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Room-temperature fabrication of electroceramic composites

Author(s): Nina Kuzmić (Author), Srečo Davor Škapin (Supervisor), Matjaž Spreitzer (Co-Supervisor), Heli Jantunen (Co-Supervisor)

Year: 2024

Type: Doctoral dissertation

In the scope of this thesis, I focused on SrTiO3 (ST)-based dielectric ceramic composites as a lead-free perovskite material, which holds great potential for use in various electronic components. Such materials are large-scale and fabricated under high energy requirements, indicating an increasing need for a more environmentally friendly processing method. …

Surfaces and interfaces in the growth of SrTiO3 on Si by pulsed laser deposition

Author(s): Tjaša Parkelj Potočnik (Author), Matjaž Spreitzer (Supervisor)

Year: 2021

Type: Doctoral dissertation

SrTiO3 (STO) thin films are used as buffer layers that enable epitaxial integration of various functional oxides with silicon. When pulsed laser deposition (PLD) is used to grow STO on Si, a thin amorphous layer is formed at the STO-Si interface that limits the use of such heterostructures in certain …

Development of SiC-based composite material for fusion application

Author(s): Aljaž Iveković (Author), Saša Novak Krmpotič (Supervisor)

Year: 2013

Type: Doctoral dissertation

Nuclear fusion offers a prospect of a safe, economical and environmentally friendly source of energy. For the advanced concepts of nuclear fusion, SiC-based fibre reinforced composites were proposed as a structural material for the first wall of the reactor vessel, enabling higher operating temperatures and efficiencies. Already developed techniques for …

Sintering and phase transition behaviour of sodium niobate

Author(s): Jurij Koruza (Author), Barbara Malič (Supervisor), Tadej Rojac (Co-Supervisor)

Year: 2013

Type: Doctoral dissertation

Sodium niobate (NaNbO3) is the end member of several alkaline niobate-based solid solutions, which represent an important group of environment-friendly lead-free piezoceramics. Even though alkaline niobates are of considerable technological importance, problems in obtaining high densities and a fine-grained microstructure are still reported and not much is known about the …

Low-temperature sintering of piezoelectric K0.5Na0.5NbO3 ceramics

Author(s): Janez Bernard (Author), Barbara Malič (Supervisor), Andreja Benčan Golob (Co-Supervisor)

Year: 2012

Type: Doctoral dissertation

The KNN solid solution was prepared from pre-synthesized binary compounds of, sodium and potassium niobate in a 1/1 molar ratio. The KNG sintering aid was prepared by homogenizing the pre-reacted binary mixtures of alkaline reagents and germanium oxide with the Na/Ge = 1/1 and K/Ge = 1/1 molar ratios. The …

Moderately porous zirconia ceramics for dental applications

Author(s): Sebastjan Perko (Author), Tomaž Kosmač (Supervisor), Aleš Dakskobler (Co-Supervisor)

Year: 2012

Type: Doctoral dissertation

This doctoral thesis describes the preparation of moderately porous Y-TZP ceramics with improved flexural strength. The main field of application is dentistry, where the elastic mismatch between the Y-TZP material and tooth substance influences the survival rate of fixed partial dentures (FPDs). By introducing porosity into the bulk samples a …

Development of silicon carbide based implants with improved biocompatibility and mechanical properties

Author(s): Katarina Rade (Author), Saša Novak Krmpotič (Supervisor), Spomenka Kobe (Co-Supervisor)

Year: 2012

Type: Doctoral dissertation

With emerging need for orthopaedic implants and prolonged exposure of organism to implants also problems connected to elution of metal ions that in some cases cause adverse reactions in the human body, emerge. The main aim of our work was therefore to investigate the potential of silicon carbide (SiC) to …

Magnetically oriented films of barium ferrite

Author(s): Simona Ovtar (Author), Darja Lisjak (Supervisor)

Year: 2012

Type: Doctoral dissertation

This work had three aims. In the first part the influences of the sizes of the particles of barium ferrite (BaM) and their magnetic properties on the stability of the suspension were investigated. In second part the deposits were prepared by electrophoretic deposition (EFN) and the influence of particle size, …

Structural and electrical properties of 0.65PMN-0.35PT thick films on different substrates

Author(s): Hana Uršič Nemevšek (Author), Marija Kosec (Supervisor), Marko Hrovat (Co-Supervisor)

Year: 2010

Type: Doctoral dissertation

A starting powder with the nominal composition 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (0.65PMN–0.35PT), which corresponds to the morphotropic phase boundary (MPB) composition, was prepared by mechanochemical activation followed by attritor milling and low-temperature calcination at 700°C. It had a narrow particle size distribution with the median particle size equal to 0.3 μm. From the …

High-alumina porcelain with improved mechanical and thermal properties

Author(s): Martina Oberžan (Author), Marija Kosec (Supervisor), Janez Holc (Co-Supervisor)

Year: 2009

Type: Doctoral dissertation

The study presents the influence of increasing the amount of β-spodumene (LiAlSi2O6) as Li2O-content flux on phase composition, microstructural evolution and physical properties of high alumina porcelain material containing ~61% of Al2O3. New porcelain compositions based on clays and high amount of calcined alumina were developed with the introduction of …