Naslov
Influence of composition on properties of bulk ZnO- Al2O3-SiO2 glass ceramics

Autori
Kurajica, Stanislav ; Šipušić, Juraj ; Župančić, Martina ; Brautović, Igor ; Albrecht, Martin

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts: 1st International Conference of the Croatian Ceramic Society (CroCerS): Advanced Ceramics in Derivative Configurations (1st ACDC 2023) / Mandić, Vilko - Zagreb : Fakultet kemijskog inženjerstva i tehnologije Sveučilišta u Zagrebu, 2023, 23-23

ISBN
978-953-6470-99-0

Skup
1st International Conference of the Croatian Ceramic Society (CroCerS): Advanced Ceramics in Derivative Configurations (1st ACDC 2023)

Mjesto i datum
Zagreb, Hrvatska, 26.04.2023. - 29.04.2023

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
glass-ceramics ; gahnite ; nucleation ; nanocrystals ; dichroism

Sažetak
Samples with different ratios of ZnO, Al2O3 and SiO2, and a constant amount of TiO2 were prepared by melting the batches at 1570 °C for 2 hours. The influence of glass composition on crystal phases, crystallite size, and appearance of prepared glass-ceramics has been investigated. As-prepared bulk glass samples were studied using differential thermal analysis (DTA). On the basis of glass transition temperature, the nucleation temperature was selected to be 740 °C. After 5 h of nucleation and heat treatment till 1150 °C, a part of the samples became white and opaque, while other samples turned out to be translucent and dichroic, i.e. bluish-grey coloured in reflected, and amber- coloured in transmitted light. Such behaviour is attributed to a combination of scattering and selective absorbance of light. On the basis of X- ray diffraction (XRD) analysis, it was established that gahnite (ZnAl2O4) is the main phase crystallizing in the course of thermal treatment, while corundum (Al2O3), willemite (Zn2SiO4), zinc titanate (Zn2Ti3O8), and rutile (TiO2) appear in some of the samples as minor phases. A trend of crystallite size reduction with the increase of Al2O3 content has been noted. This was explained through a mechanism based on nucleation by nanoscale phase separation. High resolution transmission electron microscopy (HRTEM) analysis showed that the most translucent sample is densely populated with uniformly distributed and irregularly shaped gahnite crystal grains with average size of ~11 nm.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Kemijsko inženjerstvo, Temeljne tehničke znanosti

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