Topics of PhD. 2020/2021

Doctoral study fields: INORGANIC CHEMISTRY / INORGANIC TECHNOLOGY AND MATERIALS

Development of methods for synthesis of ternary fluorides for modern applications
Supervisor: doc. Ing. Miroslav Boča, DrSc. e-mail: miroslav.boca@savba.sk

  • Object of the work will be the development of new methods for synthesis of pure inorganic fluorides or suitable modification existing ones eventually development of methods for separation of mixtures.
    Keywords: ternary fluorides, spectral characterisation, modification transitions

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Surface modification of Si3N4 microspheres by polymer chains
Supervisor: doc. Ing. Miroslav Hnatko, PhD. e-mail: miroslav.boca@savba.sk
Supervisor: Mgr. Jaroslav Mosnáček, DrSc. e-mail: jaroslav.mosnacek@savba.sk

  • Porous microspheres based on silicon nitride with addition of calcium phosphate will be modified with respect to surface treatment. First stage will be focused on the study of influence of (i) porosity and (ii) nitride to phosphate ratio in order to increase the bioactivity. Further stage will be focused on characterization of physical and biological properties of as prepared composite microspheres. Influence of polymer structure and bonding density of polymer chains on the final properties with respect to bioactivity. Study of compaction of microspheres using UV irradiation, polymerization, in the form of thin tapes will be in progress in parallel. Influence of various monomers on final structure and properties of as prepared bodies will be also studied.
    Keywords: silicon nitride, surfrace modification, bioactivity

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Functional composite materials based on layered hydrosilicates and polymers
Supervisor: Ing. Helena Pálková, PhD. e-mail: helena.palkova@savba.sk

  • The aim of the work will be the preparation of functional composite materials based on layered aluminosilicates and polymers in the form of coatings. Modifying the surface properties of aluminosilicates is an important step in increasing the compatibility of the inorganic component with the polymer matrix. The materials will be further functionalized with dyes with photophysical and photochemical properties. Interactions between inorganic-organic components, the distribution of silicate particles in the film and the effect of components on the extent of changes in the properties of composite materials will be studied.
    Keywords: hydrosilicates, coating, polymers, surfactant, modification

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Study of hybrid materials based on polymers and clay minerals by theoretical computational methods
Supervisor: Ing. Eva Scholtzová, CSc. e-mail: uacheva@savba.sk

  • A new information about interactions of organic pollutants and stability as well as physicochemical properties of the hybrid materials based on polymers and clay minerals will be obtained by theoretical computational methods.
    Keywords: pollutant, polymer, clay mineral, DFT, force field

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Utilization of industrial waste in the construction industry as an alternative for conventional building materials
Supervisor: Ing. Jaroslav Sedláček, PhD. e-mail: jaroslav.sedlacek@savba.sk

  • PhD topic is focused on a study of formation mechanisms of hydrated silicate phases from waste, influence of appropriate activator, and effect of these phases on properties of waste/Portland cement composite. Main aim is utilization of industrial waste, lower the content of cement in such “composites”, lower the energy consumption, and thus to reduce an ecological footprint.
    Keywords: up-cycling, industrial waste, cement, composite, building materials

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Influence of grain boundary chemical composition of nitride ceramics on the mechanical properties
Supervisor: prof. RNDr. Pavol Šajgalík, DrSc. e-mail: pavol.sajgalik@savba.sk
Co-supervisor: Professor Junichi Tatami, Yokohama University, Yokohama, Japan
Co-supervisor: Dr. Alexandra Kovalcikova, Institute of Materials Research, SAS, Košice, Slovakia

  • Experimental verification of the assumption that different content of rare earth oxides results in different mechanical behavior of nitride ceramics will be aim of the thesis. The model experiments on nitride ceramics with of different grain boundary compositions will be confronted with the ab initio simulations. The model experiments of the grain boundary strength measured on the microcantilevers of the single grain boundaries cut from the real microstructures will be performed in order to obtain the relevant experimental results suitable for the comparison with the simulations.
    Keywords: silicon nitride, grain boundaries, mechanical properties

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Molten/solid fluoride interface: reactions and structure of (oxo)-(fluoro)-aluminates for electronic application
Supervisor: Ing. František Šimko,PhD. e-mail: frantisek.simko@savba.sk

  • The topic is focus on the structural characteristics of alkali metal Fluoro-, oxo-, and oxo-fluoro-aluminate species which are considered as new solid complex compounds with interesting electronic properties. First fundamental experimental description of the native systems MF−AlF3−Al2O3−M2O (M = alkali metals) will be done by thermal analysis method and high temperature NMR, as well. The combination of techniques such as NMR spectroscopy, X-ray and neutron diffraction and thermal analysis will be indispensable/essential for a better description and understanding of the investigated native systems and specification and structural analysis of the different phases wherein.
    Keywords: molten salts, solid electrolytes, fast ion conductors, oxofluoroaluminate

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Joining methods for advanced ceramic materials
Supervisor: Ing. Peter Tatarko, PhD. e-mail: peter.tatarko@savba.sk

  • The development of reliable, inexpensive and user-friendly joining methods is a critical issue of the development of next generation of nuclear reactors and aerospace vehicles. The main aim of the work will be to develop new bonding methods of SiC-based materials to their counterparts, or the materials with different chemical compositions (e.g. metals). The investigation of bonding mechanism, physical and chemical processes, as well as mechanical and functional properties of the joints will be an important task.
    Keywords: ceramic materials, joining, mechanical properties, microstructure, interface

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Development of new advanced ceramics with the improved high temperature properties
Supervisor: Ing. Peter Tatarko, PhD. e-mail: peter.tatarko@savba.sk

  • TThe work will be focused on the synthesis and characterisation of new advanced ceramic materials. The aim will be to develop a material with unique microstructure and chemical composition, based on the refractory transition metal compounds and their composites. Such a material must meet the strict requirements of aerospace industry for new materials, such as the resistance against multiple ablation at temperatures above 2200°C.
    Keywords: ultra-high temperature ceramics, synthesis, mechanical properties, microstructure, aerospace industry

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Doctoral study field: CHEMICAL PHYSICS

Development and implementation of relativistic methods for the prediction of electron spectra
Supervisor: Mgr. Stanislav Komorovský, PhD. e-mail: stanislav.komorovsky@savba.sk

  • The main goal of the thesis is the theoretical development of new relativistic methods for calculation of spectroscopic parameters of both diamagnetic and paramagnetic systems, followed by their efficient implementation into the program package ReSpect (www.respectprogram.org).
    Keywords: Keywords: relativistic theory, quantum chemistry, numerical methods, computational science

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Analysis of indirect NMR spin-spin couplings between heavy nuclei
Supervisor: Dr. Olga Malkin, DrSc. e-mail: uacholga@savba.sk

  • Nuclear magnetic resonance spectra contains important information about the geometry and electronic structure of a compound under study. However, in order to use it in full extent assistance from computational quantum chemistry is necessary. While there are many theoretical tools for interpretation of indirect spin-spin couplings between lighter nuclei, analysis of spin-spin interactions between heavy nuclei remains challenging because it requires adequate inclusion of relativistic effects.
    Keywords: NMR, Relativistic quantum chemistry, DFT

Model study of interaction of organic pollutants with polymers modified by means of organoclays
Supervisor: Ing. Eva Scholtzová, CSc. e-mail: uacheva@savba.sk

  • A new information about interactions of organic pollutants and stability as well as physicochemical properties of the hybrid materials based on polymers and clay minerals will be obtained by theoretical computational methods.
    Keywords: pollutant, polymer, clay mineral, DFT, force field

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Doctoral study field: PHYSICAL CHEMISTRY

Molten systems in solar applications
Supervisor: doc. Ing. Miroslav Boča, DrSc. e-mail: miroslav.boca@savba.sk
Supervisor: Ing. Viliam Pavlík, PhD. e-mail: viliam.pavlik@savba.sk

  • Student will be dealing with simplified input/output thermodynamic calculation used for thermal storage proposal, including suggestions of salts and materials of storage.
    Keywords: alloys, corrosion, solubility

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Surfaces of polymer composites with layered nanoparticles with photosensitizing and antimicrobial properties
Supervisor: prof. RNDr. Juraj Bujdák, DrSc. e-mail: juraj.bujdak@savba.sk

  • The objective of the dissertation will be the preparation and characterization of photoactive composites of polymers with an antimicrobial effect. Polymer films will be modified with layered nanoparticles and functionalized with dye molecules. A detailed study of the relationship between properties and the structure of the materials should lead to optimization of the photochemical properties of the functional surfaces of the composites.
    Keywords: Layered silicates, photosensitization, active surfaces, organic dyes, composites

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Chemistry and electrochemistry of rare earth elements in molten fluorides: recycling and recovery
Supervisor: Ing. Michal Korenko, PhD. e-mail: michal.korenko@savba.sk

  • The identification of suitable systems, their electrochemical analysis (thermodynamic, kinetic and diffusion parameters), and the investigation of their structural properties properties (at in situ at high temperatures in molten states, as well as in deeply under-cooled samples).
    Keywords: Rare Earth elements, molten fluorides, physical chemistry and electrochemistry of molten salts

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Physico-chemical analysis of light lanthanides molten systems
Supervisor: Ing. Blanka Kubíková, PhD. e-mail: blanka.kubikova@savba.sk

  • Analysis of selected fluoride molten salt systems of lanthanides from the point of phase equilibrium, thermochemical characteristics, volume, surface and transport properties.
    Keywords: fluoride molten salts, phase equilibrium, physico-chemical properties

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Interactions of polymers and organic pollutants in cooperation with modified clay minerals studied by methods of theoretical chemistry
Supervisor: Ing. Eva Scholtzová, CSc. e-mail: uacheva@savba.sk

  • A new information about interactions of organic pollutants and stability as well as physicochemical properties of the hybrid materials based on polymers and clay minerals will be obtained by theoretical computational methods.
    Keywords: pollutant, polymer, clay mineral, DFT, force field

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Development of functionally graded biomaterials based on nitride ceramics
Supervisor: Mgr. Monika Tatarková, PhD. e-mail: monika.tatarkova@savba.sk

  • The work will focus on the development of new functionally graded bioceramics as a potential replacement of human bones. The aim is to develop composite materials with graded porosity and chemical composition, which will ensure the function of both cortical and trabecular bone.
    Keywords: silicon nitride, SiAlON, graded material, bioceramics

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Doctoral study fields: INORGANIC TECHNOLOGY AND MATERIALS

Lanthanide doped thermoelectric materials based on delafossite
Supervisor: doc. Ing. Zoltán Lenčéš, PhD. e-mail: zoltan.lences@savba.sk

  • Preparation of lanthanide-doped delafossite CuAl1-xLnxO2 (where Ln = Ce, Eu, Sm, Nd, Er) with the aim to improve the thermoelectric properties, especially to increase the electrical and decrease the thermal conductivity. The synthesis of materials will be enhanced by high-energy ball milling of starting powder and application of non-conventional heating, namely microwave heating. The final aim of the work will be the preparation of translucent/transparent thermoelectric material by using electric field assisted sintering.
    Keywords: thermoelectrics, delafossite, translucent materials

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Preparation and study of selected mechanical and optical properties of glassceramics materials in Al2O3-RE2O3 system.
Supervisor: Ing. Anna Prnová, PhD. e-mail: anna.prnova@tnuni.sk
Supervisor: Ing. Jana Valúchová, PhD. e-mail:jana.valuchova@tnuni.sk

  • The main aim of the work will be flame synthesis and basic characterization of glass micro-spheres and optimization of the crystallization conditions of these materials in order to prepare glass ceramic materials with good mechanical and photoluminescence properties by their subsequent hot pressing. The important steps of the work will be: optimization of powder precursor preparation, basic characterization of the prepared precursors, and optimization of flame synthesis conditions, characterization, structural analysis and study of thermal behaviour of glass microspheres. Further steps will be study of photoluminescence properties, dependence of these properties on the composition and content of the crystalline phases and optimization of the hot pressing conditions. By measuring of mechanical properties, such as hardness and fracture toughness, important knowledge about the application potential of these materials will be gained in the broader practice.
    Keywords: Glass-ceramic, corundum, photoluminiscence, microspheres

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3D printing of SiC- and Si3N4 based ceramics
Supervisor: Ing. Jaroslav Sedláček, PhD. e-mail: jaroslav.sedlacek@savba.sk

  • The topic is focused on the development of technology of preparation of ceramic materials based on SiC and Si3N4 using 3D printing by stereolithographic method. At present, there is a lot of suspensions for 3D SLS printing based on oxide ceramics, but the use of this technology for non-oxide ceramics is limited mainly by the need for multi-stage heat treatment of the prepared 3D structures. The main objective will be to optimize the slurry suitable for 3D printing and subsequent heat treatment of the prepared 3D structures with respect to properties, especially the mechanical strength, affecting potential applicability.
    Keywords: 3D printing, non-oxide ceramics, suspensions, optimization

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Preparation and characterization of microspheres based on Si3N4 suitable for 3D printing process.
Supervisor: prof. RNDr. Pavol Šajgalík, DrSc. e-mail: pavol.sajgalik@savba.sk
Supervisor: Prof. Paolo Colombo, University of Padova, Italy

  • Preparation of Si3N4 micro-granules with biocompatible sintering additives by freeze granulation and freeze drying. The main aim will be the preparation of micro-granules with designed macro and micro-porosity, defined strength after pre-sintering. These properties have to be preserved during the preparation of slurry for 3D printing of porous scaffolds using the direct-ink-writing process. The printed scaffolds will be sintered in nitrogen atmosphere. The final total porosity, pore size distribution and compressive strength of scaffolds will be characterized.
    Keywords: silicon nitride, 3D printing