Affiliation:
1. Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, Belgrade
2. School of Electrical Engineering, Belgrade + Serbian Academy of Sciences and Arts, Belgrade
3. Faculty of Mechanical Engineering, Belgrade
4. Faculty of Technology and Metallurgy, Department of General and Inorganic Chemistry, Belgrade
Abstract
Corundum (?-alumina) is a suiTab. material for usage in various industry
fields owing to its chemical stability, electrical and mechanical features.
It is known that properties of ceramics could be modified by addition of
different oxides, as well as by changing the consolidation parameters. In
this respect, alumina was doped with 1 wt.% of Cr2O3, Mn2O3 and NiO,
followed by 1 hour of mechanical activation in a high-energy planetary ball
mill. A sensitive dilatometer was used for sintering of powder mixtures up
to 1400 oC and recording the obtained dilatation. The final density varied
between cca. 1.9 and 3.3 g/cm3. Microstructural changes were detected by SEM
measurements. Changes in electrical permittivity and loss tangent were
associated with the preparation conditions (types of additives, duration of
mechanical activation). For a given mixture, the sintering increases the
relative permittivity and decreases losses, exhibiting the optimal values of
8.32 and 0.027, respectively, for the sample activated 60 minutes and
sintered, with the addition of MnO2. Mechanical measurements indicate
significant differences in strength with the addition of different
transition metal oxides. Samples with Mn and Ni, activated and sintered,
with strength of 121 and 86 MPa, respectively, have a significantly higher
tensile strength than the other tested samples, due to their more compact
microstructures.
Funder
Ministry of Education, Science and Technological Development of the Republic of Serbia
Publisher
National Library of Serbia
Subject
Materials Chemistry,Metals and Alloys,Condensed Matter Physics,Ceramics and Composites
Cited by
20 articles.
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