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Chemistry and Technology of Materials
Doctoral Programme,
Faculty of Chemical Technology
--- Careers--- Programme Details
Ph.D. topics for study year 2025/26Analysis of batch-to-glass conversion process
AnnotationThe goal of this project targets the analysis of one of the critical batch-to-glass conversion processes – the evolution and collapse of the primary foam at the batch-melt interface. This porous foam layer, which behaves as a form of insulation layer, results from the products of various gas evolving reactions that are being trapped in the primary melt. This project will focus on understanding the foam morphology, the reactions that lead to primary foaming. Biodegradable iron-based materials for medical applications
AnnotationThis dissertation focuses on the development of biodegradable iron-based materials tailored for medical applications, such as temporary implants. The primary aim is to design and optimize materials with enhanced corrosion rates and suitable mechanical properties, addressing the current limitations of iron-based biodegradable implants, which typically exhibit slow degradation and insufficient biocompatibility in specific medical environments. The research employs advanced metallurgical techniques, particularly powder metallurgy, to precisely control microstructure and composition. Special attention is given to alloying iron with biocompatible elements (e.g., manganese, magnesium, or zinc) and the integration of porosity to accelerate degradation. Comprehensive analysis includes mechanical property characterization and corrosion behaviour evaluation under simulated physiological conditions. By advancing the knowledge of biodegradable iron alloys, this work contributes to the development of next-generation materials that can safely degrade within the human body while maintaining structural integrity throughout their functional lifetime. The results of this research aim to inspire further studies and pave the way for the practical application of iron-based biodegradable materials in orthopaedics and cardiovascular medicine. Green Deal and its Impact on 21st Century Construction
AnnotationThe Green Deal, an ambitious plan by the European Union, has significant impacts on 21st-century construction. This plan focuses on reducing greenhouse gas emissions and promoting sustainable development, leading to innovations in construction materials and technologies. This brings a range of changes that need to be addressed. The aim of this work is to map new trends in construction and contribute to the effective reduction of the carbon footprint of construction products through appropriate raw material adjustments. This material research should primarily advance the study of admixture activation and reduce the carbon footprint. Hydration and adsorption properties of biochar usable in environmental processes
AnnotationBiochar represents natural material, which can absorb and accumulate large amounts of water compared to soils and sediments, but also adsorb, e.g. toxic elements. It can be used alone or in a combination with other waste material, such as fly ash. Mixing biochar with selected soil profiles in the form of a controlled addition can affect soil drying, which is becoming a major ecological problem due to the increasingly frequent "dry periods" and generally lower precipitation totals. Together, soil quality can be also improved due to the capture of contaminants. The method of adding a material with high absorption capacity to the ecosystem can significantly contribute to better water management, balancing the water cycle and improving the quality of contaminated soil. Single atoms catalysts for advanced fuel cells
AnnotationMetanol a čpavek jsou v současnosti považovány za paliva budoucnosti. Jejich použití úzce souvisí s vývojem palivových článků, u kterých je nutné provádět „studenou“ oxidaci metanolu a čpavku s maximální energetickou účinností. V současné době je však takový proces téměř nemožné realizovat pomocí „klasických“ a běžné dostupných materiálů a katalyzátorů. V této práci bude navřena příprava a testovaní mono-atomových katalyzátorů, tzn. atomárních redox-aktivních center zabudovaných do 2D materiálů nebo 3D struktur s velkým měrným povrchem. Příprava jednoatomových katalyzátorů bude prováděna řadou inovativních technik, které využívají elektrochemické postupy nebo depozici z plynné faze a nebo i kombinaci těchto metod. Takové katalyzátory by měly poskytovat vysoce účinnou oxidaci metanolu nebo čpavku při pokojových teplotách a atmosférickém tlaku, což potenciálně umožní učinit další krok ve vývoji energetiky budoucnosti a tak zajistit udržitelnou budoucnost. Conversion of CO2 using renewable energy sources
AnnotationV současnosti využití a konverzi CO2 lze považovat za extremně důležitou otázku. Dostupné metody zachycování a konverze CO2 (tj. příprava monomerů/polymerů nebo methanolu z CO2) vyžadují velmi náročné experimentální podmínky a jsou extrémně náročné z hlediska energetické spotřeby. Navrhovaná práce se zaměří na vytvoření nové generace materiálů, které budou schopny zajistit konverzi CO2 s použitím světelných zdrojů energie (ideálně - slunečního světla). V podstatě budou řešeny dvě klíčové otázky: zachycení a využití CO2 ze vzduchu (na rozdíl od běžných metod předchozí separace CO2) a implementace obnovitelných zdrojů energie (sluneční světlo) pro konverzi CO2 např. na monomery nebo methanol. Laser induced dewetting of noble metals for bimetallic nanoparticles formation
AnnotationLi-free batteries – development of new materials for energy storage
AnnotationZákladem moderní energetiky a mnoha elektronických zařízení (od mobilních telefonů až po elektromobily) jsou jejich baterie. Bohužel většina moderních baterií pracuje na principu redukce/oxidace lithia. Získávání lithia je však technologicky složitý a ekologicky velmi problematický proces, který kompletně niveluje současné trendy v zavádění „zelené“ energie. K omezeni použití lithia v je nutné vyvinout nové materiály, které poskytují efektivní skladovaní energie pomocí alternativních kovů, jako je např. hořčík nebo zinek. Cílem této práce je nalézt podobné materiály pro konstrukci elektrod v hořčíkových nebo zinkových bateriích. Jako výchozí bod využijeme řadu našich dosavadních výsledků, spočívajících ve vytváření rozvětvených uhlikovych nanostruktur nebo 2D materiálu dopovaných redox-aktivními atomy, které dokážou efektivně zajistit oxidaci a redukci hořčíku a zinku (stejně jako průběh podpůrných elektrochemických procesů. Mechanisms of hydrogen-induced degradation of 3D printed metallic materials
AnnotationHydrogen-based technologies have been increasingly developed in last years in context with current ecological trends in human society. However, it has been known for a long time that hydrogen deteriorates mechanical properties of some groups of metallic materials. Hydrogen embrittlement, i.e. reduction of plasticity and toughness of components caused by hydrogen, sometimes leading to catastrophic failures, was observed for titanium alloys, high-strength steels and other materials. However, it was reported recently that 3D printed materials are more sensitive to H-embrittlement due to specific structural features (refined structure, high interface area, internal stress etc.) than materials fabricated by common metallurgical routes. In the dissertation, the influence of hydrogen on mechanical properties of 3D printed materials will be explored. 3D printed materials will be exposed to H-containing environments, and resulting properties like fractures, strength, toughness, embrittlement, fatigue etc. will be explored. By using advanced techniques, like LM, SEM, TEM, XRD, AFM, FA, Kelvine probe and other, new knowledge on H-metal interactions will be obtained which will help to better design the energy/chemical devices and/or advanced hydrogen fuelled systems. Surface modification of metallic materials for use in medical applications
AnnotationMetallic materials still play an irreplaceable role in medicine. The surface state significantly influences the properties and behaviour of biomaterials. This is especially the interaction on the metal-electrolyte phase boundary, i.e. biocompatibility and corrosion behaviour, although mechanical properties can also be affected. In the course of the work, the surfaces of metallic biomaterials will be modified in order to increase their utility properties. The modified surfaces will then be evaluated using standard material, electrochemical and spectroscopic methods. Nanocrystalline materials for advanced photonics
AnnotationActive optical fibers are a key component of fiber lasers and distributed luminescence sensors. As their power increases and their use in extreme environments, including nuclear reactors, requires new materials with enhanced luminescence efficiency and temperature stability. Rare earth-doped nanocrystalline materials represent a suitable alternative to conventional glass and single crystals. The work targets the preparation and characterization of transparent nanocrystalline materials on the system Y2O3-Al2O3-SiO2 doped with rare earth elements. The effects of the composition and conditions of preparation on the reaction and growth mechanisms of nanocrystals evenly distributed in an amorphous matrix will be studied. The studied system's composition will be modified to reduce the phonon energy of nanocrystals and increase the luminescence efficiency in the infrared region and for conversion of high-energy radiation. A theoretical model of energy transfer in rare-earth ions will be elaborated, and the results will be compared with experimental results of luminescence measurements. The selected materials will be used for the preparation of active optical fibers, which will be used for the preparation of fiber lasers and distributed scintillators. Tool composites with gradient structure
AnnotationCurrently, the mass deployment of the production of "green steel", i.e. iron reduced by hydrogen, is being considered. In such a case, however, strengthening by interstitial carbon is missing, so alternative alloying concepts are explored. One possibility is the use of maraging steels, which contain cobalt, classified as a critical raw material. Therefore, this work focuses on the development of a tool material consisting of an iron-based matrix with silicide-based reinforcement. In order to achieve good abrasion resistance and mechanical properties, the creation of a gradient structure will be tested, where the silicide content will be high at the surface and will decrease towards the core. The design will be used to predict the mechanical properties of the composite based on knowledge of the matrix and silicide properties. Cold sintering of ceramics – theory and experiment
AnnotationThis dissertation follows one of the latest trends in ceramic science, which is low-temperature (≤400 °C) sintering of ceramics, known as cold sintering. The application of such a low temperature is made possible by the presence of a liquid phase and the application of high pressure. The work focuses on the theory of the entire process, specifically on the effects of the liquid phase (water or solutions of acids and bases), temperature, pressure, and dwell time on sintering. These theoretical foundations will be verified and developed based on experiments, which will include the preparation of ceramic materials (oxides and halides) and the characterization of their composition and microstructure using methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, the characterization of mechanical properties, particularly hardness and fracture toughness (using indentation methods), but also elastic properties (using dynamical methods) and thermal diffusivity or conductivity (using transient heat transfer methods). Part of the work will be image analysis and the modeling of relations between composition, microstructure and properties. Novel glass materials for fiber lasers
AnnotationFiber lasers are in focus of intense research thanks to their high efficiency, beam quality, high average power, compactness and other advantages that are beneficial for increasing scope of applications. Silica optical fibers doped with rare-earth ions represent hearts of these lasers. Knowledge of stability of their optical properties is important for wide employment of fiber lasers. Attention will be focused on investigation of glassy materials of various matrices doped with thulium emitting at 2 um spectral region. Glassforming, refractive index, spectroscopic and mechanical properties of the prepared materials will be studied. Achieved results leading to forecast of suitable materials in form of optical fibers together with methods of their preparation will be verified later by testing in fiber lasers. Cutting-edge cermet composites for high kinetic energy dissipation
AnnotationTurquoise hydrogen, a product of modern approach to methane pyrolysis, appears along with a waste by-product carbon. Modifying the process by adding metal oxide particles, the carbon is transformed into a variety of carbide phases and carbon-based nanostructures. Among these, the TiC and WC, exhibiting one of the highest hardnesses among carbides, will be used for a targeted preparation of cutting-edge materials capable of high kinetic energy dissipation. For this purpose, the carbides/carbon nanostructured composite mixtures prepared by plasma cracking of methane will be thoroughly investigated at the level of powders and their compacts. High fracture toughness Ni-Ti and CoCrNi alloys will further embody them. The incorporation strategy will be initially tested on sandwich structures compacted by SPS, providing the general knowledge to be utilised for DED additive manufacturing. Alternating layers, their composition, mutual intermixing and interconnection will lead to the synthesis of functionally-graded materials with the potential of being implemented as ballistic protection. Advanced metallic materials for medical implants manufactured by the 3D printing technology
Annotation3D printing technologies are prospective methods for the manufacture of complex structural parts and medical implants because of the ability to produce very complex shapes, highly porous structures etc. In the work, microstructures, mechanical, corrosion and biological properties of advanced Ti based alloys, stainless steels, high-stregth steels, biodegradable iron and magnesium alloys. The alloys will be prepared by SLM, DED and WAAM processes will be investigated. In addition, the relationships between parameters of the SLM and DED process and characteristics of resulting products will be evaluated. Results of the study will propose process parameters the most suitable for obtaining desirable products. Advanced Materials for nitrogen to ammonia conversion
AnnotationČpavek je nezbytnou součásti výroby hnojiv a taky je povazován za účinný prostředek přenosu energie. Ovšem současna výroba čpavku je velmi náročná z hlediska energetické spotřeby a taky je založena z velké míry na použiti fosilních paliv, tzn. neobnovitelných materiálových zdrojů. Proto se hledají alternativní moznosti přípravy čpavku z běžných materiálových zdrojů jako jsou atmosféricky dusík a voda. Ideálně tato příprava by mela byt méně energeticky náročná než konvenční. Tato práce je zaměřena na studium a inovativních hybridních materiálů schopných aktivovat dusík a zajistit jeho chemické proměny na čpavek. Jedna se o výzkum v oblasti elektrochemicky nebo foto-elektrochemicky aktivních materiálu, mezi kterými patří cela rada sloučenin na bázi boridu, sulfidu, kovových slitin a tak dále. Hlavním cílem práci bude vyvinout katalyzátor, v respektive radu katalyzátorů, které zaručí moznost dosáhnout vysoké Faradayové a kvantové účinnosti v reakci aktivaci dusíku a výroby čpavku. Advanced materials for water reduction and oxidation
AnnotationPotřeba ochrany životního prostředí a vývoje udržitelných zdrojů energie vede k vývoji energetiky založené na „vodíku“, která poskytuje z ekologického hlediska ideální „materiálový cyklus“. Jedna důležitá otázka v této oblasti však dosud zůstává nevyřešená – příprava/výroba levného a „zeleného“ vodíku. Běžné metody, kdy se vodík vyrábí z ropy, nelze považovat za optimální. Proto v poslední době byla velká pozornost zaměřena na tzv. „zelený“ vodík, tj. vodík vyrobený z vody elektrolýzou. „Běžnou elektrolýzu“ však také nelze považovat za perfektní metodu z hlediska energetické náročnosti. Navrhovaná práce bude zaměřena na využití především světlem řízeného štěpení vody s minimálním zapojenim jiných zdrojů energie. Bude vyvinuta a použita nová generace materiálů, které jsou schopny účinné absorbovat celé spektrum slunečného záření a iniciovat fotolýzu vody při osvícení. Advanced Materials for Green Hydrogen Production
AnnotationPráce je zaměřena na vývoj nových materiálů zaměřených na řešení klíčových problémů v oblasti dělení vody. Zejména mluvíme o štěpení mořské vody, elektrolýze při vysokých proudových hustotách, přímém či nepřímém zapojení sluneční energie. Jako materiály bude studována celá řada nových sloučenin, jako jsou vysoko entropické kompozity, mono-atomické katalyzátory, stabilizované klastry atd. Advanced high-entropy alloys with modifiable properties
AnnotationHigh entropy alloys belong to a relatively new group of materials which are characterized by the preferential formation of solid solutions instead of intermetallic compounds. These materials exhibit several excellent properties, foremostly high strengths while maintaining sufficient ductility, good corrosion resistance and others. By suitable processing of these alloys, it is possible to achieve further substantial improvement of these already very good properties. The work will be focused on the preparation of new advanced high-entropy alloys combining significantly higher strengths while maintaining sufficient plasticity. Switchable supercapacitors for intelligent energy harvesting
AnnotationVývoj společnosti vede k odchodu od nenahraditelných zdrojů energie a přechodu k obnovitelným alternativám. Vzhledem k tomu, že obnovitelná energie obvykle prochází fází „konzervace“ ve formě elektřiny, vyvstává otázka, jak elektřinu skladovat. Tento problém lze vyřešit pomocí struktur, jako jsou superkondenzátory, které jsou schopny ukládat a uvolňovat relativně velké množství elektřiny a nevyžadují „přístupy“ na bázi lithia (na rozdíl od baterií). Použití superkondenzátorů je však omezeno jejich neřízenou rychlostí vybíjení. Tato práce je zaměřena konkrétně na tvorbu chytrých materiálů a struktur, které umožní řídit vybíjení superkondenzátorů. Jako základ pro takové materiály budou použity chytré hydrogely dopované uhlíkovými nanostruktury s velkým měrným povrchem. Uhlíkové nanostruktury budou zodpovědné za celkové množství náboje uskládaného superkondenzátorem. Přepínání stavu chytrého hydrogelu umožní regulovat rychlost vybíjení superkondenzátoru – dosáhnout pulzních hodnot výstupní energie nebo naopak konstantního vybíjení bez poklesu výstupního napětí. Jako typické aplikace takových materiálových struktur mohou být uvedeny ostrý záblesk fotoaparátu nebo nepřetržitý provoz mobilního telefonu „do posledního procenta nabití“, realizované v rámci jednoho zásobníku energie bez zavádění dalších jednotek elektroniky. Preparation and characterization of biocompatible metal composite materials
AnnotationThe work deals with the preparation of composite materials with a metal matrix and reinforcement from biocompatible materials. The goal of the work is to find a suitable preparation technique and characterize the resulting material. Its microstructure, mechanical properties, tribological properties and corrosion resistance will be studied. Preparation and properties of nanocrystalline aluminium alloys with transition metals
AnnotationThis work is devoted to preparation of nanocrystalline aluminium alloys with transition metals and description of their microstructure. The alloys will be prepared by rapid solidification techniques and also by mechanical alloying. Prepared alloys will be compacted by spark plasma sintering. Microstructure and properties of compact materials will be descibed. The aim of this work is do describe the influence of alloying elements on microstructure and properties of alloys and to find optimal conditions for their compaction. Melting processes in vitrification technologies
AnnotationThe analysis of the processes during the vitrification process is performed using a mathematical model. Input data of the model will be obtained by a set of experimental methods including high temperature monitoring of melting processes, analysis of released gases, thermal analysis and determination of oxidative reduction equilibrium in melts. Towards durable organic coatings produced by environmentally friendly technologies
AnnotationEuropean steel industry is currently preparing for the CO2 emission reduction (55% by 2030) and climate neutrality (by 2050) targets set by the European Union. Industrial organic coatings are still generally based on solvent borne paint formulations and thermal curing technologies that use fossil constituents and fuels. It is expected that a transition from thermal curing to radiation curing coatings will be the critical step in achieving the sustainability goals. While radiation curing (UV/EB) technologies are already being used in several other industries, the high requirements for product performance and durability still hamper their industrial deployment. A major bottleneck is long lab to market time, requiring rigorous and time-consuming product testing. Recently, developments in sample preparation and microscopic analysis techniques have shown that observation of early-stage, "hidden" coating performance has the potential to reveal coating defects and molecular-level degradation mechanisms in 1/3 of the time of conventional coating evaluation techniques. This project will increase the use of sustainable coatings by understanding relevant early-stage microstructural degradation and physico-chemical changes. Lab to market time will be decreased by introducing novel characterization techniques that are able to reveal initial degradation kinetics on a molecular level, allowing faster lifetime prediction models of coating systems. The project will be supported by major European steelmakers and paint producers. Development of a system for monitoring of corrosion under insulation
AnnotationCorrosion under insulation poses a serious risk to the chemical and petrochemical industry from a safety, environmental and ultimately economic point of view. Corrosion monitoring with early warning functions would be an effective tool to ensure operational safety. This work focuses on the development of a new device for corrosion monitoring under insulation. The principle of the technique based on the electrical resistance method will be inovated. New corrosion sensors, electronics, software and data transfer and treatment will developed as well. A lifetime of waste dosposal package for spent nuclear fuel in conditions of deep geological repository
AnnotationThe student will deal with the current issue of spent nuclear fuel canister materials and the influence of corrosion mechanisms on their lifetime. The first part of the thesis focuses on the influence of microbial effect on the localization of the attack. In this part of the work, electrochemical techniques (potentiostatic method), resistometric probe, wire array electrode and ZRA method will be used. Furthermore, the determination of the critical dry bulk density of bentonite to limit proliferation and its effect on corrosion processes will be carried out. The second part will focus on the preparation of artificial aggregates of corrosion products with different porosities and its effect on the mechanical properties of the aggregates. Techniques of digital image analysis, BET porosimetry, mechanical testing and nanoindentation will be used. The last part of the work will focus on the stress corrosion cracking of carbon steel in bentonite pore solution. Mechanical tensile stress-strain techniques with slow strain rate and microscopy will be used. |
Updated: 21.1.2022 15:24, Author: Jan Kříž