Thermoelectric properties of pseudobrookite-based ceramics prepared from natural Fe-Ti-rich heavy mineral sand concentrate

Daneu, Nina (author), Radošević, Tina (author), Bernik, Slavko (author), Hanžel, Darko (author), Mazaj, Matjaž (author), Maček Kržmanc, Marjeta (author), Verhovšek, Dejan (author), Kocjan, Andraž (author), Vrabec, Mirijam (author), Spreitzer, Matjaž (author), Guilmeau, Emmanuel (author)

Pseudobrookites (Fe$_2$TiO$_5$-FeTi$_2$O$_5$) are promising candidates for high-temperature oxide thermoelectrics. In this work, we used natural Fe-Ti-rich heavy mineral sand (HMS) as an abundant and environmentally friendly raw material for the preparation of pseudobrookite-based ceramics. The main components of the initial powder were ilmenite (FeTiO$_3$) and pseudorutile (Fe$_2$Ti$_3$O$_9$) with various degrees of alteration. Pre-oxidation of the as-received powder was used for modification of the Fe$^{2+}$:Fe$^{3+}$ ratio and exsolution of rutile. The starting powders were densified by conventional sintering (CS; 1200 °C, 5 h, pressureless) and spark plasma sintering (SPS; 1100 °C, 5 min, 150 MPs) in argon. The thermoelectric properties of the sintered compacts depend mainly on the Fe:Ti ratio, the Fe$^{2+}$:Fe$^{3+}$ ratio, and the fraction and distribution of rutile in the microstructures. The samples exhibit comparable properties as the pseudobrookite-based ceramics prepared from high-purity chemicals indicating that, with some further optimization, natural Fe-Ti-rich HMS are an interesting alternative for the preparation of pseudobrookite-based ceramics for thermoelectric applications.

• Language: English
• Keywords: Fe-Ti-rich heavy mineral sands, natural raw materials, Fe$_2$TiO$_5$, FeTi$_2$O$_5$, processing, microstructure, Fe$^{2+}$:Fe$^{3+}$ ratio, thermoelectric characteristics
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2023
• Number of pages: Str. 7499-7507
• Numbering: Vol. 43, iss. 16
• PID: 20.500.12556/RUL-153024
• UDC: 666
• ISSN on article: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2023.07.071
• COBISS.SI-ID: 160364803
• Publication date in RUL: 14.12.2023

Record is a part of a journal

• Title: Journal of the European ceramic society
• Shortened title: J. Eur. Ceram. Soc.
• Publisher: Elsevier
• ISSN: 0955-2219
• COBISS.SI-ID: 6342151

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• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
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