原料预处理对BaTiO3压电陶瓷的物性影响

BaCO₃微粉原料通常由尺寸较大的棒状颗粒所组成, 这些棒状颗粒在一次球磨过程中由于不容易粉碎, 从而对经预烧、二次球磨所得到的BaTiO₃陶瓷微粉的化学组分的均匀性和颗粒度产生影响, 进而影响后序烧结制备的BaTiO₃陶瓷的微观组织结构和压电性能。本研究重点探讨了以BaCO₃和TiO₂为原料、通过固相反应途径制备BaTiO₃陶瓷时, 实施原料预处理对所制备的BaTiO₃压电陶瓷物性的影响。研究发现, 配料前对BaCO₃原料实施球磨预处理可明显地降低棒状颗粒的尺寸, 从而可获得颗粒度细化的BaTiO₃陶瓷微粉, 进而制备致密度更高和晶粒尺寸更小而压电性能更高的BaTiO₃陶瓷材料。研究中对BaCO₃微粉进行不同时间的球磨预处理, 然后制备钛酸钡陶瓷, 考察了其压电性能、介电性质、铁电性能和微观结构等物理性质。利用同样的BaCO₃微粉原料, 未经球磨预处理所制备的BaTiO₃陶瓷的压电系数d₃₃最高值为410 pC/N, 而实施合适的球磨预处理制备的BaTiO₃陶瓷的压电系数d₃₃最高值可达470 pC/N。

Raw-material Pre-milling on Physical Property of BaTiO3 Piezoelectric Ceramics

BaCO₃ powder usually consists of large rod-shaped particles, which can not be easily broken up into fine ones when ball-milled together with TiO₂ powder. This may lead to chemical compositional non-uniformity and large particle sizes of the subsequently synthesized BaTiO₃ powder through the calcination and the secondary ball-milling procedure, and may eventually affect the microstructure and the piezoelectric properties of resultant BaTiO₃ ceramics. Effects of the pre-milling treatment of BaCO₃ powder on physical properties of the resultant BaTiO₃ ceramics prepared by conventional solid-state reaction were investigated. The results show that an additional ball-milling treatment of BaCO₃ powder before being mixed with TiO₂ powder can remarkably reduce the size of the rod-like particles, which is an effective way to get good-quality BaTiO₃ fine powder. In such a way, a series of small-grained dense BaTiO₃ ceramics are fabricated with significantly high piezoelectric coefficient d₃₃. The BaTiO₃ ceramics were prepared with the BaCO₃ powders ball-milled for different time before mixing with raw TiO₂ powder. Physical properties of the resultant BaTiO₃ceramics, including piezoelectric properties, dielectric properties, ferroelectric properties, and microstructure were investigated. A much enhanced d₃₃ value of 470 pC/N was achieved for the BaTiO₃ ceramics prepared with the BaCO₃ powders ball-milled for 8 h, in comparison to the maximum value of 410 pC/N for those BaTiO₃ ceramics prepared with un-ball-milled BaCO₃ powders.