【作者】 张慧君；

【导师】 刘正堂； 田长生；

【作者基本信息】 西北工业大学 ， 材料学， 2006， 硕士

【摘要】 铅基PZT材料在压电陶瓷领域一直占据着研究和应用的主导地位。但是铅毒性很高,随着人们对生存环境质量要求的提高,作为无铅材料的碱性铌酸盐目前备受压电材料研究领域关注。本文选取铌酸钾钠陶瓷体系,通过固相反应合成法制备了（1—x）Na_0.5K_0.5NbO₃-xLiTaO₃二元系压电陶瓷,优化出性能最佳的组分;制备出具有较大生长各向异性的片状NaNbO₃（NN）微晶模板;分别选取片状Bi₄Ti₃O₁₂（BIT）微晶和片状NN微晶为模板,以TGG法和RTGG法制备NKN-LT织构陶瓷。 采用传统方法制备出（1—x）Na_0.5K_0.5NbO₃-xLiTaO₃陶瓷,研究了LiTaO₃（LT）含量对Na_0.5K_0.5NbO₃（NKN）材料晶体结构和压电性能的影响,优化出性能最佳的组分,确定了其准同型相界。结果表明:组分为0.94 Na_0.5K_0.5NbO₃-0.06LiTaO₃的陶瓷位于准同型相界附近,且具有较佳的压电性能,为下一步制备织构陶瓷的研究提供配方依据。 从TGG和RTGG法的工艺要求和微晶模板的选择原则出发,选择片状BIT和片状NN两类粉体用于NKN-LT织构陶瓷制备的微晶模板。分析了两步熔盐法制备片状NN微晶的反应原理,确定了相应的制备工艺,最终确定以片状NN微晶粉体为反应模板,并系统研究了过量NaCO₃对NN粉体的显微组织结构、形貌影响。结果表明,NN微晶粉体的尺寸主要取决于第一步熔盐法合成的中间化合物尺寸,当第二步熔盐工艺条件合适的情况下,对中间化合物的结构破坏最小,最终目标微晶的尺寸变化不大。采用两步熔盐法成功地制备了适合流延工艺要求的片状NN微晶,微晶尺寸均匀,分散性好,直径与厚度比大,直径在10～20μm之间,厚度在1～3μm。 分别以片状BIT和NN为微晶模板,采用流延工艺和TGG、RTGG技术分别制备了NKN-LT织构陶瓷,研究加入微晶模板后的NKN-LT织构陶瓷的烧结工艺、织构度、微观组织结构和电性能的变化规律。结果表明:以片状BIT和NN为微晶模板制备NKN-LT织构陶瓷分别属于TGG和RTGG法,并确定了相应的烧结工艺。以BIT和NN为微晶模板制备的陶瓷,其织构度均随着烧结温度升高而升高,但是织构度均很低,结合烧成工艺确定具有最佳织构度的烧成温度。更多还原

【Abstract】 Piezoelectric materials based on Pb（Zr,Ti）O₃ solid solution （PZT） have been widely used , but one of the major drawbacks of PZT materials is the lead content. Accordingly, these materials may be restricted in near future because of environmental issues. In the field of lead-free piezoelectric ceramics, many researches focus on the alkali metal niobate-based materials. In this paper, sodium potassium niobate-based ceramics were selected as the experimental system. （1—x） Na_0.5K_0.5NbO₃-xLiTaO₃ ceramics was prepared by traditional method, and the morphotropic phase boundary（MPB） was confirmed. Plated-like powder NaNbO₃ were synthesized by molten salt process;textured NKN-LT ceramics were fabricated by TGG and RTGG technique.The results shows that the ceramic with the composition of 0.94NKN-0.06LT is closed to MPB and has better piezoelectric properties, the composition of NKN-LT ceramic were optimized for fabrication texture NKN-LT ceramics.From analyzing the processing parameters and rules of selecting template particles of TGG and RTGG technique, plated-like powder BIT and NN、 KN were selected. Plated-like powder NN templates were synthesized by two-step molten salt process. The reaction were explained and then made out the processing parameters of NN templates. The effects of excessive Na₂CO₃ content on replacement reaction were investigated systematically. The plated-like powder NN was synthesized by two-step molten salt process. The average size of plated-like powder NN is 10²0μm in diameter and 1³μm in thickness. Plated-like powder NN is suitable for tape casting.The NKN-LT ceramics were fabricated by TGG an RTGG method and tape casting process. Plated-like powder BIT and NN were selected as the template for texture ceramics. The ceramic process parameter、 texture fraction、 microstructure and piezoelectric properties were discussed.更多还原