Research Of Additive Particle Size On Properties Improvement Of AgSnO₂ Contact Materials For Low-voltage Electrical Appliances

Electrical contact is the core component of low-voltage switch electrical appliances,and the reliability of electrical contact is a key index to evaluate its performance.AgSnO₂contact material is now widely used in low-voltage switch electrical equipment in the environmental protection material,but AgSnO₂ electrical contact material generally has a large contact resistance,higher temperature rise defects,mainly because of the melt silver and the second phase SnO₂ wettability is poor.A large number of studies have shown that the introduction of additives can improve the wettability of the silver matrix and the second phase,and the particle size is one of the basic physical properties of the powder,which directly affects the final properties of the material to some extent.The effects of particle size of additives on wettability,physical properties and electrical contact properties of AgSnO₂ contact materials for low-voltage electrical appliances are discussed in this paper.At first,Bi₂O₃ and La₂O₃ oxides were firstly selected as additives in this paper,and six different particle size values of additives were determined in combination with electrical contact related research and powder particle size common in the market.The wetting angles of AgSnO₂,AgSnO₂/Bi₂O₃ and AgSnO₂/La₂O₃ contact materials under different particle size conditions were measured respectively,and their variation laws were analyzed.Secondly,three contact materials AgSnO₂,AgSnO₂/Bi₂O₃ and AgSnO₂/La₂O₃ were respectively prepared by powder metallurgy.The conductivity,density and hardness of AgSnO₂ contact materials were tested,and the effect of additive particle size on the physical properties of AgSnO₂ contact materials was analyzed.JF04C electric contact tester was used to test contact resistance,arc energy,fusion welding force,material transfer and loss,and analyze the effect of additive particle size on the improvement of electrical contact performance of AgSnO₂ contact materials.Finally,the influence degree of additive particle size on the properties of contact materials was evaluated by grey correlation degree and improved entropy weight TOPSIS method.Combined with the test and evaluation results,when determining the particle size of additives respectively,the properties of AgSnO₂/Bi₂O₃ and AgSnO₂/La₂O₃ contact materials are relatively better,so as to improve the properties of AgSnO₂ contact materials for low-voltage electrical appliances.