Tribology Commons^™

Molecular Dynamics Study Of Characterization In Metal-Free Friction Materials, Yizhan Zhang

Electronic Theses and Dissertations

Metallic friction materials currently used in industry may adversely impact the environment. Substitutions for metals in friction materials, on the other hand, can introduce operational safety issues and other unforeseeable issues such as thermal-mechanical instabilities and insufficient strength. In view of it, this dissertation focuses on developing different kinds of materials from simple structure to complex structure and evaluating the material properties with the assistance of molecular dynamics (MD) tools at the nano scale.

First, the concept of the contacted surfaces in friction at the atomic scale was introduced in order to get accurate understanding of the friction process compared …

Solid State Synthesis And Characterization Of Apatite Based Ceramic Waste Form For The Immobilization Of Radioactive Iodine, Md Imdadul Islam

LSU Doctoral Dissertations

The growing demand for nuclear power in the United States and worldwide is accountable for addressing the major concern of radioactive waste, involving the technical challenges of maintaining the nuclear fuel cycle and immobilizing high-level wastes for safe disposal in geological storage. The appropriate selection of waste forms for spent nuclear fuel such as fission products and radionuclides can be effective means for a feasible and sustainable nuclear fuel cycle. But highly volatile radionuclides such as iodine (129) are of specific concern due to its extraordinary long half-life (15.7 million years). Due to its poor solubility and high volatility at …

Pulse Reverse Current Electrodeposited Tio2 Doped Ni-W Coating, Sydney Hughes

Williams Honors College, Honors Research Projects

Nickel-Tungsten (Ni-W) coatings via the pulse reverse current method have been under development as a potential replacement for typical Chromium/Cadmium coatings. To increase the effectiveness of Ni-W as a coating, dopants have been tested to decrease microcracks and pores and increase overall tribological performance. Previous research by Timken Engineered Surfaces Laboratory showed that Ni-W doped with TiO₂ nanoparticles had a positive effect on coating performance. The purpose of this study was to determine the ideal solution parameters (i.e. TiO₂ concentration, pH) to maximize the benefit of the dopant when samples are subjected to tribological testing. Here, solutions of …

In-Vivo Corrosion And Fretting Of Modular Ti-6al-4v/Co-Cr-Mo Hip Prostheses: The Influence Of Microstructure And Design Parameters, Jose Luis Gonzalez Jr

FIU Electronic Theses and Dissertations

The purpose of this study was to evaluate the incidence of corrosion and fretting in 48 retrieved titanium-6aluminum-4vanadium and/or cobalt-chromium-molybdenum modular total hip prosthesis with respect to alloy material microstructure and design parameters. The results revealed vastly different performance results for the wide array of microstructures examined. Severe corrosion/fretting was seen in 100% of as-cast, 24% of low carbon wrought, 9% of high carbon wrought and 5% of solution heat treated cobalt-chrome. Severe corrosion/fretting was observed in 60% of Ti-6Al-4V components. Design features which allow for fluid entry and stagnation, amplification of contact pressure and/or increased micromotion were also shown …

Surface Modification Of Aluminum Alloys By Plasma Electrolytic Oxidation, Vahid Dehnavi

Electronic Thesis and Dissertation Repository

Plasma Electrolytic Oxidation (PEO) is a surface treatment for the production of ceramic oxide coatings with great properties, such as high wear and corrosion resistance, on metal substrates, particularly aluminum and magnesium alloys. Formation of PEO coatings involves complex processes and mechanisms that are difficult to study. Currently, the PEO process is in a transition phase from research to commercial application, with a primary focus on the corrosion and wear protection of light alloys, and has recently generated interest as a promising surface treatment for biomedical applications.

To justify the industrial application of PEO, a more systematic and in-depth study …

Prediction Of Tribological Behavior Of Candidate Materials For Rotor Seals, John W. Franzino, Will F. Michul

Materials Engineering

To reduce high costs associated with manufacturing and testing materials for rotor seals, a procedure needs to be developed to quickly and accurately test candidate materials as they are released. The test should reduce the amount of fabrication required and model working conditions in order to accurately assess the tribological behavior of candidate materials. A possible solution was examined that utilized a rig meant to model operational stresses and wear. Compression modulus data was then taken in order to quantify the accumulation of damage due to microcracking, the primary mode of failure, through a damage index parameter. Testing results concluded …