What is nickel plating?
The method of plating a layer of nickel on a metal or certain non-metal by electrolytic or chemical methods is called nickel plating. Nickel plating includes electroplating nickel and electroless nickel plating. Nickel plating is in the electrolyte composed of nickel salt (called the main salt), conductive salt, pH buffer medium, wetting agent, the anode with metal nickel, the cathode for plating, through direct current, deposited on the cathode (plating) layer of uniform, dense nickel coating.
Bright nickel is obtained from the plating solution with brightener, and dark nickel is obtained from the electrolyte without brightener.
Nickel plating characteristics, performance
Features
- The stability of the electroplated nickel layer in the air is very high, because the metal nickel has a strong passivation ability, can quickly generate an extremely thin passivation film on the surface, can resist the corrosion of the atmosphere, alkali and some acids.
- Electroplating nickel crystal is extremely small, and has excellent polishing properties. The polished nickel coating can obtain a mirror-like luster, while maintaining its luster in the atmosphere for a long time. Therefore, electroplating is often used for decoration.
- The hardness of the nickel coating is relatively high, can improve the wear resistance of the surface of the product, in the printing industry commonly used nickel plating layer to improve the hardness of the lead surface, because the metal nickel has high chemical stability, some chemical equipment is also commonly used thicker nickel coating to prevent corrosion by the medium.
Performance and use
Nickel plating has a wide range of applications. It can be used as a protective decorative coating to protect the base material from corrosion or play a bright decorative role on the surface of steel, zinc die casting, aluminum alloy and copper alloy. It is also often used as an intermediate coating of other coatings, on which a thin layer of chromium is plated, or a layer of imitation gold is plated with better corrosion resistance and more beautiful appearance.
In terms of functional applications, nickel plating on parts in special industries is about 1~3mm thick, which can achieve the purpose of repair. Especially in the continuous casting mold, electronic component surface mold, alloy die-casting mold, complex shape aerospace engine components and micro electronic components manufacturing more and more widely.
Solutions for white spots
- Improve the pre-treatment cleaning process, using the method of ultrasonic cleaning, so that the particles with poor adhesion after carburizing fall off in the cleaning
- Timely filtration of the plating solution.
- Improve the pickling process: mainly to reduce the concentration of pickling solution, add appropriate corrosion inhibitors and properly control the pickling time to avoid over-corrosion by taking the above measures, so that the product electroplating white spot problem has been fundamentally solved.
Electrolytic nickel plating process
- Material preparation: First of all, the item to be treated should be cleaned and treated according to the requirements to ensure its surface finish and quality.
- Pretreatment: The specific operation includes pickling, washing and fat removal to make the surface of the item thoroughly clean.
- Electrolytic nickel plating: Put the pre-treated items into the electrolytic cell, add the appropriate amount of electrolyte and anode, and reduce nickel ions to form metal nickel deposits on the surface of the items through electrochemical reaction.
- Water washing: wash the treated items to remove residual electrolyte and impurities, etc.
- Drying: Dry the washed items to remove surface moisture.
- Assembly: Package and assemble the baked goods to ensure that their surfaces are not damaged.
