机械合金化制备纳米ZrB_2-TiB_2复合粉末（英文）

ZrB_2-TiB_2 Nanocomposite Powder Prepared by Mechanical Alloying

采用Zr、Ti、B为原料(摩尔比:1:1:4),在氩气气氛保护下,采用机械合金化方式,在球料比10:1、球磨转速500 r/min实验条件下制备了纳米结构的ZrB_2-TiB_2。采用X射线衍射仪(XRD)、场发射扫描电镜(FESEM),透射电镜(TEM)仪器,对不同球磨时间粉末的相组成、微观结构进行了表征。结果发现,原始粉末经120 h球磨后,粉末主要由ZrB_2和TiB_2组成,平均尺寸在20 nm左右,TiB_2分布于ZrB_2基体上。文章还探讨了该体系获得目标产物的机械合金化机制。

Diborides, including zirconium diboride（ZrB_2） and titanium diboride（TiB_2）, have a number of desirable ceramic qualities that make suitable for preparing ceramic-matrix composites. However, synthesizing a composite based on these materials usually requires high temperatures and complex synthetic methods. In the present study, a nanocrystalline ZrB_2-Ti B_2 powder was synthesized via mechanical alloying（MA） of the mixture of elemental Zr, Ti, and B powders mixed at a Zr/Ti/B mole ratio of 1：1：4, a 10：1 ball-to-powder weight ratio and 500 r/min rotational speed in a planetary ball-mill under argon atmosphere using a ZrO_2 vial and balls. The effect of milling time on the phase change was investigated by X-ray diffraction（XRD）, and the microstructure evolution of the powder mixture was monitored by field emission scanning electron microscopy（FESEM） and transmission electron microscopy（TEM）. It is found that after 120 h of milling, a nanoscale composite powder with -20 nm mean particle size can be obtained. Moreover, TEM examination clearly shows the composite powder is composed of the nanoscale TiB_2 and ZrB_2 particles. Finally, the milling mechanism was discussed.