Characterization of Fine-Grained Bismuth Vanadate Ceramics Obtained Using Nanosized Powders
Characterization of Fine-Grained Bismuth Vanadate Ceramics Obtained Using Nanosized Powders
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使用纳米粉末获得的细粒钒酸铋陶瓷的表征
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
K. Varma
中科院分区：
文献类型：
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作者：
K. Shantha;K. Varma
采用机械活化法在室温下制备了晶粒尺寸小于50 mm的钒酸铋（n-BiV）纳米粉体。与传统制备的微米级钒酸铋（m-BiV）粉末相比，n-BiV粉末显示出增强的烧结性，并产生具有均匀微观结构的陶瓷。高密度（~98%的理论值），细晶粒（平均晶粒尺寸为~2 $mu$m）的陶瓷，获得使用n-BiV具有高的介电常数和高的热释电系数，并与低介电损耗，在室温下和在转变温度。这些细晶陶瓷表现出扩散相变和弛豫行为，这归因于这些陶瓷中的缺陷和/或成分不均匀性的不规则分布。细晶陶瓷表现出铁电电滞回线，具有更高的剩余极化和更低的矫顽场值比粗晶陶瓷。
Nanocrystalline bismuth vanadate (n-BiV) powders with a crystallite size of <50 mm have been prepared, at room temperature, by subjecting a stoichiometric mixture of bismuth oxide and vanadium pentoxide to mechanical activation. The n-BiV powders show enhanced sinterability, in comparison to the conventionally prepared micrometer-sized bismuth vanadate (m-BiV) powders and yield ceramics with a uniform microstructure. High-density (~98% of the theoretical value), fine-grained (average grain size of ~2 $mu$m) ceramics, obtained using n-BiV have a high dielectric constant and a high pyroelectric coefficient and are associated with low dielectric loss, both at room temperature and at the transition temperature. These fine-grained ceramics show diffused phase transition and relaxor behavior, which are attributed to the irregular distribution of defects and/or compositional inhomogeneities in these ceramics. The fine-grained ceramics exhibit ferroelectric hysteresis loops with higher remanent polarization and lower coercive field values than the coarse-grained ceramics.