Pregled bibliografske jedinice broj: 149527
The influence of particle size on crystallization of Zno-Al2O3-SiO2 glass ceramics
The influence of particle size on crystallization of Zno-Al2O3-SiO2 glass ceramics // Nonmetal inorganic materials, Manufacturing - processing - application, Proceedings / Karić, Asim (ur.).
Zenica: Faculty for metallurgy and materials science, Zenica, 2004. str. 131-140 (predavanje, međunarodna recenzija, cjeloviti rad (in extenso), znanstveni)
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Naslov
The influence of particle size on crystallization of Zno-Al2O3-SiO2 glass ceramics
Autori
Kurajica, Stanislav ; Tkalčec, Emilija
Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni
Izvornik
Nonmetal inorganic materials, Manufacturing - processing - application, Proceedings
/ Karić, Asim - Zenica : Faculty for metallurgy and materials science, Zenica, 2004, 131-140
Skup
Vth International scientific and expert symposium Nonmetal inorganic materials, Manufacturing - processing - application
Mjesto i datum
Zenica, Bosna i Hercegovina, 28.04.2004. - 29.04.2004
Vrsta sudjelovanja
Predavanje
Vrsta recenzije
Međunarodna recenzija
Ključne riječi
activation energy; crystallization; gahnite; glass-ceramics; zinc-aluminosilicate
Sažetak
Crystallization behavior of powder glass with various particle sizes from 63 μ m to 500 μ m and bulk glass (~5 mm), with the composition: 55.6 mol% SiO2, 22.8 mol% Al2O3, 17.7 mol% ZnO and with 3.84 mol% of TiO2 as nucleating agent, has been studied by differential thermal analysis (DTA) and X-ray diffraction (XRD). The DTA scans of all powder samples are characterized with two exothermal peaks, while bulk glass scan has one exothermal peak. Two crystalline phases: zinc-aluminosilicate s.s. with high-quartz structure, Znx/2AlxSi3-xO6, and gahnite, ZnAl2O4, are formed in powder samples after first peak. The ratio of these phases depends on particle sizes. As coarser the powder, more gahnite fraction is produced. Eventually, in bulk glass gahnite is the sole crystalline phase. As the temperature in powder samples increases the second DSC peak appears, due to the second step gahnite crystallization. Simultaneously, the amount of zinc aluminosilicate s.s. decreases and the quantity of zinc and aluminum incorporated in the structure reduce until almost pure high-quartz structure is formed. The activation energies of zinc-aluminosilicate s.s. and gahnite crystallization has been determined by non-isothermal method to be 510± ; ; 18 and 344± ; ; 17 kJmol-1, respectively.
Izvorni jezik
Engleski
Znanstvena područja
Kemijsko inženjerstvo
POVEZANOST RADA
Projekti:
0125002
Ustanove:
Fakultet kemijskog inženjerstva i tehnologije, Zagreb
Profili:
Stanislav Kurajica
(autor)
