机械球磨在碳纳米管铝基含油轴承制备中的作用

Effect of mechanical milling on preparing carbon nanotubes aluminum base oil-impregnated bearing

采用机械球磨法制备添加不同含量(10.0%、0.5%,质量分数)碳纳米管的铝基混合粉末及烧结含油轴承,测定轴承的压溃强度和含油率,采用SEM和XRD分析物料的显微形貌和物相组成,研究了机械球磨的混料效果,分析了球磨时间对轴承的压溃强度和含油率的影响规律及其机理。结果表明,机械球磨能实现碳纳米管和铝粉的均匀混合,球磨后的铝粉呈片状或层状结构,碳纳米管被剪短后弥散分布在铝粉颗粒中;球磨能促使碳元素在铝粉中固溶,使得铝的晶面衍射角向左偏移、晶面间距变大;由于碳原子的固溶强化及碳纳米管的弥散强化,铝基含油轴承的压溃强度显著提高,机械球磨12h的样品的压溃强度达到198MPa,含油率约为17.0%,具有一定的实用价值。

The aluminum powders were mixed with 10. 0wt% and 0. 5wt% MWNTs respectively by mechanical milling, and the oil-impregnated bearing was prepared by sintering. The crushing strength and oil content of the bearing were measured. The microstructure and phase of mixed powder were analyzed by SEM and XRD. The mixing results and the effect of milling time on crushing strength and oil content were investigated. It is shown that carbon nanotubes and aluminum powder can be well-mixed by mechanical milling. The milled aluminum powders become to sheet-like or layered structure, and carbon nanotubes are cut off and dispersed in aluminum particles. Mechanical milling promotes the solid solution of carbon element in aluminum powders ,makes the diffraction angel of the crystal plane of aluminum offset to the left and increases the distance of crystal plane of aluminum. Due to the solid solution strengthening of carbon atom and dispersion strengthening of small carbon nanotubes, the crushing strength of aluminum base oil-impregnated bearing increases significantly. The strength of samples reaches 198MPa and oil content is about 17.0% after milled for 12h, which can be used in practice.