• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The investigation of potential corrosion resistant phosphorus containing and polymer films using x-ray photoelectron spectroscopy

Asunskis, Amy Louise January 1900 (has links)
Doctor of Philosophy / Department of Chemistry / Peter M.A. Sherwood / This dissertation will examine the fabrication of different phosphorus containing films and their use as corrosion preventative films and adhesion materials between polymers and metal and metal alloys. Orthophosphate films are used in several metals and metal alloys to prevent corrosion and promote adhesion between paints or polymers and metal substrates. One key component is to examine the use of different phosphorus containing acids that might lead to phosphorus containing films which would compliment the mainly orthophosphate films currently in use. The objectives of this study are to see if it is possible to fabricate different phosphorus containing films, use them to adhere polymers to metal and metal alloys, and test the phosphorus containing films’ and polymer films’ corrosion protection properties. The thermoplastic resin, Poly(ether ketone ketone), or PEKK was found to adhere well to different phosphorus containing films and protect the underlying layers from oxidation in 4-D water. The phosphorus containing films were created by electrochemical deposition in different 5 M phosphorus containing acids. The metal or metal alloy was abraded to remove the native oxide and treated in the electrochemical cell. The second, separate polymer films were created by dip coating the metal or metal alloy in a polymer solution. The film thickness in both cases was controlled to be less than 100Å to ensure that the underlying metal or metal alloy could be detected. The surface chemical analysis was collected using X-ray photoelectron spectroscopy, or XPS. Core level and valence band XPS were used to distinguish the differences in the chemistry at the surfaces. The valence band XPS spectra were interpreted using spectra generated by multiple scattered wave calculations and band structure calculations. In the cases were more than one film was present subtraction and addition spectrum were used to interpret the chemistry in the interface region of the films.
2

Revêtement de Phosphate de calcium sur dioxyde de titane pour des implants métalliques pour des applications médicales / Compound coatings of Ca-phosphates and/ titanate on metallic implants for medical applications

Mohamed, Ibrahim 10 September 2013 (has links)
Pour combiner les bonnes propriétés mécaniques des matériaux métalliques et obtenir des surfaces bioactives, des revêtements de phosphate de calcium (Ca-P) ont été développés. Le but est d’améliorer la biocompatibilité et la bioactivité du système et créer une barrière contre l’éventuelle libération d’ions toxiques du substrat métallique. Notre démarche a été de développer une nouvelle voie de synthèse. Après un polissage mécanique et décapage chimique du substrat de Titane ou Ti–6Al–4V une couche intermédiaire en titanate de sodium a été obtenue par un prétraitement alcalin sur les substrats. Elle a été ensuite soumise à un traitement thermique afin de créer une couche alvéolaire nanométrique. Celle-ci facilite la croissance une couche de phosphate de calcium par voie autocatalytique d'une manière similaire au procédé de formation de l'os naturel. La caractérisation et l’étude des revêtements des Ca-P obtenus par les trois bains (acides, alcalins et oxydant) sur les substrats métalliques ont été réalisés. Les dépôts ont été étudiés d’un point de vue structural et morphologique. La stabilité des couches de Ca-P a été mesurée dans le fluide corporel (SBF) pour des périodes différentes utilisant des analyses biochimiques. En conclusion, cette méthode est une solution peu coûteuse, fiable, et utilisable à l'échelle industrielle. La couche de Ca-P aussi bien que le titanate de sodium obtenus peuvent permettre d’être imprégnés par des agents actifs comme un ou plusieurs agents antibactériens. / To combine the good mechanical properties of metallic substrate with the bioactivity of some ceramics, to obtain bioactive surface, a calcium phosphate (Ca-P) coating has been developed. The goal is to improve the biocompatibility and bioactivity of metallic implant and create a barrier against the possible release of toxic ions from the metallic substrate. Our approach has been to develop a new synthetic route. After mechanical polishing and chemical etching of the titanium or Ti-6Al-4V substrates, an interlayer of sodium titanate was obtained by an alkaline pretreatment of the substrates. Then, it was subjected to a heat treatment to create a nanometeric layer. The latter facilitates the growth of a layer of Ca-P by means of an electroless manner similar to the forming process of the natural bone. Characterization and study of Ca-P coatings obtained by the three baths (acids, alkalis and oxidizing) on metallic substrates have been made. The deposits were studied from a structural and morphological point of view. The stability of Ca-P layers was measured in simulated body fluid (SBF) for different periods using biochemical analyzes. In conclusion, this method is a cheap and reliable solution that can be used on an industrial scale. The Ca-P as well as the sodium titanate layers can afford to be impregnated with active agents such as one or more antibacterial agents.

Page generated in 0.108 seconds