Zinc-nickel copper plate
Nickel-nickel silver sheet is an alloy composed of copper with nickel and zinc added. Due to its silvery-white metallic luster and excellent corrosion resistance, it is also known as “German Silver.” It is widely used in instrumentation, medical equipment, and decorative applications. Common grades include BZn15-20 (15% nickel, 20% zinc) and BZn18-18 (18% nickel, 18% zinc). BZn15-20 offers the most balanced overall performance, with a tensile strength of ≥400 MPa and an elongation of ≥25%, combining sufficient strength with good processability. Sheet thickness typically ranges from 0.5-10 mm and widths up to 1000 mm. The surface finish is Ra ≤ 0.8 μm and can be polished to a mirror finish, meeting the aesthetic requirements of decorative and precision components.
The production process for zinc-nickel silver sheet requires precise control of alloy composition and rolling parameters to ensure stable performance. First, high-purity electrolytic copper (99.95%), nickel plate (99.9%), and zinc ingot (99.9%) are selected as raw materials and smelted proportionally in a medium-frequency induction furnace at a temperature of 1150-1200°C under an inert gas atmosphere to prevent oxidation. Thorough stirring is required during the smelting process to ensure uniform distribution of nickel and zinc elements, with compositional deviations controlled within ±0.5%. Ingots are semi-continuously cast to a thickness of 300-500mm and then undergo homogenization annealing (650-700°C for 6-8 hours) to eliminate casting stress and compositional segregation. During the hot rolling stage, the ingot is heated to 800-850°C and rolled in multiple passes to a thickness of 10-20mm, with a reduction of 20-30% per pass. Cold rolling is used to produce thin-walled sheets, gradually rolling to the target thickness. Intermediate annealing temperatures are set at 500-550°C to restore the material’s plasticity. After straightening (straightness ≤ 1mm/m) and trimming, the finished sheets undergo corrosion resistance testing (salt spray test ≥ 2000 hours) and mechanical property testing to ensure quality.
In the instrumentation field, zinc-nickel silver sheet is an ideal material for precision components. The pointers and dials of aviation instruments are made of BZn15-20 sheet. Its silvery-white color contrasts sharply with the instrument scales, improving reading clarity by 30%. One aviation instrument manufacturer achieved a 99.5% product qualification rate. The casings of marine surveying and mapping instruments are made of 3-5mm thick zinc-nickel silver sheet, which resists corrosion from seawater and humid air. One marine instrument showed no visible rust after 1000 hours of testing in a salt spray environment. The load plates of precision balances are made of 1-2mm thick zinc-nickel silver sheet. After mirror polishing, the surface roughness Ra is ≤0.02μm, minimizing the impact of airflow on weighing accuracy. The measurement error of a laboratory balance is controlled within ±0.1mg.
The medical device and food industries have strict requirements for the corrosion resistance and safety of zinc-nickel-copper plate. Surgical instrument handles and housings are made of BZn18-18 plate. This surface passivation treatment eliminates toxic precipitates and complies with ISO 10993 biocompatibility standards. A medical device manufacturer’s surgical forceps have received EU CE certification. Contact components of food packaging machinery are made of zinc-nickel-copper plate, which resists corrosion from acidic and alkaline food substances while preventing metal ion migration and contamination. This has extended the service life of equipment on a canning production line to eight years. Dental instrument trays utilize 1mm-thick zinc-nickel-copper plate, which combines strength with resistance to oral fluid corrosion. Customer satisfaction at a dental equipment manufacturer has increased by 25%.
With the development of high-end manufacturing, the performance of zinc-nickel silver sheet continues to improve. Manufacturers have developed high-strength zinc-nickel silver sheet (tensile strength ≥500 MPa) for use in the casings of deep-sea exploration instruments. It can withstand pressure at a depth of 500 meters (approximately 5 MPa), resulting in a 40% increase in the equipment availability rate of a deep-sea detector. For the decorative sector, antibacterial zinc-nickel silver sheet (with added silver ions) has been developed, with an inhibition rate of ≥99% against Staphylococcus aureus. After adopting this material in the copper decorations of a high-end hotel, the pass rate in hygiene inspections increased to 100%. Continuous rolling technology is used in the production process, achieving a thickness tolerance of ±0.01 mm. This has increased the assembly efficiency of precision components at an instrument factory by 15%. In the future, with the advancement of medical and marine engineering, zinc-nickel silver sheet will develop features with even higher corrosion resistance and improved processing properties, expanding its application in high-end fields.
