Surface treatment method for copper alloy rivet type electrical contact

Abstract

The invention discloses a surface treatment method for a copper alloy rivet type electrical contact. The surface treatment method comprises the following steps: (1) a hydrocarbon deoiling process; (2) low-temperature annealing process; (3) rough polishing; (4) grinding; (5) pickling; (6) fine polishing; and (7) cleaning. According to the characteristics of a copper alloy material, burrs of the copper alloy rivet type electrical contact are softened through low-temperature annealing, it is guaranteed that the silver-copper joint is not cracked, and the yield is increased; according to the method, after hydrocarbon deoiling is carried out to reduce oil stain residues and low-temperature annealing treatment is carried out to soften burrs, rough polishing and vibration grinding are carried out to remove the burrs and ring marks, foreign matter on the surface of the rivet electrical contact is removed through acid pickling, then fine polishing is carried out on the rivet electrical contact, and finally cleaning and drying are carried out, so that the surface uniformity of the rivet electrical contact is improved, and the quality of the rivet electrical contact is improved. Therefore, the contact resistance is reduced, and the performance of the rivet-type electrical contact is improved.

Description

Technical Field

[0001] The invention relates to the processing of rivet type electric contacts, and in particular to a surface processing method of copper alloy rivet type electric contacts. Background Art

[0002] Rivet-type electrical contact materials have good mechanical strength and electrical conductivity. They are important core components that affect the working reliability of switch electrical contact systems. Rivet-type electrical contact materials are widely used in electrical equipment such as relays, circuit breakers, and thermostats. Contact resistance is one of the key parameters for evaluating the performance of rivet-type electrical contact materials. Contact resistance directly affects the electrical contact's electrical conductivity, heating conditions, and the reliability and efficiency of the entire electrical equipment in the circuit. If the contact resistance of the rivet-type electrical contact is too large, the electrical contact system will heat up and energy consumption will increase. When the system is operating, premature welding or sticking may occur, affecting the electrical contact effect. In severe cases, it may also cause electrical contact failure. Therefore, contact resistance is a key factor in studying electrical contact reliability. The contact pressure, contact mode, and properties of the electrical contact itself are all factors that affect contact resistance. The properties of the electrical contact itself include resistance, shape, hardness, surface roughness of the electrical contact, surface foreign matter, surface flatness, etc.

[0003] At present, electrical contacts can be made of pure metal materials, alloy materials and composite materials. Among them, copper alloy is a commonly used alloy material for making electrical contacts. The Chinese invention patent with publication number CN118417820A discloses a surface treatment method for rivet-type electrical contacts. This method mainly removes stress in rivet-type electrical contacts by high-temperature annealing, but this method is not targeted at the surface treatment of electrical contacts of different materials, especially not suitable for treating the surface of copper alloy rivet-type electrical contacts, because copper alloy rivet-type electrical contacts have a higher hardness than ordinary copper, and the burrs of the rivet electrical contacts after forming are relatively hard and the silver-copper joint is prone to cracking.

[0004] In summary, the existing surface treatment method of rivet-type electrical contacts made of copper alloy is improved to make the method more unique to the material, which is of great significance for reducing the contact resistance and improving the performance of copper alloy rivet-type electrical contacts. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a surface treatment method for a copper alloy rivet type electrical contact.

[0006] The technical solution adopted by the present invention is as follows: A surface treatment method for a copper alloy rivet-type electrical contact comprises the following steps:

[0007] (1) Degreasing process: subjecting the copper alloy rivet-type electrical contact to be treated to ultrasonic degreasing treatment;

[0008] (2) Annealing process: the copper alloy rivet-type electrical contacts after degreasing in step (1) are loaded into a material boat and pushed into an annealing furnace for annealing at a temperature of 200° C.;

[0009] (3) Rough polishing process: pouring the copper alloy rivet-type electrical contact after cooling in step (2) into a magnetic polishing machine for rough polishing;

[0010] (4) grinding process: pouring the copper alloy rivet electrical contact after rough polishing in step (3) into a grinding barrel, adding a grinding auxiliary agent and grinding;

[0011] (5) Pickling process: the copper alloy rivet-type electrical contact ground in step (4) is transferred and placed in a soaking tank filled with acid solution for soaking;

[0012] (6) Fine polishing process: the copper alloy rivet-type electrical contact after pickling in step (5) is transferred to a fine polishing machine for fine polishing. The fine polishing machine can be a jewelry polishing machine;

[0013] (7) Cleaning process: Add passivation liquid into an ultrasonic cleaning machine, and transfer the copper alloy rivet-type electrical contact after fine polishing in step (6) into the ultrasonic cleaning machine for ultrasonic cleaning. After cleaning, take out the copper alloy rivet-type electrical contact and place it in a thermal suction drying device for dehydration and drying.

[0014] Preferably, in step (1), hydrocarbon is used for ultrasonic degreasing treatment.

[0015] Preferably, in step (2), the annealing time is 1 h.

[0016] Preferably, in step (3), the rough polishing time is 20-30 min; in step (6), the fine polishing time is 40-60 min; and polishing liquid is added to assist polishing in both rough polishing and fine polishing.

[0017] Preferably, the polishing liquid comprises the following components: 10-15 parts of oxalic acid, 10-15 parts of hydrofluoric acid, 20-30 parts of sodium dodecylbenzene sulfonate, 30-60 parts of citric acid, and 100-150 parts of pure water.

[0018] Preferably, in step (4), the grinding aid comprises 300-400 ml of abrasive, 100-150 ml of abrasive and 3000-6000 ml of pure water, the grinding speed is 60-90 Hz, and the grinding time is 6-8 h.

[0019] Preferably, the abrasive comprises the following components: 300-450 parts of ferrosoferric oxide, 20-40 parts of magnesium oxide, 60-100 parts of chromium oxide, and 10-20 parts of ferrous oxide.

[0020] Preferably, the abrasive is a φ15×15mm epoxy resin triangular pyramid.

[0021] Preferably, in step (5), the acid solution comprises the following components: 60-80 parts of sulfuric acid, 60-80 parts of hydrogen peroxide, 5-10 parts of hydrochloric acid, and 200-400 parts of pure water, and the acid solution immersion time is 30-60 minutes.

[0022] Preferably, in step (7), the ultrasonic cleaning time is 30-40 min.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. In view of the fact that copper alloy has a higher hardness than ordinary copper, the present invention uses low-temperature annealing to soften the burrs of the copper alloy rivet-type electrical contact and ensure that the silver-copper joint does not crack, thereby improving the yield rate and laying a foundation for subsequent polishing and grinding processes, providing a higher-quality electrical contact surface;

[0025] 2. The present invention reduces residual oil pollution from manufacturing by hydrocarbon degreasing, softens the burrs by low-temperature annealing, and then performs rough polishing. Then, the burrs and ring marks are removed by vibration grinding, and foreign matter on the surface of the rivet electrical contact is removed by pickling. The rivet type electrical contact is then finely polished, and finally cleaned and dried. This method improves the surface uniformity of the rivet type electrical contact, reduces its contact resistance, and thus improves the performance of the rivet type electrical contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0027] Figure 1 This is a process flow chart of the technical solution of the present invention;

[0028] Figure 2 This is a graph showing the bonding strength test results of Example 1 of the present invention;

[0029] Figure 3 This is a graph showing the bonding strength test results of Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0030] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0031] Example 1 :

[0032] This embodiment provides a copper alloy rivet type electrical contact surface treatment method, comprising the following steps:

[0033] (1) Degreasing process: the copper alloy rivet-type electrical contact to be treated is immersed in hydrocarbon for ultrasonic degreasing treatment;

[0034] (2) Annealing process: the degreased copper alloy rivet-type electrical contacts are loaded into a material boat and pushed into an annealing furnace for annealing at a temperature of 200°C for 1 hour;

[0035] (3) Rough polishing process: pour the cooled copper alloy rivet-type electrical contact into a magnetic polishing machine, and take out the rivet-type electrical contact after polishing for 30 minutes;

[0036] (4) Grinding process: pour the roughly polished copper alloy rivet electrical contact into a grinding barrel, add 300 ml of abrasive, 100 ml of abrasive, and 3000 ml of pure water, the grinding speed is 60 Hz, and the grinding time is 8 h;

[0037] (5) Pickling process: transfer the ground copper alloy rivet-type electrical contacts to a soaking tank filled with acid solution and soak for 30 minutes;

[0038] (6) Fine polishing process: the pickled copper alloy rivet-type electrical contacts are transferred to a jewelry polishing machine for polishing for 60 minutes;

[0039] (7) Cleaning process: add a passivation solution into an ultrasonic cleaning machine, and transfer the finely polished copper alloy rivet-type electrical contact into the ultrasonic cleaning machine for ultrasonic cleaning. After cleaning for 40 minutes, take out the rivet-type electrical contact, and finally place the rivet-type electrical contact into a thermal suction drying device for dehydration and drying.

[0040] The abrasive of this embodiment includes the following components: 300 parts of ferroferric oxide, 20 parts of magnesium oxide, 60 parts of chromium oxide, and 10 parts of ferrous oxide;

[0041] The abrasive in this embodiment is a φ15×15mm epoxy resin triangular pyramid;

[0042] The polishing liquid of this embodiment includes the following components: 10 parts of oxalic acid, 10 parts of hydrofluoric acid, 20 parts of sodium dodecylbenzene sulfonate, 30 parts of citric acid, and 100 parts of pure water;

[0043] The acid solution of this embodiment includes the following components: 60 parts of sulfuric acid, 60 parts of hydrogen peroxide, 5 parts of hydrochloric acid, and 200 parts of pure water;

[0044] Example 2 :

[0045] The processing steps of this embodiment are the same as those of embodiment 1, except that the dosage of processing auxiliary materials is different:

[0046] In this embodiment, 400 ml of grinding material, 120 ml of abrasive, and 4000 ml of pure water were added to the grinding barrel, the grinding speed was 60 Hz, and the grinding time was 8 hours;

[0047] The abrasive in this embodiment includes the following components: 350 parts of ferrosoferric oxide, 30 parts of magnesium oxide, 80 parts of chromium oxide, and 15 parts of ferrous oxide;

[0048] The polishing liquid in this embodiment includes the following components: 12 parts of oxalic acid, 12 parts of hydrofluoric acid, 25 parts of sodium dodecylbenzene sulfonate, 40 parts of citric acid, and 120 parts of pure water;

[0049] The acid solution in this embodiment includes the following components: 70 parts of sulfuric acid, 70 parts of hydrogen peroxide, 7 parts of hydrochloric acid, and 300 parts of pure water.

[0050] Example 3 :

[0051] The processing steps of this embodiment are the same as those of embodiment 1, except that the dosage of processing auxiliary materials is different:

[0052] In this embodiment, 400 ml of grinding material, 150 ml of abrasive, and 6000 ml of pure water were added to the grinding barrel, the grinding speed was 60 Hz, and the grinding time was 8 hours;

[0053] The abrasive in this embodiment includes the following components: 450 parts of ferroferric oxide, 40 parts of magnesium oxide, 100 parts of chromium oxide, and 20 parts of ferrous oxide;

[0054] The polishing liquid in this embodiment includes the following components: 15 parts of oxalic acid, 15 parts of hydrofluoric acid, 30 parts of sodium dodecylbenzene sulfonate, 60 parts of citric acid, and 150 parts of pure water;

[0055] The acid solution in this embodiment includes the following components: 80 parts of sulfuric acid, 80 parts of hydrogen peroxide, 10 parts of hydrochloric acid, and 400 parts of pure water.

[0056] Comparative Example 1 :

[0057] The dosage of the processing auxiliary materials in the grinding and polishing process of this comparative example is the same as that of Example 1. The difference from Example 1 lies in the process sequence and annealing temperature. This example adopts the following process and annealing temperature:

[0058] (1) Grinding process: Place the copper alloy rivet-type electrical contact into a grinding barrel, add 50 ml of abrasive, 60 ml of abrasive, and 2000 ml of pure water, the grinding speed is 120 Hz, and the grinding time is 30 min;

[0059] (2) Degreasing process: the ground copper alloy rivet-type electrical contact is immersed in hydrocarbon for ultrasonic degreasing treatment;

[0060] (3) Annealing process: the degreased copper alloy rivet-type electrical contacts are loaded into a material boat and pushed into an annealing furnace for annealing at a temperature of 400°C for 4 hours;

[0061] (4) Polishing process: putting the annealed copper alloy rivet-type electrical contact into a centrifugal polisher, and taking out the rivet-type electrical contact after polishing for 20 minutes;

[0062] (5) Cleaning process: add passivation liquid into an ultrasonic cleaning machine, and transfer the polished copper alloy rivet type electrical contact into the ultrasonic cleaning machine for ultrasonic cleaning. After cleaning for 30 minutes, take out the copper alloy rivet type electrical contact, and place the copper alloy rivet type electrical contact into a thermal suction drying device for dehydration and drying.

[0063] Comparative Example 2 :

[0064] The difference between this comparative example and Example 1 is that the polishing liquid composition is different:

[0065] The polishing liquid of this comparative example includes the following components: 50 parts of citric acid, 5 parts of fluoroboric acid, 8 parts of hydrochloric acid, 2 parts of phosphoric acid, and 60 parts of pure water.

[0066] After processing according to the operating steps described in Examples 1-3, a copper alloy rivet-type electrical contact was obtained, and its contact resistance effect was tested. The verification data is as shown in the following table;

[0067]

[0068] From the above contact resistance test results, it can be seen that the average contact resistance of the copper alloy rivet electric contact treated in Example 1 is the smallest, while the average contact resistance of the copper alloy rivet electric contact treated in Comparative Example 1 is the largest, which shows that the treatment process and annealing temperature of Example 1 are more effective in treating the surface of rivet-type electric contacts made of copper alloy, that is, more targeted; and the average contact resistance of the copper alloy rivet electric contacts treated in Examples 2-3 and Comparative Example 2 is slightly greater than that in Example 1, which shows that the contact resistance of the copper alloy rivet electric contacts treated with the dosage of processing auxiliary materials in Example 1 is smaller and its performance is better.

[0069] like Figure 2-Figure 3 As shown, from the bonding strength test results of the copper alloy rivet electrical contacts of Example 1 and Comparative Example 1, it can be concluded that, compared with Comparative Example 1, the treatment process and low-temperature annealing temperature of Example 1 are more targeted for treating rivet-type electrical contacts made of copper alloy, that is, the bonding strength after treatment is better.

[0070] In summary, combined with the test results of contact resistance and bonding strength, the processing procedure, low-temperature annealing temperature and processing auxiliary material dosage used in Example 1 are more suitable for processing rivet-type electrical contacts made of copper alloy, that is, more targeted.

[0071] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A surface treatment method for a copper alloy rivet-type electrical contact, characterized in that: The following steps are involved: (1) Degreasing process: subjecting the copper alloy rivet-type electrical contact to be treated to ultrasonic degreasing treatment; (2) Annealing process: the copper alloy rivet-type electrical contacts after degreasing in step (1) are loaded into a material boat and pushed into an annealing furnace for annealing at a temperature of 200° C.; (3) Rough polishing process: pouring the copper alloy rivet-type electrical contact after cooling in step (2) into a magnetic polishing machine for rough polishing; (4) grinding process: pouring the copper alloy rivet electrical contact after rough polishing in step (3) into a grinding barrel, adding a grinding auxiliary agent and grinding; (5) Pickling process: the copper alloy rivet-type electrical contact ground in step (4) is transferred and placed in a soaking tank filled with acid solution for soaking; (6) Fine polishing process: transferring the copper alloy rivet-type electrical contact after pickling in step (5) to a fine polishing machine for fine polishing; (7) Cleaning process: Add passivation liquid into an ultrasonic cleaning machine, and transfer the copper alloy rivet-type electrical contact after fine polishing in step (6) into the ultrasonic cleaning machine for ultrasonic cleaning. After cleaning, take out the copper alloy rivet-type electrical contact and place it in a thermal suction drying device for dehydration and drying.

2. A copper alloy rivet type electrical contact surface treatment method according to claim 1, characterized in that: In step (1), ultrasonic degreasing treatment is performed using hydrocarbons.

3. A copper alloy rivet type electrical contact surface treatment method according to claim 1, characterized in that: In step (2), the annealing time is 1 h.

4. A surface treatment method for a copper alloy rivet-type electrical contact according to claim 1, characterized in that: In step (3), the rough polishing time is 20-30 minutes; in step (6), the fine polishing time is 40-60 minutes; polishing liquid is added to assist polishing in both rough polishing and fine polishing.

5. A copper alloy rivet type electrical contact surface treatment method according to claim 4, characterized in that: The polishing liquid comprises the following components: 10-15 parts of oxalic acid, 10-15 parts of hydrofluoric acid, 20-30 parts of sodium dodecylbenzene sulfonate, 30-60 parts of citric acid, and 100-150 parts of pure water.

6. A copper alloy rivet type electrical contact surface treatment method according to claim 1, characterized in that: In step (4), the grinding aid includes 300-400 ml of grinding material, 100-150 ml of grinding agent and 3000-6000 ml of pure water, the grinding speed is 60-90 Hz, and the grinding time is 6-8 hours.

7. A surface treatment method for a copper alloy rivet-type electrical contact according to claim 6, characterized in that: The abrasive comprises the following components: 300-450 parts of ferrosoferric oxide, 20-40 parts of magnesium oxide, 60-100 parts of chromium oxide and 10-20 parts of ferrous oxide.

8. A copper alloy rivet type electrical contact surface treatment method according to claim 7, characterized in that: The abrasive material is a φ15×15mm epoxy resin triangular pyramid.

9. A surface treatment method for a copper alloy rivet-type electrical contact according to claim 1, characterized in that: In step (5), the acid solution comprises the following components: 60-80 parts of sulfuric acid, 60-80 parts of hydrogen peroxide, 5-10 parts of hydrochloric acid, and 200-400 parts of pure water, and the acid solution immersion time is 30-60 minutes.

10. A copper alloy rivet type electrical contact surface treatment method according to claim 1, characterized in that: In step (7), the ultrasonic cleaning time is 30-40 minutes.

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