Electrocaloric properties of the Zr-substituted BaTiO3 -Na0.5TiO3 ceramics
Akkaşoğlu, Oğuz, author.

Electrocaloric properties of the Zr-substituted BaTiO3 -Na0.5TiO3 ceramics

Akkaşoğlu, Oğuz, author.

Yazar Ek Girişi
Akkaşoğlu, Oğuz, author.

Fiziksel Tanımlama
xi, 62 leaves: illustrarions, charts; 29 cm + 1 computer laser optical disc.

The aim of this study is to investigate electrocaloric properties and thermodynamic behaviour, obtaining high adiabatic temperature change (ΔT) values with a broad temperature span of zirconium doped barium titanate-sodium bismuth titanate by substitution of Zr into B-site (titanium). Ceramics are synthesized in a pellet form by solid-state reactions. Chemical composition was Ba0.7Na0.15Bi0.15TixZr1-xO3 (abbreviated as BT-NBT) where x= 0.00, 0.01, 0.02, 0.03, 0.035, 0.04 and 0.05. Phase analysis was conducted by X-ray diffraction method. Microstructural analysis and average grain size determination was performed by Scanning Electron Microscopy. To understand phase transitions and physical behaviours, dielectric measurements are performed. Ferroelectric properties are investigated by using temperature dependent polarization, strain and current-electric field relationships. Electrocaloric measurements are done by using temperature dependent polarizationelectric field data. Maxwell relations are used to calculate temperature dependent electrocaloric temperature change, ΔT, and from this data, temperature span, Tspan, was calculated. It was observed even though Zr substitution into the Ti-site rapidly decreases the Curie temperature and introduces relaxor ferroelectric character to the samples. However, the 1st order like nature of the ferroelectric-paraelectric phase transition at the Curie temperature and, consequently significant ΔT is maintained even for 4 % Zr substituted sample close to room temperature. Temperature span, on the other hand, has a lower value compared to previous works related to barium titanate systems. Electrocaloric efficiency is comparable to other works on Pb-free sytems and these results showed that BT-NBT systems have promising features for electrocaloric cooling technologies

Konu Başlığı
Ceramic materials -- Thermal properties
Barium compounds.

Yazar Ek Girişi
Adem, Umut,

Tüzel Kişi Ek Girişi
İzmir Institute of Technology. Materials Science and Engineering

Tek Biçim Eser Adı
Thesis (Master)-- İzmir Institute of Technology: Materials Science and Engineering
İzmir Institute of Technology: Materials Science and Engineering (Master).

Elektronik Erişim
Access to Electronic Versiyon.

LibraryMateryal TürüDemirbaş NumarasıYer NumarasıDurumu/İade Tarihi
IYTE LibraryTezT002845TA455.C43 A31 2023Tez Koleksiyonu