Reološka svojstva Al2O3 suspenzija koje sadrže otpadni grafit

master's thesis

• Title (english): Rheological properties of Al2O3 suspensions which contain waste graphite
• Author: Antonio Gagulić
• 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; General Mechanical Engineering (Construction)

Abstract

U postupku oblikovanja keramike lijevanjem suspenzije reološki dijagrami tečenja su ključni kako bi se postigla potpuna kontrola reoloških svojstava keramičkih suspenzija, a time i njihova stabilnost. U tu svrhu, snimaju se krivulje tečenja pripravljenih suspenzija: ovisnosti viskoznosti (η) o brzini smicanja (γ) te ovisnosti smičnog naprezanja (τ) o brzini smicanja (γ). U radu su pripravljene 60 %-tne vodene Al2O3 suspenzije s masenim udjelom 0 %, 1 %, 5 % i 10 % otpadnog grafita te uz dodatak odgovarajućih aditiva (disperzanta i veziva). Otpadni grafit smatra se prikladnim materijalom kao žrtvena faza u ovoj metodi dobivanja porozne keramike budući da je ekološki prihvatljiv, niske cijene, omogućuje dobru kontrolu poroznosti i dobro izgara pri visokim temperaturama, čime osigurava dobru poroznost. Nakon priprave suspenzija, slijedila je homogenizacija te ispitivanje reoloških svojstava snimanjem krivulja tečenja: ovisnost viskoznosti o brzini smicanja te ovisnost smičnog naprezanja o brzini smicanja. Na temelju dobivenih rezultata ispitivanja, utvrđen je utjecaj dodatka aditiva i otpadnog grafita na reološka svojstva 60 %-tnih Al2O3 suspenzija.

Abstract (english)

In the process of forming ceramics by slip casting rheological flow diagrams are crucial to achieve complete control of the rheological properties of the suspension and thus the stability of the suspension. For this purpose, the flow curves of the dependence of viscosity (η) on the shear rate (γ) and the dependence of the shear stress (τ) on the shear rate (γ) are examined. In this work, 60% aqueous Al2O3 suspensions with a mass fraction of 0 wt. %, 1 wt. %, 5 wt. % and 10 wt. % of waste graphite were prepared, with the addition of appropriate additives (dispersant and binder). Waste graphite is considered a suitable material as a sacrificial phase in this method of obtaining porous ceramics since it is environmentally friendly, low cost, allows good porosity control and burns well at high temperatures, thus ensuring good porosity. After preparation of the suspensions, homogenization was performed, and rheological properties were determined by recording flow curves of viscosity dependence on shear rate and shear stress dependence on shear rate. Based on the obtained test results, the influence of the addition of additives and waste graphite on the rheological properties of 60% Al2O3 suspensions was determined.

• Keywords: aluminijev oksid; otpadni grafit; reološka svojstva
• Keywords (english): aluminium oxide; waste graphite; rheological properties
• Language: croatian
• URN:NBN: urn:nbn:hr:235:570642
• 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: 2023-07-18 10:35:59