Effect Of Relative Humidity On The Triboelectric Wear Of Copper

With the development of science and technology and the progress of the industry,the current carrying friction pairs are used more and more in the fields of transportation,aerospace,high voltage switch,micro electro mechanical system and so on.The damage of current carrying friction pairs is affected by many factors,such as service conditions and environmental factors.Based on a single point contact triboelectric wear tester equipped with atmosphere chamber,Wear mechanism of copper materials under controlled humidity was investigated under sliding contact.when RH was set as 10%,60%,92%,the wear depth declined 0.628 ?m,0.672 ?m,2.187 ?m after loading 10 A current on the sliding pairs.When the humidity was 10%,severe adhesive wear occurred on the Cu,and adhesive wear with the increase of the current,still has a large number of performance for the adhesion.When the humidity is 60%,there is a small amount of adhesion on the friction surface.With the increase of the current,the adhesion is reduced and the surface becomes smooth.When the humidity is 92%,with the increase of the current,the adhesive wear is retarded and the surface roughness decreased.The method of Material removal is abrasive wear and a small amount of spalling.The results suggested that the wear mechanism was affected by the coeffects of current and humidity.The oxidation of wear surface was improved by the coeffects of current and humidity,especially when the humidity is 92% and the current is 10 A,the number of oxygen atoms on the surface increases by 2.55 times.It is obvious that the mechanism of the influence of the friction induced by mechanical action and the current induced electrochemical oxidation on the current carrying wear is different.without electricity,the humidity increase contributes to the material removal but did not significantly improve the adhesive wear;electrochemical oxidation occurs through current,oxidation degree increased significantly,the degree of oxidation was increased,and formed oxide film which reduces the adhesive wearFor the current carrying friction pairs,the increase of the humidity increases the friction chemical oxidation and electrochemical oxidation,which results in the increase of surface oxidation and the formation of the wear form transform from the adhesive wear to abrasive wear and oxidation wear.The results of this paper are helpful to understand the surface oxidation and surface contact state of the current carrying friction pairs in humidity environment.At the same time,the results of humidity control can be directly applied to the transformation of current carrying friction tester.