Periodic Reporting for period 1 - SSLiP (Scaling-up SuperLubricity into Persistence)
Berichtszeitraum: 2022-04-01 bis 2023-03-31
Friction and wear between moving parts contribute significantly to the world's energy consumption. To address this challenge, SSLiP proposes a novel approach that utilizes the concept of structural superlubricity, which occurs at a lattice misfit between clean, flat, rigid crystalline surfaces, resulting in extremely low friction. However, this effect has only been observed in the micrometer scale and laboratory times.
To bring this concept to the macroscale and enable real-life applications, SSLiP will use tribo-colloids, which are colloidal particles coated in 2D materials. These tribo-colloids will produce a dynamic network of superlubric contacts, replicating the low friction effect on larger length scales. The team will also develop regenerative tribochemical and structural mechanisms to overcome the inherent degradation and failure modes of the network.
Through careful design of the coatings, carrier fluid, and mechanical properties of the core particles, the sliding chemistry and collective behavior of the colloids can be controlled. The team will synthesize and experiment with individual contacts, visualize colloid dynamics during sliding, and characterize the chemical properties in-situ. These experiments will be combined with multiscale simulations and theory to develop a coherent framework.
The ultralow friction technology developed by SSLiP will have a significant impact on reducing energy loss in products, such as passenger cars responsible for approximately 2 billion tonnes of CO2 per year, and increasing the lifetime of parts. The technology will also enable new possibilities, such as much higher writing speeds in hard disks. SSLiP aims to realize macroscale, industrially relevant superlubricity defined as a net friction coefficient of <0.01 operating at 10’s MPa nominal pressure that persists without degradation under boundary lubrication conditions.
To bring this concept to the macroscale and enable real-life applications, SSLiP will use tribo-colloids, which are colloidal particles coated in 2D materials. These tribo-colloids will produce a dynamic network of superlubric contacts, replicating the low friction effect on larger length scales. The team will also develop regenerative tribochemical and structural mechanisms to overcome the inherent degradation and failure modes of the network.
Through careful design of the coatings, carrier fluid, and mechanical properties of the core particles, the sliding chemistry and collective behavior of the colloids can be controlled. The team will synthesize and experiment with individual contacts, visualize colloid dynamics during sliding, and characterize the chemical properties in-situ. These experiments will be combined with multiscale simulations and theory to develop a coherent framework.
The ultralow friction technology developed by SSLiP will have a significant impact on reducing energy loss in products, such as passenger cars responsible for approximately 2 billion tonnes of CO2 per year, and increasing the lifetime of parts. The technology will also enable new possibilities, such as much higher writing speeds in hard disks. SSLiP aims to realize macroscale, industrially relevant superlubricity defined as a net friction coefficient of <0.01 operating at 10’s MPa nominal pressure that persists without degradation under boundary lubrication conditions.
Fabrication and functionalisation of the essential tribocolloid and tribomesostructure components of the superlubricious contact network is progressing. Pyrolytic carbon films as first generation of tribocolloids were produced via chemical vapor deposition (CVD) technique on silicon wafer substrates with varying deposition times to achieve different thicknesses. The films were characterized using Raman spectroscopy and scanning electron microscopy (SEM) and Atomic force microscope (AFM), which demonstrated that the PyC coating exhibited high quality conformality on the substrate. The PyC-coated samples were utilized as standard samples to evaluate the friction coefficient of the material. Two different tribomesostuctures were successfully synthesized, PyC-coated SiO2 micro particles and pyrolized photoresist film-coated SiO2 micro particles. The coatings exhibited promising conformity, low roughness and low friction. The micro particles were coated in powder form and deposited on the substrate using spin-coating of the dispersed colloids on silicon wafer for further tribological testing.
SSLiP has acquired and customized a high-resolution contact mechanics system to measure mesoscale superlubricity in both dry and wet contacts. SSLiP have designed and implemented testing protocols and algorithms that have successfully measured micro-Newton scale superlubricity. This system can measure small amplitude superlubricity at extreme pressures of up to 9 GPa, which corresponds to the substrate's hardness limit, and extract the friction coefficient. This is almost an order of magnitude improvement over previously reported state-of-the-art pressures. SSLiP has demonstrated "tribocolloid scale" superlubricity of 10 micrometer contacts undergoing full dry sliding contact at high pressures of up to a gigapascale of pressure. The consortia hase utilized the PyC conformal coating system for the first generation tribocolloid and countersurface patterns, which has shown good friction with a CoF of approximately 0.05 in microscale single contact measurements and macro scale sliding conventional friction tests. Overall, SSLiP's system and testing protocols have shown great potential in measuring and improving superlubricity at extreme pressures, viewed as an essential feature to build macroscale networks of superlubricious contacts.
SSLiP has acquired and customized a high-resolution contact mechanics system to measure mesoscale superlubricity in both dry and wet contacts. SSLiP have designed and implemented testing protocols and algorithms that have successfully measured micro-Newton scale superlubricity. This system can measure small amplitude superlubricity at extreme pressures of up to 9 GPa, which corresponds to the substrate's hardness limit, and extract the friction coefficient. This is almost an order of magnitude improvement over previously reported state-of-the-art pressures. SSLiP has demonstrated "tribocolloid scale" superlubricity of 10 micrometer contacts undergoing full dry sliding contact at high pressures of up to a gigapascale of pressure. The consortia hase utilized the PyC conformal coating system for the first generation tribocolloid and countersurface patterns, which has shown good friction with a CoF of approximately 0.05 in microscale single contact measurements and macro scale sliding conventional friction tests. Overall, SSLiP's system and testing protocols have shown great potential in measuring and improving superlubricity at extreme pressures, viewed as an essential feature to build macroscale networks of superlubricious contacts.