钙钛矿型陶瓷透氧膜及其封接材料的制备与性能研究

发布时间：2018-02-21 05:37

  本文关键词： 钙钛矿型陶瓷透氧膜 Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ) 表面改性 Co_3O_4纳米颗粒催化剂 BaFe_(1-y)Pr_yO_(3-δ)材料 陶瓷玻璃封接材料　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：钙钛矿结构氧化物由于具有离子-电子混合电导特性,使其在氧传感器、氧气分离膜和固体氧化物燃料电池等领域得到了广泛的应用。一直以来,透氧性能和稳定性是制约陶瓷透氧膜实际工业应用的关键因素。目前提高透氧膜透氧性能的手段主要有表面修饰和降低膜厚等,而发展无Co材料可改善其稳定性。此外,透氧膜反应器能否长时间正常运行与封接材料的可靠性也密切相关,因此发展陶瓷透氧膜密封技术也意义非凡。本论文首先以Ba_(0.5)Sr_(0.5)Co_(0.8)Fe0.2O_3-w材料为研究对象,通过表面负载Co304纳米颗粒催化剂来探索其对透氧性能的影响。其次,发展了无Co透氧膜材料BaFeO_(3-δ),通过B位部分掺杂Prn+使其在低温下保持立方相结构。最后,研制了一种适用于透氧膜反应器封接的陶瓷玻璃密封剂。本论文第二章在Ba_(0.5)Sr_(0.5)Co_(0.8)Fe0.2O_(3-δ)陶瓷透氧膜表面通过涂覆技术负载了一层Co_3O_4纳米颗粒催化剂。XRD测试结果表明,Co_3O_4为单一的尖晶石结构。SEM照片显示样品经500 ℃热处理后,Co_3O_4颗粒大小约为100nm且修饰层厚度约为20 μm。透氧率测试结果表明表面负载Co_3O_4纳米颗粒催化剂显著提升了Ba_(0.5)Sr_(0.5)Co_(0.8)Fe0.203-5透氧膜的透氧性能。当测试温度为600℃时,表面修饰前后透氧膜的透氧率分别为0.1080和0.4302 ml·cm~(-2)·min~(-1),此外,在600～800 ℃范围内,透氧膜的表观活化能从修饰前的91.42 kJ·mol-1降低至50.71 kJ·mol-1。本论文第三章通过固相法合成了 BaFe1-yPryO_(3-δ)粉体。XRD测试结果表明,BaFeO_(3-δ)和BaFe_(0.975)Pr_(0.025)O_(3-δ)在室温下分别为六方相和三斜相,其余粉体为立方相,证明掺杂Prn+有利于材料的在低温下保持立方相。烧结体试样的电导率和透氧率都随着掺杂量的增加而增加,当掺杂量y=0.1时,两者可分别达到6.5 S·cm~(-1)和1.112 ml·cm~(-2)·min~(-1)。BaFe_(0.975)Pr_(0.025)O_(3-δ)的高温XRD测试结果表明粉体随着温度升高由三斜相逐渐向立方相转变,到700 ℃时完全转变为立方相,这使得该材料在此温度附近的透氧率突然增加。本论文第四章研制了一种适用于透氧膜器件封接的陶瓷玻璃密封剂。陶瓷粉和玻璃粉按不同比例球磨得到总体粒度约为1μm的复合粉体,通过与有机载体混合后制得陶瓷玻璃密封胶。XRD测试结果表明封接材料经高温处理后有相结构的转变,但陶瓷/玻璃质量比为6:4的封接材料相对比较稳定。在200～800℃范围内该种封接材料的热膨胀系数为9.54×10-6 K~(-1),从400 ℃升高到800 ℃,电阻率从1.13×106 Ω·cm降低到6.85×105 Ω·cm。透氧膜器件的气体泄漏率在600和800 ℃的测试温度下分别为0.0165和0.0075 ml·cm~(-2)·min~(-1)。
[Abstract]:Perovskite oxides have been widely used in oxygen sensors, oxygen separation membranes and solid oxide fuel cells due to their ionic and electronic conductivity. Oxygen permeability and stability are the key factors restricting the practical industrial application of ceramic oxygen permeable membranes. At present, the main methods to improve the oxygen permeability of ceramic oxygen permeable membranes are surface modification and reduction of film thickness, while the development of Co-free materials can improve their stability. Whether oxygen permeable membrane reactor can run normally for a long time is closely related to the reliability of sealing material, so it is very important to develop ceramic oxygen permeable membrane sealing technology. The effect of surface supported Co304 nanoparticles on oxygen permeability was investigated. Secondly, the Co free oxygen permeable membrane material BaFeO- 未 was developed, and the cubic phase structure was maintained at low temperature by partially doped Prn at position B. A ceramic glass sealant suitable for sealing oxygen permeable membrane reactor has been developed. In the second chapter of this thesis, a layer of Co_3O_4 nanoparticle catalyst. The spinel structure. SEM photos showed that the particle size of Cos _ 3O _ 4 was about 100nm and the thickness of modified layer was about 20 渭 m after heat treatment at 500 鈩，

本文编号：1521151