Nb^5＋掺杂BaZr0.1Ti0.89Fe0.01O3陶瓷的晶体结构及介温特性

Crystal Structure and Dielectric Properties of Nb-doped BaZr_(0.1)Ti_(0.89)Fe_(0.01)O_3 Ceramics

采用传统固相法制备BaZr_(0.1)Ti_(0.89)Fe_(0.01)O_3–yNb_2O_5(BZTF–y Nb)陶瓷,研究了Nb_2O_5作为改性剂对BZTF陶瓷晶体结构、微观形貌及弥散相变的影响。结果表明:所有试样均形成单一的钙钛矿晶相结构,Nb_2O_5对晶体结构有一定的调整作用。当掺入量为0.75%(摩尔分数)时,试样常温下为四方相结构。当0.00≤y≤0.75%时,试样的介电常数随掺杂量y的增加而逐渐增大,介电损耗则呈现急剧减小趋势。Nb_2O_5可使四方相更加稳定,Curie温度移向高温方向。同时,铁电相向顺电相转变的相变峰变得宽化和弥散,提高试样的介温稳定性。烧结温度为1 300℃、Nb_2O_5含量为0.75%时陶瓷试样有最佳的介电性能:介电常数ε=6 039,介电损耗tanδ=0.007,Curie温度T_C与弥散系数γ分别为16℃和1.98。

BaZr（0.1）Ti（0.89）Fe（0.01）O3–yNb2O5（BZTF–yNb） ceramics were synthesized via a conventional solid state reaction route. The effect of Nb2 O5 addition on the crystal structure, microstructure and diffuse phase transition of BZTF ceramics were investigated by X-ray diffraction, scanning electron microscopy and capacitance measurement. The results show that all the samples have a single perovskite structure, and the crystal structure of Nb-doped BZTF is slightly adjusted. The tetragonal structure of 0.75%（in mole fraction） Nb-doped samples was determined at room temperature. The dielectric constant increases and the dielectric loss decreases with the increase of Nb2O5 content from 0.00% to 0.75%. Nb2O5 can stabilize the tetragonal structure, increase the Curie temperature and make the phase transition from ferroelectric phase to paraelectric phase, indicating the stable temperature-dependent dielectric properties. It is indicated that 0.75% Nb-doped sample sintered at 1 300 ℃ has the optimal dielectric properties（ε=6 039, tanδ=0.006, TC=16 ℃ and γ=1.98）.