Materials Science and Engineering / Malzeme Bilimi ve Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4719

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Author: search.filters.author.Biesuz, Mattia

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  • Article
    Citation - WoS: 5
    Citation - Scopus: 6
    Formation of Monolithic Srtio3-Tio2 Ceramic Heterostructures by Reactive Hydrothermal Sintering
    (Elsevier, 2023) Karacasulu, Levent; Kartal, Uğur; İçin, Öykü; Bortolotti, Mauro; Biesuz, Mattia; Ahmetoğlu, Çekdar Vakıf
    In a one-pot approach, monolithic SrTiO3-TiO2 ceramic heterostructures were obtained using the reactive hydrothermal liquid phase densification (rHLPD). Structural, morphological, and photocatalytic properties of the obtained ceramics were analyzed. The relative density of the formed components reached about 80% with reaction time, temperature, and NaOH concentration variation. It was observed via Rietveld refinement that there was no XRD detectable phase other than TiO2 and SrTiO3 in the final structure. The monolithic SrTiO3-TiO2 ceramics obtained by hydrothermal reaction at 120 °C for 24 h in 1 M NaOH concentration showed a dielectric constant being around 500, and the dielectric loss was below 0.25 at frequencies higher than 10 kHz. The SrTiO3-TiO2 heterostructured monoliths having only 20 vol% total porosity and low specific surface area, demonstrated ∼60% efficiency (in 5 h) in degrading Methylene Blue photo-catalytically. © 2023 Elsevier Ltd
  • Article
    Citation - WoS: 19
    Citation - Scopus: 19
    Processing of Polymer-Derived, Aerogel-Filled, Sic Foams for High-Temperature Insulation
    (Wiley, 2023) Zambotti, Andrea; Ionescu, Emanuel; Gargiulo, Nicola; Caputo, Domenico; Ahmetoğlu, Çekdar Vakıf; Santhosh, Balanand; Biesuz, Mattia
    Porous polymer-derived ceramics (PDCs) are outperforming materials when low-density and thermal inertia are required. In this frame, thermal insulating foams such as silicon carbide (SiC) ones possess intriguing requisites for aerospace applications, but their thermal conductivity is affected by gas phase heat transfer and, in the high temperature region, by radiative mechanisms. Owing to the versatility of the PDC route, we present a synthesis pathway to embed PDC SiC aerogels within the open cells of a SiC foam, thus sensibly decreasing the thermal conductivity at 1000 degrees C from 0.371 W center dot m(-1)K(-1) to 0.243 W center dot m(-1)K(-1). In this way, it was possible to couple the mechanical properties of the foam with the insulating ability of the aerogels.The presented synthesis was optimized by selecting, among acetone, n-hexane, and cyclohexane, the proper solvent for the gelation step of the aerogel formation to obtain a proper mesoporous colloidal structure that, after ceramization at 1000 degrees C, presents a specific surface area of 193 m(2)center dot g(-1). The so-obtained ceramic composites present a lowest density of 0.18 g center dot cm(-3), a porosity of 90% and a compressive strength of 0.76 MPa.