Study On Fretting Characteristics And Environmental Characteristics Of Contact Pairs Of Different Materials

Fretting and the environment are two factors that have the greatest impact on the reliability of electrical connectors during storage and use.In this paper,the contact properties of different substrate materials are used to study the fretting properties and environmental characteristics of the research object.Based on the fretting contact resistance test system,the variation of the fretting-contact resistance and the fretting wear characteristics of the contact pair under the influence of contact pressure,ambient temperature,substrate material and material thickness were investigated.Accelerated temperature and humidity experiments and salt spray corrosion experiments were carried out on the contact pairs after the fretting,and the environmental characteristics of the contact pairs were evaluated by testing the change values of the static contact resistance in the fretting area before and after the accelerated environmental experiment.In this paper,the contact of 7 different materials is used as the research object.They are:Au(Bronze)-Ni(Cu),Au(Bronze)-Ag(Cu),Au(Bronze)-Sn(Cu),Ag(Bronze)-Ni(Cu)),Ag plating(yttrium copper)-plating Sn(Cu),Ag plating(yttrium copper)-Au(pcb)plating,Sn plating(yttrium copper)-Au(pcb)plating.It was found that as the contact pressure increases,the fretting performance of the contact pair becomes superior.This influence law has nothing to do with the plating material and the ambient temperature.It is not the thicker the surface coating thickness,the better the fretting performance of the contact pair.The probability of obtaining fine fretting performance at medium thickness is lower than that of thin coating thickness and thick plating thickness.The fretting performance of the contact pair at high temperatures is better than at room temperature.When the contact pressure is 50 g,the order of the excellent contact performance percentage is(thickness,high temperature)>(thin thickness,high temperature)>(medium thickness,high temperature)>(medium thickness,room temperature).When the contact pressure is 100 grams,the order of the excellent contact performance percentage is(thickness,high temperature)>(thin thickness,high temperature)=(medium thickness,room temperature)>(medium thickness,high temperature).All contact pairs can obtain optimal fretting contact performance under certain conditions.The contact resistance is between 19 mΩ-34 mΩ,and the material of contact has little effect.The contact pairs can also obtain the worst fretting contact performance under certain conditions.The contact resistance value can be divided into two kinds:more than 500 mZ,100 mQ-500 mn.In the analysis of the results of five groups of orthogonal experiments,it can be found that among the three main factors affecting fretting performance,temperature,coating thickness and pressure,pressure has the greatest impact on Fretting performance.With the increase of contact pressure,the fretting performance of the contact pair becomes better.The influence law of the influencing factors is similar to the experimental results of the overall fretting experiment.Compared with gold plating,the fretting sensitivity of silver plating is weaker.Seven kinds of contact pairs were subjected to fretting experiments under various fretting conditions,and the temperature and humidity environment storage and salt spray environment storage experiments were carried out respectively.After the experiment,the static contact resistance of the fretting area was tested,and the result was a humid heat and salt spray environment.The contact resistance after storage is increased compared to before storage.Different materials increase in different proportions.