机械球磨Y2O3粉末的组织结构演变

Microstructure evolution of Y2O3 powder during mechanical milling

采用行星式球磨机对 Y2O3粉末进行球磨,利用 X 射线衍射、扫描电镜和透射电镜对粉末进行组织及结构表征,研究 Y2O3在机械球磨过程中粒度、形貌、显微组织及结构的演变。结果表明,原始 Y2O3粉末为单一立方结构,粒度呈双峰分布,在高能磨球的作用下,粉末发生破碎、层片化和结构转变。球磨 60 h 后的 Y2O3粉末尺寸细小均匀,完全分散,呈单峰、对数正态分布。球磨过程中,首先立方结构的 Y2O3 发生结构破坏,出现小尺寸的晶格缺陷并非晶化;晶格缺陷区域扩大,形成非晶态和纳米尺寸晶体的复合结构,最终完全转变为非晶态结构。球磨后 60 h 的 Y2O3粉末呈不规则块状组织和短棒状组织,不规则块状组织为非晶态基体和少量纳米晶的复合结构,短棒状组织为完全非晶结构。

Y2O3 was mechanical milled by planetary ball mill and its particle size, morphology and the microstructure evolution were systematically investigated by XRD, SEM and TEM. The results show that raw Y2O3 powder has cubic structure, and undergoes crushing, flaky and structure transforming during mechanical milling because of the collision effects of high energy milling balls. Raw Y2O3 powder with bimodal distribution is crushed, refined and dispersed completely, and its particle size shows a single peak and lognormal distribution after mechanical milling for 60 h. The cubic structure Y2O3 powder was destroyed and formed small scaled lattice defects during mechanical milling. The lattice defects region expands to a composite structure which consist of amorphous and nano-grains, and finally completely transformed into amorphous structure. The Y2O3 powders transform to irregular bulk structure and short rod structure after mechanical milling for 60 h. The irregular bulk structure is composite structure which consist of amorphous matrix and a few nano-grains, and the short rod structure is completely amorphous.