氟醚油基磁性液体及其密封相关性能

The perfluoropolyether oil based ferrofluid and its sealing-related properties

采用化学共沉淀法制备氟醚油基磁性液体并将其磁性能与进口产品对比,根据实际密封工况对比分析该磁性液体在各种环境下的性能,如挥发、耐高低温、耐腐蚀及摩擦、导热等性能。结果表明氟醚基磁性液体的饱和磁化强度为16.33 emu/g,高于同类进口产品的14.56 emu/g;温度越高、基液分子量越小则磁性液体的挥发性越强;具有优于硅油基磁性液体的耐强酸、强碱腐蚀性;在约200℃高温时性能稳定且耐高温性优于煤油、甲苯基磁性液体,在-70℃低温时未达到结晶温度能够保持流动性,使用环境温度范围为-70~200℃;具有与各种常规亲油、亲水性溶剂不发生溶解的特性;颗粒间的团聚及摩擦作用导致磁性液体的摩擦系数比基液大很多,导热性随颗粒含量增加而增大。高饱和磁化强度氟醚油基磁性液体的制备及其各性能研究,将为其在各种环境下工业密封应用提供依据,从而拓宽其应用范围。

Perfluoropolyether oil(PFPE-oil)based ferrofluid was prepared through chemical precipitation and its magnetization was studied by contrast to imported products.According to actual sealing working condition,the volatility,resistance of high and low temperature,the resistance of strong acid and strong alkaline,etc of the ferrofuid were researched through contrastive analysis.The results show that the prepared PFPE-oil based ferrofluid has saturation magnetization of 16.33 emu/g,higher than 14.56 emu/g of imported product.The higher volatility of the ferrofluid results from lower molecular weight of PFPE-oil or higher preparation temperature.The PFPE-oil based ferrofluid has better strong acid and base resistance than silicone oil based ferrofluid.The ferrofluid has high temperature resistance of about 200℃,better than kerosene oil and methylbenzene based ferrofluid;-70℃doesn’t reach the crystallization temperature and thus the fluids could ramain mobility;thus the ferrofluid can be used at temperature ranging from-70℃to 200℃.It has insolubility with conventional organic solvents,neither hydrophilic nor hydrophobic.The friction coefficient of PFPE-oil based ferrofluid is higher than that of PFPE-oil for interparticle’s friction and aggregations.The heat conductivity coefficient of the ferrofluid increases with the solid content.The study on the preparation and performance of PFPE-oil based ferrofluid with high saturation magnetization will provide the basis for its sealing application under various conditions,and enlarge the sealing application range.