The neutral and environmentally friendly appearance of copper bars and copper alloys and their use
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Regarding the commonly used pure metal conductive materials, the order of conductivity from high to low is silver, copper, gold, aluminum, tin, zinc, iron, lead, etc..Because metallic silver is expensive, copper is generally used as a good conductor of electricity.Therefore, copper and its alloy materials are the basic metal materials in the production of parts such as high-power power transmission equipment, transformation and distribution equipment, and high-current rectifier equipment..However, in the atmospheric environment (especially in humid or marine environments), copper and its alloys are oxidized to black or green rust, which significantly reduces the conductivity of the lap surface of the electrical connector. In order to hinder the oxidation of copper or improve the surface conductivity of copper conductors (such as copper bars), silver plating, tin plating (hot tin), nickel plating (such as matt nickel), gold plating (pins of circuit boards), etc. are generally used. Plating skills to modify the surface conductivity of copper.No matter what kind of surface plating technology is selected, it is necessary to pre-plating the copper parts that have changed color to remove the oil stain and oxide film on the copper surface.The methods to remove oil stains are mostly chemical or electrochemical methods, such as chemical degreasing method, which contains rich organic solvent degreasing (sometimes called physical degreasing), saponification degreasing and emulsification degreasing.The electrochemical degreasing method includes cathodic electrolytic degreasing and anode electrolytic degreasing.There are many ways to remove the surface oxide layer of copper and its alloys, and the commonly used methods are briefly described as follows: 2 Introduction to the method of removing copper oxide film 2.1 Alkaline removal method Alkaline removal method includes two types, one is alkaline cyanide removal method: select highly toxic sodium cyanide (10～20g/L) to soak the copper parts to remove the oxide film on the surface.This method can only be carried out in electroplating plants that have environmental protection measures and wastewater treatment conditions..The second type is the alkaline electrolysis removal method: electrolyzing copper parts in a solution rich in sodium hydroxide (100～150g/L) and sodium tartrate (20～30g/L) to achieve the intention of removing the copper oxide film, but this The method is not suitable for removing the oxide film on the surface of the messy-shaped copper parts. 2.2 The principle of acid removal of copper oxide film is very simple. The chemical action of acid and copper oxide on the surface of copper is used to generate copper salt and water to remove the copper oxide film..In practice, the acid stripping method is often used.In most cases, the copper black film can be removed by soaking the copper parts with 20-40% nitric acid.Another advantage of using nitric acid to remove the copper black film is that it can also chemically emit light on copper parts while removing the black film..However, when nitric acid is used to remove the copper black film, toxic nitrogen oxide gas will be generated, which is harmful to the human body and pollutes the environment.. In order to prevent the nitric acid from removing the toxic gas from the copper black film method, some people use sulfuric acid (15-30%) to remove the copper film method. The method of using this method to remove the copper black film will not release the toxic gas..However, this method has no effect on the copper parts, and the output power is low..Therefore, some people add hydrogen peroxide, phosphoric acid, chromic anhydride, etc. in the sulfuric acid solution to improve the light extraction effect, and some people add hydrochloric acid (10-20%) in the sulfuric acid solution to increase the speed of removing the black film.. Regardless of the acidic black mask method, there are four major questions: 1.After the film is removed, the appearance is very simple and reddened again (or colorful), and subsequent plating is difficult; 2.The acid solution pollutes the environment and needs to be discharged after wastewater treatment; 3.Regarding most copper alloys, the appearance of parts is rough after acid treatment. For example, brass (copper-zinc alloy) will show dezincification corrosion after acid treatment, and there will be red copper powder residue on the surface, so it is not suitable for subsequent plating..4.The acid copper black film removal method is not suitable for removing black film on the surface of the assembled assembly, otherwise it will corrode other parts of the assembly. 2.3 Mechanical polishing method: In order to prevent a series of questions about the alkaline and acidic copper black film removal method, we have to choose the most primitive mechanical polishing method to remove the copper black film.Use a polishing wheel or other polishing tools to polish away the black film on the surface of the copper parts.But this approach also has two major flaws: 1. Low production power, high labor intensity, dust and noise pollution; 2.The parts with sudden changes in shape (such as corners) cannot be polished. 3FJY environmental protection removal method In order to deal with the various questions that exist in the above-mentioned methods to remove copper black film, Xi’an Chuangjing Metal Surface Disposal Co., Ltd. successfully launched the FJY series of environmentally friendly rapid copper black film removal technology and anti-copper surface re-oxidation technology..This series of skills not only overcomes many questions about environmental pollution and other common skills at the time, but also doubles the production power; not only can simply remove the copper black film at the corners, but also does not corrode the copper substrate during the film removal process..This technology has been successfully applied to silver plating of copper parts, tin plating and nickel plating of bus bars, some surface conductive treatments of thermoplastic sleeve rows, epoxy-coated rows, and some conductive post-treatments of electrical assemblies and composite copper components..This skill has simple construction and low cost, which is the best choice to replace traditional skills. Regarding the newly processed copper bars, the FJY series of anti-copper oxidation and discoloration technology can also be used, and the copper appearance will not change color for a long time..The anti-tarnishing treatment of copper parts can eliminate the pre-plating process of removing the oxide film before plating, which is simple in operation and saves costs.. 4 Introduction to Application 1.Vacuum interrupter to remove the copper black film: The vacuum interrupter is a key part of the power system. In order to improve the electrical conductivity of the electrical connection part, it is necessary to carry out silver plating on the external surface of the arc extinguishing chamber..In the treatment process before silver plating, the surface polishing method was used to remove the oxide film on the surface of the copper parts. The noise and dust pollution were severe, the corners were incompletely polished, and the surface finish was reduced after polishing..After using FJY to remove the copper black film technology, you can simply remove all the oxide film on the surface of the copper part, and can maintain the original smoothness of the surface of the work piece..The silver-plated surface has a mirror-like luster, and the silver-plated layer’s resistance to discoloration can be greatly improved. 2.Busbar to remove the copper black film: Busbars (commonly known as busbars) are widely used in high-current power transmission systems. Many different standard conductive bars are used in the production of high-power transformer and distribution equipment, electrolytic rectifier equipment, and soft connection. , The most commonly used conductive row is pure copper row. Recently, new copper-aluminum composite row has been selected, and some people use aluminum-based copper-plated row.However, no matter which type of conductive bar is used, its electrical connection surface is made of pure copper material.Pure copper will have black film or patina due to oxidation and corrosion in the atmospheric environment, and the surface touch resistance will increase and the conductive function will deteriorate..Selecting FJY copper black film removal technology can remove all the oxide film on the busbar surface without corrosion, which is convenient for subsequent surface silver plating, nickel plating, tin plating (or hot tin) processing. 3.The copper black film of the bushing row: some users of the copper busbar need to heat seal the bushing at the non-overlapping part of the copper busbar, or spray epoxy resin encapsulation materials.During the heating and curing process of heating thermoplastic sleeve or epoxy resin, the lap surface of the exposed copper bar is slightly oxidized and discolored, resulting in poor touch of the electrical connection surface.Regarding this type of copper busbars, acid and alkali removal methods must not be used. If mechanical polishing or sandpaper polishing is used, it will not only take labor and time, but also cannot completely remove the oxide layer..The FJY environmentally friendly film removal method is used, which not only produces high power, but also completely removes the oxide layer on all parts of the exposed surface. 4.Transformers and other assemblies have some copper black films removed: many electricians are equipped, and some of their assemblies (such as transformers, etc.) need to be subjected to surface conductive processing (such as tin plating, silver plating, nickel plating, etc.).Regarding this type of equipment, it is impossible to perform overall electroplating, and only the brush plating method can be used..In the pre-treatment process of brush plating, only some methods to remove the oxide film can be used.Yueqing Renhe Electronics Co., Ltd. is the best copper bar manufacturer in Zhejiang, focusing on the production of new energy electric vehicle battery copper bar connection, electrical connection copper bar, braided copper bar, flexible copper bar connection, cable connection and insulation protection cover. R&D and sales.Products comply with EU environmental protection, UL flame retardant, ISO9001 management system certification requirements.