Chuding Zhang,Decai Li,Wenxi Zhao,Shilin Nie,Jingwei Yang
The preparation of high-performance magnetic fluids with high viscosity, high saturation magnetization and high stability, has remained a pivotal challenge limiting the advancement of associated applications. In the present study, we synthesized modified magnetic nanoparticles through an innovative approach combining in-situ carbon nanotube (CNT) generation with chemical co-precipitation. These nanoparticles were then co-coated with OA/PIBA, resulting in the preparation of advanced PAO20-based magnetic fluids. The effects of CNT modification on particle microstructure and magnetic properties were studied by transmission electron microscopy and vibrating sample magnetometer, the magnetoviscous properties of magnetic fluids were studied by a rotating rheometer equipped with a magnetic field module, and the stability of the prepared magnetic fluids under a strong magnetic field was tested by a self-made LC oscillation circuit. The results show that the saturation magnetization of the prepared magnetic fluids surpasses 32 emu/g, while their viscosity reaches a remarkable 6625 mPa·s (at 0.24 T, 100 1/s shear rate and 25 °C), which is significantly higher than that of traditional magnetic fluids (usually about 100 mPa·s). Furthermore, when exposed to a 0.6 T magnetic field, the magnetic fluids could exhibit Rosensweig instability that persists for over 468 h. The stability is at least 93 times superior to that of unmodified PAO20-based magnetic fluids. Based on these encouraging results, it can be fully predicted that the CNT-modified PAO20-based magnetic fluids developed in this study will play a pivotal role in various applications, including sealing, lubrication, and vibration reduction. Their exceptional properties will hold immense promise for numerous engineering applications.
Le Li,Hongyu Liu,Xiaoqiang Fan,Zhengfeng Cao,Lining Wu,Xiangyuan Ye
A single Ti 3 C 2 T x is not sufficient to meet the dispersing stability and lubricating performance requirements of lubricating oil in complex working conditions. Environmentally friendly high-performance Ti 3 C 2 T x composite lubricating oil additives combine the advantages of Ti 3 C 2 T x and other materials and have a promising long-term high-efficiency lubricating prospect. In this study, Ti 3 C 2 T x /SiO 2 heterostructures were prepared as lubricant additives to enhance the tribological performance of PAO20. Tribological tests indicate that the addition of 0.15 wt% Ti 3 C 2 T x /SiO 2 heterostructures reduced the average wear volume by 65.9 % at 392 N due to the synergistic effect of Ti 3 C 2 T x and SiO 2 . The excellent lubricating performance of Ti 3 C 2 T x /SiO 2 heterostructures is primarily attributed to the rolling effect of SiO 2 and the dual friction mechanism of Ti 3 C 2 T x /SiO 2 friction film during synergistic friction. The Ti 3 C 2 T x /SiO 2 friction film and SiO 2 enhance the interface load-bearing capacity and anti-friction/wear performance. This structural design of Ti 3 C 2 T x /SiO 2 heterostructures provides a new perspective for the design of Ti 3 C 2 T x composite lubricant additives .
In view of the promising application potential of two-dimensional MXenes (Ti 3 C 2 T x ) in lubrication, along with the challenge of their poor dispersibility in non-polar base oil, this work reports the surface functionalisation of Ti 3 C 2 T x through the covalent grafting of alkylphosphonic acid (TDPA). TDPA grafting converts the surface properties of Ti 3 C 2 T x from polar to non-polar, significantly enhancing its dispersion stability in non-polar PAO20 base oil. Tribological performance tests showed that as an additive, TDPA-Ti 3 C 2 T x improved the anti-wear performance of PAO20 by 38.1%. Its excellent performance is mainly attributed to the high mechanical strength, easy interlayer shear characteristics of the modified nanosheets, and the synergistic effect of the protective tribochemical film formed in situ during the friction process. The TDPA functionalisation strategy is an effective way to realise the efficient application of Ti 3 C 2 T x in non-polar lubricating systems, and provides a new idea for the design of high-performance lubricating additives.
危险品化学品经营许可证（带存储）