Strukturna i električna svojstva željeznih fosfatnih stakala

master's thesis

• Author: Nedjeljko Žuvela
• Mentor: Željko Skoko (mentor)
• Committee member: Željko Skoko (predsjednik povjerenstva)
• Committee member: Dalibor Paar (član povjerenstva)
• Committee member: Tina Bosner (član povjerenstva)
• Committee member: Ivan Kupčić (član povjerenstva)
• Committee member: Ilja Gogić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Mathematics); Zagreb
• Defense date and country: 2020-02-28, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Mathematics

Abstract

Cilj ovog diplomskog rada bilo je pobliže se upoznati sa željeznim fosfatnim staklima i istražiti strukturna svojstva željeznog fosfatnog stakla molnog sastava \(40Fe_{2}O_3-60P_2O_5\). Prvi dio rada govori općenito o staklim, o povijesnom razvoju, te vrstama i primjeni stakala. Slijedi opis metoda (rendgenska difrakcija i elektronska mikroskopija) i uređaja koji su korišteni pri izradi ovog rada. U drugom dijelu rada detaljno su opisana željezna fosfatna stakla i prikazani su rezultati naših istraživanja provedenih na tim staklima, točnije na \(40Fe_2O_3-60P_2O_5\). \(40Fe_2O_3-60P_2O_5\) je grijan na visokim temperaturama, raspona od \(530\, ^\circ\)C do \(800\, ^\circ\)C, tijekom različitih vremenskih perioda (1h, 6 h, 12 h, 24 h i 48 h) i praćen je utjecaj provedenih termičkih postupaka obrade na strukturu. Postupci s kraćim vremenima grijanja (1 h i 6 h) na temperaturama do \(590\, ^\circ\)C (\(530\, ^\circ\)C, \(560\, ^\circ\)C i \(590\, ^\circ\)C) rezultirali su nastankom amorfnih struktura. Što je bilo potpuno očekivano za staklo. Rastom temperature i duljine tretiranja, udio amorfne faze u strukturi \(40Fe_2O_3-60P_2O_5\) se sve više smanjivao, pri čemu je dugotrajno grijanje materijala na vrlo visokoj temperaturi (\(800\, ^\circ\)C i 48 h) rezultiralo njegovom potpunom kristalizacijom. To nam je potvrdilo pretpostavku da kristalizacija ovisi o temperaturi ali i vremenu grijanja. Daljnja istraživanja ovog sustava, provedena u Laboratoriju za funkcionalne materijale na Institutu Ruđer Bošković, pokazala su električnu vodljivost polaronskog tipa pri čemu se električna vodljivost povećava nastajanjem dodatnih kristalnih faza \( (Fe_4(P_2O_7)_3 i Fe(PO_3)_3) \) zbog veće koncentracije parova \(Fe^{2+}\)/\(Fe^{3+}\) iona.

Abstract (english)

The main aim of this work was to learn more about properties of iron phosphate glasses and to investigate the structural properties of iron phosphate glasses of molar composition \(40Fe_{2}O_3-60P_2O_5\). The first part of the diploma thesis deals with glasses in general; their historical development, types and possible applications. Also, description of methods (X-ray diffraction and electron microscopy) and devices used in this diploma work is given in this section.Ferrous phosphate glases are described in the second part of the work and the results of our study of molar composition \(40Fe_2O_3-60P_2O_5\) are given. We heated \(40Fe_2O_3-60P_2O_5\) at different temperatures ranging from \(530\, ^\circ\)C to \(800\, ^\circ\)C,during time periods of 1h, 6 h, 12 h, 24 and 48 h and monitored the influence of different procedures on formation of the crystal structure. Treatment at temperatures up to \(590\, ^\circ\)C (\(530\, ^\circ\)C, \(560\, ^\circ\)C i \(590\, ^\circ\)C)with shorter times (1 h and 6 h) resulted in the formation of amorphous structures, as expected for this type of glass. By increasing temperature and the heating time proportion of amorphous phase in structure decreased, wherein the long-term heating of the material to very high temperature (\(800\, ^\circ\)C i 48 h) resulted in its complete crystallization. In this way, assumption that crystallization depends of the temperature as well as of the heating time was confirmed. Further studies of this system, performed at Rudjer Boskovic Institute, Laboratory for Functional Materials revealed polaronic conductivity with an increase in electrical conductivity upon formation of two additional crystalline phases \((Fe_4(P_2O_7)_3\) and \(Fe(PO_3)_3)\) mostly due to higher concentration of the \(Fe^{2+}\)/\(Fe^{3+}\) ion pairs.

• Keywords: željeza fosfatna stakla; rendgenska difrakcija; elektronska mikroskopija; kristalizacija
• Keywords (english): iron phosphate glasses; X-ray diffraction; electron microscopy; crystallization
• Language: croatian
• URN:NBN: urn:nbn:hr:217:943353
• Study programme: Title: Mathematics and Physics Education; specializations in: Mathematics and Physics Education; Course: Mathematics and Physics Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije matematike i fizike (magistar/magistra edukacije matematike i fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-11-12 15:29:24