纳米Sn粒子的制备及其作润滑油添加剂的摩擦学性能研究

用化学还原法制备了表面经油酸修饰的纳米Sn粒子,并在透射电镜(TEM)下观测到所制备的纳米Sn粒子呈球形、平均粒径为20 nm。在MSR-10D四球摩擦磨损试验机上考察了纳米Sn粒子作为CF-4 15W/40润滑油添加剂的摩擦学性能,并在扫描电子显微镜(SEM)和能谱分析仪(EDS)上对钢球磨斑表面进行了形貌观测和表层成分分析。试验结果表明,纳米Sn粒子作为润滑油添加剂具有一定的减摩性能和较好的抗磨性能,当所添加的体积分数仅为0.1%时,添加纳米Sn粒子润滑油的摩擦力比基础油降低了16.64%,其磨斑直径比基础油减小了38.4%。分析认为,纳米Sn粒子通过隔离摩擦表面而改善了润滑油的减摩抗磨性能。     

冷挤压成形用纳米改性润滑油润滑性能研究

采用化学共沉淀法制备了亲油性的、粒径为10 nm球形Fe3O4粒子,在CSS-2220型电子万能试验机上对LY12进行冷挤压成形试验,研究了纳米Fe3O4粒子作冷挤压润滑油添加剂的润滑性能,并与传统的“氟硅化-皂化”润滑方法及添加微米石墨润滑油的润滑性能进行了对比。结果表明:与传统“氟硅化-皂化”的润滑效果相比,添加纳米Fe3O4粒子的润滑油,可明显降低冷挤压件的表面粗糙度,提高挤压件的表面质量;与微米级石墨粉作冷挤压润滑油添加剂的润滑效果相比,添加纳米Fe3O4粒子的润滑油在提高挤压件表面质量的同时使挤压时的挤压力明显降低。     

热挤压润滑油用纳米润滑添加剂润滑性能的研究

采用化学沉淀法分别制备了经表面修饰的纳米Fe3O4和纳米CuO粒子,在透射电镜下研究了纳米粒子的粒径大小、形貌及其分散性;在四球摩擦试验机上,研究了纳米Fe3O4和纳米CuO粒子对润滑油承载能力的影响,同时在CSS-2220型万能试验机上,对比研究了添加纳米Fe3O4和纳米CuO粒子的润滑油在LY12热挤压成形过程中的润滑性能.试验结果表明:所制备的纳米Fe3O4和纳米CuO粒子均呈球形、平均粒径分别为10和20 nm,在润滑油中均具有良好的分散性;纳米Fe3O4和纳米CuO粒子均可以提高润滑油的最大无卡咬载荷,其中纳米Fe3O4粒子的性能优于纳米CuO粒子;添加纳米Fe3O4和纳米CuO粒子的润滑油均可降低挤压变形功,挤压件表面SEM形貌结果表明,纳米粒子的存在有效地隔离了挤压件与模具表面的直接接触,减少了挤压件表面犁沟数量,降低了热挤压变形功.     

Synthesis of γ-AlOOH Nanoparticle and Its Tribological Properties as Additives in Liquid Paraffin

An experiment procedure was presented for the synthesis of γ-AlOOH nanoparticles by a dehydration process which employed the solution of H₂O₂ as dehydrator. The phase and morphology of the product were investigated by XRD and TEM. The tribological properties of γ-AlOOH nanoparticles with the average diameter of 15?nm as additives in liquid paraffin were investigated by a four-ball tester, and the worn surfaces were analyzed by SEM and EDS. Results show that the average size of synthesized γ-AlOOH nanoparticles increases with the increase of the pH value and temperature of the reactant. The γ-AlOOH nanoparticles as additives could exhibit good tribological properties due to their covering effect, which prevents the direct contact of asperities and reduces the adhesion. As the real area of contact decreases with the decrease of applied load, the optimum concentration varies from 0.4% to 0.1% when the applied load decreases from 294?N to 200?N.