Introduction
Tin has the advantages of corrosion resistance, discoloration resistance, non-toxic, easy brazing, softness, low melting point and good ductility. Through special pre-treatment process, a firmly bonded, bright, dense, uniform and continuous alloy coating is formed on the surface of composite materials. Tin coating has been widely used in packaging industry, electronic industry, alloy manufacturing, hardware and electrical appliances due to its excellent characteristics.
Application
- Protective coating of steel plate
Based on excellent ductility and corrosion resistance, the main use of non-porous tin plating is as a protective coating for steel sheets. Metal tin is soft and ductile, so tin-plated bearings can play a role in adhesion and friction reduction.
- Surface protection of food processing and storage containers
Under sealed conditions, in some organic acid media, the potential of tin is negative than that of iron, which becomes an anodic coating with chemical protection. At the same time, because tin ions and their compounds are non-toxic to humans, tin coatings are widely used in food processing and surface protection of storage and transportation containers.
In the electronic industry, tin has low melting point, good weldability, electrical conductivity and not easy to change color. Tin plating is often used instead of silver plating, which is widely used in the surface protection of electronic components, connectors, leads and printed circuit boards. Tin plating on copper wires can not only improve solderability, but also isolate the role of sulfur in insulating materials.
Tin coating has many other uses, such as remelting tin coating in hot oil above 232°C, a bright patterned tin layer can be obtained, which is often used as a decorative coating for daily crystals.
Under certain conditions, tin will produce needle-like single crystal "whiskers", which will cause short circuits. In addition, in low temperature environments, tin is prone to "tin pest" and turns into powdered gray tin. Co-precipitation of pencil, bismuth, antimony, etc. in tin can prevent the above things from happening.
Because the tin plating layer is thin and uniform, which can greatly save the shortage of tin resources in the world, tin plating has been developed rapidly.
Classification of tin plating
According to the main salt used in electroplating, tin electroplating can be divided into alkaline tin plating and acid tin plating.
Acidic tin plating is a reaction of divalent tin, the cathode current efficiency is close to 100%, and electroplating can be carried out at room temperature. Compared with alkaline tin plating, it has the characteristics of low power consumption and low energy consumption. However, the acid tin plating solution itself has no degreasing ability, and the requirements for the pretreatment of the substrate are relatively high.
The main salts of acid tin plating are: sulfate tin plating, fluorosilicic acid, perchloric acid, fluoroboric acid, chloride, methanesulfonate, sulfamate, etc.
Alkaline stannate solution has simple composition and self degreasing ability. The plating solution has good dispersion ability. The coating has fine crystallization, few pores, and is easy to braze. However, it requires heating, consumes large energy, and has low current efficiency. The deposition rate of the coating is at least twice as slow as that of the acid solution, and it is generally a non bright coating.
The main salts of alkaline tin plating are potassium stannate and sodium stannate.
Alfa Chemistry
As a supplier of electroplating chemicals, Alfa Chemistry has always shown great interest in tin plating intermediates. Alfa Chemistry is committed to providing a wide range of tin plating intermediates. If you do not find what you need, please contact us. We also offer product customization according to customer's detailed requirements.
