Study On The Optimization Of Wettability And Electrical Contact Properties Of AgSnO₂ Contact Materials By Second Phase Particle Size

The electrical contact is the core component of the switch electrical appliance that is responsible for making and breaking the circuit.The performance of the contact material is directly related to the capacity,life and reliability of the switching device.Therefore,electrical contact materials are very critical materials in electrical appliances.Ag Sn O₂electrical contact material is an environmentally friendly electrical contact material that has been widely used in recent years.However,in practical applications,there are also disadvantages such as increased contact resistance,severe temperature rise,poor ductility,and difficult processing.This is mainly caused by the poor wettability between its second phase Sn O₂and Ag.Scholars usually improve the wettability between the second phase Sn O₂with Ag and improve the performance of Ag Sn O₂contact materials by adopting different preparation methods and selecting appropriate additives.In recent years,some scholars have improved the performance of Ag Sn O₂contact materials by changing the particle size of the material.Sn O₂is the main component of Ag Sn O₂electrical contact materials,and the size of the Sn O₂particle size has a direct impact on the performance of Ag Sn O₂contact materials.In order to improve the performance of Ag Sn O₂contact materials,the effect of Sn O₂particle size on the wettability and electrical contact properties of Ag Sn O₂contact materials was investigated.It is expected to optimize the performance of Ag Sn O₂electrical contacts,which has important theoretical significance and practical application value.In this paper,the influence of original powder size on wettability was analyzed from the wettability basic theory.The related concepts of adhesion work and surface free energy are consulted to theoretically derive the relationship between the material particle size and wettability.Bi₂O₃and Ti O₂were selected as additives,and powder metallurgy method was used to prepare Ag Sn O₂,Ag Sn O₂/Bi₂O₃,Ag Sn O₂/Ti O₂contact materials under different particle size conditions.The wettability test and electrical contact performance test were performed on the prepared samples respectively.The wettability of the samples was tested by the site-drop method and wettability images of the samples with different particle size were obtained.The obtained images were processed to obtain the wettability angle data of each sample.Based on the wetting angle data,the influence of the second phase particle size of the material on the wettability of the contacts was analyzed and verified with the theoretical analysis.The JF04C test system was used to test the electrical contact performance of the prepared electrical contact materials,and obtained data such as contact resistance,arc energy and welding strength.The data of materials transfer and materials loss were obtained by measuring the mass change of cathode and anode contact before and after electrical contact test.According to the collected electrical performance data,the effects of second phase particle size and wettability on electrical contact properties of Ag Sn O₂contact materials were analyzed.According to the test results,the appropriate values of the second phase particle size of the three types of electrical contact materials were selected to achieve the purpose of improving the performance of Ag Sn O₂electrical contact materials.