Optimize TiB2 Ağ Yapılı SiC Kompozitlerinin Geliştirilmiş Termoelektrik Özellikleri

Year 2025, EARLY VIEW, 1 - 1

Zeynep Sude Bulut Salih Çağrı Özer

https://doi.org/10.2339/politeknik.1625094

Abstract

Yenilenebilir enerji kaynaklarının azlığı ve fosil yakıt tüketiminin artışı nedeniyle, yenilenebilir ve sürdürülebilir enerji üretimi için malzemelerin geliştirilmesi, termoelektrik güç üretimi de dahil olmak üzere önemli bir konu haline gelmiştir. SiC gibi ileri teknoloji seramikleri yüksek sıcaklık termoelektrik uygulamaları için tercih edilen alternatif malzemelerden biridir. SiC yüksek Seebeck katsayısı değerlerine sahip olmasına rağmen, sahip olduğu nispeten düşük elektriksel ve termal iletkenlik özellikeri termoelektrik uygulamalar için istenmemektedir. SiC’ün elektriksel iletkenliğini artırmak için geçiş metal borürlerin ikincil faz olarak eklenmesi yaygın bir yöntemdir. Bu çalışmada, SiC granülleri, basit bir kuru kaplama yöntemi kullanılarak TiB₂ tozlarıyla kaplanmış ve ardından iletken ağyapıları oluşturmak için spark plazma sinterleme sürecine tabi tutulmuştur. TiB₂ ağının morfolojisini optimize etmek amacıyla, kaplama işlemi öncesinde SiC granülleri 25-50 µm’den 75-100 µm’ye kadar değişen partikül boyutu aralıklarına göre sınıflandırılmıştır. Matris granül boyutu dağılımına bağlı olarak elektriksel iletkenlikte ≈%130-500 oranında artıs elde edilmiştir ve iletkenliğin SiC granül boyutlarının artmasıyla azaldığı görülmüştür. Değerlendirildiğinde bu durumun, TiB₂ ağının daha yüksek bir yoğunluğa sahip olmasına bağlı olarak perkolasyon eşiğini düşürdüğünü ve elektriksel iletkenlikte yüksek miktarda artışlara neden olduğu anlaşılmıştır. Sonuç olarak, termoelektrik performansı belirleyen ZT değeri 25-50 µm partikül boyut aralığında ≈%50 oranında artırılmıştır.

Keywords

Termoelektrik , Silikon Karbür , Titanyum Borür , Ağyapılı Mikroyapı , Spark Plazma Sinterleme

Project Number

1919B012327999

Improved Thermoelectric Properties of SiC Composites with Optimized TiB2 Network Structures

Abstract

Due to the scarcity of renewable energy sources and the increase in fossil fuel consumption, the development of materials for renewable and sustainable energy production has become an eminent concern, including thermoelectric power generation. Advanced ceramics such as SiC is a desirable alternative material for high-temperature thermoelectric applications. Although SiC has a high Seebeck coefficient, it has relatively low electrical and thermal conductivities, which are undesirable properties for thermoelectric applications. Introducing transitional metal borides as a secondary phase to enhance the electrical conductivity of SiC is a common method. In this study, SiC granules were coated with TiB₂ powders using a simple dry coating method and subsequently subjected to spark plasma sintering to produce composites with conductive network structures. To modify the morphology of the TiB₂ network, SiC granules were classified with particle size ranges of 25-50 µm to 75-100 µm prior to the coating process, Increases of ≈130-500% in electrical conductivity was achieved depending on the matrix granule size distribution, which decreased with increasing SiC granule sizes, showed that the higher concentration of TiB₂ network lowered the percolation threshold causing drastic increases in electrical conductivity. The ZT value increased by ≈50% in the 25-50 µm range.

Keywords

Thermoelectric , Silicon Carbide , Titanium Boride , Network Structure , Spark Plasma Sintering

Ethical Statement

The author(s) of this article declare that the materials and methods used in this study do not require ethical committee permission and/or legal-special permission.

Supporting Institution

the Scientific and Technological Research Council of Turkey (TUBITAK)

Project Number

1919B012327999

Thanks

This study was financially supported by the Scientific and Technological Research Council of Turkey (TUBITAK) with the project 1919B012327999. The authors also would like to thank Prof. Dr. Servet Turan and the Ceramic Research Center for their help with raw materials and thermal analysis equipment.

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