Nb_2O_5-ZrO_2体系低膨胀陶瓷的制备与表征

Preparation and Characterization of Low Expansion Ceramics for Nb_2O_5-ZrO_2 System

采用干压成型和高温固相反应烧结法制备了Nb2O5-ZrO2二元体系低膨胀陶瓷材料。研究了ZrO2含量对制备的陶瓷样品的物相组成、微观结构、热膨胀性能和抗弯强度等的影响。结果表明:在1390℃保温2 h烧成,纯Nb2O5陶瓷由单斜相Nb2O5组成,存在明显的开裂现象,表现出低的抗弯强度(25.9 MPa)和低的热膨胀系数(0.5×10-6℃-1)。加入ZrO2后,发生了复杂的固相反应生成了多相的Nb2O5-ZrO2体系陶瓷材料。ZrO2含量为12.5~15%时,可有效促进Nb2O5-ZrO2体系陶瓷的烧结致密化,形成致密的微观结构和避免开裂现象,样品表现出低热膨胀性能,抗弯强度显著提高。ZrO2含量为15%时,样品的热膨胀系数和抗弯强度分别为2.0×10-6℃-1和68.5 MPa。

Nb2O5-ZrO2 system low expansion ceramic materials were prepared by dry pressing and high temperature solid-state reaction sintering techniques. The influences of ZrO2 content on the phase composition, microstructure, thermal expansion performance, bending strength of prepared ceramic samples were investigated. Results show that the pure Nb2O5 ceramic, composed of monoclinic phase Nb2O5, shows obvious microcracking phenomena, and exhibits low bending strength(25.9 MPa) and low thermal expansion coefficient(0.5×10-6℃-1) after sintered at 1390 ℃ for 2 h. After the addition of ZrO2, complex solid phase reactions occurred and generated the multiphase Nb2O5-ZrO2 binary system ceramic material. The addition of 12.5~15% ZrO2 could effectively promote the sintering densification of prepared ceramic materials and avoid the generation of microcracks to form a dense microstructure. Low thermal expansion properties and greatly enhanced flexural strength were obtained for the prepared samples. The sample with 15% ZrO2 shows a thermal expansion coefficient and flexural strength of 2.0×10-6℃-1 and 68.5 MPa, respectively.