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|Title:||Coatings for corrosion protection of metals and alloys|
Veldhuis, Stephen C.
|Department:||Materials Science and Engineering|
|Keywords:||coating;corrossion;ceria;polymer;EPD;co-deposition;Other Materials Science and Engineering;Other Materials Science and Engineering|
|Abstract:||<p>Thin films prepared by electrochemical and physical vapor deposition (PVD) methods were investigated for corrosion protection of metals and alloys. Various electrochemical methods were developed, such as electrophoretic deposition (EPD), electrolytic deposition (ELD) and combined methods. EPD method has been developed for the deposition of polymer films, including poly(2-vinylpyridine) (PVP) and co-polymer poly(4-vinylpyridine-<em>co</em>-butyl methacrylate) (PVPBM). The method involved the electrophoresis of protonated polymer macromolecules, base generation at the cathode surface, charge neutralization and deposition of water insoluble polymer films. Nanostructured CeO<sub>2</sub> ﬁlms were prepared by cathodic ELD and EPD. Cathodic ELD involved electrosynthesis of CeO<sub>2</sub> nanoparticles in the cathodic reaction and film formation. New dispersion agents were developed for CeO<sub>2</sub> particles for application in EPD processes. The kinetics of ELD and EPD and deposition mechanisms were investigated.</p> <p>Composite polymer-CeO<sub>2</sub> ﬁlms were deposited using various strategies, based on ELD or EPD of CeO<sub>2</sub> and EPD of polymers. The composite films were deposited as monolayers, multilayers or materials of graded composition. The deposition yield and film composition can be varied.</p> <p>The composite films were studied by electron microscopy, X-ray diffraction, thermogravimetric and differential thermal analysis. Electrochemical testing showed that polymer and composite films provided corrosion protection of stainless steel substrates.</p> <p>Corrosion protection properties of coatings deposited on commercial AMPCO and TZM alloys was investigated. CrN, CrN-D, and TiC were deposited by PVD method. Ni coatings were deposited by electroplating. The analysis of Tafel plots and impedance spectroscopy data showed that CrN and CrN-D coatings deposited by PVD showed better corrosion protection of AMPCO and TZM alloys, compared to TiC and Ni coatings. The results of this investigation pave the way for the fabrication of novel coatings with advanced corrosion protection, wear and mechanical properties, using combined PVD and electrochemical methods.</p>|
|Appears in Collections:||Open Access Dissertations and Theses|
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