@ARTICLE{Hotlos_Agnieszka_Diffusion_2024, author={Hotlos, Agnieszka and Boczkal, Grzegorz and Karpinski, Marcin}, volume={vol. 73}, number={No 3}, journal={Archives of Electrical Engineering}, pages={629-642}, howpublished={online}, year={2024}, publisher={Polish Academy of Sciences}, abstract={Mechanisms of contact diffusion during relay-contacts operation were investigated. The contacts with the same geometry but different chemical composition were tested. The 1st relay-contact in a pair was made of copper, and the 2nd had a surface coated with a layer of silver about 500 micrometers thick. Different numbers of work cycles ranging from 8.5 k to 550 k were applied. AC current in the system was limited to 5 A. The closed/open periods were set at 250/250 ms. The resistance of the contacts was measured every 100 cycles. The microstructure of the working surfaces of the contacts after different numbers of operating cycles was investigated. On the surface of Cu contacts eutectic precipitates are formed and on the complementary bimetal contact tiny Cu-rich precipitates were generated on the silver surface. Crossection observations showed mutual material diffusion between the contacts. The depth of silver diffusion into the copper contact after 550 k operating cycles reaches 30 micrometers. The resistance of the contact system was stabilized after 40 k cycles at a level of 0.25 Ohm.}, type={Article}, title={Diffusion between Cu and Cu/Ag contact materials of relays during multiple cycles under AC operation}, URL={http://www.czasopisma.pan.pl/Content/132626/05_2k.pdf}, doi={10.24425/aee.2024.150887}, keywords={bimetal, contact diffusion, contacts wear, electric arc erosion}, }