20.500.12556/RUL-184227 Vpliv pogojev sintranja na mikrostrukturo in električne lastnosti trdne raztopine cirkonijevega oksida in itrijevega oksida diplomsko delo Effect of Sintering Conditions on the Microstructure and Electrical Properties of Zirconia - Yttria Solid Solution diploma work V diplomskem delu sem preiskoval mikrostrukturo in električne lastnosti cirkonijevega oksida stabiliziranega z itrijevim oksidom (ZrO2)0.92(Y2O3)0.08 ali (angl. Yttria Stabilized Zirconia ali YSZ), ki je osnovni gradnik celic s trdnim oksidnim elektrolitom (angl., Solid Oxide Cells ali SOC). SOC se v zadnjem času izkazujejo kot učinkovit vmesni člen med obnovljivimi viri energije in porabniki za stabilizacijo električnega omrežja. V času presežka energije proizvajajo vodik, ob pomanjkanju energije pa ga pretvarjajo v električno energijo. SOC so sestavljene iz gorivne in kisikove elektrode, ter trdnega oksidnega elektrolita. SOC delujejo pri visokih temperaturah, običajno med 700 °C in 1000 °C, zato sta kontrolirana izdelava in razumevanje lastnosti materialov ključnega pomena. V diplomskem delu sem pripravil elektrolit, trdno raztopino YSZ, in ga podrobno preučil. V literaturnem pregledu je podrobno opisana keramika YSZ, tehnologije izdelave ter električne lastnosti. Eksperimentalen del obsega pripravo keramične suspenzije, ki je vključevala prašek YSZ, topilo, vezivo in plastifikator. S tehniko nalivanja plasti na podlago sem pripravil keramično plast, ki sem jo s postopkom laminacije združili v večplastno strukturo. Iz večplastne strukture sem z laserskim izrezovalnikom pripravil vzorce v obliki diskov. S pomočjo segrevalnega mikroskopa sem nato določil območje sintranja keramike YSZ. Vzorce sem sintrali v komorni peči v temperaturnem območju od 1300 °C do 1500 °C, 3h. Mikrostrukturo sintranih vzorcev sem analizirali z vrstičnim elektronskim mikroskopom. Električne lastnosti sem ovrednotil z elektrokemijsko impedančno spektroskopijo s katero sem preko Nyquistovih diagramov ločil prispevke zrn, mej med zrni in elektrod k celotni upornosti materiala. Rezultati so pokazali, da višanje temperature sintranja povečuje velikost zrn, hkrati pa dobimo nižjo relativno gostoto. Ugotovil sem, da z večanjem zrn ionska prevodnost materiala narašča. Pri temperaturi 1450 °C in višje pa je poroznost materiala tako velika, da pore pričnejo zmanjševati ionsko prevodnost in izničijo vpliv večanja zrn. Lastnosti keramike YSZ so odvisne od številnih procesnih parametrov, ki vključujejo pripravo stabilne suspenzije, pogoje nalivanja, natančno izdelavo zložkov in izbor ustreznih pogojev sintranja. Z obvladovanjem teh parametrov lahko pripravimo keramiko z gosto in enakomerno mikrostrukturo, kar je ključno za načrtovanje lastnosti YSZ predvsem za uporabo v SOC. Ključne besede: cirkonijev oksid, celice s trdnim oksidnim elektrolitom, sintranje, elektrolit, nalivanje plasti, impedančna spektroskopija In my bachelor thesis, I have researched the zirconia solid solution (ZrO₂)0.92(Y₂O₃)0.08 with additions of yttria or (YSZ) which is a key component of solid oxide cells (SOC). SOC have recently emerged as an effective interface between renewable energy sources and consumers for stabilizing electrical power grid. During periods of energy surplus, they produce hydrogen, and during energy shortages, they convert it back into electrical energy. SOC consist of a fuel electrode, an oxygen electrode, and a solid oxide electrolyte. Since SOC operate at high temperatures, typically between 700 °C and 1000 °C, controlled manufacturing and a deep understanding of materials are of key importance. YSZ ceramic electrolyte was prepared and studied in detail. The literature review describes the structural properties of the electrolyte, manufacturing technologies, and the measurement of electrical properties. The experimental procedure involved preparing a ceramic suspension containing YSZ powder, solvents, binders, and plastifiers. Ceramic tapes were produced using the tape casting technique and then joined into a multilayer structure through lamination. Disc-shaped samples were cut from this structure using a laser cutter. The sintering range of the YSZ ceramics was determined with a heating microscope. The samples were sintered in a chamber furnace at temperatures from 1300 °C to 1500 °C for 3 hours. The microstructure of the sintered samples was analysed by scanning electron microscopy. The electrical properties were evaluated using electrochemical impedance spectroscopy, which enabled the separation of grain, grain boundary, and electrode contributions to the total resistance of the material via Nyquist plots. The results showed that increasing the sintering temperature increases the grain size, while simultaneously leading to a lower relative density. Ion conductivity was found to increase with larger grain size. However, at temperatures of 1450 °C and above, the porosity of the material becomes so significant that the pores begin to affect and slightly reduce the ionic conductivity, offsetting the effect of increased grain size. The properties of YSZ ceramics depend on the several processing parameters, which include the preparation of a stable suspension, casting conditions, precise component shaping, and the selection of appropriate sintering conditions. By controlling these parameters, we can produce ceramics with a dense and uniform microstructure, which is crucial for tailoring the properties of YSZ, especially for use in SOC. cirkonijev oksid celice s trdnim oksidnim elektrolitom sintranje elektrolit nalivanje plasti impedančna spektroskopija zirconia sintering electrolyte tape casting impedance spectroscopy true false false B. Perko Slovenski jezik Angleški jezik Diplomsko delo/naloga 2026-07-02 09:00:11 2026-07-02 09:00:45 2026-07-13 13:32:02 0000-00-00 00:00:00 2026 0 Ljubljana 0 Ljubljana XIII, 34 f. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 669 114152 284581123 29504.pdf 29504.pdf 1 67FFAF887BF5BFF107015C91473C4B43 90be3cd735f884febef7f00ad748c69982dd757bd236629c1a6fc90a35d3d331 a3fa3c0f-75e3-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=236836 Naravoslovnotehniška fakulteta 0 0 0