Tin Alloy

What Is Tin Alloy?

Tin alloy is a non-ferrous alloy composed of tin as the base and other alloying elements. The main alloying elements are lead, antimony, copper and so on. Tin alloy has low melting point, low strength and hardness. It has high thermal conductivity and low thermal expansion coefficient, is resistant to atmospheric corrosion, has excellent anti-friction properties, and is easy to weld with steel, copper, aluminum and its alloys. , Is a very good solder and also a very good bearing material.

Tin can interact with lithium, sodium, potassium, copper, silver, and gold of group I of the periodic table, beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, and mercury of group II, and aluminum of group III , Gallium, indium, thallium, ytterbium, lanthanum, uranium, and group IV silicon, germanium, lead, titanium, zirconium, hafnium, and group V phosphorus, arsenic, antimony, bismuth, vanadium, niobium, and group VI Group selenium, tellurium, chromium, and group VII manganese and group VIII iron, cobalt, nickel, rhodium, palladium, platinum, etc. form binary and multiple alloys and intermetallic compounds.

Binary alloys of tin mainly include: Sn-PbSn-Sb, Sn-Bi, Sn-Fe, Sn-Cd, Sn-Al, etc.

The Properties Of Tin

The element symbol is Sn, the atomic number is 50, and the atomic weight is 118.69. Metal tin is a heavy non-ferrous metal material with a low melting point. Tin has a low melting point, low strength, hardness, high plasticity, and low recrystallization temperature. It does not produce obvious work hardening after cold working. Tin is mainly pressure processed into plates and foils, which are used to manufacture parts in industrial sectors such as electrical appliances and meters.

Tin has a β-Sn⇌α-Sn allotropic transformation in the solid state. Above 13°C, β tin is stable; below 13°C, α tin is stable. Beta tin has a body-centered cubic crystal lattice, which is white, and is also called “white tin”; α tin has a diamond-shaped cubic crystal lattice, which is gray, and is also called “gray tin.” When β tin is transformed into α tin, the specific volume increases by about 27%, and the whole piece of white tin will turn into gray powder. This phenomenon is called “tin epidemic”. The white tin block is in close contact with the gray tin at room temperature and will also be infected. It will gradually rupture spontaneously into the metal along the contact part. In order to prevent “tin epidemic”, the storage and transportation temperature of tin should not be lower than 10°C. Tin is extremely stable in the atmosphere, and is not corroded in softened fresh water. The corrosion rate in hard tap water is very small, only 0.001～0.0046g/(m·d).

The main physical and mechanical properties of tin are shown in the table below.

Performance	Data
density（20℃）/g•cm-3 Melting point/℃ Boiling point/℃	7.3 231.9 2625
Average mass heat capacity（0～100℃）/J•（kg• K）-1	226
Heat of fusion/kJ•mol-1 Heat of vaporization/kJ•mol-1 Thermal conductivity（0～100℃）/W•（m•K）-1 Resistivity（20℃）/μΩ•cm tensile strength/MPa Elongation/% Brinell hardness (as cast)/MPa	7.08 296.4 73.2 12.6 16.7 80～90 49～52

The Uses Of Tin Alloys

Tin alloys have good corrosion resistance and are widely used as coating materials. Sn-Pb series (62% Sn), Cu-Sn alloy series are used for bright anti-corrosion hard coatings, and Sn-Ni series (65% Sn) Used as a decorative anti-corrosion coating. Sn-Zn series alloys (75% Sn) are used in electronic components and televisions, radios, etc. The Sn-Cd series alloy coating has seawater corrosion resistance and is used in the shipbuilding industry. Sn-Pb alloy is a widely used solder. The alloy solder composed of tin and antimony, silver, indium, gallium and other metals has the characteristics of high strength, non-toxicity, and corrosion resistance, and has special uses. Tin and bismuth, lead, cadmium, and indium form a low melting point alloy. In addition to being used as an insurance material for electrical equipment, steam equipment and fire protection devices, it is also widely used as a medium and low temperature solder. Tin-based bearing alloys are mainly based on Sn-Sb-Cu and Sn-Pb-Sb series. The addition of copper and antimony can increase the strength and hardness of the alloy.

The Classification Of Tin Alloys

Commonly used tin alloys are divided into:

•  – Tin-based bearing alloy. Collectively referred to as Babbitt alloy with lead-based bearing alloy. Contains 3% to 15% antimony, 3% to 10% copper, and some alloy varieties also contain 10% lead. Antimony and copper are used to improve the strength and hardness of the alloy. Its friction coefficient is small, and it has good toughness, thermal conductivity and corrosion resistance. It is mainly used to manufacture sliding bearings.
•  – Tin solder. Mainly tin-lead alloy, and some tin solder also contains a small amount of antimony. Tin alloy containing 38.1% of lead is commonly known as solder, with a melting point of about 183°C. It is used for welding components in the electrical instrument industry, as well as for sealing automobile radiators, heat exchangers, and food and beverage containers.
•  – Tin alloy coating. Utilizing the anti-corrosion properties of tin alloy, it is coated on the surface of various electrical components, which is both protective and decorative. Commonly used are tin-lead series, tin-nickel coatings and so on.
•  – Pin alloy (including lead-tin alloy and lead-free tin alloy) can be used to produce various exquisite alloy jewelry and alloy crafts, such as rings, necklaces, bracelets, earrings, brooches, buttons, tie clips, hat ornaments, and craft ornaments , Alloy photo frames, religious emblems, miniature statues, souvenirs, etc.

The Prospects Of Tin Alloy

Tin alloys are widely used in various industries such as industry, agriculture, defense technology, medicine, etc., and are commonly used in the electronics industry, such as electronic components, solders, fuses, etc. Many tin companies are now vigorously researching the composition, structure and properties of tin alloys, and carrying out deep processing of tin. This will not only provide scientific basis for researching new tin alloy materials, formulating hot working process plans, and opening up new application areas of tin alloys, Moreover, reduction smelting in tin metallurgy, crude tin fire refining, and certain intermetallic compounds of tin are of great significance in many aspects such as the semiconductor industry and the preparation of superconducting materials. Tin is easy to form compounds with many metal and non-metal elements in the periodic table. Due to the diversity of its atomic bonds and crystal structure, this type of compound has many special physical and chemical properties, which shows the search for new materials and new uses of tin. Broad prospects.