Structural and phase state of the SnO2-Ag coating formed on copper by the electroexplosive method

The phase and elemental composition of the surface layer of the copper electrical contact of the KPV-604 contactor coated with the SnO2−Ag composite by electric explosion spraying is studied using transmission electron microscopy. The scale of structural elements of the coating surface varies within a very wide range after electric explosion spraying—from hundreds of micrometers to tens of hundreds of nanometers. Two layers may be morphologically distinguished in the coating volume: the proper coating and the heat-affected layer gradually turning into the substrate. A nanocrystalline structure was detected. The main phases of the coating are SnO2, Ag3Sn, Cu10Sn3, Cu3Sn, Cu6Sn5, Ag4Sn, and CuO. The copper volume adjacent to the coating has a structure indicative of a high level of deformation of the surface layer of the specimen due to the electroexplosive method of the coating formation.