Graduation Semester and Year

2007

Language

English

Document Type

Thesis

Degree Name

Master of Science in Materials Science and Engineering

Department

Materials Science and Engineering

First Advisor

Efstathios Meletis

Abstract

Diamond like carbon (DLC) films have gained grounds in the biomedical field as an inert, biocompatible, low friction and wear resistant coating and are widely used in heart valves, coronary artery stents, dental implants, knee prosthesis and other vascular devices. In addition, Ag nanoparticles/films can prevent the formation of biofilm on biomedical implants by degrading the metabolic activities like permeability and respiration and also impair DNA replicability. Thus, Ag-doped DLC (Ag-DLC) can serve as a multifunctional bio coating combining desirable antibacterial and physical/ mechanical characteristics. In the present study, Ag-DLC films were synthesized utilizing a hybrid Plasma CVD and Magnetron sputtering process in a CH4/Ar glow discharge. Nanocomposite films containing Ag nanoparticles in an amorphous DLC matrix with various amounts of Ag were synthesized and characterized by Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS). Tribological experiments were performed to assess the frictional behavior and wear resistance of the Ag-DLC films as a function of Ag content. Anodic polarization experiments were conducted to characterize the electrochemical behavior of the Ag-DLC films. TEM results revealed that Ag nanoparticles of 4-7 nm in size were uniformly distributed in an amorphous DLC matrix. Microhardness of DLC films exhibited a hardness of 22 GPa and it gradually decreased with increasing Ag content in the films. Wear rate of DLC film was 1.9 x 10-8 mm3/Nm and it increased to 8 x 10-7 mm3/Nm for Ag-DLC (5% Ag) film. Electrochemical behavior experiments showed that Ag-DLC films exhibited an inert behavior compared to the pure silver.

Disciplines

Engineering | Materials Science and Engineering

Comments

Degree granted by The University of Texas at Arlington

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