H.J.FAN
,
M.Zacharias
材料科学技术（英文）
Vapor-phase growth of ZnO nanowires based on gold catalyst is usually accompanied with lateral crawling growth on the substrate surface. We present results from our systematic experiments where the growth temperature and catalyst size are controlled. The data corroborate that it is possible to obtain clean vertical nanowire arrays while avoiding the crawling growth. On the other hand, crawling growth can be manipulated to obtain root-interconnected nanowire arrays, which could be useful for certain applications. Our results also imply that the previously suggested growth mechanism for the wire-on-wall hybridstructure might be incorrect. Finally, we show the formation of sub-millimeter long, straight ZnO nanowalls by combining a gold-catalyzed epitaxial growth of vertical nanowires and their mergence due to a confined crawling growth. These unconventional nanostructures might have unique electric or optical transport properties.
关键词:
Nanowire
,
nanowall
,
ZnO
,
crawling
,
growth
田明
,
王超
,
杨斌
,
刘焜
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2017.06.003
目的 粉末润滑边界层状态预示着润滑条件的优劣.粉末颗粒以其良好的润滑性能和承载能力以及对极端工况的适应性,被广泛应用于诸多领域,因此需对粉末润滑界面的摩擦润滑性能展开深入研究.方法 利用UMT-2多功能摩擦磨损测试仪,结合形状测量激光显微系统对粉末润滑界面边界层的微观形态进行观察和机理分析.重点研究载荷(1、2、4、6 MPa)、速度(2、4、8、16 r/min)、粉末层厚度(1.5、3.5、5.5、7.5μm)以及表面粗糙度(0.389、0.745、1.751、3.112μm)等工况条件对粉末润滑的影响机制.结果较大的接触载荷有利于形成致密的边界层,提高润滑性能.在速度较低时,不利于形成完整、致密的边界层,润滑较差,甚至产生爬行现象,随着速度的增加,润滑效果改善,但过大的速度又会加快粉末耗散.适量的粉末层厚度能够使摩擦界面间形成完整、厚实的边界层,提供良好的润滑能力.粗糙度适当的表面有利于粉末润滑剂存储、边界层的形成以及润滑作用的维持.结论 合理选择接触载荷、速度、粉末层厚度以及试样表面粗糙度有助于提高粉末颗粒的润滑性能.
关键词:
粉末
,
润滑界面
,
边界层
,
爬行
,
摩擦
,
微观形态
