Zinc-nickel copper strip
Nickel-nickel strip, a member of the nickel-nickel series, offers excellent elasticity, corrosion resistance, and weldability, while also boasting an attractive silvery-white luster. It is widely used in electronics, watches, medical devices, and other fields. Key grades include BZn15-20 and BZn18-18. BZn15-20 strip has an elastic limit of ≥250 MPa, making it suitable for springs and elastic components. BZn18-18 strip offers superior corrosion resistance and is primarily used in humid or corrosive environments. Strip thickness ranges from 0.05-3 mm, widths from 50-600 mm, dimensional tolerances of ±0.005 mm, and a surface finish of Ra ≤0.4 μm, meeting the requirements of precision stamping and welding.
The production process for white copper strip requires multiple precision machining steps to ensure dimensional accuracy and uniform performance. First, high-quality ingots are produced using the same smelting and casting processes as white copper sheet. After hot rolling to a thickness of 10-15mm, the ingots undergo an initial cold rolling process to a thickness of 2-5mm. Intermediate annealing at 550-600°C eliminates work hardening. In the finishing rolling stage, the strip is rolled to the target thickness through multiple passes at a rolling speed of 30-60m/min, with a controlled reduction of 10-20% per pass to ensure flatness (flatness deviation ≤ 0.5mm/m). For products requiring high elasticity, low-temperature annealing (300-350°C) is required to achieve a hardness of HV 150-200. After slitting and cleaning, the finished strip undergoes a bend test (180° crack-free) and weldability testing to ensure product quality.
In the electronics field, zinc-nickel copper strip is a core material for connectors and shielding components. The RF connectors of 5G communication equipment use 0.1-0.3mm thick BZn15-20 strip, which is precision-stamped to form contact springs. Its excellent elasticity ensures a plug-in/plug-out cycle of 10,000 or more, reducing connector failure rates by 30% for one communications equipment manufacturer. Smartphone shielding covers use 0.05-0.1mm thick zinc-nickel copper strip. Through stamping and welding, it achieves a shielding effectiveness of 80dB or more against electromagnetic interference, improving signal stability for one mobile phone brand by 20%. Laptop battery connectors use BZn18-18 strip, whose corrosion resistance ensures over five years of use in humid environments. This has reduced the battery interface repair rate for one computer manufacturer by 40%.
Nickel-nickel copper strip is widely used in the watchmaking and precision instrument industries. High-end mechanical watch cases and straps utilize 0.5-1mm thick nickel-nickel copper strip. Through stamping, polishing, and electroplating, its appearance rivals that of silver, while offering better wear resistance than sterling silver. One watch brand’s straps have a lifespan of up to 10 years. Precision instrument hands and scales utilize 0.1-0.2mm thick BZn15-20 strip. Its excellent ductility allows for the production of fine scales, improving the reading accuracy of one precision instrument by 15%. Timer springs utilize 0.05mm thick nickel-nickel copper strip, boasting an elastic recovery rate of ≥95%. One timer maintains a timekeeping error within ±1 second per day.
With the advancement of high-end manufacturing and consumer upgrades, the performance of zinc-nickel silver strip continues to innovate. Manufacturers have developed ultra-thin zinc-nickel silver strip (0.01-0.03mm thick) for use as conductors in flexible electronic devices, with a wearable device boasting a flex lifespan of 50,000 cycles. Heat-resistant zinc-nickel silver strip has been developed for high-temperature environments, with an elasticity retention rate of ≥90% at 150°C. Suitable for automotive electronic sensors, it has improved the stability of engine sensors for one automaker by 25%. Using asynchronous rolling technology, the strip’s thickness tolerance is controlled to ±0.002mm, increasing connector assembly accuracy at one electronics factory to 99.8%. In the future, as electronic devices evolve towards miniaturization and higher precision, zinc-nickel silver strip will evolve towards thinner gauges and higher elasticity to meet the needs of more high-end applications.
