Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555998
Title: Investigating the formulation of silica-based ceramic core materials for investment casting
Author: Wilson, Paul James
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2011
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Thesis embargoed until 01 Feb 2026
Access from Institution:
Abstract:
An investigation has been performed into the formulation of silica-based ceramic core materials for investment casting. The formulation of 3 materials that are currently used by Ross Ceramics was investigated in detail and the data from this used to determine the elements of the formulation that should be investigated in more detail. The techniques used included a variety of mechanical tests at both room and high temperatures, dilatometry, phase analysis by XRD and chemical analysis by XRF, pore analysis by simple Archimedes tests and mercury porosimetry and both scanning electron and transmitted light microscopy. A large number of materials were created with different formulations and the various characterisation techniques employed were used to determine the function of the different constituent. It was determined that the function of zircon was to prevent grain boundary movement at elevated temperatures via the Zener effect, by acting as a non-reactive secondary phase. The zircon also had an additional consequence from the inherent contamination, with alumina, from the ball-mill procedure performed by the supplier. This had the effect of significantly affecting several high temperature properties. The effect of several dopant materials: TiO2, Al2O3, MgO, cristobalite seed and Molochite addition was also investigated. The latter two were determined to function mainly by their inherent contamination. The other additives affected the materials in different ways depending on the amount used and the presence of any phase eutectics that had detrimental effects on the high temperature material properties. The particle size distribution of the materials was also investigated. It was determined from the experiments that the D20 was an important factor for deterring final material properties and that most materials obeyed a modified Griffith’s crack theory relation, with the exception of materials with a larger zircon particle size than that of the main silica constituent. From this work new materials could be created using the knowledge gained and material properties could be optimised to meet specific requirements by changing zircon quantity, dopant levels and particle size.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (D.Eng.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.555998  DOI: Not available
Keywords: Q Science (General) ; TS Manufactures
Share: