Electrochemically formed passive layers on titanium and zirconium, and their optical, surface and corrosion properties are presented. With the use of higher applied AC voltages, the passive layers become thicker and more protective of the underlying metal, as determined from thickness measurements by scanning electron microscopy and focused ion beam instruments, as well as passive layer corrosion resistance measurements by electrochemical polarization curve and inductively coupled plasma mass spectrometry experiments. The surface morphology of all samples was studied with atomic force microscopy, profilometry, visible light microscopy, transmission electron microscopy, and finally electron backscattered diffraction experiments. The passive layers were found to be uniform in their surface structure with no cracks or fractures. However, the samples prepared at VAC = 60-80 V showed defects, which were increasingly prevalent at higher VAC. These defects are thought to be attributed to a process of localized electrochemical breakdown. The aforementioned increase in corrosion resistance is in spite of the defects, which were observed for the samples prepared at VAC = 60-80 V. Surface morphology, in relation to optical properties, was also investigated through reflectance spectroscopy measurements. A correlation between grain colouration and light reflected from the sample surface was observed through measurements using visible light microscopy as well as near infrared ultraviolet visible reflectance spectroscopy. These experiments showed a red-shift of wavelength maxima (λmax) values as voltages, and therefore thickness, were increased. This is the reason that different colours are seen for different thicknesses; the red shift causes different wavelengths to be reflected constructively and destructively. Overall, these passive layers are protective of an already remarkable metal and, with greater knowledge of their properties, their potential may be observed in a wide range of applications. / Thesis (Master, Chemistry) -- Queen's University, 2011-09-19 19:44:07.148
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/6733 |
| Date | 20 September 2011 |
| Creators | Holmberg, Rebecca |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
Page generated in 0.0038 seconds