Sliding Contact Characteristics And Reliability Analysis Of Different Contact Materials Of Connector

The golden finger connector adopts the structure form of the combination of the golden finger of the circuit board and the elastic reed socket,and forms a connection or disconnection connection through the insertion operation.During insertion and pullout,the contact interface of golden finger connector is equivalent to sliding contact pair,and there are problems of sliding wear and material corrosion.Because of the need to improve the flow capacity of golden finger connector,the contact still has the problem of temperature rise and heating.Therefore,new requirements are put forward for the sliding electrical contact characteristics,wear resistance and environmental reliability of golden finger connector matching materials.Based on the background of the expansion of a golden finger connector,the sliding electrical contact characteristics and environmental corrosion resistance of contact pairs are studied,aiming at the contact surface materials,coating thickness,contact pressure and environmental temperature of commonly used power connectors,so as to provide material selection suggestions for practical application.Through the sliding simulation experiment system,the contact resistance of the sliding electrical contact process was measured by contact,and the wear was detected by non-contact three-dimensional topography instrument.Orthogonal experiments were designed to study the effects of contact on the combination of contact and sample coatings,coating thickness,sliding period,contact pressure and ambient temperature on sliding contact resistance and sliding wear.Finally,the environmental reliability of each contact combination was studied by salt spray corrosion test and sliding resistance retest.The material combinations studied in this paper include Au(beryllium copper)-Sn(copper),Ag(beryllium copper)-Ag(copper),Au(beryllium copper)-Ag(copper),Ag(beryllium copper)-Au(PCB),Sn(beryllium copper)-Sn(copper),Au(beryllium copper)-Au(PCB),Au(beryllium copper)-Au(PCB).The results show that the sliding resistance of contact pair is low and stable when the surface coating material of contact or sample is gold or silver.The sliding contact resistance fluctuates greatly when the coating material on one side of the contact or sample is tin.From the results of sliding wear,the wear resistance of the gold coating material is better under slight wear conditions.With the increase of pressure,the wear depth and slideway width of the gold coating will increase rapidly.When the surface coating material is silver,the wear of silver contacts is serious under mild and moderate conditions,and the corresponding sample slideway becomes wider,but the resistance performance is good because the sample slideway keeps new contact surfaces.When the thickness of silver coating is thick enough,it can be applied to the conditions of high pressure and long sliding period.When the surface coating material is tin,tin is soft,wear resistance is poor and initial wear is serious,but there is no cold work hardening phenomenon in the contact area,contact wear does not increase significantly,and later wear degree is saturated.Considering sliding contact resistance and sliding wear,the positive pressure and sliding period of Au(beryllium copper)-Au(copper)have significant effects on the resistance and wear.For sliding conditions under 100 g positive pressure and 250 cycles.Ag(beryllium copper)-Ag(copper)has little influence on sliding contact resistance,and the resistance is low and stable;contact wear is large,coating thickness is the most significant factor affecting sliding wear,which is more suitable for sliding under positive pressure of 100 g,and wear change is small over 120 cycles.If the sample silver coating is thick enough,it can be applied to longer sliding cycle conditions.The contact resistance of Sn(belyllium copper)-Sn(copper)decreases with the increase of temperature,but the wear is aggravated and should be controlled below 45 C.The effect of sliding period on wear is also significant.It is suitable for sliding operation period below 120 under conditions of high pressure,medium temperature and medium coating thickness.Au(beryllium copper)-Ag(copper)temperature has a great influence on wear and tear,so it should be used at room temperature as far as possible.The pressure below 100g should be adopted and less sliding period should be used to avoid serious wear.The sliding period of Au(beryllium copper)-Sn(copper)has the most significant effect on wear.Abrasion increases over 120 cycles and contact resistance decreases with temperature rising,but the wear increases and should be controlled below 45 C.It is suitable for working period below 120 under medium pressure,medium temperature and medium coating thickness.The sliding period of Au(beryllium copper)-Au(PCB)has a significant effect on sliding wear.The sliding period under 100 g pressure and 120 g and the working temperature below 45 C should be adopted to avoid serious wear.Ag(beryllium copper)-Au(PCB)temperature should be controlled below 45 C,and over 250 cycles should be checked.Sn(beryllium copper)-Au(PCB)sliding period and positive pressure have significant effects on wear.Contact resistance fluctuation often occurs in the case of more than 100 m_,which is suitable for sliding operation period of less than 120 under medium pressure.After salt spray corrosion,the probability of the initial contact resistance exceeding 100 m_under nine orthogonal conditions after corrosion is taken as the evaluation index of corrosion resistance,and then the probability of the contact resistance decreasing to less than 10 m within 10 cycles during the 50-cycle sliding process of samples after corrosion under nine orthogonal conditions is taken as the evaluation index of the recovery of electrical contact performance.Ag(beryllium copper)-Ag(Cu),Au(beryllium copper)-Ag(Cu),Ag(beryllium copper)-Au(PCB)contact pairs ranked the top three in salt spray corrosion resistance.Choosing suitable electrical contact materials requires comprehensive consideration of sliding electrical contact characteristics and environmental characteristics.For example,short mechanical life,low current application conditions,Sn(beryllium copper)-Sn(copper),Au(beryllium copper)-Sn(copper);medium mechanical life,medium current application conditions,Ag(beryllium copper)-Au(PCB);long mechanical life,high current,Ag(beryllium copper)-Au(PCB),Ag(beryllium copper)-Ag(copper).