The goal of this effort, a collaboration between researchers the University of Pennsylvania and the Laboratory of Tribology and Dynamics of Systems (LTDS; Lyon, France), is to develop a physically-based understanding of the tribomechanical functional behavior of an important class of thin film materials known as diamond-like nanocomposites (DLNs). DLNs are fully amorphous films consisting of an interpenetrating, interbonded network of silica glass and hydrogenated amorphous carbon. They exhibit impressive durability, meaning mechanical (stability, strength) and tribological (low friction and low wear) performance, even under harsh conditions (elevated temperatures, high contact stresses, and ultrahigh vacuum, humid, and oxidizing environments). The team pursues a closely integrated, interdisciplinary, multi-scale, multi-technique program to determine how the tribo-mechanical functionality of DLNs depends on the bulk and surface material properties, and how these properties are determined by the structure and composition. The collaboration brings together complementary expertise needed because of the interdependency of the material properties, and because of the multiple techniques required to execute the work. The integrated research approach is applied to DLN films with systematically varied compositions to explore the structure-property-functional behavior relationships directly.
The outcome of the research can aid in the design of new and further improved classes of DLNs specifically, and amorphous materials more generally. This is important since diamond-like materials are currently in demand for use as coatings in the harsh operating conditions found in applications ranging from advanced energy systems to the manufacturing, aerospace, automotive, and information storage sectors, and also in nanomanufacturing and nanomechanical device applications. Amorphous materials in general are ubiquitous and have broad applications, and so new scientific insights into how their functional behavior is determined by their composition, structure, and material properties is desirable. From an education perspective, this research provides international exchange experiences for Ph.D. as well as for undergraduate students, exposing them to unique and complementary capabilities at each location. The project will also bring LTDS into ongoing collaborations between the University of Pennsylvania and Sandia National Laboratories, the U.S. Naval Academy, and Hunter College-City University of New York.