Mikrovalno sinteriranje porozne aluminijeve oksidne keramike koja sadrži otpadni grafit

master's thesis

• Title (english): Microwave sintering of alumina ceramics witch contain waste graphite
• Author: Marin Medved
• Mentor: Lidija Ćurković (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2023-07-20, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom radu cilj je bio istražiti mogućnost dobivanja porozne keramike metodom žrtvene faze
koristeći otpadni grafit uz sinteriranje uzoraka u hibridnoj mikrovalnoj peći. Otpadni grafit
korišten je jer je lako dostupan, izgara na temperaturi nižoj od temperature sinteriranja keramike
i ekološki je isplativ. Uzorci su mikrovalno sinterirani jer se radi o nekonvencionalnom
postupku koji je sve više u primjeni te su uspoređena svojstva materijala prije i nakon postupka
sinteriranja.
Pripremljene su suspenzije koje sadrže 60% Al2O3 praha sa različitim masenim udjelima
otpadnog grafita od 0, 1, 5 i 10 % te dodatak disperzanta i veziva. Sirovci su dobiveni lijevanjem
pripravljenih suspenzija u gipsane kalupe nakon što je suspenzija homogenizirana u
planetarnom kugličnom mlinu. Kako bi se usporedila svojstva prije i nakon sinteriranja,
sirovcima su izmjerene dimenzije i masa. Uslijedilo je sinteriranje u hibridnoj mikrovalnoj peći
na 1600 °C. Sinteriranim uzorcima pomoću pretražnog elektronskog mikroskopa (SEM)
analizirana je mikrostruktura, nakon čega su im određeni promjena mase i gustoće, poroznost i
skupljanje. Na temelju dobivenih rezultata koji su prikazani u tablicama i na slikama na kraju
rada doneseni su zaključci te je utvrđen utjecaj otpadnog grafita na svojstva porozne keramike
sinterirane u mikrovalnoj peći.

Abstract (english)

In this study, the aim was to investigate the possibility of obtaining porous ceramics using the
sacrificial phase method, by using waste graphite and sintering the samples in a hybrid
microwave oven. Waste graphite was used because it is readily available, burns at a lower
temperature than the ceramic sintering temperature, and is environmentally cost-effective. The
samples were microwave-sintered since it is an unconventional process that is increasingly
being used, and the material properties before and after the sintering process were compared.
Suspensions containing 60 wt.% of Al2O3 powder with varying weight percentages of waste
graphite (0%, 1%, 5%, and 10%), dispersant, and binder were prepared. The green bodies were
obtained by pouring the suspension into plaster molds after homogenization in a planetary ball
mill. In order to compare the properties before and after sintering, the dimensions and mass of
the green bodies were measured. Subsequently, sintering was performed in a hybrid microwave
oven at 1600 °C. The sintered samples were analyzed using a scanning electron microscope
(SEM) to examine the microstructure, followed by measurements of mass and density change,
porosity, and shrinkage. Based on the obtained results presented in tables and figures at the end
of the study, conclusions were drawn regarding the influence of waste graphite on the properties
of porous ceramics sintered in a hybrid microwave oven.

• Keywords: porozna keramika; aluminijev oksid; otpadni grafit; mikrovalno sinteriranje
• Keywords (english): porous ceramics; aluminium oxide; waste grapfite; microvawe sintering
• Language: croatian
• URN:NBN: urn:nbn:hr:235:630392
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-07-11 12:46:47