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2022.7.13
Cu, Ni, Sn, Zn, CD, etc. are all examples of traditional single metal plating. plating procedures based on this include composite plating, non-metallic plating, plating alloys, brush plating, and the plating of rare and valuable metals, among others. Single metal plating coatings come in a wide variety of qualities and applications, as do the procedures used to apply them, but their essential philosophies are always the same. Let’s take a look at metal plating’s categorization and use nowadays.
Protective ornamental metal plating and wear-resistant metal plating are the most common types of metal plating. For one, the goal is to avoid rust and enhance the aesthetics of items, while for another it’s to make mechanical components harder, more wear- and corrosion-resistant, and more temperature-resistant.
A silver-bluish white metal, metal possesses excellent atmospheric passivation and may retain its shine for an extended period of time. The metal plating layer has a hardness of roughly hv1000 and is very wear resistant.
Chrome plating offers a high level of thermal stability. Its look and hardness remain unchanged even after being heated to 500 °C in the air. The coating’s capacity to reflect light is second only to silver coating in terms of strength.
With a coating thickness of 0.25 M, the coating is microporous; with a coating thickness of more than 0.5 M, the coating has network microcracks, and the coating only provides mechanical protection to the substrate when the friction reaches 20um.
Metal plating is used to protect metal objects from atmospheric corrosion and rust while also improving their aesthetic appeal. Non-metallic materials, such as plastic, are also routinely coated with it.
Chrome plating is commonly used in vehicles, motorcycles, bicycle sewing machines, clocks, home appliances, medical gadgets, instruments and furniture. Chrome plating is characterized by the following attributes:
-To begin, the coating is very thin, measuring about 0.25 to 0.3 micrometers in thickness.
-There must be an intermediate coating applied to the steel substrate before the metal plating layer can have a significant anti-corrosion effect.
-The chrome layer has a smooth, bright, and lovely appearance to it.
Protective decorative metal plating is now classified into general protective decorative metal plating and high corrosion resistant protective decorative metal plating. One utilizes a regular metal plating solution while the other employs unique process parameters to modify the structure of the metal plating layer to produce excellent corrosion resistance.
Chrome plating may be used for a variety of purposes, including:
Multi-coating systems like copper/metal, nickel/copper/nickel/metal/nickel must be used for chrome plating on steel and zinc alloy as well as aluminum alloy in order to get the best results.
metal plating, a cosmetic and corrosion-resistant coating for copper and copper alloys, may be applied straight after polishing, although it is more common to use brilliant nickel plating, which is more corrosion-resistant.
Today, the most common coating system in China is the copper, nickel, and metal one, with regular metal solutions and composite metal plating solutions both being used as necessary. About 300g/l of chromic anhydride is present in this solution. For the metal layer to be free of large fissures,
Good conductivity, high cell voltage, and a narrow solution change range are only some of the benefits of this material It is important to consider the base material’s intermediate layer while determining the protective decorative wiring solution and operation circumstances.
Ornamental coating that is highly resistant to corrosion
Since the mid-1950s, the use of multi-layer nickel has substantially enhanced the corrosion resistance of the plated sections in the protective ornamental nickel/metal or copper/nickel/metal crossover systems. Studies demonstrate that nickel/metal coating corrosion resistance is highly dependent on the structural properties of the coating, in addition to its quality and thickness. metal electrodeposition differs from typical plating techniques in that it not only uses a unique bath solution, but it also produces metal metal with unique characteristics. A coating thickness of just 0.25 to 0.5 micrometers may be achieved by using a metal plating solution that contains 250 grams of chromic anhydride and 2.5 grams of sulfuric acid. However, because of the tremendous internal stress, the surface of the metal layer shows a few coarse fractures. The corrosion of the bottom layer was exacerbated as a result of this, resulting in aesthetic problems on the plated portions. As a result, a metal plating procedure that does not fracture was created. In spite of the fact that crack-free metal is resistant to accelerated corrosion and exposure, coarse cracks nevertheless form in the metal layer during usage. A metal coating’s surface cracks and holes may actually increase the coating’s corrosion resistance in certain circumstances. To improve corrosion resistance, new procedures for creating microcrack and microporous metal were developed in the mid-1960s after extensive research on the microstructure of chrome coatings conducted in other countries.
Bright nickel, sometimes known as nickel seal, is used to create microporous metal. Bright nickel may be improved by adding insoluble nonconductive particles like barium sulfate or silicon dioxide. Using compressed air, vigorously mix the plating solution to ensure that all solid particles are evenly distributed across the nickel surface. A microporous layer of microporous chrome cannot be plated onto non-conductive particles during the metal plating process. One of the most important aspects of this procedure is finding an accelerator with outstanding performance that will help ensure that solid particles in the nickel layer are distributed evenly. Insoluble, non-conducting particles must have a diameter of no more than 1 m. Nickel seals have a thickness of between 0.5 and 1.0 micrometers.
Chromic microcracks In the mid-1960s, a novel plating technology for producing microcrack metal by plating high stress nickel was devised. The process involves plating a small coating of high stress nickel (approximately 1 millimeter thick) onto the brilliant nickel. After metal plating, the metal layer will generate microcrack metal due to nickel’s high internal tension. The PNS (pots nickelstrike) method has a metal layer with a thickness of 0 M.
Metal plating that is resistant to wear and tear
A kind of functional plating is wear-resistant metal plating. For the most part, it is used to enhance the physical and chemical qualities of mechanical components, such as hardness and wear-resistance as well as moisture and corrosion resistance.
metal wear-resistant valves, crankshafts, rainbow pistons, and piston rings are just a few examples of the many applications of metal that can be found in several industries, including automotive, plastics, and glass. Wear-resistant metal plating may extend the service life of certain devices. Wear-resistant metal may also be used to repair damaged or over-cut workpieces, allowing them to be reused.
Parts made of carbon steel matrix, as well as aluminum and aluminum alloys, zinc alloys, stainless steel, high alloy steel, and other metals, need wear-resistant metal plating. Depending on the features and needs of the plating process, substrate materials must be prepared.
Wear-resistant metal layers typically have a thickness of 250 m. Make your selections based on what the components need. Parts may be repaired with plating as thick as 8001000 m. Steel pieces do not need an intermediate coating.
For the time being, China’s wear-resistant metal plating technique relies on the following formula and process conditions:
Colorless anhydride (CrAn) 225-250G/L
Oxidizing agent: sulfuric acid 2.25 to 2.50 g/l
Trivalent metal 3 to 8 grams per liter at a temperature of between 50 and 60 degrees Celsius
55 to 60 a/dm2 current density
Pores in the chrome plating are visible
The gas red sleeve of an internal combustion engine, as well as the piston ring and the rotor engine, all of which are prone to dry friction, utilise micro loose pores.
Chrome-plated surfaces have a very limited ability to lubricate. As a result, the service life of the components is dramatically decreased while operating under circumstances of high pressure, high speed, and high temperature. This problem may be rectified by plating loose hole metal on the metal layer surface. It is possible to plate loose hole metal using several techniques.
Using rolling tools to push the substrate surface into a cone or tiny pit after sandblasting and polishing it is one mechanical approach. (2) Chemical method. After the chrome plating, the pits remain. Even though this technique is straightforward and quick to manage, the lubricating oil adhesion is less than optimal.
metal-plated surfaces are treated chemically with hydrochloric acid, which increases the size and depth of the metal-plated layer’s original fissures and holes. Many losses occur and it is difficult to dissolve uniformly with this procedure.
As a final step in the electrochemical plating process, the components are given a shot of anode porosity to accentuate and deepen the original shallow and narrow network fractures on the wear-resistant metal layer. Parts with chrome-plated surfaces are more resistant to corrosion because they store lubricating oil.
Loose hole metal plating by electrochemical technique relies heavily on the initial density of metal plating cracks, thus the composition and process parameters of metal plating solution must be carefully monitored.
Chrome plating in black.
Electrodeposited black metal has the best physical and chemical qualities of the black coatings created by chemical or electrochemical processes. It’s not only aesthetically pleasing, but it’s also resistant to wear, corrosion, and extreme temperatures.
metal-coated objects, such as guns, optical instruments, photography equipment, gold pens, and certain light industrial products such as bicycle components may all benefit from a black metal coating.
Metal metal and metal oxide constitute the bulk of the black metal coating, which is predominantly Cr2O3. The black metal coating has a hardness range of hv130150.