Mechanically Driven Growth of Hydrocarbons at Sliding Interfaces to Control Degradation and Wear

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Although tribology has been an active field of study, the limited understanding of friction and wear processes continues to lead to failure of the moving systems used in various applications. Although current approaches to protecting the surfaces by deposition of damage-resistant coatings provide temporary solutions, eventually the coatings degrade and wear off. This award supports fundamental research to elucidate how the damage in the materials can be reversed by in-situ replenishment of protective coatings. Insights from this study will enable repair of the damaged surfaces without having to disassemble the entire mechanical system. Not only will this research promote scientific advances, but it will also improve the performance of the mechanical part assemblies. It will provide a new solution to more reliable and energy-efficient transportation and manufacturing systems, in which repair of the surfaces will prolong the operation lifetimes significantly. This award will also offer new educational opportunities for undergraduate and graduate students in the areas of materials science, mechanics, and surface science, with an emphasis on recruiting and retaining women and minorities in STEM disciplines. Mechanically induced surface degradation creates a significant problem for mechanical assemblies and is the major cause for the loss of usefulness. High-contact pressure and shear during relative movement of the sliding interfaces causes local heating and as well as complex compression. For a correct combination of materials in sliding contact, these conditions may induce tribochemical reactions leading to the formation of protective films directly at the contact. This project focuses on understanding the friction- and wear-induced deformation of catalytic metal interfaces immersed in a hydrocarbon environment, which causes an in-situ growth of layered carbon films on the sliding surface. To elucidate the material growth processes, this research will combine in-situ Raman analysis of the surfaces exposed to stresses during macroscale tribology tests, with electron microscopy post-characterization of the wear track cross-sections. The characterization data will be correlated with the mechanical characteristics of the films to evaluate the triboactive response of the dynamic system to the applied mechanical stresses, and to quantify the damage tolerance of the grown films in different environments. The research will also investigate alternative solutions to tribocatalysis activation.This project is jointly supported by the Civil, Mechanical, and Manufacturing Innovations Division and the Chemical, Bioengineering, Environmental and Transport Systems Division in the Engineering Directorate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.