Cu纳米颗粒添加体的[BMIm]NTf_2离子液体法制备及其摩擦学性能

用离子液体法制备Cu纳米颗粒并将其用于摩擦学研究优于常用的方法,以往对此报道不多。通过微波辐射合成了1-丁基-3-甲基咪唑双三氟甲基磺酰亚胺{BMIm]NTf2}离子液体,利用化学还原法分别在水溶液和BMIm]NTf2中制备了Cu纳米颗粒,采用XRD,TEM,TG和DTA对其结构进行了表征;将2种纳米Cu颗粒溶于N68基础油中,采用四球摩擦磨损试验机对2种纳米Cu添加体的摩擦学性能进行了试验,并对磨痕表面进行了SEM分析。结果表明:BMIm]NTf2离子液体中制备的Cu纳米颗粒为面心立方结构,粒径为3～25nm,能够显著改善N68基础油的抗磨减摩性能;与水溶液中制备的纳米Cu添加体相比,其摩擦系数下降了24.6%,钢球磨斑直径下降了18.8%,PB值提高了16.4%。

Preparation of Cu Nanoparticle Additive in [BMIm]NTf2 Ionic Liquid and Evaluation of Its Tribological Behavior

Ionic liquid 1-butyl-3-methylimi-dazolium bis(trifluoromethyl) sulfimide (abridged as BMIm]NTf2) was prepared with the assistance of microwave irradiation. Cu nanoparticles were then prepared by chemical reduction separately conducted in aqueous solution and in as-synthesized ionic liquid. The microstructure and composition of the two kinds of Cu nanoparticles were analyzed by means of X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and differential scanning calorimetry. The two kinds of as-prepared Cu nanoparticles were separately dispersed in N68 base oil, and the tribological properties of resultant dispersions were evaluated using a four-ball friction and wear tester. The worn surface morphology was examined using a scanning electron microscope. It was found that Cu nanoparticles prepared in BMIm]NTf2 ionic liquid had face-centered cubic structure and grain sizes of 3～25 nm, and were able to significantly improve the friction-reducing and antiwear abilities of the base oil. As compare with those of the Cu nanoparticle additive prepared from the aqueous solution, the friction coefficient and wear scar diameter of the Cu nanoparticle additive prepared from the ionic solution were reduced by 24.6% and 18.8% respectively, and the PB value was increased by 16.4%.