Microstructure and electric conductivity of composite (BeO + TiO2) ceramics

Specimens of composite (BeO + TiO^sub 2^) ceramics with TiO^sub 2^ added in an amount of 5, 10, 20, 30, and 40 mass% are obtained. The temperature dependence of the conductivity of the (BeO + 30 mass % TiO^sub 2^) ceramics is studied. Conduction is ensured by the titania additive present in the cera...

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Bibliographic Details
Published in:Refractories and industrial ceramics 2007-11, Vol.48 (6), p.429-434
Main Authors: Kiiko, V S, Gorbunova, M A, Makurin, Yu N, Neuimin, A D, Ivanovskii, A L
Format: Article
Language:English
Subjects:
Ceramics
Conductivity
Dioxides
Electrical conductivity
Heating
Inclusions
Microstructure
Nonuniform
Preserves
Titanium dioxide
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Summary:Specimens of composite (BeO + TiO^sub 2^) ceramics with TiO^sub 2^ added in an amount of 5, 10, 20, 30, and 40 mass% are obtained. The temperature dependence of the conductivity of the (BeO + 30 mass % TiO^sub 2^) ceramics is studied. Conduction is ensured by the titania additive present in the ceramics in a strongly reduced state. The maximum temperature (950 K) at which the (BeO + 30 mass % TiO^sub 2^) ceramics preserves its conductive properties in air for a long time and, possibly, the capacity to efficiently absorb microwave radiation is determined. Heating in air at a temperature exceeding 960 K is accompanied by the processes of oxidation of reduced TiO^sub 2^, which causes disordering of the structure and lowering of the conductivity. An electron microscope study is used to show that the distribution of TiO^sub 2^ in the BeO of the [BeO + (5, 10, and 30 mass %) TiO^sub 2^] system is nonuniform; inclusions of large regions of grouped TiO^sub 2^ microcrystals are encountered. This affects the physicochemical properties of the ceramics, the thermal and electrical conductivities in particular. In order to ensure a uniform distribution of TiO^sub 2^ in the volume of the ceramics it is recommended to introduce the dioxide into the composition of the BeO powder from solutions (hydrochemical method).[PUBLICATION ABSTRACT]
ISSN:1083-4877
1573-9139
DOI:10.1007/s11148-008-9012-8