EVOLUTION OF THE STRUCTURE OF COPPER COATINGS DEPOSITED FROM PULSE VACUUM ARC PLASMA

Abstract

The work is devoted to the study of the structure of metal layers deposited from vacuum arc plasma. Under conditions of high gradients of temperature fields and thermal plasma density of the arc, coatings are formed with a non-uniform structure, porous, with drops of metal on the surface. The study of metal layers deposited from thermal plasma is relevant due to the unusual properties and unique structure of these coatings. The purpose of our study is to trace the evolution of the structure of a copper coating deposited from the plasma of a vacuum arc in a pulsed operating mode. The peculiarity of the method is that the pulsed mode involves low energy consumption, so it is more economical than a stationary arc, however, the characteristic physical features of arc plasma are preserved. The practical goal is to deposit a thin layer of copper on aluminum for energy applications. As a result of the experiments, during the deposition time of 15-40 minutes, a process of significant compaction of the copper layer on the surface of the aluminum substrates was observed. The influence of deposition time on the size of surface defects was analyzed. Before 30 min of deposition, the formation of a highly dispersed nanosize structure of spherical clusters was observed in the coating; after 30 min, the transformation of the coating structure into a thick layer with high homogeneity was observed. This behavior can be explained by the initial formation of a coating of layers of nano-sized dust. When the substrate temperature changes, nanoscale clusters enlarge and disintegrate, accompanying phase transitions. An accompanying undesirable factor was the precipitation of metal oxide phases. The development of this area of research is necessary due to the fact that in pulsed arcs a high rate of layer deposition is achieved, therefore it is necessary to improve the properties of coatings by developing this method