The home is the territory of ceramics and crafts. It is a major site for the consumption, use and display of ceramics. However, ideas about the consumption of ceramics in the home have not been fully explored within its writing or practices. This research proposes a critical and theoretical framework for ceramics which relocates it in the contemporary context of consumption, in the home and the everyday (Attfield, 2000). This work draws on recent studies of material culture and consumption (Miller, 2001) which focus on the social role of the domestic object and which explore our relationships with things. This research is practice-based where my art practice is the main research method and methodology, art practice as research. The research began with a literature and contextual review of the field of ceramics and craft writing and practice. Conclusions drawn from this research identified the over-riding research question - what differentiates art, craft and design? and formed the basis of the Practice Manifesto which identified the issues and approaches the practical research would adopt, a starting point and a guide for the studio research. The completed practical research consists of a new series of work entitled About Ceramics ... This work explores the meaning of ceramics, how ceramics are used, experienced, valued and understood. It rejects traditional concerns and approaches to the subject and instead adopts a critical, conceptual approach. The resulting artworks embrace elements from across the disciplines of art, craft and design. Although predominantly made up of industrially made objects, the work also contains a significant craft or hand-made element. As such, the work inhabits the spaces "in between" established categories and provides an alternative, hybrid model for practice. The work is made using ordinary, everyday, mass-produced objects and materials, privileging a lower class of objects and practices (such as DIY & home/ hobby crafts) previously excluded from the ceramics and craft fold. For example, Basketweave explores ideas about ceramics, DIY and home decoration and is made entirely from wallpaper (brick wall pattern). This work blurs the boundaries of art, craft and design - at what point does the decoration become the form, or the craft become art? Collection of Objects (about ceramics) explores ideas about collections and display and the status of objects. A collection of objects (which includes an enamel facsimile of an 18th century Sevres porcelain plate, a brick teapot and a wooden mug tree) are displayed on a pine kitchen dresser. The objects presented here are not valuable as craft objects or antiques, or for their aesthetic status, but because they have a relationship to, have been influenced by, or simply would not exist without ceramics. The central work in this series is What sort of mug do you take me for? It consists of a forest of over-sized mug trees (made from wood, MIDIF & pegs), each mug tree displaying a separate mug collection. This work further explores ideas about collections and collecting in the home, linking the processes collecting and display in the home with those of identity construction. Although ideas about taste and class, and about the aesthetic status of objects are central to this work, the objects employed here are not simply acting as symbols of class or as "bad" taste, they are also acting as signifiers of identity. This work demonstrates how the seemingly insignificant objects in our homes (such as a ceramic mug), and the ways we own, use and display those objects, play an important role in the construction and expression of self. This work invites its and your classification, asking What sort of mug do you take me for? In The Value of Things, Cummings and Lewandowska (2000) identify that the drive to collect is the same regardless of whether a collection is for the home or the museum. It is the hierarchies of art, craft and design which dictate the value and status of things. These hierarchies however are not in operation in the majority of homes and this makes the home an important site for understanding ceramics and for extending current concepts of art, craft and design. This research offers new perspectives and provides an alternative model for both writing and practice. It proposes a theoretical and critical framework for ceramics which relocates ideas about the subject in the context of its consumption and use in the home, linking ideas about the use and display of everyday domestic objects with the processes of identity construction.

This PhD thesis reports three novel ambient pressure drying (APD) synthesis methods for producing aerogels and characterisation of the resulting products. Motivated by overcoming the disadvantages of the conventional APD method, a novel approach, which utilises sodium bicarbonate solution instead of the organic low-surface-tension (LST) solvent (e.g. hexane, heptane, etc.) usually employed, has been successfully developed to produce silica aerogels. The novel APD method dramatically reduces costs (~70 times) in comparison with conventional approaches, and it solves the problems associated with generation of hydrochloric acid by trimethylchlorosilane. In order to fabricate nickel nanoparticle/silica (NiNP/SiO2) aerogel composites a new process was developed based on conventional APD with an organic LST solvent. A straightforward approach for dispersing the nickel nanoparticles in a silica aerogel matrix was established. The catalytic activity of the NiNP/SiO2 aerogel composites for the hydration reaction of carbon dioxide in water was then investigated. Finally, to develop the first ambient pressure dried zinc oxide aerogels, zinc-based aerogels were fabricated from zinc nitrate salt precursors by conventional APD with organic LST solvents. The microstructure of the resulting zinc-based aerogels was studied, and the macropores were found to have a flower-like multilayered nanoplate structure. After mild heat treatment, zinc oxide aerogels were generated from the zinc-based aerogels. Depending on the phase composition of the zinc-based aerogels and the different synthesis conditions, general routes for ambient pressure drying synthesis of zinc oxide aerogels are suggested. The morphologic characterisations of synthesised aerogels was performed by transmission electron microscope (TEM), scanning electron microscope (SEM), and scanning transmission electron microscope (STEM). The elemental and structural analysis of prepared aerogel materials was investigated by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD), respectively. The specific surface area and pore size are analysed by Brunauer–Emmett–Teller (BET) and Barrett-Joyner-Halenda (BJH) methods via nitrogen gas physisorption.

Nanoceramic powders were produced via a plasma processing route by QinetiQ Nanomaterials Ltd. The powders were characterised in terms of agglomerate size, morphology, phase analysis and surface chemistry. The powders were made into suspensions and the UV absorbency properties were investigated. It was found that the mixtures produced different products depending on the concentration of titania in the starting material. Powders containing less than 30% titania were solid mixtures of zinc oxide and titania; these powders absorbed UV radiation as well and in some cases better than the individual powders. The powders containing more than 30% titania were shown to have titanium ions incorporated into the zinc oxide structure. This reduced the band gap of the powder which meant that the powders did not absorb UV radiation. For all the powders that absorbed UV radiation, it was found that particles around 100 nm absorbed large amounts of UV radiation and did not interact with visible radiation, producing a clear, transparent suspension which gives ideal characteristics for a sunscreen formulation. The suspensions were found to absorb the most UV radiation above 3 wt %. The powder containing 95 % zinc oxide 5 % titania was shown to absorb more UV radiation and scatter less visible radiation than the individual powders, showing the potential to provide an improvement to the properties of sunscreen formulations.

Gas turbine manufacturers have achieved continuingly improved engine efficiency and thrust-to-weight ratio by designing with increased Turbine Entry Temperature (TET). The protection of High Pressure Turbine (HPT) aerofoils with thin insulating ceramic coatings, referred to as Thermal Barrier Coatings (TBC's), has emerged as the next key technology to allow for further increases in TET. Electron Beam Physical Vapour Deposition (EB-PVD) is today's most promising processing route for the manufacture of TBC's applied on aerofoils. The purpose of this work was to generate a sound understanding of the relationship between the EB-PVD process and the structure of Zr02- 8wt%Y2O3 ceramic deposits, which could be exploited to achieve improved TBC performance. In particular, the role of deposition temperature and the potential benefits in using RF and DC plasma assistance of the EB-PVD process were investigated, together with their influence on the erosion performance of EB-PVD TBC's. The significance of particulate erosion as a degradation mode is assessed under conditions representative of the HPT environment. New explorable routes to achieve reduced thermal conductivity of EB-PVD TBC's are identified. It is shown that EB-PVD TBC's deposited at low temperature contain a massive content of microscopic voidage (-50%) which is responsible for their lack of thermal stability. The growth of EB-PVD TBC's at elevated deposition temperatures is explained in terms of dynamic sintering, whereby diffusion processes compete against the high rate arrival of vapour atoms to overcome the spontaneous defectiveness of the atomic build up. Modelling of the gas discharge physics has highlighted scope for improving the effectiveness of plasma assistance in causing ceramic structural damage, capable of modifying the coating thermal properties. The erosion rate of EB-PVD TBC's is shown to be controlled by their degree of plastic deformation upon particle impacts, which in turn depends on the ceramic column diameter and inherent porosity.

Large scale nuclear fusion and astronomy scientific programmes have increased the demand for large freeform mirrors and lenses. Thousands of one metre class, high quality aspherical optical components are required within the next five to ten years. Current manufacturing process chains production time need to be reduced from hundred hours to ten hours. As part of a new process chain for making large optics, an efficient low damage precision grinding process has been proposed. This grinding process aims to shorten the subsequent manufacturing operations. The BoX R grinding machine, built by Cranfield University, provides a rapid and economic solution for grinding large off-axis aspherical and free-form optical components. This thesis reports the development of a precision grinding process for rapid manufacturing of large optics using this grinding mode. Grinding process targets were; form accuracy of 1 m over 1 metre, surface roughness 150 nm (Ra) and subsurface damage below 5 m. Process time target aims to remove 1 mm thickness of material over a metre in ten hours. Grinding experiments were conducted on a 5 axes Edgetek high speed grinding machine and BoX R grinding machine. The surface characteristics obtained on optical materials (ULE, SiC and Zerodur) are investigated. Grinding machine influence on surface roughness, surface profile, subsurface damage, grinding forces and grinding power are discussed. This precision grinding process was validated on large spherical parts, 400 mm ULE and SiC parts and a 1 m Zerodur hexagonal part. A process time of ten hours was achieved using maximum removal rate of 187.5 mm 3 /s on ULE and Zerodur and 112.5 mm 3 /s on SiC. The subsurface damage distribution is shown to be "process" related and "machine dynamics" related. The research proves that a stiffer grinding machine, BoX, induces low subsurface damage depth in glass and glass ceramic.

Mechanical reinforcement glass fibre has been shown to demonstrate significant loss of tensile strength following exposure to elevated temperatures; for example when heat treatment is performed, or due to thermal recycling. Numerous previous studies have confirmed this phenomenon and, while some have attempted to explain possible mechanisms of strength loss, a complete understanding has not yet been presented in the literature. In the work presented in this thesis the phenomenon of strength loss due to heat treatment was investigated using boron-free E-glass fibres, which were coated with either γ-aminopropyltriethoxysilane (γ-APS) or had no surface coating applied during manufacture (unsized/bare). Novel methods of heat treatment were developed and techniques including tensile testing and various thermal analyses were employed. The fibre surface was investigated by X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray spectroscopy (SEM-EDX). By application of a single fibre heat treatment approach it was found that the retained fibre tensile strength after conditioning can be underestimated when using the standard method of heat treating fibre bundles. Strength loss may be comprised of two components: the first component, mechanical handling damage, was carefully controlled using the single fibre heat treatment approach, but is also minimised by presence of sufficient surface γ-APS coating. The second component is the fundamental strength loss due to thermal effects, which was found to be most critical in the temperature range 450 – 600 °C.The effect of water during heat treatment of unsized fibre was studied using a Thermal Volatilisation Analyser (TVA) in which simultaneous application of vacuum and elevated temperature is possible. It was found that single fibres conditioned using TVA at 450 °C had a strength that was not significantly different from that of fibres that were conditioned similarly but in a standard air furnace. Surface chemical changes of heat treated fibres were investigated. Results of XPS analysis suggested that the surface concentration of calcium increased with increasing conditioning temperature up to 600 °C. Results obtained using Energy Dispersive X-ray spectroscopy (SEM-EDX) showed an increase in the concentration of potassium in the near surface region when fibres were heat treated in excess of 600 up to 700 °C. Significant physical changes at the fibre surface were also observed following heat treatment between 600 – 700 °C. Results of AFM analysis showed that the RMS surface roughness approximately doubled and features became visible by SEM.Across the entire temperature range 200 – 700 °C, over which both roughness and retained fibre strength were investigated, a general trend of increasing surface roughness and decreasing fibre strength was found; however, there was not a correlation between regions of most significant strength loss and large increases in roughness.

Water transport properties in cement are important for the cement industry. At the nanoscale, a nondestructive experimental method, 1 H nuclear magnetic resonance [NMR] relaxometry, can be used to quantify these properties. However, recent results have proven difficult to reconcile with current understanding of cement. The purpose of this work is to use Molecular Dynamics [MD] simulations to try and better understand water in cement and hence better interpret some of the NMR data. In particular, MD simulations are used to investigate water dynamics in two sizes of nanopores in analogues of calcium-silicate-hydrate [C-S-H], which is the active phase of cement paste. These pores are gel pores (3-5 nm) and interlayer spaces (1 nm). First, a bulk water system is studied and the water diffusion coefficient and NMR relax ation times are calculated. The results are compared to literature values and used to validate the methods. Then, different C-S-H analogues based on SiO 2] α -quartz crystal, tobermorite 11 ̊ A and modified tobermorite 14 ̊ A are presented. Two different sets of interatomic poten tials are used for these model simulations: CLAY FF+SPC/E and Freeman+TIP4P. These simulations are then compared. A model called MD4 which is based on modified tobermorite 14 ̊ A and using CLAY FF+SPC/E potentials is selected for further work. The density profile of water oxygen in MD4 is used to identify four water layers with different properties in the gel pore (L1, L2, TL and B) and one water layer in the interlayer pore (IL). Diffusivity and desorption analyses are performed on water populations related to these layers. The importance of the calcium ions close to the surface is highlighted. The NMR dipolar correlation function is generated for water using data from the MD4. This function underpins relaxation analysis. These outputs are compared to Korb’s single water layer model of surface NMR relaxation. Korb’s model is not supported by the new data. However, a new relaxation model of surface relaxation that takes into account water in two layers is supported by the data. Exchange is possible between these layers and is important for diffusivity as well as relaxation. Simulations are carried out as a function of temperature and used to calculate water trans- port activation energies in bulk and in MD4. Finally, the analysis of water exchange between the interlayer and gel pores is performed. It is shown that the exchange time in simulations is ≈69000 times smaller than measured experimentally. Some possible failings in the model that would account for this are discussed.

Major tunnelling projects in London have generated enormous amounts of excavated clay, and there will be even larger production of excavated London clay in the next few years. This research focuses on investigating the technical feasibility of processing excavated London clay into a supplementary cementitious material (SCM) suitable for the use in concrete. Excavated London clay was calcined at a range of temperatures between 600 and 1000 °C for 2 hours. The as-received and calcined London clay samples were characterized using techniques including XRF, XRD, FTIR, TGA/DTG, ICP, SEM, nitrogen adsorption, laser diffraction, isothermal conduction calorimetry and pycnometry. London clay is a complex mix of various types of clay and non-clay minerals, such as kaolinite (30.2 wt.%), illite (11.9 wt.%), montmorillonite (41.3 wt.%), chlorite, pyrite, goethite, feldspar and quartz (16.6 wt.%). Calcining excavated London clay resulted in oxidation, dehydration, dehydroxylation, amorphization and recrystallization, causing significant compositional and structural changes to clay and non-clay minerals. The degree of change depended on the calcining temperature. At 600 °C, kaolinite was entirely dehydroxylated, and the removal of octahedral hydroxyls led to a collapse of the 1:1 layered structure. As a result, metakaolin was formed. In contrast, the dehydroxylation of illite and montmorillonite started below 600 °C but finished at around 800 °C. Additionally, the two clay minerals did not suffer significant loss in crystallinity from complete dehydroxylation. The collapse of the 2:1 layered structure of illite and montmorillonite took place only when the calcining temperature was 900 °C and above. It was also observed that the recrystallization of spinel occurred above 950 °C. The assessment of pozzolanic reactivity for calcined London clays was performed using the strength activity index (SAI) test, Frattini test, portlandite consumption test and the Chapelle test. The results showed that excavated London clay can be transformed into a SCM by calcining, and the optimum calcining temperature is 900 °C. The decrease at 950 °C can be attributed to the occurrence of spinel recrystallization. London clay calcined at 900 °C was used to produce concrete at replacement levels up to 30 wt.% and three water-to-binder ratios (0.3, 0.4, 0.5). A CEM-I replacement of up to 30 wt.% showed no detrimental effect on workability or the compressive strength of concrete. In addition, the concrete with 30 wt.% of CEM-I substituted by calcined London clay and a w/b ratio of 0.3 had greater strength than control concrete after 28 days curing. At a replacement of 20 wt.% and a w/b ratio of 0.4, the concrete containing calcined London clay had similar 90-day compressive strength to those incorporating pulverised fuel ash, ground granulated blastfurnace slag and silica fume. Carbon emission estimation showed that a 30 wt.% substitution of CEM-I by calcined London clay in concrete produces 27% less CO2 emission compared to 100 wt.% CEM-I. This study has demonstrated that it is technically feasible to use calcined London clay as a supplementary cementitious material for use in concrete.

A temperature-stable, ultra-high permittivity dielectric ceramic, based on CTLNT, has been successfully fabricated at significantly reduced sintering temperatures with no deterioration of microwave properties, through the addition of a Bi_4B_2O_9 (BBO) sintering aid. This work has been an extension of previous findings where it was shown that 0.2CaTiO_3-0.8(Li_0.5Nd_0.5)TiO_3 (CTLNT) with 4wt% BBO as a liquid-phase sintering aid gives rise to exceptional microwave (MW) dielectric properties, (relative permittivity, ε_r = 127, quality factor, Qf_0 = 2700 GHz, and temperature coefficient of the resonant frequency, τ_f = +4 ppm/°C) at reduced sintering temperatures (1200°C). Prior to this, it has been exceptionally difficult to produce a large ε_r dielectric material, with both a low sintering temperature and near-zero temperature stability, without dramatic deterioration of the dielectric properties of the material. This contribution set out to investigate and understand the sintering mechanism between the CTLNT + xwt% BBO system, to aid in the development of designer sintering aids in the development of other microwave dielectric ceramic materials and devices. CTLNT + 1, 3, 4 and 5wt% BBO compositions were fabricated and a variety of analysis techniques were used, such as density, XRD, SEM, TEM, EDS and MW characterisation. Density increased with increasing BBO concentration and sintering temperature, and the MW results reflected the changes in density. The 1wt% BBO composition showed the greatest variation between the sintering temperatures, and 4wt% composition demonstrated optimum MW results of: ε_r=125, Qf_0=2518 GHz and τ_f=4 ppm/°C, at a sintering temperature of 1200°C. The variation of τ_f with changes in BBO concentration was non-linear, which suggested a chemical reaction was taking place. XRD results revealed no secondary phases, regardless of BBO concentration. SEM results showed increased crystal grain size as BBO concentration and sintering temperatures increased, as well as increased contrast variation on the polished surface and darker-contrast amorphous phase in the fracture surface. The contrast variation in the polished surfaces were also indicative of a chemical reaction. Using a combination of XRD, TEM and SEM it was demonstrated that highly polarisable Bi3+ ions entered the CTLNT perovskite lattice and locally increasing ε_r. The accompanying ex-solution of TiO2 precipitates, observed and analysed under SEM and TEM, as the BBO concentration increased implied the formation of Ti vacancies (V_Ti^'''') in the perovskite matrix to compensate for the extra positive charge of the Bi3+. The ex-solution of Ti indicates Bi3+ ions substitute onto the A-site of the perovskite crystal system for lower valence ionic elements, after the following generic defect equation: 4(A)_A^x+(Ti)_Ti^x⇒4(Bi)_A^∙+V_Ti^'''' The residual phase was found to be a boron-rich liquid-phase, which acted as the sintering aid, with a large negative τ_f which compensates for the positive τ_f of the CTLNT. The CTLST + xwt% BBO system (S = Sm) was then investigated to determine if a similar mechanism would occur. CTLST + 1, 2, 3 and 4wt% BBO compositions were fabricated and underwent the same analysis techniques. Density increased with increasing BBO concentration up to 1250°C, after which density fell for all samples; the 4wt% BBO composition exhibited the largest density, at 1250°C. The MW results reflected this trend, which saw a general increase in ε_r as BBO concentration and sintering temperature increased, which fell universally at 1300°C. 〖Qf〗_0 would generally increase with increased BBO concentration, across all sintering temperatures, while a dip was observed at 1250°C, and the 4wt% BBO composition demonstrated optimum properties of: ε_r = 105.7, Qf_0 = 3295 GHz and τ_f = -4 ppm/°C, sintered at 1200°C. Contrary to the CTLNT system, the variation of τ_f with BBO content and sintering temperature was linear. SEM reflected density changes, where crystal grain increased with increasing BBO concentration, up to 1250°C. At 1300°C, samples suffered from dissolution into the liquid-phase, increasing pore sizes, decreasing density and, thus, impacting on the MW properties of the samples. Similar to the CTLNT system, contrast variation was observed, in addition to darker B-rich liquid phase in the fracture surface. EDS from both SEM and TEM revealed that Bi was present within the CTLST matrix, however no TiO2 precipitates were observed. Large Zr contamination within CTLST is the likely cause of the difference in defect chemistry, as excess of Zr substitution onto the perovskite B-site compensates for Bi substitution onto the A-site, negating the need for TiO_2 precipitates to ex-solve. Multi-layer ceramic capacitors (MLCCs) of the CTLNT + 4wt% BBO composition were fabricated to determine whether the temperature stabilities of the material in conjunction with a large ε_r would allow the material to be a suitable candidate as a Class 1 C0G/NP0 MLCC device. Fabrication of the devices followed the conventional method, but required modification due to delamination. These modifications included: longer firing times to allow for binders and plasticisers to burn-out fully; calcined alumina powder base to fire and sinter samples upon, to avoid sticking issues; and solvent wetting of individual layers to adequately fuse layers together pre-firing and sintering. Successful MLCC devices had case sizes of EIA ‘2928’ and IEC ‘7472’. SEM and EDS revealed no mixing or exchange of materials between the dielectric and the platinum internal electrode, and generally good adhesion between both materials. Electrical tests revealed that, despite the temperature stability observed at 1-3 GHz in the MW study, that the MLCC devices would be classed as EIA “M8J” and IEC “P1000”, however maximum available test frequency of 1 MHZ is much lower than the average operating frequencies of class 1 devices, which lie between 100 MHz – 30 GHz.

The present research addresses some of the major problems pertaining to two different types of ceramic nanocomposite; viz. participate reinforced polycrystalline alumina-based nanocomposites and multiwalled carbon nanotube (MWCNT) reinforced aluminoborosilicate glass/ceramic (ABS) nanocomposites. With respect to the former, a novel and economical processing route based upon solid solution-precipitation technique is explored. Dense and homogeneous solid solutions of 10 wt.% Fe₂O₃ in Al₂O₃ were produced by pressureless sintering at 1450°C in air. Aging of the solid solutions in a reducing atmosphere at temperatures in the range 1250°C-1550°C for different durations (up to 50 h) resulted in the precipitation of FeAl₂eO₄ as second phase particles throughout the bulk of the samples. The optimum aging schedules resulted in a final microstructure comprising nanosized (~ 100 nm) intragranular FeAl₂eO₄ particles, along with coarser micro-sized particles along the matrix grain boundaries and triple point corners. The hybrid nano/micro composites possessed improved fracture toughness (by ~ 40%), flexural strength (by ~ 50%) and abrasive wear resistance (by a factor of ~ 2.5) with respect to monolithic Al₂O₃. With respect to the ABS-MWCNT nanocomposites, we report here the ability to develop dense nanocomposites, containing uniformly dispersed nanotubes up to a content of 10 wt.%, by an ultrasonication-assisted sol-gel technique followed by hot pressing. The optimised ABS-10 wt.% MWCNT nanocomposite possessed nearly double the strength, and a fracture toughness improvement of ~ 150% with respect to the unreinforced ABS. The carbon nanotubes have been observed to bridge crack openings of the order of ~ 100 nm which provides the major contribution towards the improvement in fracture toughness. The nanocomposites, showed an electrical percolation threshold of between 2.5 to 5 wt.% MWCNT and possessed significantly higher electrical conductivities (by a factor of 10⁶) with respect to the unreinforced ABS glass/ceramic. Furthermore, 40% improvement in thermal conductivity (~ 1.8 W m^-1 K¹) over that of unreinforced ABS glass/ceramic was recorded with ABS-15 wt.% MWCNT nanocomposite.