Priprava i karakterizacija porozne aluminijeve oksidne keramike koja sadrži otpadni grafit

master's thesis

• Title (english): Preparation and characterization of porous alumina ceramics which contain waste graphite
• Author: Leon Jozić
• 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 pripravljena je porozna aluminijeva oksidna keramika s različitim udjelima otpadnog grafita. Sirovci su oblikovani postupkom lijevanja suspenzije u gipsani kalup. U tu svrhu pripravljene su 60 %-tne vodene Al2O3 suspenzije s različitim masenim udjelima (0, 1, 5 i 10 %) otpadnog grafita te uz dodatke disperzanta Dolapix PC 75 (0,4 %) i veziva PVA (0, 5 %).
Suspenzije su homogenizirane u planetarnom kugličnom mlinu nakon čega slijedi lijevanje u gipsane kalupe za dobivanje sirovaca.... More Prije samog lijevanja suspenzijama su određena reološka svojstva na rotacijskom viskozimetru. Lijevanjem u gipsani kalup su dobiveni sirovci Al2O3 keramike s masenim udjelom 0, 1, 5 i 10 % otpadnog grafita koji su sinterirani (konvencionalnim postupkom) u električnoj peći. Režim sinteriranja se sastojao od zagrijavanja na temperaturu od 800 °C pri brzini zagrijavanja od 5 °C min-1, izotermnog držanja na toj temperaturi u trajanju od 2 sata da izgori sav otpadni grafit, zatim zagrijavanje do 1600 °C pri brzini zagrijavanja od 5 °C min-1 te ponovno držanje od 2 sata da se završi proces sinteriranja keramike. Poslije toga je uslijedilo hlađenje u peći na sobnoj temperaturi. Dobivenim keramičkim proizvodima je analizirana mikrostruktura pretražnim elektronskim mikroskopom (SEM) te je određen gubitak mase, gustoća, poroznost i skupljanje.
Rezultati su na kraju rada raspravljeni te je donesen zaključak. Less

Abstract (english)

In this study, porous alumina ceramic with varying proportions of waste graphite was prepared. Green bodies were formed by pouring the suspension in plaster mold. For this purpose, 60 % aqueous Al2O3 suspension with different mass fractions (0, 1, 5 and 10 %) of waste graphite, along with addition of dispersant Dolapix PC 75 (0,4 %) and a binder PVA (0, 5 %) were prepared.
The suspensions were homogenized in a planetary ball mill, followed by pouring into a plaster mold to obtain green... More bodies. Prior to pouring of the suspensions, the rheological properties were determined using a rotational viscometer. Casting into plaster mold yielded green boodies of Al2O3 ceramic with mass fractions of 0, 1, 5 and 10 % of waste graphite, which were then sintered (by conventional technique) in an electric furnace. The sintering regime involved heating to a temperature of 800 °C at a heating rate of 5 °C min-1 , isotermic holding at that temperature for 2 hours to burn off all the waste graphite, followed by heating to 1600 °C at a heating rate of 5 °C min-1 and another 2-hour hold to complete the ceramic sintering process. Subsequently, cooling was performed in the furnace at room temperature. The obtained ceramic products microstructure was analyzed using a scanning electronic microscope (SEM), and the mass loss, density, porosity and shrinkage were determined.
The results were discussed at the end of the study, and a conclusion was reached. Less

• Keywords: aluminijev oksid; porozna keramika; otpadni grafit; sinteriranje; lijevanje suspenzija
• Keywords (english): alumina; porous ceramics; waste graphite; sintering; slip-casting
• Language: croatian
• URN:NBN: urn:nbn:hr:235:619288
• 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: 2023-07-19 11:40:22