Erosion resistance of composite Ag-CaF sub 2 contacts

The erosion resistance of composite Ag-CaF sub 2 contacts in the commutation of constant current I=1-10A was studied. With the aid of metallographic analysis it was shown that in comparison with cast silver contacts, composite contacts even at I=1A show a stronger tendency to change the direction of mass transport, which increases with increase of the current to I < =4A. In this range of cummutation currents there is a small loss of material, accompanied by the removal of a considerable part of Ag-CaF sub 2 particles from the working zone to the periphery of the contacts, which promotes their improvement. The laws revealed in the work allowed us to recommend the composite Ag-CaF sub 2 contacts for use in relay technology. Tests in microwswitches confirmed the high erosion resistance of composite contacts in the range I=1-3A.