Cadmium metal

Cadmium metal foil is a very thin cadmium metal sheet material, with silver blue-grey metallic luster, soft texture, a certain degree of ductility, chemical properties of active, due to the toxicity of cadmium use is limited, but in the electroplating, batteries, electronic components and other fields have had many applications.

Characteristics

Element symbol: Cd

Atomic number: 48

Atomic weight: 112.41

Density: 8.65 g/cm3, relatively high density, which makes the cadmium metal foil has a certain sense of weight.

Melting point: 320.9 ℃, relatively low melting point, easy to melt under certain temperature conditions, easy to process and mould.

Boiling point: 765℃, high boiling point ensures that cadmium metal foil exists in the form of solid or liquid under the regular environment, and is not easy to volatilise.

Colour: silver blue-white, with metallic luster, the appearance of a certain degree of recognition.

Texture: soft and ductile, can be processed into very thin foils, easy to cut, stamping and other processing operations.

Thermal conductivity: 0.969 W/cm・Kelvin (@298.2K), has some thermal conductivity, but the thermal conductivity is not very high, the performance in heat transfer is in the middle level.

Specific heat capacity: 0.0555 cal/g・Kelvin (@25℃), the specific heat capacity is small, the heat absorbed or released when the temperature changes is relatively small, and the temperature changes are relatively fast.

Heat of melting: 1.46 cal/g/mol, the melting process needs to absorb a certain amount of heat to overcome the inter-atomic forces, so that it changes from solid to liquid.

Heat of Vaporisation: 23.9 kcal/g atom (@765°C), a large amount of heat needs to be absorbed during the process of vaporisation to change it from a liquid state to a gaseous state.

Resistivity: 6.83 micro ohm・cm (@0℃), low resistivity, a good electrical conductor, can effectively conduct current, this property makes it have some applications in electronics, electrical and other fields.

Electronegativity: 1.7 (Bowling scale), electronegativity reflects the ability of atoms to attract electrons in the formation of chemical bonds, cadmium is moderately electronegative, and is chemically active in the formation of compounds with other elements.

Applications

Electroplating field:

As electroplating material: cadmium metal foil can be used for electroplating to form cadmium plating layer on the surface of other metals. Cadmium plating layer has good corrosion resistance, abrasion resistance and decorative properties, and can be used to protect metal products from corrosion and abrasion, for example, plating on the surface of some mechanical parts, hardware tools and so on, to improve their service life and appearance quality.

Improve the performance of plating solution: in the plating process, cadmium metal foil can be added to the plating solution as an additive to improve the conductivity and dispersion of the plating solution, thus improving the efficiency and quality of plating.

Battery field:

Manufacture of nickel-cadmium batteries: in the past, cadmium metal foil was an important part of nickel-cadmium batteries. Nickel-cadmium batteries have high charge/discharge cycle life and good high-current discharge performance, and are commonly used in portable electronic equipment, power tools and so on. However, due to the toxicity of cadmium and the potential harm to the environment, nickel-cadmium batteries have been gradually replaced by other types of batteries (such as lithium-ion batteries, etc.).

Welding field: Cadmium metal foil can be used as a component of solder or flux in the welding process. Cadmium’s low melting point and good fluidity enable it to melt and fill the weld quickly during the welding process, improving the quality and strength of the weld. However, cadmium also needs to be used with caution in soldering applications due to the potential for cadmium vapour to be generated during the soldering process, which can be hazardous to the health of soldering workers.

Electronic component field:
Semiconductor manufacturing: Cadmium can be used in the doping of semiconductor materials to change the electrical properties of semiconductors. Cadmium metal foil can be used as a cadmium source, in the semiconductor manufacturing process through evaporation, sputtering and other methods of cadmium doped into the semiconductor material, the preparation of semiconductor devices with specific electrical properties, such as diodes, transistors and so on.

Electromagnetic shielding: Because cadmium has good electrical conductivity, cadmium metal foil can be used to make electromagnetic shielding materials. Cadmium metal foil wrapped in electronic equipment or cables around, can effectively block the external electromagnetic interference, to protect the normal operation of electronic equipment.