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The widely growing market of miniaturized electronic devices demands for alternative substrate materials and manufacturing technologies on which fine pitch components can be mounted. Glass has been identified as a potential substrate material as it offers a number of advantages including a coefficient of thermal expansion closely matched to that of silicon that may reduce the thermo-mechanical stresses on the interconnects in the flip-chip assemblies. In addition to this, its dimensional stability and optically transparent nature facilitates alignment of multiple layer structures, enabling accurate drilling of microvias to capture pads and the potential for applications in optical interconnect.

Apatite based glass-ceramics are some of the most bioactive materials found to date. They do not require fibrous encapsulation and bond to bone directly through an apatite layer. Apatite based glass-ceramics exhibit relatively poor biaxial flexural strength, hence limiting their applications to non-load bearing implants. The addition of mica results in a material that is highly machinable, and provided that a suitable interlocking microstructure can be produced, the strength will be increased. The aim of this work is to investigate how altering the heat treatment affects the crystallisation and the final mechanical properties of three different compositions of glass-ceramic. The glass system studied is the ternary glass system; barium fluorphlogopite (Bao.sMgafSiaAlOiojFz), fluorapatite (CaiofPO^eFz) and cordierite (MgzAUSisOis). The three compositions differ by the mol% of fluorapatite forming feedstock in the precursor glass. Glass-ceramics formed by heat-treating a glassy precursor are investigated using differential scanning calorimetry, kinetic neutron diffraction and scanning electron microscopy. The mechanical properties of the samples are characterised by their biaxial flexural strength and Vickers hardness. The phases formed and the microstructures of the samples are linked to the mechanical properties and an assessment of the final material's implant suitability is made.

Annealed glass has the propensity to fast fracture. So, the need for redundancy in structural glass elements is a fundamental necessity. Currently, redundancy is provided by laminated glass, whereby, if one glass pane fails, then the remaining intact pane(s) sustain the loads. However, for the in-service (unbroken state) condition the element is at least twice as thick as necessary. This leads to increased weight and increased cost. The presented work develops and investigates a cheaper, lighter alternative redundant system using a GFRP sheet bonded to one annealed glass pane. Consequently, a new material, Reinforced Glass, is created. For the in-service (unbroken state) condition it is shown that, under load, the Reinforced Glass has a similar structural response to ordinary annealed glass. A review of annealed structural glass design methods is presented - facilitating design for the unbroken state. Design recommendations are given. For the broken state an analytical, predictive model was developed, which was validated through experimental testing. The model draws similarities to Reinforced Concrete, whereby a compression block is generated in the broken glass - which is balanced by the GFRP tension reinforcement. Unique predictive equations are produced for application in design for the broken state. The model is validated for various thicknesses of glass.

Effects of non-stoichiometric composition in zirconium carbide (ZrCx) ceramics on crystallographic, microstructural, and thermophysical properties relevant to nuclear fuel applications were investigated through complementary experimental and computational studies. ZrCx compositions (32.1-50.3 at% C) were synthesised by carbothermal reduction of ZrO] and rapidly densified by spark plasma sintering (SPS). A novel thermal analysis technique employed pulsed laser heating and optical pyrometry to generate time-temperature thermogram data suitable for the identification of latent heat exchanges indicative of extremely high temperature (> 3000 K) liquidus, solidus, and eutectic transitions in the Zr-C system. Liquidus temperatures were measured for hypoeutectic ZrC+C compositions, an area of the phase diagram lacking in accurate measurements. Discontinuous changes in temperature indicated that emissivity of ZrC decreases upon the transition from solid to liquid; based on an estimated solid emissivity of 0.6, liquid emissivity decreased to 0.46-0.58. Dendritic microstructures confirmed that ZrC existed in the liquid phase, and diffraction identified the recrystallised material as ZrC. Microstructures nearest the melted surface (100-700 p,m) were homogeneous and consistent with the equilibrium phase diagram. Material at greater depth was heat-affected but contained metastable phases due to solute segregation. The shape and temperatures of phase transitions were largely insensitive to laser pulse timescale and repeated melting, supporting the attainment of local thermodynamic equilibrium. The ground state carbon-deficient ZrCx structure was simulated from first principles using the CASTEP code. Carbon vacancies induced local atomic displacements and global lattice contraction. Bulk modulus decreased and formation enthalpy became less negative with increasing vacancy concentration. Ab initio calculations were combined with a statistical mechanical representation of non-stoichiometry in ZrCx to characterise the energetic favourability of various spatial distributions of vacancies. A preference was demonstrated for non-random distribution of carbon atoms and vacancies on the carbon sublattice, characterised by vacancies taking mutual third nearest neighbour positions along < 211 > directions, avoiding first and second nearest neighbour positions, but tolerating first nearest neighbours at sufficiently high vacancy concentration.

Slip casting and ceramic injection moulding are two techniques used in industry to produce advanced ceramics, which are ceramic parts with a good net shape, high complexity and of high strength. When slip or paste formulations are made up for use in these two shape forming techniques, it is often the binder that gives the formulation the flow characteristics and strength to be shaped and removed from the mould successfully with little or no defects. Water based binders are becoming more prominent in industry in recent times than traditional oil or wax based binders. They have a number of advantages including their low toxicity, easy and quick removal and good flow properties. Latex is a relatively new water based binder which has been used in a number of ceramic shape forming techniques in industry including gel casting and tape casting. Using a novel formulation of latex as a binder, which increases in viscosity following neutralisation and heat treatment, this thesis attempts to use this binder to form advanced ceramic parts using ceramic injection moulding and slip casting. Adaptations were made to latex formulations, ceramic mix formulations, and the choice of additives, and heating sequences in order to optimise the ceramic part production. It was shown that such binders, when mixed with ceramic, are able to form ceramic parts of reasonable quality and strength using ceramic injection moulding and gel casting. It is also thought that such binders can be further adapted to suit other shape forming techniques such as tape casting.

MgO-Al2O3-SiO2 (MAS) and LiO2-Al2O3-SiO2 (LAS) glass ceramic systems is a material which is reported to have very good mechanical properties and thermal stability. These properties are suitable not only for replacing the conventional materials but also embark new fields which can satisfy the technical demands especially in aerospace applications. However, this work is primarily focusing on the fabrication of glass ceramic matrix composites. Since these glass ceramics are reported to have good thermo-mechanical properties, the study embarked upon the fundamentals of processing of MAS and LAS glass ceramic fibres, in order to open a new avenue for advanced glass fibre composites in high temperature applications. The present work aims to develop fundamental information for fabrication of MAS and LAS glass ceramic fibres and development of the glass ceramic fibre reinforced polymer (GCFRP) composite. The thesis gradually evolves in the direction of this goal by developing suitable bulk glass ceramics, glass ceramic fibres and glass ceramic fibre reinforced polymer composites. In the first part, the bulk MAS and LAS glass ceramics were prepared using melting and casting process. This was followed by controlled heat treatments at different temperatures. The crystallisation behavior of both glass ceramics showed that the temperature increase enhanced the rigidity of the glass structure, thereby superior and reliable properties such as density, nanohardness and reduced Young's modulus were successfully derived in the MAS and LAS system prepared at different annealing and subsequent heat-treatment regimes. The thermo-mechanical properties were correlated to the crystalline phases present in the system. SEM analysis showed that there was a significant variation in morphology of the crystalline phases with the changes in the heat treatment temperatures. In the second part, the mechanical properties of magnesium aluminium silicate (MAS) and lithium aluminium silicate (LAS) single fibres were investigated. The fibres were prepared using different methods namely melt drawing (MAS) and continuous drawing (LAS) respectively. The glass ceramic fibres were subjected to the optimised thermal treatments and the physical appearance observed indicated an absence of distortion before being tested using single fibre test (SFT). Relations between the properties of glass ceramic fibres and heat treatment conditions were clearly demonstrated by changes in density and Young's modulus. The latter was obtained with an acoustic approach which was successfully used in both systems. The glass and glass ceramic fibre selected were tested using the SFT and showed that different methods in fibre manufacturing process and different gauge lengths in the single fibre tests generate significantly different values in the mechanical properties of glass and glass ceramic fibres. The fibre strength distributions were strongly correlated with the diameter values of the tested fibres, and variation of the Weibull parameters depended on the gauge lengths. Moreover, scanning electron microscopy (SEM) examination of the fracture surfaces revealed the presence of fracture-inducing flaws located at the surface or in the interior of the fibre. Finally, an analysis of the fibrous glass ceramic MAS and LAS system was further developed towards the application in advanced composite materials. The manufacturing of single ply unidirectional glass ceramic fibre reinforced polymer composites was cautiously prepared at the fibre volume fraction of 30% by hand lay up technique due to the limited and fragile nature of the fibres. Both glass ceramic fibre composites were tested using dynamic mechanical thermal analysis (DMTA). The results showed distinctive differences in the storage modulus, E’ and tan δ between composites reinforced with MAS and LAS fibres. This indicates that the epoxy resin was strongly influenced by the presence of fibres of an appreciable fibres alignment. In addition, the quality of the laminate depended on the fibre volume fraction and void content. The investigation of surface fracture through fractography indicated a correlation between the properties of composites with the crystallinity of their structures. SEM photomicrographs displayed visibly good interfaces for all uncoated glass ceramic fibre systems in which MAS and LAS glass ceramic fibres were well bonded with the epoxy, compared to LAS and MAS uncoated glass fibre composites which revealed a weaker interface due to poor interfacial adhesion. Finally, their excellent dynamic thermo-mechanical properties conclude the scientific development carried out in this thesis, with the prospect of the continuing work into development of high-temperature applications in the aerospace industry.

Three kinds of oxide glasses doped with Er3+ ions were chosen for investigation. Both the properties of glass and fluorescence from rare earth dopant ions are measured and discussed. In Er3+ ion doped silicate glass, the changes in the structure of glass as a result of fluorine addition are studied by measuring the glass properties: density, molar volume, refractive index, IR and UV edges. The absorption and emission cross- sections of Er3+ ion increase with increasing value of F/O ratio as do the full width of half maximum (FWHM) and figure-of-merit (FOM) for gain and bandwidth. In Er3+ ion doped heavy metal germanate glass, the structural units of forming network in germanate glass change with the addition of PbO, Bi2C>3, Ga2C>3 and TeC>2. The molar volume, glass transition temperature Tg, IR and UV edges have been measured and discussed with the relation of glass structure. More Er3+ ion sites result in the increase of absorption and emission cross-sections, emission FWHM and FOM for gain. In Er3+ doped Te02 - ZnO - R2O (R2O = Li20, Na20 and K2O) tellurite glass system, glass properties such as density, molar volume, transition temperature Tg, IR and UV edges are measured and discussed. The glass structure has been characterised using Raman spectra. The role of F' and Cl' has also been studied in tellurite glass. Crystallisation kinetics has been analysed in tellurite glass using isothermal and non- isothermal methods. The properties of Er3+ absorption and emission have been measured and discussed with the change of glass structure and concentrations. FOM for gain and bandwidth have also been compared and discussed in Er3+ doped modifies silicate, HMO germanate, tellurite and ZBLAN fluoride glasses. The tellurite glass fibre has been made and the emission spectra of Er3+ ion in fibre have been measured. Absorption and emission spectra have been studied in Tm -doped tellurite glass, it shows to be a highly promising host for a 1.47 (im amplifier capable of providing extended short-wavelength gain and a continuous band with the tellurite EDFA. Nd3+- doped tellurite and silicate glasses have also been studied, amplifier operating around 1.34 (j.m is clearly desirable in tellurite glass. A continuous gain band extending from 1310 to 1600 nm may become possible by using Nd3+, Tm3+ and Er3+ amplifiers.

The aim of this thesis is to develop a method to produce melt-derived bioactive glass scaffolds, without the glass crystallizing into a glass-ceramic, while establishing an interconnected pore network suitable for bone tissue regeneration. In order to achieve this, the scaffold must have the ability to closely mimic the porous structure of cancellous bone and its mechanical properties. Two bioactive glasses were used in this project, both are modified from the Bioglass® composition: ICIE 16 (49.46% SiO2, 36.27% CaO, 6.6% Na2O, 6.6% K2O and 1.07% P2O5, all in mol%) and ICIE 16M (49.46% SiO2, 27.27% CaO, 6.6% Na2O, 6.6% K2O, 3% ZnO, 3% MgO, 3% SrO and 1.07% P2O5, all in mol%). Gel-cast foaming produced improved pore networks over alternative methods for producing porous scaffolds. There are many variables in the process. An initial protocol was established and each of the variables assessed systematically. The relationships between each component, the gelling time and the foam body volume were evaluated to develop an optimized protocol for the process. The size of the glass powder was critical in determining the sintering efficiency. A suitable drying and sintering program was also determined to prevent crystallization of the glass and formation of crystal species from by-products of the process. The scaffolds were characterized in terms of the interconnect size, the rate of hydroxycarbonate apatite (HCA) formation in simulated body fluid (SBF) solutions, the ion release rate and the compressive strength. The results showed that ICIE 16M sintered better and was stronger than ICIE 16, however in the bioactivity aspect of view, the rate of HCA formation in SBF was faster for ICIE 16 than ICIE 16M.

Stiff and strong ceramic fibres have been incorporated into brittle glass matrices in order to increase their mechanical strength and fracture toughness. In the present work, a novel processing technique has been investigated, in which the reinforcing fibres are “sandwiched” unidirectionally between glass slides and heat-treated for consolidation into composites by viscous flow of the glass matrix, filling the gaps between the reinforcing fibres. Highly dense and transparent composites were produced combining alumina (Nextel ™) or sapphire fibres with soda-lime silicate or borosilicate glasses. Their microstructural, optical and mechanical properties were investigated and compared to those of the unreinforced glass matrix processed under the same conditions. Moreover, a sol-gel technique was developed for coating the fibres with a ZrO2 interfacial layer. As-received and ZrO2 coated Nextel ™ and sapphire fibre-reinforced composites were produced, with fibre contents of up to 1 vol. % and total light transmittance in the range of 70 to 93 % of the matrix transmittance. Sapphire fibre-reinforced borosilicate glass composites exhibited the highest measured flexural strength (73 MPa), followed by ZrO2 coated Nextel ™ fibre-reinforced soda-lime silicate composites (0.6 vol. %), which exhibited mean flexural strength of 64 MPa. The introduction of a ZrO2 interfacial layer effectively increased the flexural strength of the composites compared to the unreinforced matrix and the as-received fibre-reinforced composites. In addition, there was evidence of fibre pullout and crack deflection upon failure during flexural and fracture toughness tests, as well as a fail-safe behaviour upon flexure, which enabled the composites to retain their integrity. A robust processing methodology was thus demonstrated of producing high quality oxide fibre-reinforced glass matrix composites, with high optical transparency and favourable fracture properties. The composites produced are promising materials for a wide range of applications, notably in the construction industry, special machinery and architecture.