Chemistry and microwave properties of Bi{sub 2}O{sub 3} doped Ba{sub 4.5}Nd{sub 9}Ti{sub 18}O{sub 54}

Conference · Tue Aug 01 04:00:00 EDT 1995

OSTI ID:86570

Suvorov, D; Valant, M; Kolar, D ^[1]

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1. Univ. of Ljubljana (Slovenia)

Ceramics based on the BaO-Nd{sub 2}O{sub 3}-TiO{sub 2} system are widely used the electronics industry due to their high permittivity and low dielectric losses. An especially interesting part of the phase diagram is the solid solubility region with the general formula Ba{sub 6-x}Nd{sub 8+2/3x}Ti{sub 18}O{sub 54} (O < X < 2.25). For microwave applications such materials are doped with Pb or Bi oxides (or titanates) to compensate the relatively high temperature coefficient of resonant frequency tf. In the present paper, a study of Bi{sub 2}O{sub 3}-doped 1:1:4-BT{sub 4} ceramics is reported with regard to the formation of solid solution and liquid phase during sintering, and the microstructural development and its influence on the microwave properties. It was found that on addition of up to 2.5 mol % Bi{sub 2}O{sub 3}, Bi{sup 3+} is incorporated on Nd{sup 3+} sites in the Ba{sub 4.5}Nd{sub 9}Ti{sub 18}O{sub 54} phase. When the solid solubility limit is exceeded, Bi{sub 2}O{sub 3} concentrates at the grain boundaries at Bi-rich phase, forming a liquid phase and causing a considerable decrease of the Q-value and an increase of tf.

• OSTI ID: 86570
• Report Number(s): CONF-941199--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
BISMUTH OXIDES
CRYSTAL STRUCTURE
GRAIN BOUNDARIES
MICROSTRUCTURE
NEODYMIUM COMPOUNDS
PERMITTIVITY
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
SYNTHESIS
TITANATES
TITANIUM OXIDES