碳纳米管基膨润土润滑脂的制备及摩擦学性能研究

Preparation and Tribological Properties of Carbon Nanotube Bentonite Grease

为制备摩擦学性能优良的多壁碳纳米管基膨润土润滑脂,采用油酸对多壁碳纳米管(MWCNTs)进行修饰,在实验室自主设计的超声辅助球磨试验装置上,制备在PAO6中均匀稳定分散的多壁碳纳米管悬浮液,并以悬浮液为基础油制备MWCNTs增强的膨润土润滑脂。探讨不同分散方法(球磨分散、超声分散、超声和球磨分散)对多壁碳纳米管分散稳定性的影响,研究润滑脂的摩擦因数、磨斑直径随多壁碳纳米管质量分数的变化。实验结果表明:经油酸修饰的多壁碳纳米管在超声和球磨综合作用下分散稳定性最好;随多壁碳纳米管质量分数的增加,膨润土润滑脂的摩擦因数、磨斑直径先减小后增大,其中多壁碳纳米管质量分数为0.03%时,所制备的膨润土润滑脂摩擦学性能最佳,磨斑直径最小(0.690 mm),比美孚28号航空润滑脂(符合美国军方规格MIL-G81322C,磨斑直径0.807 mm)降低了14.5%。

In order to prepare multi-walled carbon nanotube-based bentonite grease with excellent tribological properties,oleic acid was used to modify multi-walled carbon nanotubes(MWCNTs).On the basis of the self-designed ultrasonic-assisted ball milling test device in the laboratory,the uniformly and stably dispersed suspension of MWCCNTs in PAO6 was successfully prepared,and the bentonite grease with excellent tribological properties was prepared with the suspension as the base oil.The effects of different dispersion methods(ball milling dispersion,ultrasonic dispersion,ultrasonic and ball milling dispersion) on the dispersion stability of MWCNTs were studied,and the changes of grease friction coefficient and wear spot diameter with the mass fraction of MWCNTs were studied.The results show that oleic acid-modified MWCNTs have the best dispersion stability under the combined action of ultrasound and ball mill.With the increase of MWCNTs mass fraction,the friction coefficient and wear spot diameter of bentonite grease is first decreased and then increased.When the mass fraction of MWCNTs is 0.03%,the bentonite grease prepared has the best tribological performance and the smallest specular diameter(0.690 mm),which is 14.5% lower than the Mobil 28 aviation grease(in line with the U.S.military specification MIL-G81322 C,and the specular diameter is 0.807 mm).