Year: 2014
Type: article
Abstract: We describe here structure and temperature dependences of conductivity σ(T ), the Seebeck coecient α(T ), thermal conductivity λ(T ) and gure-of-merit ZT (T ) in Ca3Co4O9 ceramics, doped with Fe and Y, depending on compacting pressure (0.2 or 6 MPa) and temperature (300 < T < 700 K).It is shown that introduction of iron and yttrium to ceramics does not alter the crystalline structure of the material.Increasing the pressure in the compacting process before the additional diusion annealing leads to a smaller-grained structure and increase σ and λ due to reducing of the synthesized samples porosity.The Seebeck coecients of nanocomposite ceramics Ca3Co3.9Fe0.1O9and (Ca2.9Y0.1)(Co3.9Fe0.1)O9have linear dependences on temperature is not changed after increase of compacting pressure.Electrical-to-heat conductivity ratio (σ/λ) for the samples compacted at high (6 GPa) pressure increases not more than 2030% in comparison with ones compacted at low (0.2 GPa) pressure, whereby ZT is increased more than 50%.The main reason for this eect is samples porosity reduction with the compacting pressure increase.
Source: Acta Physica Polonica A
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
Funder: European Commission
OpenAlex ID: W1966154282