Electroplating is a "beautician" for surface treatment of packaging materials. It can obtain a functional, decorative and protective metal film layer on the substrate. Its products are everywhere, no matter what field it is in, or where people live In any aspect, you can find the flash point of electroplating results.
1. Concept electroplating is to plate one or more metal coatings on the surface of the workpiece by means of electrodeposition, giving the workpiece a beautiful appearance or specific functional requirements. During electroplating, the coated metal or other insoluble material is used as the anode, and the metal product to be plated is used as the cathode. The cation of the coated metal is reduced on the metal surface to form a coating. In order to eliminate the interference of other cations and make the coating uniform and firm, it is necessary to use the solution containing the coating metal cation as the plating solution to keep the concentration of the coating metal cation unchanged. The purpose of electroplating is to plate a metal coating on the substrate to change the surface properties or size of the substrate. Electroplating can enhance the corrosion resistance of metals (mostly coated metals use corrosion-resistant metals), increase hardness, prevent wear, improve electrical conductivity, lubricity, heat resistance, and beautiful surface. 2. Principle In the plating tank containing electroplating solution, the parts to be plated after cleaning and special pretreatment are used as the cathode, and the anode is made of plated metal, and the two poles are respectively connected to the negative pole and the positive pole of the DC power supply. The plating solution is composed of an aqueous solution containing a metal-plating compound, conductive salts, buffers, pH adjusters and additives. After being energized, the metal ions in the plating solution move to the cathode under the action of the potential difference to form a plating layer. The metal of the anode forms metal ions into the plating solution to maintain the concentration of the plated metal ions. In some cases, such as chromium plating, it is an insoluble anode made of lead or lead-antimony alloy, which only serves to transfer electrons and conduct current. The concentration of chromium ions in the electrolyte must be maintained by periodically adding chromium compounds to the plating solution. During electroplating, the quality of the anode material, the composition of the plating solution, temperature, current density, energization time, stirring intensity, precipitated impurities, power supply waveform, etc. will affect the quality of the coating, and need to be controlled in a timely manner.
1. The main performance of the electroplated parts refers to the bonding force of the workpiece and the metal, corrosion resistance, heat resistance, mechanical strength, and the bonding force is related to the material itself (SUS304 steel plate, thickness 0.35MM, size 32 * 40CM), The chemical and physical properties are related, and the bonding force between different types of materials and metal coatings is very different. The corrosion resistance of electroplated parts is very different due to the combination of plating layers and the thickness of the plating layer. The reason why the performance is higher than that of metal parts with the same plating layer is that the corrosion of the electroplated parts is different from the corrosion of metal parts. First, the electroplated parts are corroded according to the anode protection mechanism. Completely shedding. Therefore, for electroplated parts that require high corrosion resistance, a double-layer nickel or multi-layer nickel system should be used. Secondly, the metal plating layer cannot form the principle of corroding the battery. For horizontal expansion. Heat resistance Heat resistance depends mainly on the heat resistance of the metal coating (nickel, chromium) itself, and the bonding strength of the metal coating. Mechanical strength The mechanical strength and material of the electroplated parts (Nickel, chromium) are closely related, in general, their rigidity is improved after electroplating.
三. System composition
1. Electroplating equipmentThe biggest functional advantage of electroplating is that on the surface of metal and non-metal parts, a new metal layer with a high gloss can be formed, which directly improves the visual grade of the original part. Compared with directly forming parts with metal, the cost is much lower. Electroplating of specific areas on the surface of the same part can be done with special wax and paint on areas that do not require electroplating. Chrome plating is widely used in the surface treatment of the transportation and furniture industries. 2. The main materials are about 30 types of electroplated metals Among them, there are more than ten kinds of galvanized, cadmium, copper, nickel, chromium, silver, tin, gold, iron, cobalt, lead, antimony, platinum, titanium, and cymbals. In addition to single metal coatings, there are many alloy coatings, such as copper tin, copper zinc, copper nickel, iron nickel, lead tin, zinc tin, zinc iron, zinc nickel, copper cadmium, zinc cadmium, tin iron, tin cobalt, Ferro-tungsten, etc. For plastics, ABS is the most commonly used, because ABS can withstand a high plating temperature of 60 ° C (140 ° F), and its plating layer and non-plating layer have high bonding strength. Most metals can be electroplated, but different metals have different grades. Purity and plating efficiency. The most common ones are: tin, chromium, nickel, silver, gold and rhodium (rhodium: a kind of platinum), which is extremely expensive and can maintain high brightness for a long time, can resist most chemicals and acids. It is most commonly used to gloss the surface of products Products with very high degree requirements, such as trophies and medals), nickel metal can not be used for electroplating products that contact the skin, because nickel is irritating and toxic to the skin. Cadmium, tin plating, zinc plating, etc.
4. Process flow
1. Basic process (polishing → polishing) → hanging → degreasing and degreasing → washing → (electrolytic polishing or chemical polishing) → pickling activation → (pre-plating) → electroplating → washing → (post-processing) → washing → drying → Down hook → inspection packaging 2. The role of each process
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