镁合金在轧制过程中通常采用铝合金轧制液,甚至进行无润滑轧制.轧制过程中无润滑油会导致轧后板材表面质量差、能耗高,而铝合金轧制液通常采用含氯、硫、磷等元素的有机化合物作为添加剂,此类添加剂不容易分解,废液的排放会对环境造成一定污染.基于此,本工作采用不同比例的 SiO2和 MoS2纳米颗粒复合加入 EOT5#机械油中,在双辊轧机上研究两种纳米颗粒复合比例对 AZ31镁合金冷轧过程中轧制力和轧后板材表面质量的影响.采用场发射扫描电镜(FESEM)和 X射线光电子能谱仪(XPS)对 SiO2/MoS2复合纳米基润滑油润滑条件下轧后板材表面形貌和成分进行了分析,探讨了 SiO2/MoS2复合纳米基润滑油的协同润滑机理.结果表明,SiO2和 MoS2纳米颗粒在基础油中添加质量分数之比为0.25:0.75时具有最佳的润滑性能.SiO2/MoS2复合纳米基润滑油优良的润滑性能降低了镁合金轧制过程中的轧制力,改善了轧后板材的表面质量.分析认为,不同形貌和润滑机理的 SiO2和 MoS2纳米颗粒共同作用是实现协同润滑的关键因素.%Currently,there are no suitable lubricants for the cold rolling process of Mg alloy.Occasional,the lubricants used for Al alloy rolling is used or even skip the lubricants.Cold rolling process without lubricants will lead to poor surface quality of pro-ducts and high energy consumption.The application of conventional oil-based lubricant in Al alloy rolling processes relies heavily on sulphur,chlorine and phosphorous-containing additives.These additives cause negative effects on the environment even at low con-centrations during the disposal of waste fluids.Based on this,AZ31 Magnesium alloy sheets were processed by cold rolling lubricated with different SiO2/MoS2 mixing ratios hybrid nanolubricants.The cold rolling performance was investigated by measuring rolling force as well as the surface roughness of the sheets.The morphology and composition of surface were characterized by means of field emission scanning electron microscope (FESEM)and X-ray photoelectron spectrum (XPS),and the synergistic lubrication mecha-nism of SiO2/MoS2 hybrid nanolubricants was discussed.The results indicated that the optimal SiO2/MoS2 mixing ratio in the base oil was 0.25:0.75.The excellent lubrication properties of the SiO2/MoS2 hybrid nanolubricant effectively reduced the rolling force and improved the surface quality of sheets during cold rolling process,compared with those of pure nanolubricants and neat oil without nanoparticles tested in the same conditions.The synergistic effect in the SiO2/MoS2 combinations may be explained in terms of the micro-cooperation of various nanoparticles with different shapes and lubrication mechanisms.
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