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Nanopowder Preparation and Dielectric Properties of a Bi 2 O 3 –Nb 2 O 5 Binary System Prepared by the High‐Energy Ball‐Milling Method
Author(s) -
Zhou Di,
Wang Hong,
Yao Xi,
Pang LiXia,
Zhou HuanFu
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.02017.x
Subject(s) - materials science , natural bond orbital , amorphous solid , analytical chemistry (journal) , triclinic crystal system , ball mill , ceramic , dielectric , scanning electron microscope , mineralogy , permittivity , crystallography , crystal structure , metallurgy , chemistry , composite material , density functional theory , computational chemistry , optoelectronics , chromatography
The high‐energy ball‐milling (HEM) method was used to synthesize the compositions of BiNbO 4 , Bi 5 Nb 3 O 15 , and Bi 3 NbO 7 in a Bi 2 O 3 –Nb 2 O 5 binary system. Reagent Bi 2 O 3 and Nb 2 O 5 were chosen as the starting materials. The X‐ray diffraction patterns of the three compositions milled for different times were studied. Only the cubic Bi 3 NbO 7 phase, Nb 2 O 5 , and amorphous matters were observed in powders after being milled for 10 h. After heating at proper temperatures the amorphous matters disappeared and the proleptic phases of BiNbO 4 and Bi 5 Nb 3 O 15 could be obtained. The Scherrer formula was used to calculate the crystal size and the results of nanopowders are between 10 and 20 nm. The scanning electron microscopy photos of Bi 3 NbO 7 powders showed drastic aggregation, and the particle size was about 100 nm. The dielectric properties of ceramics sintered from the nanopowders prepared by HEM at 100–1 MHz and the microwave region were measured. Bi 3 NbO 7 ceramics showed a good microwave permittivity ɛ r of about 80 and a Q × f of about 300 at 5 GHz. The triclinic phase of BiNbO 4 ceramics reached its best properties with ɛ r =24 and Q × f =14 000 GHz at about 8 GHz.