Electrical contacts are core components in electrical switches, responsible for making and breaking circuits and carrying load currents. They are widely used in low- and high-voltage electrical equipment—such as air circuit breakers, relays, and AC/DC contactors—across sectors ranging from civilian use to military, aerospace, and aviation applications. Presented below is a method for preparing an eco-friendly silver-tungsten alloy electrical contact material.
Image of the preparation method for silver-tungsten alloy electrical contact materials
This method for preparing silver-tungsten alloy electrical contact materials addresses the issues of cadmium contamination and susceptibility to overheating during use associated with existing silver-cadmium oxide contact materials. The preparation method comprises the following steps:
(1) Melting pure silver ingots and atomizing them to produce pure silver powder;
(2) Mixing the pure silver powder with tungsten powder to form a silver-tungsten mixed powder, with a composition of 70 wt% pure silver powder and 30 wt% tungsten powder;
(3) Further pulverizing the silver-tungsten mixed powder via ball milling for a duration of 20–28 hours;
(4) Compacting the pulverized silver-tungsten mixed powder into a green compact using cold isostatic pressing;
(5) Sintering the green compact into a silver-tungsten alloy ingot;
(6) Cutting the silver-tungsten alloy ingot into the specified dimensions for the electrical contact.
Important considerations for this preparation method:
1) In step (1), the melting temperature is 1150°C with a refining time of 3 minutes; the pure silver powder has a particle size of -150 mesh.
2) In step (3), the ball-to-powder ratio is 5:1.
3) The sintering process in step (5) involves repeated pressing and sintering; for each pressing cycle, the pressure is 300 MPa and the holding time is 3 minutes; for each vacuum sintering cycle, the temperature is 900°C and the sintering time is 3 hours. Silver-tungsten alloy electrical contact materials prepared using this method serve as excellent substitutes for silver-cadmium oxide contact materials; they offer a combination of advantages—including being non-toxic, thermally stable, and resistant to contact welding—and are widely used in applications such as home appliances, lighting switches, protective switches, contactors, and power relays.
Post time: Oct-08-2026