Browsing by Subject "Electrochemical deposition"
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Item Electrochemical deposition of green rust on zero-valent iron(Texas A&M University, 2006-08-16) Kulkarni, Dhananjay VijayPerchloroethylene (PCE) is a toxic contaminant that has been introduced into the environment over many years through industrial and agricultural wastes. Research has been done in the past to investigate PCE degradation by zero-valent iron (ZVI), green rust (GR) and a mixture of both. The combination of ZVI and green rust has been reported to be more effective for degrading PCE than either of them alone. Forming green rust electrochemically has the potential for depositing GR more effectively on the surface of ZVI where it will be able to more easily transfer electrons from ZVI to contaminants such as PCE. Therefore, the goal of this research was to determine the feasibility of electrochemically depositing green rust on zero-valent iron and to characterize it in terms of its composition, crystal properties and amount produced. XRD analysis was conducted to determine composition and crystal properties and a procedure was developed to measure the amount produced. Equipment was constructed to deposit green rust electrochemically onto ZVI. A chain of experiments with varying voltage, pH, time and amounts of ZVI were conducted to determine feasible experimental conditions for GR formation. Then, a method was developed to accurately measure the amount of surface oxides of iron deposited on the zero-valent iron substrate. This method was tested and found useful for measuring iron in: i) standard solutions of soluble iron with different concentrations of reagents; ii) suspensions with solid iron hydroxides by themselves; and iii) suspensions with solid iron hydroxides and ZVI. Electrochemical experiments were conducted and the amounts of iron hydroxides deposited on the ZVI surface were measured. XRD analysis of the deposits on the surface was conducted and the patterns of XRD-peaks were compared to that of type 2 ?? sulfate green rust.Item Electrochemical deposition of metal ions in porous laser sintered inter-metallic and ceramic preforms(2010-12) Goel, Abhishek, 1986-; Bourell, David Lee; Beaman Jr., Joseph J.Selective laser sintering (SLS) is a commercial, powder-based manufacturing process that produces parts with complicated shape and geometry based on a computer solid model. One of the major drawbacks of SLSed inter-metallic and ceramic parts is their high porosity because of the use of binder system. High porosity results in poor mechanical, electrical and thermal properties of the preform and hence renders it unsuitable for various applications. This thesis attempts to infiltrate SLSed preforms by carrying out electrochemical deposition of metal ions inside the interconnected pore network. One of the major benefits of carrying out this novel process is low processing temperature as opposed to existing methods such as melt infiltration. Low temperature reduces both energy consumption and associated carbon-footprint and also minimizes undesirable structural changes. Both conductive and non-conductive preforms may be electrochemically infiltrated, and MMCs produced by this method have potential for use in structural applications.