Reference on the research, scientific and organisational activities of KRIVTSUN Igor V.
I.V. Krivtsun, born in 1954 in Konstantinovka, Ukraine. Graduate of the Faculty of Physics of the Taras Shevchenko National University of Kyiv. Physicist (M.D.) in “General Physics, Theoretical Physics” (1976). Postgraduate at the Institute for Theoretical Physics of the Academy of Science of Ukraine. Candidate of Physical-Mathematical Sciences (Ph.D.) in speciality “Theoretical and Mathematical Physics” (1987). Doctor of Technical Sciences in speciality “Electric-Thermal Processes and Units” (2003). Staff worker of the E.O. Paton Electric Welding Institute of the National Academy of Sciences of Ukraine since 1976, Head of the Department for Gas Discharge Physics and Plasma Devices since 2004, Deputy Director in science since 2008. Academic Status of Senior Scientist in speciality “Welding and Related Technologies” (2003). Corresponding Member of the National Academy of Sciences of Ukraine in speciality “Materials Science, Welding of Metals” (2006). Award of the National Academy of Sciences of Ukraine “For Scientific Achievements” (2009). Full Member (Academician) of the National Academy of Sciences of Ukraine in speciality “Materials Science, Welding of Metals” (2012). State Prize of Ukraine in Science and Technology (2012).
I.V. Krivtsun is a noted scientist in the field of gas discharge physics and theory of welding processes. He made a prominent contribution to development of the above research areas. His basic studies are dedicated to investigation of the physical phenomena occurring in the low-temperature technological plasma (welding arcs, plasma jets, optical and other types of gas discharge), as well as processes of interaction of the electric arc plasma and laser radiation with a material treated under conditions of arc, plasma, laser and hybrid welding, surfacing and coating.
I.V. Krivtsun elaborated the theory of electromagnetic properties of heterogeneous plasma and plasma-like systems of different geometries. In his studies published in a period of 1977-1989, I.V. Krivtsun offered an ingenious approach and elaborated a procedure for calculation of spectra of spontaneous radiation of the arc plasma, coefficients of absorption and reflection of laser radiation by metal in laser welding and surface treatment. He developed the efficient methods for calculation of composition, thermal-physical properties, transport coefficients and optical characteristics of the welding arc thermal plasma, allowing for its multi-component structure resulting from the use of shielding gas mixtures and evaporation of electrode and flux materials.
The research activities of I.V. Krivtsun in a period of 1990-2006 dedicated to hybrid laser-arc processes of welding and treatment of metals have received wide recognition both in Ukraine and abroad. As shown in his pioneering studies on theoretical investigation and mathematical modelling of the hybrid processes, interaction of the focused CO2-laser beam with the electric arc column plasma can result in formation of a special kind of gas discharge, i.e. the combined laser-arc discharge. I.V. Krivtsun scientifically grounded that this discharge acting as a heat source that possesses the fundamentally new capabilities of controlling the concentration of heat and electromagnetic energies can be used as a basis for building of a new class of plasma devices, i.e. the integrated laser-arc plasma torches, for implementation of the hybrid processes. For this he elaborated the baseline principles of design and methods for calculation of different application laser-arc plasma torches.
I.V. Krivtsun paved the way for a new research area, i.e. hybrid laser-plasma processes of welding and materials treatment. He worked out the theory of interaction of the focused laser beam and arc plasma with the condensed media, which made it possible to describe from the common standpoints the processes of the arc (plasma), laser and combined laser-plasma effects on compact and dispersed materials. I.V. Krivtsun derived expressions for calculation of the heat flow introduced into the weldment by each of the components of the combined heat source, specified the basic mechanisms of mutual laser and arc impacts on the surface of the melt in hybrid laser-plasma welding and cladding. He was the first to reveal the peculiarities of laser and combined laser-plasma heating of fine particles of metallic and ceramic materials caused by interference of the electromagnetic fields induced in such particles by the laser beam, as well as by optical heterogeneity of the particles formed in their heating.
Such new hybrid processes as laser-microplasma welding of small sections of metals, laser-plasma powder cladding and spraying of ceramic materials, as well as laser-plasma deposition of diamond and diamond-like coatings were developed under the leadership of I.V. Krivtsun. A series of the unique integrated laser-arc plasma torches, having no analogues in the world practice, were built for practical implementation of the above technological processes.
The theory of energy, mass and charge transfer processes occurring in the multi-component gas discharge plasma in contact with the surface of an evaporating metal (anode) in arc, laser and hybrid welding and surface treatment has received further development in the studies by I.V. Krivtsun and his disciples published in the last years. The system of kinetic equations with model collision integrals to describe both elastic and non-elastic collisions of particles in the multi-component plasma was suggested, and the procedure to numerically solve the model kinetic equations for different-geometry plasma systems was worked out. The mathematical model of the processes of surface evaporation of metals and alloys into the arc plasma, as well as of the processes of volumetric condensation of ionised metal vapour under the arc, laser and hybrid welding conditions was developed on the basis of the kinetic approach.
Along with the fruitful research activities, I.V. Krivtsun is also active in educational, scientific and organisational work. In 2009 he became a professor of the Chair of Laser Devices and Physical-Engineering Technologies at the National Technical University of Ukraine “Kyiv Polytechnic Institute”, and since 2010 he has been the head of this Chair. He is in charge of the post-graduate and doctorate courses at the E.O. Paton Electric Welding Institute of the NAS of Ukraine. He trained two candidates (Ph.D.) and one doctor of sciences. I.V. Krivtsun is a permanent member of specialised thesis defence boards at the National Technical University of Ukraine “Kyiv Polytechnic Institute” and at the E.O. Paton Electric Welding Institute, and a member of the editorial board of the Paton Welding Journal. I.V. Krivtsun is a full member of the American Welding Society (2009), and a member of the ASM International (2011). He actively cooperates with various R&D institutions of Germany, Russia, USA, China and other countries, regularly presents scientific reports at prestigious national and international conferences, and participates in accomplishment of a number of international research projects. I.V. Krivtsun is author (co-author) of over 190 scientific publications, including 3 monographs and 7 patents.
- Laser-arc discharge: Theory and applications / V.S. Gvozdetsky, I.V. Krivtsun, M.I. Chizhenko, et al. // Welding and Surfacing Rev. – Harwood Academic Publ., 1995. – Vol. 3. – 148 p.