The tribological properties of Ni-Cr-CaF2 as well as Ni-Cr-PbO/Si3N4 tribo-couples were investigated. The transferring behavior of solid lubricants at the interface of Ni-Cr alloy/Si3N4 tribo-couples were analyzed by scanning electron microscopy. The results showed a significant presence of CaF2 on the Si3N4 surface, while a completely transferred Pb film was not found on the Si3N4 surface due to its poor wetting capability on Si3N4.