溶剂热制备纳米钛酸钡粉体的结晶度和尺寸调控

Tetragonality and size control of barium titanate nanopowders prepared by solvothermal method

以溶剂热的方法制备纳米四方相钛酸钡粉体,通过改变反应时间、前驱物钡钛摩尔比n(Ba)/n(Ti)来调控粉体的粒径大小、粒度分布和四方相结晶度。BET比表面积、激光粒度分析、SEM、XRD、FTIR测试结果表明,延长反应时间可减少钛酸钡粉体—OH含量,四方相结晶度有所提高,粉体粒径随之变大,粒度分布变宽;随着n(Ba)/n(Ti)的提高,钛酸钡粉体—OH含量相应减少,粉体颗粒尺寸呈先增大后减小的趋势,但基于"尺寸效应",粉体四方相结晶度并未因—OH含量的减少而线性增大。当反应时间为1h,n(Ba)/n(Ti)为2.5时,合成钛酸钡粉体粒径小、粒度分布较窄且具有较高的四方相结晶度,适用于制备小于2μm瓷膜的MLCC。

Tetragonal BaTiO3 nanopowders have been prepared by solvothermal method,the tetragonality,particle size and distribution of as-prepared BaTiO3 particles were optimized by adjusting soaking time and molar ratio of precursors n(Ba)/n(Ti),The characterization of specific surface area,laser particle size,SEM,XRD and FT-IR indicated that prolonging soaking time could reduce the content of—OH,leading to enhance the tetragonality of as-prepared BaTiO3 nanopowders,meanwhile the particle size and distribution became larger.With n(Ba)/n(Ti)increasing,the particle size first increased and then decreased,correspondingly the content of—OH became lower,but because of size effect the tetragonality did not present a tendency of linear increase due to less content of—OH.The BaTiO3 nanopowders synthesized in the condition of 1hsoaking time and n(Ba)/n(Ti)=2.5was suitable for preparing MLCC consisted of less than 2μm ceramic tape due to small particle size,narrow distribution and high tetragonality.