Microstructure dependent thermophysical properties of Ni-Zn ferrite-BaTiO3 functionally graded ceramics

• Published in: Journal of materials science Vol. 34; no. 1; pp. 99 - 104
• Main Authors: SARRAUTE, S, SØRENSEN, O. T, SØRENSEN, B. F, HANSEN, E. R
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 1999; Springer Nature B.V
• Subjects: Barium titanates; Ceramics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Dielectric properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Elasticity, elastic constants; Exact sciences and technology; Functionally gradient materials; Heat capacities of solids; Magnetic properties; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Microstructure; Percolation theory; Permittivity (dielectric function); Physics; Thermal expansion; Thermal expansion; thermomechanical effects and density; Thermal properties of condensed matter; Thermal properties of crystalline solids; Thermomechanical properties; Thermophysical properties; Zinc ferrites; Nickel oxides; Elasticity; Percolation theory; Thermomechanical properties; Barium titanates; Experimental study; Oxide ceramics; Ferrites; Young modulus; Thermal expansion; Zinc oxides; Composite materials; Functionnally graded material; Iron oxides; Microstructure; Permittivity; Thermophysical properties
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/A:1004417708696

The purpose of this work was to examine the microstructure dependent thermophysical properties of a mixture of two materials. These were a dielectric powder based on BaTiO3 and a magnetic Ni–Zn ferrite. The thermophysical properties of the ceramics were studied as a function of the dielectric volume fraction in the magnetic powder. For the thermal expansion coefficient, the experimental results were compared with different theoretical models used for functionally graded materials. The percolation theory was found to be a good model for Ni-Zn ferrite–BaTiO3 functionally graded ceramics. Two percolation thresholds were found and a fourth-order polynome fitted all the experimental data of the thermomechanical properties.