Cadmium metal

Cadmium metal powder is a kind of silver-white with blue luster powder, soft texture, chemical properties are more active, it has toxicity, in the industry for batteries, electroplating and other fields.

Characteristic

CAS No.: 7440-43-9

Molecular formula: Cd

Atomic number: 48

Molecular weight: 112.41

Appearance: Silver-blue-grey metallic luster powder, colour between silver-white and blue-grey.

Phase state (at room temperature and pressure): solid state

Melting point: 594.22K (321.07℃)

Boiling point: 1040K (767℃)

Density: about 8.65g/cm³ at room temperature, 7.996g/cm³ in liquid state (at melting temperature).

Coefficient of thermal expansion (at 20°C): 30.8 µm/mK

Crystal structure: Hexagonal crystal system

Resistivity: 72.7 nΩ-m

Chemical properties: Cadmium is chemically more active and can react chemically with many substances. In air, cadmium metal powder is easily oxidised. It reacts with acid to produce the corresponding cadmium salt and hydrogen.

Applications

Battery manufacturing:

Nickel-cadmium batteries: in the past, cadmium metal powder was an important part of nickel-cadmium batteries. Nickel-cadmium batteries have better charging and discharging performance and high cycle life, and were once widely used in various portable electronic devices, power tools and so on. For example, many of the batteries in early mobile phones, digital cameras and other devices used nickel-cadmium battery technology, in which cadmium plays a key role in the electrode reaction. However, due to the toxicity of cadmium, potential hazards to the environment and human health, the use of nickel-cadmium batteries has been gradually reduced, replaced by more environmentally friendly nickel-metal hydride batteries, lithium-ion batteries and so on.

Plating field:

Protective plating: cadmium metal powder can be used for electroplating on the surface of steel and other metals to form a layer of protective plating. This is because cadmium has good corrosion resistance, can effectively prevent steel rust and corrosion in harsh environments, to extend the service life of metal products. For example, in some marine environments or corrosive industrial environments, cadmium plating on metal parts can improve their corrosion resistance.

Decorative plating: In addition to the protective effect, cadmium plating can also be used to obtain a specific appearance effect. Cadmium plating has a unique luster and colour, which can add aesthetics to the product, and is commonly used in the surface treatment of some decorative items and hardware accessories.

Pigment production: cadmium compounds can be used as pigments, cadmium metal powder can be used to prepare these pigments. For example, cadmium red, cadmium yellow and other pigments have bright colours and good stability, and are widely used in plastics, paints, inks and other industries for providing products with rich colours.

Semiconductor field: In the semiconductor industry, cadmium can be used as a dopant for semiconductor materials to change the electrical properties of semiconductors. Although its application is not as extensive as common semiconductor materials such as silicon and germanium, it is still used in some specific semiconductor devices.

Nuclear reactor control rods: cadmium has a strong ability to absorb neutrons, so it can be used in nuclear reactor control rods, as a neutron absorber to control the rate of nuclear fission reaction, to ensure the safe operation of nuclear reactors.

Welding materials: Cadmium metal powder can be added to welding materials to improve the performance of welding materials. For example, in some special welding processes, the addition of cadmium can reduce the melting point of the welding material, improve the efficiency and quality of welding.