copper-nickel alloy
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 of each other 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%.
Adding nickel to pure copper can significantly improve strength, corrosion resistance, hardness, electrical resistance and thermoelectric properties, 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.
Nickel-nickel copper (also called silver-nickel copper), uses: crystal oscillation element housing, crystal housing, slider for potentiometer, medical machinery, building materials, etc.
Complex white copper
The white copper alloy with manganese, iron, zinc, aluminum and other elements is called complex white copper (i.e. white copper with more than three elements), including iron white copper, manganese white copper, zinc white copper and aluminum white copper. In complex white copper, the second main element symbol and the component number group other than the copper content represent the content of various elements. For example, BMn3-12 means that the nickel content is about 3% and the manganese content is about 12%. There are 4 models of complex white copper:
① Iron white copper: models are BFe5-1.5 (Fe) -0.5 (Mn), Bfe10-1 (Fe) -1 (Mn), Bfe30-1 (Fe) -1 (Mn). The amount of iron added to iron white copper does not exceed 2% to prevent corrosion cracking. It is characterized by high strength and significantly improved corrosion resistance, especially the ability to resist flowing seawater corrosion.
② Manganese white copper: models are BMn3-12, BMn4.0-1.5, BMn43-0.5. Manganese white copper has a low temperature coefficient of resistance and can be used in a wide temperature range. It has good corrosion resistance and good processability.
③ Zinc white copper: Models include BZn18-18, BZn18-26, BZn18-18, BZn15-12 (Zn) -1.8 (Pb), BZn15-24 (Zn) -1.5 (Pb). Zinc white copper has excellent comprehensive mechanical properties, excellent corrosion resistance, good hot and cold processing formability, easy cutting, and can be made into wires, bars and plates for the manufacture of precision parts in the fields of instruments, meters, medical equipment, daily necessities and communications.
④ Aluminum white copper: Models include Bal13-3 and Bal16-1.5. It is an alloy formed by adding aluminum to copper-nickel alloy, with a density of 8.54-0.3. The alloy performance is related to the ratio of nickel to aluminum in the alloy. When Ni:Al=10:1, the alloy performance is best. Commonly used aluminum nickel silver include Cu6Ni1.5Al, Cul3Ni3Al, etc., which are mainly used for various high-strength corrosion-resistant parts in industrial sectors such as shipbuilding, power, and chemical industry.
Ordinary nickel silver
Copper-nickel binary alloy (i.e. binary nickel silver) is called ordinary nickel silver. In ordinary nickel silver, the letter B represents the content of added nickel, such as: B5 means that the nickel content is about 5%, and the rest is about copper content. Models include B0.6, B19, B25, and B30.
Industrial nickel silver
Industrial nickel silver is divided into two categories: structural nickel silver and nickel silver for precision resistance alloys (electrical nickel silver).
(1) Structural nickel silver:
Structural nickel silver is characterized by good mechanical properties and corrosion resistance, and beautiful color. Among structural nickel silver, the most commonly used are B30, B10, and zinc nickel silver. In addition, there are aluminum nickel silver, iron nickel silver, and niobium nickel silver. B30 has the strongest corrosion resistance among nickel silvers, but is more expensive. The performance of aluminum nickel silver is close to that of B30, and the price is low, so it can be used as a substitute for B30. Nickel silver has been produced and used in China since the 15th century and is known as "Chinese silver". Nickel silver or German silver also belongs to this type of nickel silver. Zinc can be dissolved in copper and nickel in large quantities, producing a solid solution strengthening effect and corrosion resistance. Nickel silver 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 nickel silver can significantly improve the strength and corrosion resistance of the alloy, and its precipitates can also produce precipitation hardening.
Structural nickel silver is widely used in the manufacture of precision machinery, chemical machinery and ship components.
(2) Nickel silver for precision resistance alloys (electrical nickel silver):
Nickel silver for precision resistance alloys (electrical nickel silver) has good thermoelectric properties. BMn 3-12 manganese copper, BMn 40-1.5 constantan, BMn 43-0.5 copper tin 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, 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 resistivity temperature coefficient, and is suitable for making standard resistance elements and precision resistance elements. It is a material for manufacturing precision electrical instruments, rheostats, meters, precision resistors, strain gauges, etc. Constantan and copper tin have high thermoelectric potential and can also be used as thermocouples and compensation wires.
