Silver alloy properties

1. Sterling silver, fine-grained silver contacts, contacts, rivets, contacts

Sterling silver contacts Sterling silver has the highest electrical conductivity, thermal conductivity, plasticity and arc corrosion resistance, and has low contact resistance, easy processing and welding, so it is an ideal contact material for making continuous closed electrical connections (electrical connection material). It is currently one of the most commonly used materials in small-capacity low-voltage electrical appliances. Such as automatic switches, thermostats, roasters, ovens, timers, thermal relays, computers, etc. Fine-grained silver is the addition of trace elements to silver to refine the grains, so it has similar electrical and thermal conductivity and stable contact resistance as silver, and has better strength and hardness than silver, and electrical life is higher than pure silver.

2. Ag/Cu composite contact

Silver copper has high hardness and good wear resistance, and is mainly used in electrical appliances with sliding friction when the contacts are opened and closed.

The contact has good electrical conductivity and the surface is not easy to be oxidized. When copper (3-28%) is added, the burning resistance of silver can be significantly improved. Therefore, the contact material doped with copper can be applied to currents up to 16A. strength. Because the addition of copper, especially when the copper content is high (such as 10%), can reduce the material transfer phenomenon under DC working conditions. It is widely used in the whole field of electrical switches, such as AC contactors, relays, power tool switches, buttons, timers, household appliances, etc.

3. AgNi/Cu composite contacts AgNi5/Cu, AgNi10/Cu, AgNi15/Cu, AgNi20/Cu

Silver-nickel electrical contacts have good electrical conductivity. The contact resistance is small and stable, the material transfer under DC current is small, the wear resistance is good, and it is non-toxic. Silver-nickel 10 is manufactured by co-precipitation powder sintering extrusion method, silver-nickel 20 and silver-nickel 30 are manufactured by powder sintering extrusion method, and the contacts are widely used in AC switches as electrical contacts in low-voltage technology. The advantage is that it can be welded to the contact bridge without an additional weldable layer, so that the preparation process of the contact parts can be simple and economical. Such as relay command switches, cam switches, auxiliary contactors, instrument switches, thermostat washing machine timers, automatic switches, relays, automotive electrical switches, etc.

A silver alloy made by adding nickel to silver. Adding a small amount of nickel can refine the grains, improve the hardness, wear resistance and burnout resistance of silver, and the contact resistance is also slightly increased. Since silver and nickel are not mutually soluble, they are prepared by powder metallurgy, and the nickel content is generally 5% to 40%. The silver-nickel alloy electrical contact material has good electrical and thermal conductivity, strong resistance to metal transfer, arc burning, electrical erosion, good wear resistance, high strength, and good ductility and cutting ability. The resistance is higher than that of silver, and the physical properties of silver-nickel alloys are shown in the table. To prepare silver-nickel alloy, chemical co-deposition method was used to obtain silver and nickel mixed powder, and then chemical method was used to make silver and nickel-coated powder. The general process of chemical pulverizing is more complicated and the cost is high. With the development of pulverizing technology, in recent years, the mechanical atomization method has been used to obtain extremely fine powder, and then mixed, pressed, sintered, and extruded to obtain silver with the same reliable performance. Nickel alloy. Recently, silver and nickel co-spray powder and mechanical alloying technology have been developed, and the obtained material has better performance. A small amount of rare earth elements can be added to the silver-nickel alloy to improve its properties. Silver-nickel alloys are mostly used in low-voltage electrical appliances. AgNi10 is mostly used for AC contactors below 20A; AgNi (15-40) can withstand larger loads. As a contact material, silver-nickel alloy is widely used in various switches, controllers, voltage regulators, circuit breakers, automotive electrical appliances, magnetic starters and so on.


4. Silver cadmium oxide/copper composite contacts AgCdO10/Cu, AgCdO12/Cu, AgCdO15/Cu

Silver cadmium has good electrical conductivity and has a certain arc extinguishing ability. Silver-cadmium alloy contacts are often used for contact electricity of car horn electrical appliances and some instruments. Silver cadmium oxide is resistant to electrical wear, anti-welding, and has low and stable contact resistance. In silver cadmium oxide, cadmium oxide is dispersed in the silver matrix, thus increasing the hardness and wear resistance of the material. When the dispersed cadmium oxide particles are decomposed under the action of the arc, a large amount of heat is absorbed, which is beneficial to cooling and extinguishing the arc. Vigorous evaporative blowing arc occurs during decomposition, purifying the contact surface, thereby reducing electrical wear, increasing electrical life and maintaining low contact resistance. The silver cadmium oxide wire is manufactured by the pre-oxidation method; the silver cadmium oxide contact piece is added with trace elements (T) and is manufactured by the alloy internal oxidation method, and the brazing surface has a silver layer.

This contact is the most important class of silver-metal oxide contact materials. What determines the special properties of the contact is the fine CdO in the silver lattice points. When the temperature is higher than 900°C, CdO sublimates, which cools the contact surface, reduces the arc energy and extinguishes the arc, and at the same time, the presence of cadmium oxide improves the welding resistance of the contact. Typical application range: low voltage contactors, relays, automatic switching flash relays, auxiliary switch series, timers, starters, circuit breakers and leakage protection switches, such as CJ10, CJ20 series, S060 small switches and TH series circuit breakers.


5. Silver zinc oxide/silver tin oxide AgZnO/AgSnO

Silver tin oxide is processed from powder by special process, and has excellent resistance to arc erosion, wear resistance and welding resistance. It is an ideal environmentally friendly electrical contact material to replace silver cadmium oxide, and has been gradually used in the fields of AC and DC contactors, relays and low-voltage circuit breakers. The oxide of this contact has higher thermal stability than CdO. For AgZnO contact materials, because ZnO has high stability, the contact resistance is increased, but it can be compensated by structural means. For example, higher contact forces can be used.

In the AgSnO material, due to a small amount of special metal oxide additives, its contact resistance is guaranteed to be within the allowable range. When disconnected, the performance of the contact is determined by burning, arcing and arcing. In this regard, silver-metal oxide contact materials are mainly characterized by burn resistance. The AgCdO contact material produced by powder metallurgy method is more resistant to burning and less arcing than the material prepared by internal oxidation method. In the high load state, the material loss of AgSnO material is significantly lower than that of AgCdO. AgCdO13 contact material also showed similar performance. AgZnO material is most suitable for contactors and air switches with large switching capacity. Such as DZ5, DZ12, DZ13 and DZ15 series circuit breakers, TCK7 DC contactors and leakage switches. AgSnO2 contact material is environmentally friendly and non-toxic, and has excellent resistance to welding and arc erosion. Generally speaking, under the condition of large current, AgSnO2 has better arc erosion resistance than AgCdO; under lamp or capacitive load, AgSnO2 shows stronger resistance to current impact than AgCdO and AgNi; The contact resistance of AgSnO2 is slightly higher than that of AgCdO under normal load, but it shows low and stable contact resistance under DC lamp or motor load; under DC condition, AgSnO2 material transfers less than AgCdO. AgSnO2 contact material is widely used in medium and large capacity AC/DC contactors, AC/DC power relays, automotive electrical appliances and medium and small capacity low voltage circuit breakers.


6, silver tin oxide indium oxide contacts, contacts, rivets AgSnO2In2O3

Silver tin oxide indium oxide (AgSnO2ln203) is currently the most commercially valuable alternative material for silver cadmium oxide (AgCdO), because it has better stability and higher hardness than silver cadmium oxide, so it has better resistance to fusion welding And the resistance to burnout, especially the needle-like oxide precipitated during the internal oxidation process is oriented perpendicular to the surface of the contact, which is very beneficial to the performance of the contact. This material replaces AgCdO material and is used in the field of low-voltage electrical appliances such as circuit breaker switches, relays, etc., especially for automotive DC electrical appliances such as contact