Maksim Dorogov

Abstract:

Metallic and non-metallic whiskers have been the subject of research interests for more than 50 years. Numerous studies devoted to whiskers proved that they have unique mechanical and electrical properties. Whiskers are already widely used in electronics and chemical industry. Therefore, the study of structure and formation mechanisms of whiskers and methods for their creation is an important scientific task. This research is devoted to the investigation of metal whiskers obtained by annealing in the air of electrolytic coatings and monolayers of icosahedral small copper particles. A set of contemporary physical methods, such as scanning and transmission electron microscopy, X-ray diffraction, local energy-dispersive X-ray spectroscopy and low-temperature gas adsorption are used for this study. It is shown that the whiskers are needle-like nanocrystals of copper oxide CuO with length up to 15 um and less than 100 nm in diameter. The whisker demonstrates high mechanical properties. Throughout the process of electrocrystallisation and subsequent annealing, long-range mechanical stresses appear in coatings, which, in the presence of oxygen in the atmosphere, intensify the formation of whiskers. The disclination-type defects in electrodeposited particles, as well as in the substrate, influence the formation and growth of whiskers. The growth of whiskers is provided by copper cation transport from the depth of the coating to the surface. The delivery of metal cations to the whiskers is due to the pipe-diffusion through the disclination and dislocation cores or nanopore channels. This work has been performed under the support of RFBR research project No. 13-02-00221 and the grant No. 14.B25.31.0011 from the Ministry of Education and Science of Russian Federation (resolution # 220) at Togliatti State University.