Structure of SnO2-Ag coating formed on copper by electroexplosion

Studies of the phase and elemental composition of the surface layer of the copper electric contact of the KPV-604 contactor subjected to electro-explosive spraying of the composite SnO2-Ag-coating were carried out by means of transmission electron microscopy. The scale of elemental structure of the coating surface varies within a very wide interval after electro-explosive spraying - from hundreds of micrometers to tens of hundreds of nanometers. According to the morphological structure, two layers can be distinguished in the coating volume: the coating itself and the heat affected layer smoothly transferring into the bulk of the sample. A nanocrystalline structure was detected. The main phases of the coating are SnO2, Ag3Sn, Cu10Sn3, Cu3Sn, Cu6Sn5, Ag4Sn and CuO. The volume of copper adjacent to the coating has a fragmented structure indicating a high level of deformation of the sample surface layer under the electro-explosive formation of the coating.