Among copper alloys, nickel silver has excellent corrosion resistance and is easy to shape, process and weld.
It is widely used as corrosion-resistant structural parts in shipbuilding, petroleum, chemical industry, construction, electricity, precision instruments, medical equipment, musical instrument manufacturing and other departments. Some nickel silver also has special electrical properties and can be used to make resistor elements, thermocouple materials and compensation wires. Non-industrial nickel silver is mainly used to make decorative handicrafts.
White copper composition
White copper is a copper-based alloy with nickel as the main added element. It is silvery white and has a metallic luster, hence the name white copper. Copper and nickel can be infinitely dissolved in each other to form a continuous solid solution, that is, no matter how much the proportion is, it is always an α--single-phase alloy. When nickel is melted into red copper and the content exceeds 16%, the color of the resulting alloy becomes as white as silver. The higher the nickel content, the whiter the color. The nickel content in white copper is generally 25%.
Advantages and Disadvantages
Adding nickel to pure copper can significantly improve strength, corrosion resistance, hardness, electrical resistance and thermoelectricity, and reduce the temperature coefficient of resistivity. Therefore, white copper has exceptionally good mechanical and physical properties compared to other copper alloys. It has good ductility, high hardness, beautiful color, corrosion resistance, and deep drawing properties. It is widely used in shipbuilding, petrochemical industry, electrical appliances, instruments, medical equipment, In daily necessities, handicrafts and other fields, it is also an important resistor and thermocouple alloy. The disadvantage of white copper is that the main added element-nickel is a scarce strategic material and is relatively expensive.
Common white copper
Copper-nickel binary alloy (i.e. binary white copper) is called common white copper. In common white copper, the letter B indicates the content of nickel, such as B5 indicates that the nickel content is about 5%, and the rest is about copper content. Models include B0.6, B19, B25, and B30.
Industrial white copper
Industrial white copper is divided into two categories: structural white copper and white copper for precision resistance alloy (electrical white copper).
(1) Structural white copper: Structural white copper is characterized by good mechanical properties and corrosion resistance, and beautiful color. Among structural white copper, the most commonly used are B30, B10 and zinc white copper. In addition, there are aluminum white copper, iron white copper and niobium white copper. B30 has the strongest corrosion resistance among white coppers, but is more expensive. Aluminum white copper has similar performance to B30 and is inexpensive, so it can be used as a substitute for B30. Zinc white copper has been produced and used in China since the 15th century and is called "Chinese silver". The so-called nickel silver or German silver also belongs to this type of zinc white copper. Zinc can be dissolved in copper and nickel in large quantities, producing a solid solution strengthening effect and corrosion resistance. Zinc white copper can be smoothly cut into various precision parts after adding lead, so it is widely used in instruments and medical devices. This alloy has high strength and corrosion resistance, good elasticity, beautiful appearance and low price. The aluminum in aluminum white copper can significantly improve the strength and corrosion resistance of the alloy, and its precipitates can also produce precipitation hardening. Structural white copper is widely used in the manufacture of precision machinery, chemical machinery and ship components.
(2) White copper for precision resistance alloy (electrical white copper): White copper for precision resistance alloy (electrical white copper) has good thermoelectric properties. BMn 3-12 manganese copper, BMn 40-1.5 constantan, BMn 43-0.5 copper and new constantan with manganese instead of nickel (also known as nickel-free manganese white copper, containing 10.8-12.5% manganese, 2.5-4.5% aluminum and 1.0-1.6% iron) are manganese white copper with different manganese contents. Manganese white copper is a precision resistance alloy. This type of alloy has high resistivity and low temperature coefficient of resistivity, and is suitable for making standard resistance elements and precision resistance elements. It is a material for making precision electrical instruments, rheostats, meters, precision resistors, strain gauges, etc. Constantan and copper have high thermoelectric potential and can also be used as thermocouples and compensation wires.
Density of white copper: White copper is an elegant name for copper-nickel alloy, and its density is between copper and nickel, 8.9--8.88
