What is electroplating?
Electroplating refers to the salt solution containing the metal to be plated, under the action of direct current, the metal to be plated is used as the cathode, and the metal to be plated or other inert conductor is used as the anode to obtain a firmly bonded metal on the surface of the substrate through electrolysis. Membrane surface engineering technology.
Why electroplating?
The purpose of electroplating is to improve the appearance of the material, and at the same time impart various physical and chemical properties to the surface of the material, such as corrosion resistance, decoration, wear resistance, brazing, and electrical, magnetic, and optical properties.
What are the types and applications of electroplating?
1. Galvanized
The galvanized layer has a high purity and is an anodic coating. The zinc layer acts as a mechanical protection for the steel substrate and also plays an electrochemical protection role. Therefore, the galvanized layer is widely used in machinery, hardware, electronics, instrumentation, light industry, etc., and is one of the most widely used plating types, accounting for more than 60% of the total electroplating volume.
2. Copper plating
The copper plating layer is a cathodic plating layer. It can only provide mechanical protection for the base metal. Copper plating is usually not used alone as a protective decorative coating, but as the bottom or middle layer of the coating to improve the bonding force between the surface coating and the base metal.
In the field of electronics, through-holes on printed circuit boards are copper-plated; after copper-plating on antique products, they are oxidized with a sulfide copper-protecting layer, and after appropriate post-treatment, they have reached the point of being fake.
3. Nickel plated
The nickel plating layer is a cathodic protective layer, which only plays a mechanical role in protecting the bottom metal. In addition to the direct use of some medical devices and battery casings, the nickel plating layer is often used as the bottom layer or intermediate layer and is widely used in daily hardware, light industry, household appliances, machinery, and other industries.
4. Chrome
The chrome plating layer is a cathodic plating layer and only plays the role of mechanical protection. Decorative chrome plating, the bottom layer is generally polished or electrodeposited bright plating (copper-tin alloy plating or bright nickel plating).
Widely used in exposed parts of instruments, meters, daily hardware, household appliances, aircraft, automobiles, motorcycles, bicycles, etc. Functional chrome plating includes hard chrome plating, porous chrome, black chrome, milky white chrome, etc.
The hard chromium layer is mainly used for various measuring calipers, gauges, cutting tools, and various types of shafts, and the loose chrome layer is mainly used for piston damage in the inner cavity of the cylinder;
The black chrome layer is used for parts that require matting and wear resistance, such as aviation instruments, optical instruments, photographic equipment, etc.: opalescent chrome is mainly used for various measuring tools.
5. Tin plating
Tin is a cathodic coating with respect to a steel substrate and an anodic coating with respect to a copper substrate.
The tin-plating layer is mainly used for the protective layer of thin plates used in the canning industry, and more than 95% of the malleable iron sheets are made of tin-plated iron plates. Another major use of tin plating is in the electronics and power industries.
6. Alloy plating
In a solution, two or more metal ions co-precipitate on the cathode to form a uniform and fine coating process called alloy electroplating.
Alloy electroplating is superior to single metal electroplating in terms of crystal density, coating porosity, appearance color, hardness, corrosion resistance, wear resistance, magnetic permeability, wear reduction, and high-temperature resistance.
There are more than 240 kinds of electroplating alloys, but less than 40 kinds are actually used in production. It is generally divided into three categories: protective alloy coating, decorative alloy coating, and functional alloy coating.
Widely used in aviation, aerospace, navigation, automobile, mining, military industry, instruments, meters, purpose hardware, tableware, musical instruments, and other industries.
Others include chemical plating, composite plating, non-metallic plating, electroforming technology, gold plating, silver plating, etc.
Mechanical Finishing: As machined: This means no extra surface treatment after machining. Stainless steel could resist corrosion in the air itself. Usually, no additional surface treatment is needed. Aluminum could form a fine and close oxide layer itself, protecting against…