Comparative Example 1, the local anodic degreasing time was shortened, and the time was lower than the time disclosed in the specification of the present invention. This made the nickel layer on the surface of the sealing core unable to obtain effective oxidative "passivation" (the thickness of the oxide layer was insufficient). In the hard gold plating solution, a chemical displacement reaction occurred between the nickel layer on the surface of the sealing core and the gold ions, presenting a "gold deposition" phenomenon. This chemical gold deposition layer not only caused poor adhesion of the product but also was not required for the product, resulting in unqualified products. In Comparative Example 2, the anodic activation was cancelled, resulting in the ineffective removal of the high-temperature compounds on the surfaces of the sealing core and the plug after high-temperature sealing, poor conductivity, and difficulty in effectively depositing nickel plating and hard gold plating on the surface, and even no plating in some areas, resulting in unqualified products.

[0056] The above-described embodiments are merely descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for locally electroplating hard gold on a multi-core copper lead connector, characterized in that, The local hard gold plating method includes the following steps: The sealing core and the plug in the connector are respectively electrically connected to the electroplating fixture. In the electroplating fixture, the N point of the hook head is connected to the plug, and the M point of the hook head is connected to the sealing core; The electroplating fixture connected with the connector is immersed in the chemical degreasing solution as a whole for degreasing treatment; The connector after degreasing is immersed in the acidic solution as a whole for anodic activation treatment. Among them, both the sealing core and the plug are energized; The connector after anodic activation is immersed in the nickel plating solution. Both the sealing core and the plug are energized, and nickel plating is carried out as a whole; The connector after nickel plating is immersed in the anodic degreasing solution as a whole. The sealing core is energized, and the plug is de-energized. Anodic degreasing treatment is carried out on the nickel plating layer on the surface of the sealing core; The connector after anodic degreasing is immersed in the electroplating hard gold solution. The sealing core is de-energized, and the plug is energized. Hard gold plating treatment is carried out on the surface of the plug; The connector after local hard gold plating is immersed in the pickling solution as a whole. Pickling treatment is carried out on the surface of the sealing core.

2. The local hard gold plating method for the multi-core copper lead connector according to claim 1, wherein The electroplating fixture includes two independently distributed conductive rods (410), an insulating rod (420) arranged between the conductive rods, and a mounting point (430) arranged at the end of the conductive rod. The mounting points are not electrically connected and are used to be electrically connected to the sealing core and the plug respectively.

3. The local hard gold plating method for the multi-core copper lead connector according to claim 1, characterized in that, In the degreasing treatment step, the temperature of the degreasing solution is 80 - 90 °C, the pH value is 14, and the immersion time of the connector is 10 - 30 min; The degreasing solution includes sodium hydroxide with a concentration of 50 - 80 g / L, sodium carbonate with a concentration of 20 - 50 g / L, trisodium phosphate with a concentration of 20 - 50 g / L, sodium silicate with a concentration of 5 - 30 g / L, and a surfactant with a concentration of 1 - 10 ml / L. Among them, the surfactant is one or several of sodium dodecylbenzenesulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

4. The local hard gold plating method for the multi-core copper lead connector according to claim 1, characterized in that, In the anodic activation treatment step, both the sealing core and the plug are electrically connected to the positive pole of the power supply and are immersed in the acidic solution; The anodic current density is 1 - 20 A / dm 2 , and the anodic activation time is 0.5 - 5 min; Among them, the temperature of the acidic solution is at room temperature, and the acidic solution is at least one of sulfuric acid with a concentration of 10 - 40 ml / L, benzotriazole with a concentration of 0.1 - 0.3 g / L, methylbenzotriazole with a concentration of 0.1 - 0.5 g / L, aminotrimethylenephosphonic acid with a concentration of 0.1 - 0.5 g / L, and hydroxyethylidene diphosphonic acid with a concentration of 0.1 - 0.5 g / L.

5. The local hard gold plating method of the multi-core copper lead connector according to claim 1, characterized in that, In the overall nickel plating step, the sealed core and the connector are both electrically connected to the negative pole of the power supply. The nickel plating solution is nickel sulfamate, the solution temperature is 35-65°C, the pH value is 3.0-5.0, the nickel plating time is 20-50 minutes, and the cathode current density is set to 0.8-5 A / dm 2 ; Among them, the nickel sulfamate solution contains: 250 - 500 g / L of nickel sulfamate, 5 - 50 g / L of nickel chloride, 20 - 60 g / L of boric acid, and the balance is deionized water.

6. The local hard gold plating method for the multi-core copper lead connector according to claim 1, characterized in that, The anodic degreasing treatment includes the following steps: The M point of the mounting point connected to the sealing core is connected to the positive pole of the power supply, and the N point of the mounting point connected to the plug is disconnected from the electrical connection; The negative pole of the power supply is connected to the anode degreasing solution through a wire; Turn on the power supply, the sealed core is energized with the power anode, and the anode current density is set to 1 - 5 A / dm 2 , the anode degreasing time is 0.5 - 5 min, and electrochemical anodic activation occurs on the surface of the sealed core to form an oxide layer; Among them, the temperature of the anodic degreasing solution is 50 - 80 °C, and the anodic degreasing solution contains: 50 - 80 g / L of sodium hydroxide, 20 - 50 g / L of sodium carbonate, 5 - 30 g / L of sodium silicate, and the balance is deionized water.

7. The local hard gold plating method for the multi-core copper lead connector according to claim 1, characterized in that, The hard gold plating treatment includes the following steps: The N point of the mounting point connected to the plug is connected to the negative pole of the power supply, and the M point of the mounting point connected to the sealing core is disconnected from the electrical connection; The positive electrode of the power supply is connected through a wire and placed in the hard gold solution; Turn on the power supply, connect the plug to the cathode of the power supply to energize, and set the cathode current density to 0.15 - 2 A / dm 2 , the gold plating time is 4 - 12 minutes. Anions are cathodically electrodeposited on the surface of the plug, forming a hard gold layer. Among them, the solution temperature of the hard gold solution is 50-80 °C, the pH value is 3-5, and the electroplating hard gold solution is: 2-15 g / L of potassium gold cyanide, 20-90 g / L of citric acid, 30-100 g / L of potassium citrate, 0.5-5 g / L of cobalt sulfate, and the balance is deionized water.

8. The method for local hard gold plating of the multi-core copper lead connector according to claim 1, characterized in that, In the pickling treatment step, the connector after partial hard gold plating is immersed as a whole in the pickling solution and rinsed by swinging. The temperature of the pickling solution is at room temperature, the pH value is 3-5, and the pickling time is 1-5 min; Among them, the pickling solution is at least one of 50-200 g / L of sulfamic acid, 0.05-0.2 g / L of benzotriazole, and 0.05-0.2 g / L of methylbenzotriazole.

9. A connector, characterized in that, Prepared by the method for local hard gold plating of a multi-core copper lead connector according to any one of claims 1-8, the connector includes a sealing core (10), an insulator (20), and a plug (30).

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