Izvorni znanstveni članak
Properties of Nanocrystals-formulated Aluminosilicate Bricks
Francesca Conciauro
; Department of Innovation Engineering-University of Salento, Lecce, Italy
Emanuela Filippo
; Department of Innovation Engineering-University of Salento, Lecce, Italy
Claudia Carlucci
; Chemistry Department, University of Bari, Bari, Italy
Viviana Vergaro
; CNR NANOTEC - Institute of Nanotechnology of the National Research Council, c/o Campus Ecotekne, University of Salento, Lecce, Italy
Francesca Baldassarre
; CNR NANOTEC - Institute of Nanotechnology of the National Research Council, c/o Campus Ecotekne, University of Salento, Lecce, Italy
Rosaria D'Amato
; ENEA Frascati Research Centre, Frascati Roma, Italy
Gaetano Terranova
; ENEA Frascati Research Centre, Frascati Roma, Italy
Caterina Lorusso
; Department of Innovation Engineering-University of Salento, Lecce, Italy
Paola Maria Congedo
; Department of Innovation Engineering-University of Salento, Lecce, Italy
Barbara Federica Scremin
; CNR NANOTEC - Institute of Nanotechnology of the National Research Council, c/o Campus Ecotekne, University of Salento, Lecce, Italy
Giuseppe Ciccarella
; Department of Innovation Engineering-University of Salento, Lecce, Italy; CNR NANOTEC - Institute of Nanotechnology of the National Research Council, c/o Campus Ecotekne, University of Salento, Lecce, Italy
Sažetak
In the present work, seven different types of nanocrystals were studied as additives in the formulation of aluminosilicate bricks. The considered nanocrystals consisted of anatase titanium dioxide (two differently shaped types), boron modified anatase, calcium carbonate (in calcite phase), aluminium hydroxide and silicon carbide (of two diverse sizes), which were prepared using different methods. Syntheses aim to give a good control over a particle’s size and shape. Anatase titania nanocrystals, together with the nano-aluminium hydroxide ones, were synthesized via microwave-assisted procedures, with the use of different additives and without the final calcination steps. The silicon carbide nanoparticles were prepared via laser pyrolysis. The nano-calcium carbonate was prepared via a spray drying technique. All of the nanocrystals were tested as fillers (in 0.5, 1 and 2 wt. % amounts) in a commercial aluminosilicate refractory (55 % Al2O3, 42 % SiO2). They were used to prepare bricks that were thermally treated at 1300 °C for 24 hours, according to the international norms. The differently synthesized nanocrystals were added for the preparation of the bricks, with the aim to improve their heat-insulating and/or mechanical properties. The nanocrystals-modified refractories showed variations in properties, with respect to the untreated aluminosilicate reference in heat-insulating performances (thermal diffusivities were measured by the “hot disk” technique). In general, they also showed improvements in mechanical compression resistance for all of the samples at 2 wt. %. The best heat insulation was obtained with the addition of nano-aluminium hydroxide at 2 wt. %, while the highest mechanical compression breaking resistance was found with nano-CaCO3 at 2 wt. %. These outcomes were investigated with complementary techniques, like mercury porosimetry for porosity, and Archimedes methods to measure physical properties like the bulk and apparent densities, apparent porosities and water absorption. The results show that the nano-aluminium hydroxide modified bricks were the most porous, which could explain the best heat-insulating performances. There is a less straightforward explanation for the mechanical resistance results, as they may have relations with the characteristics of the pores. Furthermore, the nanoparticles may have possible reactions with the matrix during the heat treatments.
Ključne riječi
Anatase; Boron; Aluminium Hydroxide; Calcium Carbonate; Silicon Carbide; Aluminosilicate Refractories; Nanocrystals
Hrčak ID:
157551
URI
Datum izdavanja:
1.1.2015.
Posjeta: 919 *