The Study For The Performance Of Lubrication By Ionic Liquid Modified Carbon Quantum Dots

Friction and wear is a multi-scale phenomenon which exists from atomic scale to galaxy scale,such as vascular injury,earthquake,volcanic eruptions,and even galaxy collisions.With the rapidly development of mechanical systems,friction and wear became a core issue,which resulting in significant energy loss,resource consumption and environmental pollution.Macro/microscopic superlubricity are effective methods to solve the negative effect of friction and wear.As the decrease of device scale,it is essential to pay much attention to reduce friction and wear in micro-scale.Until now,outstanding achievements were obtained in micro-scale superlubricity.However,the superlubricity achieved by reducing of Van der Waals force,surface force,adhesion and friction usually need rigorous conditions,such as high vacuum,high temperature and specific materials.Thus,microscopic superlubricity is still difficult to apply in the practical working condition.Water-soluble lubricants and IL modified nanomaterials(such as carbon nanotubes(CNTs)and fullerene)have been extensively investigated and showed the better tribological performance by reasonable design of the core-shell structure and ordered charge distribution.It could provide a way to improve the tribological properties of nano-materials with composite structures,which formed through interaction of nanoparticles with polar molecules.Carbon quantum dots(CQDs),which have intrinsic characteristics such as quasi-spherical,the high surface area and size below 10 nm,could potentially be better than traditional nanoparticles when modified with IL,and the tribological or mechanical properties of related researches on IL modified CQDs are still in its infancy.In this study,we successfully fabricated nanoparticles carbon quantum dots(CQDs)and ionic liquid(IL)nanoparticles by simple modification.The structures and properties of these particles were measured with HRTEM,FTIR,Raman Spectrometer and friction test.The results from FTIR and Raman indicate some functional groups are attached to the CQDs surface during functionalization.More importantly,IL-modified CQDs as lubricant material demonstrated excellent tribological performance and obtained a super-low friction coefficient about 0.006 and wear rate about 0.7×10-14 m~3/Nm with the CQDs content of 3.6%.The results revealed that IL-modified CQDs might provide a new idea to investigate various lubricant materials to achieve super-low friction and could be intensively studied for other practical applications.Simultaneously,the fingerprint-like carbon films(FP-C:H)were prepared on monocrystal silicon substrate based on high power pulsed plasma enhanced chemical vapor deposition.The structure of the film was characterized by high-resolution transmission electron microscopy(HRTEM)and LABRAM HR 800-type Raman spectroscope.The tribological behavior of the films in various lubricant were analyzed and compared by the ball-on-disk reciprocating friction testing machine,Olympus STM6 measuring microscope,and 3D-contourgraph.The experimental result indicated that the fabricated film have unique fingerprint-like structure and show excellent friction reduction at low load and wear resistance ability at high load with TMPTO as lubricant.The preparation of the fingerprint-like carbon films would have an outstanding development and practical prospect in lubricant using the technology of HIP-PECVD.