FEATURES OF THE STRUCTURE AND PHYSICO-CHEMICAL PROPERTIES OF COPPER PRODUCED BY THE METHOD OF ELECTRON BEAM EVAPORATION AND CONDENSATION IN VACUUM.

The structure and physico-chemical properties of copper, produced by the method of electron beam evaporation and condensation in vacuum were studied. A substrate from steel of St3 grade heated to 700 ± 15 °C was used for metal deposition. An intermediate pool from Cu-Zr-Y alloy was applied in the experiments. Evaluation of the properties of condensed copper, compared to cast one, showed a small difference in the values of specific electric resistance, and a certain increase of the level of mechanical characteristics, that is, probably, associated with the differences in its intragranular block structure. A 1.5 times increase of the condensate hardness was found in the case, when the intermediate pool was used, which is related to Zr and Y microalloying. Gravimetric studies of condensed copper corrosion in water revealed a significant influence on this process of such factors as presence of hardness salts in tap water and high specific electric resistance of distilled water. The greatest changes in the sample weight were observed in the first 10 h of corrosion testing, and then process stabilization and monotonic decrease of sample weight took place. In tap water copper is characterized by the highest corrosion resistance, weight losses being two times higher under dynamic testing conditions than this value for static testing. Under dynamic conditions, the medium movement prevents salt deposition, and electric resistance increase becomes slower. Analysis of corrosion polarization diagrams confirmed the slowing down of corrosion processes in tap water, compared to distilled water. Results of measurement of surface electric resistance of the samples before and after testing showed that the initial corrosion period with a relatively fast weight change, is characterized by an abrupt increase of electric resistance of the sample surface, which points to a predominant formation of copper oxide (I); and reduction of the dynamics of electric resistance change in the next testing periods is due to stabilization of the processes of film growth with copper oxide formation (II). [ABSTRACT FROM AUTHOR]