Topics of PhD. 2021/2022

Doctoral study field: PHYSICAL CHEMISTRY

Development of functionally graded biomaterials based on nitride ceramics
Supervisor: Ing. 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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Composites of hydrogels with layered silicates and dyes with photosensitizing and antimicrobial properties

Supervisor: prof. RNDr. Juraj Bujdák, DrSc. e-mail: juraj.bujdak@savba.sk

  • The objective of the dissertation is the preparation and characterization of photoactive composites of hydrogels with antimicrobial effect. The surface of the hydrogel will be modified by layered silicate nanoparticles functionalized with dye molecules. A detailed study of the relationship between the properties and structure of materials should lead to the optimization of photochemical and antimicrobial properties of composites.
    Keywords: nanomaterials, polymers, active surfaces, organic dyes, singlet oxygen

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Physico-chemical analysis of light lanthanides molten systems
Supervisor: Ing. Blanka Kubíková, PhD. e-mail: blanka.kubikova@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: fluoride molten salts, phase equilibrium, physico-chemical properties

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Doctoral study fields: INORGANIC TECHNOLOGY AND MATERIALS or INORGANIC CHEMISTRY

New kinds of glassceramics materials in Al2O3-RE2O3 and Al2O3-RE2O3-ZrO2 systems with interesting optical and mechanical properties
Supervisor: Ing. Anna Prnová, PhD. e-mail: anna.prnova@tnuni.sk

  • The main aim of the work will be flame synthesis, basic characterization and subsequent hot pressing of glass micro-spheres in order to prepare glass ceramic materials with good mechanical and photoluminescence properties.
    Keywords: glass microspheres, flame synthesis, hardness, fracture toughness, photoluminescence

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Corrosion and weathering of tableware glass.
Supervisor: Ing. Mária Chromčíková, PhD. e-mail: maria.chromcikova@tnuni.sk

  • The corrosion of the tableware glass (especially in dishwashing machines in the large gastronomy) and weathering during the storage as well as during the oversea transport is from the actual point of view one of the most important questions of the glass producer’s economic competition. The main aim of the dissertation is the study of composition – structure – property relationships of oxide glasses leading to the proposal of methodology enabling the prediction of glass resistance against corrosion and weathering. The methodology is established on the set of different glasses, with differences in chemical composition of the surface as well as in the bulk. The differences are justified with respect to thermodynamic modeling, surface tension measurement and surface composition analyses by progressive spectroscopic methods. Such obtained results should be put into correlation with glass corrosion and weathering process.
    Keywords: chemical durability, weathering, corrosion, spectroscopic methods

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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: delafossite, high-energy ball milling, microwave synthesis, thermoelectrics, anodes for Na-ion batteries

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Fluoride melts with potential applications in electrochemical aluminum production.
Supervisor: Ing. František Šimko,PhD. e-mail: frantisek.simko@savba.sk

  • The aim of work is related to phase and structural analysis of MF−AlF3−Al2O3 systems (M = Na, K and Rb). These systems have increasing industrial potential, especially in joint application with so-called inert anodes, in aluminium production. The aim of the work is the phase analysis and identification of primary phases.
    Keywords: molten salts, aluminium electrolysis, cryolite, oxofluoroaluminates

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Ternary fluorides for modern applications
Supervisor: doc. Ing. Miroslav Boča, DrSc. e-mail: miroslav.boca@savba.sk

  • Object of the work will be the study of inorganic fluorides for various branches of energy sector. The content of the study will be the development of synthetic methods, consequent spectral, thermochemical eventually structural characterisation and identification of systems with application potential.
    Keywords: ternary fluorides, spectral characterisation, modification transitions

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Development and implementation of efficient relativistic methods for the prediction of electron spectra
Supervisor: Dr. Olga Malkin, DrSc. e-mail: uacholga@savba.sk

  • The main goal of the thesis is the 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). This requires skills from both relativistic quantum physics and computational science. An optional goal is to apply the newly implemented methods to relevant systems in close collaborations with our foreign partners from Germany, Norway, France, Austria or Czech Republic.
    Keywords: relativistic theory, quantum chemistry, numerical methods, computational science

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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

  • The 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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Interface of Fluoride Melt/Solid Phase: Reactions and Structure of (Oxo)-(Fluoro)-Aluminates for Electronic Applications
Supervisor: Ing. František Šimko,PhD. e-mail: frantisek.simko@savba.sk

  • The topic is focused on the structural characteristics of alkali metal aluminates and oxofluoroaluminates, which can be industrially used as solid electrolytes due to their high electrical conductivity. The basic description of the multicomponent fluoride system MF−AlF3−Al2O3−M2O (M = alkali metal) and its relevant subsystems shall be clarified by thermal analysis, the phase fields shall be specified and a phase diagram of the measured systems shall be constructed. The combination of the methods used (NMR spectroscopy, X-ray diffraction and thermal analysis) will allow us to better understand the investigated systems as well as to specify the different phases and components contained in it.
    Keywords: molten salts, solid electrolytes, fast ion conductors, oxofluoroaluminates

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New 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 and characterisation of new ceramic biomaterials
Supervisor: Ing. Monika Tatarková, PhD e-mail: monika.tatarkova@savba.sk

  • The work will focus on the development of new bioceramics as a potential replacement of human bones. The aim is to form bioactive surface layer or bioactive phases in bulk ceramics.
    Keywords: bioceramics, bioactive surface, bone replacement

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Preparation and characterization of microspheres based on Si3N4 suitable for 3D printing process

Supervisor: doc. Ing. Miroslav Hnatko, PhD. e-mail: miroslav.hnatko@savba.sk

  • 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

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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

  • Experimental verification of the assumption that different content of rare earth oxides results in different mechanical behaviour of nitride ceramics will be aim of the thesis.
    Keywords: silicon nitride, grain boundaries, mechanical properties

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Preparation of ceramic anodes for sodium-ion batteries
Supervisor:doc. Ing. Zoltán Lenčéš, PhD. e-mail> zoltan.lences@savba.sk

  • The study will focus on the development of novel silicon carbide/carbon (SiC/C) ceramic anode with tailored porosity which will serve as a matrix for Na-plating. The porous ceramics will be synthesized from silicon-based polymer precursor (polycarbosilane) by crosslinking and subsequent pyrolysis in inert atmosphere. The developed ceramic matrixes will exhibit a hierarchical porosity with a defined pore type, a distinct pore size distribution and a defined ratio between micro/meso/macropores. The porous ceramic body will allow an efficient sodium deposition and a favourable integration of the anode material with the electrolyte, ensuring chemical compatibility and ceramic/electrolyte interface stability. The study will involve the DTA-TG analysis combined with simultaneous mass and infrared spectroscopy of the polymer precursors with the goal to optimize the crosslinking and pyrolysis conditions. The ceramic materials will be sintered by pressureless method and electric field-assisted method. The prepared materials will be characterised by means of phase composition, porosity (Hg intrusion and tomography), conductivity (electrical and thermal) and compressive strength. In the final stage of work the anode material will be joined to the standard electrolyte and the properties of interfaces will be characterized.
    Development of novel silicon carbide/carbon (SiC/C) ceramic anode with tailored porosity which will serve as a matrix for Na-plating. The porous ceramics will be synthesized from polymer precursor by crosslinking, pyrolysis and sintering. The ceramic anodes will exhibit a hierarchical porosity with defined pore type and distinct pore size distribution. The porous ceramic body will allow an efficient Na deposition and a favourable integration of the anode material with the electrolyte.
    Keywords: sodium-ion batteries, porous ceramics, pyrolysis, conductivity

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Composite materials based on layered hydrosilicates and cationic polymers

Supervisor: Ing. Helena Pálková, PhD. e-mail: helena.palkova@savba.sk

  • The work will be targeted to preparation of composite materials based on layered aluminosilicates as carriers, suitable for various types of organic polymeric cations with properties interesting for their use, for example as adsorbents, catalysts or materials with antibacterial properties. The variability of the chemical composition of selected layered materials in connection with the diversity of molecular structures and properties of polymeric cations and copolymers opens up wide possibilities for the preparation of well-defined systems. The essential step to achieve mutual compatibility between the components of the proposed systems is a suitably selected inorganic carrier, its properties as well as the properties of the compound selected for modification. In the prepared systems, the mutual interactions between inorganic-organic components will be studied in detail, as well as the possible influence of individual components on the extent of changes in the properties of composite materials. Optimization of the preparation of composite materials based on layered aluminosilicates with variable chemical compositions that are suitable as carriers for various types of polycations and possess interesting features e.g. antibacterial properties. The work will focus on a detailed study of the interactions between inorganic-organic components and the influence of individual components on the extent of changes in the properties of composite materials.
    Keywords: Keywords: layered aluminosilicate, cationic polymer, surfactant, modification