AgNi is a silver-based composite material widely used in low-voltage switchgear, for example in load switches and circuit breakers, as well as in switchgear for control and regulation. These materials are made possible by a certain weight of Ni. The burning resistance is higher than that of pure silver, while maintaining stable contact resistance. Since Ag and Ni are not miscible in liquid state, they can only be manufactured by powder metallurgy. The traditional process involves pressing two metal powders, sintering them, and then pressing them again. However, the material made by this method is brittle and prone to blistering. The hot extrusion method can produce materials with high density and good toughness, which can be further processed into wires, strips or profiles.

    As the Ni content increases, the formability of AgNi decreases, but materials containing 30% to 40% Ni can still be processed into strips or wires. These materials can be used to manufacture contact cladding tips or rivets via chip-free automated machining processes. The brazing and welding coating performance of AgNi material is better than that of AgCdO, and there is no need to add an additional brazable layer.

    The performance of AgNi is affected by the composition, shape, size and distribution of nickel particles. Extruded AgNi has an anisotropic metallographic structure, and its burning resistance is better in the pressing direction than in the vertical direction. The electrical, thermal and chemical properties of AgNi show significant additive properties, which benefit from the insolubility of Ag and Ni.

    Special AgNi materials, such as those with fibrous structures, can be manufactured by bunching and co-forming methods, adjusting fiber diameter and composition. The burning resistance of this material is significantly improved when the fiber direction is perpendicular to the contact surface, but the manufacturing cost is high and is generally only cost-effective in special cases with high Ni content.

——The content of the article comes from the Internet