Tb_4O_7-TiO_2 Mixture Powders Prepared by High Energy Ball Milling
- 厦门大学－已发表论文 
通过高能球磨技术制备了Tb_4O_7-18Ti O_2(质量分数,%)纳米尺度复合粉末。采用激光粒度测试仪、X射线衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对不同球磨时间的混合粉末的微观形貌组织、颗粒与晶粒大小以及晶格畸变量等进行了研究与表征。结果表明,混合粉末经过高能球磨后其颗粒与晶粒尺寸均达到了纳米级,组织均匀。Tb_4O_7相的X射线衍射峰随球磨时间的增加逐渐宽化且向大角度偏移;Ti O_2相衍射峰强度逐渐降低,在球磨4 h后消失。随球磨时间的增加,颗粒和晶粒的平均尺寸减小,球磨初期减小很快,球磨后期减小缓慢,最后趋于一个稳定值。96 h球磨后颗粒和晶粒的平均尺寸分别为200和95 nm,晶格畸变量达到1.35%。同时探讨了TiO_2相固溶和纳米晶形成原因以及微观组织演变的机制。The nanocrystalline powders of Tb_4O_7-18wt%Ti O_2 were prepared by high energy ball milling. Systematical investigations were carried out on microstructure, particle and grain size, lattice distortion and morphology of the Tb_4O_7-18wt%Ti O_2 milled powders using laser particle analyzer, X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The results show that the nanocrystalline and nanoparticle powders are synthesized and microstructure is homogeneous after high energy ball milling. With the increase of ball milling time, the diffraction peaks of Tb_4O_7 phase are broadened gradually and move to large angles. Meanwhile, the diffraction peaks of Ti O_2 phase weaken gradually and disappear after 4 h milling. At the initial stage of ball milling, both particle size and crystalline size decrease significantly, then the sizes decline slowly and tend to be stable at the late stage of ball milling. After 96 h milling, the average particle size and crystalline size are 200 nm and 95 nm, respectively. The lattice distortion is up to 1.35%. The reason of solid solution of Ti O_2 and nanocrystalline formation and the mechanism of microstructure evolution were also discussed.