<p>The introduction of metal supported cells may be a key innovation in the development of solid oxide fuel cell (SOFC) technology. The objective of this study was to develop a process of co-firing the ceramic layers of a solid oxide fuel cell attached to their porous metal support. This is a major departure from the traditional fuel cell architecture where the support layer is a ceramic composite made of YSZ and NiO.</p> <p>The problems to be eliminated during the fabrication process include the warping, cracking and delamination of the cell during the co-sintering process.</p> <p>In this study, the porous metal layer was produced by the freeze tape casting process. During co-sintering, it is necessary to match the relative shrinkage between the metal and ceramic layers. Different parameters which can influence the relative shrinkage were explored, including the heating rate, sintering temperature, sintering time, cell thickness, solid loading of the green tapes, applications of wet and dry hydrogen in the sintering atmosphere, as well as a change of the electrolyte material. Specifically, GDC was tested as an alternative electrolyte to YSZ.</p> <p>Since the porous metal substrate is exposed to air during fuel cell operation, it must be protected from oxidation. Therefore, the pack cementation method was used to apply a layer of aluminum onto the metal substrate. Variables such as temperature and exposure time of the coating materials were investigated in this thesis.</p> / Master of Applied Science (MASc)

<p>The superior high-temperature elastic-plastic properties coupled with greater damage tolerance when compared with monolithic ceramics make ceramic matrix composites, CMCs, promising candidates for challenging applications such as engine components, rocket nozzles, cutting tools and nuclear energy reactor core components. Anelastic recovery is the time-dependent back strain observed upon the load removal following creep. In whisker-reinforced CMCs this can be a factor limiting operating conditions. Plastic strain misfit between two phases is thought to be the main driver in terms of the interactions within a percolating network. However, the network deformation mechanisms are still unclear and a previous neutron diffraction study showed an unexpected decrease of peak width after creep contradicting the theoretical predictions.</p> <p>In this contribution, the finite element method (FEM) is applied to a representative volume element (RVE) with proper boundary conditions in order to simulate the creep deformation and hot pressing processes. Three geometries have been generated and studied: a 3D randomly-oriented short-fiber unit cell without fiber to fiber contact, generated by a random sequential adsorption algorithm; 3D regularly aligned single fiber unit cells; and 2D regularly aligned percolating unit cells. Deformation mechanism has been studied from an energy point of view and compared with a modified analytical model. Then a virtual diffraction model has been developed providing a framework to transfer information between the FEM simulations (strain fields) and the diffraction pattern in terms of the peak width (full width at half maximum: <strong><em>FWHM</em></strong>) and peak position as a measure of stress distribution and mean stress state respectively. Furthermore, the coupling effects of external stress, deformation mode, and thermal stress on the diffraction patterns have been studied.</p> <p>The critical importance of a percolating whisker network for the anelastic recovery is demonstrated based on the 3D multi-whisker random unit cell. Whisker bending is shown to be the dominant mechanism over contact effects during the creep deformation of a composite containing a well aligned percolating whisker network based on the 2D unit cell model. Good qualitative agreement was found between our FEM simulations and the analytical model of Wilkinson and Pompe with regards to the maximum recoverable strain and the characteristic relaxation time. The analytical model captures all the critical factors characterizing the strain recovery, e.g., the effect of creep pre-exponent constant, whisker Young’s modulus and aspect ratio. Furthermore, it is found that the deformation from an initial stress-free state inevitably introduces peak broadening of whiskers inside the matrix. Several factors determine the peak-width and -shift, i.e., creep strain, applied stress, aspect ratio and geometry. However, thermal stress from the cooling stages following creep and hot pressing processes shelters this broadening effect and complicates the trends. Wide-ranging peak-width changes from narrowing to broadening are predicted depending on the geometry and applied stress. The peak position is shifted to a lower angle due to this thermal effect. This clearly explains the contradicting phenomena motivating this work and leads to that recommendation that a diffraction source with high angular resolution is needed to detect the subtle change of peak profile during creep.</p> / Doctor of Philosophy (PhD)

Submitted in partial fulfilment of the requirements of the degree of Master of Technology: Fine Art, Department of Fine Art and Jewelry Design, Durban University of Technology, Durban. South Africa, 2015. / This dissertation documents and evaluates the subversion of traditional porcelain in the work of the selected artists from 2000-2012. The artists selected for research are Edmund de Waal (1964), Paul Scott (1953), Katharine Morling (1972), Rachel Kneebone (1973) and Clare Twomey (1968). They are British ceramists who work in porcelain in diverse ways, thus providing evidence of a wide range of the subversion of traditional porcelain. An explanation of the research methodology used is provided. The research begins by providing a history of porcelain from the earliest times to the present, documenting the shift of porcelain from the East to the West, as well as the history and properties of porcelain (white china clay). The position of porcelain in the discipline of ceramics is discussed. This includes a thorough investigation and analysis of the physical properties of porcelain and its functional application through history. The meaning of the term subversion, in the context of ceramics, is clarified and evidence of the subversion of traditional porcelain is provided through a discussion of the selected artists’ work. Conclusions are drawn and analysed. My art practice in the form of an exhibition entitled Entwined is discussed in the context of the subversion of traditional porcelain. This includes a discussion of my working method, an explanation of the body of work and an analysis of similarities and differences between my work and that of the selected artists. The dissertation concludes with a discussion of the research findings and provides suggestions for further research.

Enduring qualities of texture and colors in pottery objects have come about when naturally-occurring minerals where used.

This kyanite quartzite deposits at Leigh, Baker and Willis Mountains located in the south central Virginia Piedmont were investigated to determine their genesis, extent, and geologic and petrographic character. Kyanite quartzite in Virginia typically contains 20-40 per cent kyanite, 0-5 per cent pyrite, 0.5-1.5 per cent rutile, a per cent or so of mica or clay with the balance quartz. They occur as single beds within metamorphic rocks ranging from slates and phyllites of the greenschist facies south of Leigh Mountain, to schists and gneisses of the amphibolite facies at Baker and Willis Mountains. Post-kyanite hydrothermal alteration along fractures has altered large segments of the Baker Mountain deposit to clay and topaz. The protolith of kyanite quartzite is believed to have been extraordinarily pure mixture of quartz and kaolinite which was produced by either Iateritic weathering or by circulating meteoric waters. Isochemical regional metamorphism is believed to have occurred in a high pressure, moderate temperature environment in which water was either deficient or able to escape. Fluorine may have had a catalytic effect in promoting kyanite crystallization. No evidence was found of hydrothermal introduction of alumina, or localization of kyanite as a result of differential stress. The rocks enclosing kyanite quartzite in the Leigh Mountain area are believed to be basal members of the lower Paleozoic (?) Volcanic-Slate series. The gneisses surrounding Willis and Baker Mountains may be more highly metamorphosed, infolded remnants of the same series. The kyanite deposits of Virginia are extensive and well situated for mining. Possible reserves of kyanite quartzite containing over 25 per cent kyanite available for open pit mining are measured in tens of millions of tons.

Neste trabalho foram estudadas as propriedades dosimétricas de aluminatos de cálcio e lítio sintetizados pela técnica sol-gel e codopados/dopados com os terras-raras európio e térbio. No aluminato de cálcio as caracterizações morfológicas apresentaram fase predominante do Ca12Al14O33 com grãos variando entre 150 - 270 &#956;m, sistema poroso de 200 - 290 nm. As incorporações dos dopantes foram observadas com a formação dos compostos de CaEuAl3O7 e CaTbAl3O7 para as calcinações em 1100 °C e apresentaram os melhores resultados luminescentes. A caracterização luminescente revelou alta intensidade LOE para a amostra codopada com 0,8 mol% de Eu,Tb e baixa intensidade TL-UV que não pode ser correlacionado com a LOE na faixa de doses estudadas (irradiações-? de 0,08 - 16 Gy). Foram reportados três picos na TL-VIS, 92, 216 e 310 °C para o aluminato puro e 92, 135 e 216 °C para o codopado. Usando a técnica de LOE, a mínima dose detectável (MDD) obtida foi de 16 mGy com a amostra codopada e o menor fading foi de 5% do pico de 216 °C para TL-Vis do puro. Pelos estudos de Tm-Tstop e deconvoluções (CGCD) foi possível ajustar as curvas TL-VIS com 6 picos de cinética de ordem geral e 4 componentes CW-LOE com 2.ª ordem. Pela LM-LOE foram obtidos elevados valores de seções de choque de fotoionização, o que justificou a alta sensibilidade óptica deste material. No aluminato de lítio (calcinação a 900 °C) a caracterização morfológica revelou grãos com dispersão de 25 - 70 µm, fase predominando de &#947;- LiAlO2. Após a incorporação dos dopantes de Tb houve a formação dos compostos Al2Tb4O9 e TbAlO3 e de estruturas longitudinais de ~500 nm nas superfícies dos grãos. As amostras apresentaram um sistema luminescente altamente complexo, com sobreposição de 6 picos na TL-VIS do aluminato puro (65, 100, 140, 203, 304 e 370 °C), 7 picos na TL-VIS do dopado (70, 100, 140, 184, 211, 295 e 340 °C). A MDD obtida foi de 5 mGy pela técnica LOE e de 2,2 mGy do pico de 211 °C da TL-VIS do aluminato de lítio dopado com Tb. O menor fading obtido foi 1,5 % do pico de 140 °C do aluminato puro na TL-VIS. Pelos estudos de Tm-Tstop e CGCD, as curvas TL-VIS foram ajustadas utilizando 9 picos e as de TL-UV com 8 e 7 picos para as amostras pura e dopada, respectivamente. Neste aluminato também foram observados fenômenos inéditos de ganho de luminescência de até 2 vezes a intensidade LOE inicial oriundos das transferências energéticas mediante estimulação térmica e óptica pós irradiação. Um modelo fenomenológico de bandas simplificado utilizando duas armadilhas profundas de competição está sendo proposto neste trabalho. O aluminato de lítio dopado apresentou elevada intensidade LOE e estabilidade térmica mesmo após 300 °C de tratamento térmico, entretanto, demonstrou alta sensibilidade à exposição óptica. As curvas de LM-LOE foram ajustadas com 4 componentes de elevadas seções de choque de fotoionização o que confere com a alta sensibilidade óptica reportada. / In this work dosimetric proprieties of calcium and lithium aluminates synthetized by solgel technique and codoped/doped with rare earth europium and terbium were studied. Morphological characterization showed Ca12Al14O33 (C12A7) as a predominant phase, with grains size distribution between 150 -270 &#956;m and a porous system between 200-290 nm for the sample calcined at 1100 °C. This calcination revealed the greatest luminescence results. The dopant incorporation phases, observed by XRD patterns, matches to CaEuAl3O7 and CaTbAl3O7 compounds. Luminescence characterization showed intense OSL signal when the samples were codoped with the concentration of 0,8 mol% of Eu,Tb. However, due to low TL-UV intensity, OSL signal could not be correlated with TL-UV glow curve of this aluminate. TL-VIS detection showed peaks at, 92, 216 and 310 °C for pure calcium aluminate and at 92, 135 and 216 °C for the codoped one. The lowest minimum detectable dose (MDD) obtained was 16 mGy in OSL detection from codoped calcium aluminate and the lowest fading was 5% from aluminate for 216 °C TL peak in VIS region. By Tm-Tstop studies and CGCD deconvolution TL-VIS glow curve could be fitted using 6 peaks, with general order kinetic, and CW-OSL decay curve was fitted with 4 components of second order. LMOSL experiments resulted in high photo-ionization cross-sections, which explains the optical response of this sample. For lithium aluminate, morphological characterization showed grains size dispersion between 25- 70 &#956;m, with predominant phase of &#947;-LiAlO2 for pure sample, as well Al2Tb4O9 and TbAlO3 for Tb to doped one. Furthermore, SEM images showed long and longitudinal structures (500 nm) emerging from grain surface after Tb doping process. Luminescence characterization showed intense OSL, TL-UV and TL-VIS signals for sample doped with 0,2 mol% and calcined at 900 °C, which comprehends a complex luminescence system, with overlapping of 6 peaks in TL-VIS for pure aluminate (65, 100, 140, 203, 304 and 370 °C), 7 peaks for TL-VIS of doped one (70, 100, 140, 184, 211, 295 and 340 °C). The MDD obtained was 5 mGy for OSL and 2,2 mGy for 211 °C for TL-VIS peak, both for 0,2 mol% of Tb. The lowest fading was 1,5% for pure lithium aluminate of the 140 °C TL-VIS peak . By Tm-Tstop studies and CGCD deconvolution, TL-VIS glow curves were fitted using 9 peaks and for TLUV region, 8 and 7 peaks for pure and doped samples, respectively. Strictly, lithium aluminate revealed several energetic transfers evolving two possible depth trap explain by a simplified model of luminescence bands. The energetic transfer increments the final luminescence of the sample up to 2 times the initial OSL signal. Besides, even after 300 °C of thermal treatment, OSL signal keep its intense luminescence. However, the samples are highly sensitize by optical stimulation. In LM-OSL deconvolution, 4 components with elevated photo-ionization cross-sections were determined and fitted the experimental curve, which explains the highly optical sensitization.

O tratamento de efluentes de indústrias e efluentes domésticos é realizado em Estações de Tratamento de Esgoto as chamadas (ETE\'s), onde se tem como produtos finais, uma corrente de água tratada e um resíduo sólido, o lodo de esgoto. A presente Tese tem como objetivo o estudo do processamento térmico do lodo de esgoto seco da ETE de Barueri, São Paulo, visando avaliar seu uso como fonte de energia e obter, por queima, um material cerâmico. Este trabalho foi proposto como uma alternativa para o reuso deste material, eliminando sua disposição final no solo. Evita-se, assim, a contaminação pelos materiais contidos nas cinzas obtidas nesse processo e, conseqüentemente, a contaminação de lençóis de água subterrâneos. Foi feita a caracterização do lodo e dos principais produtos obtidos nas diversas etapas de queima do lodo, que foram estudadas principalmente por análises térmicas, complementadas por outras análises instrumentais. Os resultados indicam a possibilidade de utilizar o lodo como fonte alternativa de energia, visto ter apresentado um poder calorífico inferior da ordem de 40% do de um óleo combustível. O tratamento térmico em presença de ar, aplicado ao lodo de esgoto até a temperatura de 1050°C, elimina totalmente os componentes orgânicos presentes no lodo original. O material cerâmico final, formado do processamento térmico dos argilo-minerais originalmente presentes no lodo, apresenta os elementos traço de metais pesados fixados na matriz cerâmica sinterizada assim obtida. Ensaios de lixiviação ácida e de solubilidade em água indicam a possibilidade de uso deste material sólido final em formulações cerâmicas, sem prejuízo à saúde humana e ao meio ambiente. / The domestic and industrial wastewater goes to a treatment station. The effluent is a water with na low level of pollution. The solid waste generated is the dry sludge. This is the object of the present Dissertation. We intend to use the sludge as a source of energy and also as a raw material for the ceramic industry. The heating power of the dry sludge is close to 40% of the value reported for heating oil. Using the ashes as ceramic raw material there will no contamination of the underground water. Characterization of the sludge fired at 1050°C were performed through thermal analysis, x-ray diffraction, x-ray fluorescence and scanning electron microscopy. The leaching test of the calcinated sludge shows very low concentration of contaminants. Therefore the technique is applicable for the recycle of wastewater sludge.

A questão ambiental é um tema muito importante em nossos dias, é por isso que muitas empresas têm interesse em valorizar seus resíduos, seja para minimizar custos ou para vender um produto que pode ser usado como matéria-prima em outras indústrias. O estabelecimento de uma legislação mais rigorosa sobre o destino final dos resíduos sólidos tem sido acompanhado, de uma progressiva rejeição das disposições tradicionalmente aceitas. Por isso é necessário estudar novas alternativas para a disposição de resíduos industriais e pesquisar algumas aplicações para transformá-los em materiais com um valor agregado. Este trabalho tem como objetivo estudar a incorporação de dois resíduos em massas cerâmicas: lodo gerado no processo de tratamento de esgoto doméstico e lama vermelha (resíduo do processo Bayer de produção de alumina). Além desses resíduos foram empregadas umas argilas que são usadas na fabricação de materiais de cerâmica vermelha. Tanto os resíduos como as argilas tiveram sua composição mineralógica caracterizada por difração de raios X (DRX) e composição química por fluorescência de raios X (FRX). Esses resíduos foram misturados com argila e foram produzidas massas cerâmicas para avaliar seu desempenho nas propriedades fundamentais (resistência mecânica à flexão, densidade aparente, porosidade e absorção de água). Os corpos de prova foram conformados por prensagem uniaxial (25 MPa, 60×20×~4 mm³), e foram estudadas várias composições e duas temperaturas de queima (950°C e 1050°C), temperaturas usuais de queima em produtos de Cerâmica Vermelha. Alguns dos resultados obtidos cumprem com os parâmetros exigidos para a fabricação de diferentes tipos de produtos cerâmicos como tijolos, telhas e revestimentos cerâmicos. / Nowadays the environmental protection is an important matter. For that reason many companies are concerned about giving value to their residues, either to minimize operation costs or to sell raw material to other industries. With more restrictive legislation about wastes management, the traditional disposals are being rejected. Therefore, it is necessary to study new alternatives of final disposal and research new applications to transform industrial wastes into added-value products. This work aims to study the incorporation of two industrial wastes in ceramic materials; sewage sludge from a municipal wastewater treatment plant and red mud (a by-product of the Bayer process to produce alumina). In addition to those residues, it was used two local clays that are usually incorporated in ceramic bricks. Both residues as well as the clay were characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF). The residues and the clay were mixed, and prismatic probes were conformed to evaluate their technological properties (bending resistance, bulk density, porosity and water absorption). The ceramic probes were pressed uniaxially (25 MPa, 60×20×~4 mm³) and two temperatures (950°C and 1050°C), normally used in traditional ceramic industry, were studied. Some of the results fulfill the required parameters for the fabrication of different kinds of ceramic products as bricks, roof tiles and floor tiles.

Compósitos mesoporosos de ZrO2-CeO2 estão sendo desenvolvidos devido às suas excelentes propriedades morfológicas e estruturais, necessárias para várias aplicações, que incluem sensores de gás, catálise automotiva e ânodos de células a combustível de óxido sólido. Nesse trabalho foi desenvolvido um novo método de síntese sol-gel com template cooperativo utilizando o polímero tribloco P-123 e os cloretos de Zr/Ce como precursores dos óxidos. Foram sintetizados ZrO2-x(mol)%CeO2 com x = 50, 70 e 90% de CeO2, uma vez que esses materiais apresentam melhores características para aplicações catalíticas. Dois processos de calcinação diferentes foram testados (até 540 e 400ºC). O NiO (60% m/m) foi impregnado para que o material obtenha a condutividade eletrônica necessária para aplicação em ânodos de SOFC. Os resultados de difração de raios X indicaram sistemas cuja fase cristalográfica predominante é a cúbica tipo fluorita (a fase tetragonal é minoritária). Fase única cúbica foi obtida para 90% de CeO2 após a calcinação até 400ºC. Dentre as características morfológicas dos materiais calcinados até 540ºC, os resultados de adsorção/dessorção de N2, imagens de microscopia eletrônica e espalhamento de raios X a baixos ângulos apresentaram aglomerados cristalinos de ZrO2-CeO2, formando um sistema mesoporoso bicontínuo, aleatéorio e sem forma definida, homogêneo em composição, com área superficial intermediária (30-40 m2/g), com alta dispersividade de poros/partículas. A calcinação a 400ºC apresentou menor dispersividade, menor tamanho de poros e maior área superficial (> 100 m2/g). O recobrimento da matriz de ZrO2-CeO2 pelas nanopartículas de NiO é superficial, sem obstrução ou preenchimento dos poros. A partir da redução à temperatura programada, observou-se que independentemente do conteúdo de CeO2, a porcentagem de redução do Ce4+ foi maior e ocorreu a menores temperaturas (início da redução em 300ºC) do que o padrão de CeO2 (750ºC). Esse comportamento se repete com as amostras após a incorporação com NiO, que se reduz a Ni também em baixas temperaturas (320ºC). A atividade catalítica para conversão do CH4 em oxidação total foi similar para ambas temperaturas de calcinação, para 90% de CeO2, atingindo 50% de conversão de CH4 para ~ 540ºC. Nos experimentos de absorção de raios X in-situ, na borda K do Ni e na borda LIII do Ce, foi possível observar que todos os conteúdos de CeO2 são ativos para oxidação parcial e total de CH4, assim como decomposição do CH4 e oxidação do CO, que ocorreu em torno de 600ºC. Os resultados de espectroscopia de impedância eletroquímica mostraram que, materiais com alto conteúdo de CeO2, apresentam baixa resistividade, de 0,97 cm2 a 750ºC em atmosfera de 5% CH4/3\\%H2O/N2. Portanto, o material desenvolvido neste trabalho apresenta as melhores propriedades morfológicas, estruturais, elétricas e catalíticas relatadas na literatura para aplicações como ânodo de SOFC e catalisador, comparado a materiais similares relatados na literatura. / Mesoporous ZrO2-CeO2 composites are being developed due to their excellent morphological and structural properties, which are necessary for their use in several applications, including gas sensors, three way catalysts (TWC) and solid oxide fuel cells (SOFCs). In this work a new synthesis method was developed based on a template cooperative sol-gel approach, using the tri-block polymer P-123 and Zr/Ce chlorides as the oxides\' precursors. Since high cerium oxide quantities lead to better catalytic performance, the ZrO2-x(mol)%CeO2 were synthesized with x = 50, 70 and 90. Two different calcination processes were tested (until 540 and 400 ºC). NiO was impregnated in order to obtain enough electronic conductivity for their application as SOFC anodes. X-ray diffraction results showed that these systems are biphasic and crystallized preferentially into cubic fluorite type structure together with smaller quantities of the tetragonal zirconia-ceria phase. A 100% cubic phase was retained for 90% of CeO2 after 400 ºC calcination. Textural and morphological characteristics for 540ºC calcination evaluated from N2 sorption, electronic microscopy images and small angle X-ray scattering revealed a two-density (pores/particles) random crystalline clusters of mesoporous ZrO2-CeO2, with homogeneous composition, average superficial area (30-40 m2/g), high dispersivity of pores/particle sizes. Calcination until 400 ºC presented a narrower pore size distribution and smaller pores, with higher superficial area (> 100 m2/g). It was observed that NiO particles formed an uniform layer over the ZrO2-CeO2 without filling or blocking the zirconia-ceria pores. Temperature programmed reduction experiments showed that for all ceria contents the reduction percentage of Ce4+ species in the samples was higher and at lower temperatures (beginning of reduction at 300 ºC) than standard CeO2 (750 ºC). After NiO impregnation this behavior was similar, with NiO reducing at lower temperatures (320 ºC) as well. Catalytic activity for methane total oxidation reaction was similar for both calcination temperatures, for 90% CeO2, showing 50% of CH4 conversion around 540 ºC. Absorption X-ray in-situ experiments at Ni K-edge and Ce LIII-edge showed that all ceria contents are active for total and partial methane oxidation, CH4 decomposition and CO oxidation at 600 ºC. Electrochemical impedance spectroscopy measurements showed low resistivity for higher ceria content, 0,97 Ocm2 at 750 ºC in 5% CH4/3% H2O/N2 atmosphere. Resuming, the material developed in this work presents the best morphological, structural, electrical and catalytical properties for applications as SOFC anode and catalyst, compared to similar materials reported in the literature.

Neste trabalho foram estudadas as propriedades dosimétricas de aluminatos de cálcio e lítio sintetizados pela técnica sol-gel e codopados/dopados com os terras-raras európio e térbio. No aluminato de cálcio as caracterizações morfológicas apresentaram fase predominante do Ca12Al14O33 com grãos variando entre 150 - 270 &#956;m, sistema poroso de 200 - 290 nm. As incorporações dos dopantes foram observadas com a formação dos compostos de CaEuAl3O7 e CaTbAl3O7 para as calcinações em 1100 °C e apresentaram os melhores resultados luminescentes. A caracterização luminescente revelou alta intensidade LOE para a amostra codopada com 0,8 mol% de Eu,Tb e baixa intensidade TL-UV que não pode ser correlacionado com a LOE na faixa de doses estudadas (irradiações-? de 0,08 - 16 Gy). Foram reportados três picos na TL-VIS, 92, 216 e 310 °C para o aluminato puro e 92, 135 e 216 °C para o codopado. Usando a técnica de LOE, a mínima dose detectável (MDD) obtida foi de 16 mGy com a amostra codopada e o menor fading foi de 5% do pico de 216 °C para TL-Vis do puro. Pelos estudos de Tm-Tstop e deconvoluções (CGCD) foi possível ajustar as curvas TL-VIS com 6 picos de cinética de ordem geral e 4 componentes CW-LOE com 2.ª ordem. Pela LM-LOE foram obtidos elevados valores de seções de choque de fotoionização, o que justificou a alta sensibilidade óptica deste material. No aluminato de lítio (calcinação a 900 °C) a caracterização morfológica revelou grãos com dispersão de 25 - 70 µm, fase predominando de &#947;- LiAlO2. Após a incorporação dos dopantes de Tb houve a formação dos compostos Al2Tb4O9 e TbAlO3 e de estruturas longitudinais de ~500 nm nas superfícies dos grãos. As amostras apresentaram um sistema luminescente altamente complexo, com sobreposição de 6 picos na TL-VIS do aluminato puro (65, 100, 140, 203, 304 e 370 °C), 7 picos na TL-VIS do dopado (70, 100, 140, 184, 211, 295 e 340 °C). A MDD obtida foi de 5 mGy pela técnica LOE e de 2,2 mGy do pico de 211 °C da TL-VIS do aluminato de lítio dopado com Tb. O menor fading obtido foi 1,5 % do pico de 140 °C do aluminato puro na TL-VIS. Pelos estudos de Tm-Tstop e CGCD, as curvas TL-VIS foram ajustadas utilizando 9 picos e as de TL-UV com 8 e 7 picos para as amostras pura e dopada, respectivamente. Neste aluminato também foram observados fenômenos inéditos de ganho de luminescência de até 2 vezes a intensidade LOE inicial oriundos das transferências energéticas mediante estimulação térmica e óptica pós irradiação. Um modelo fenomenológico de bandas simplificado utilizando duas armadilhas profundas de competição está sendo proposto neste trabalho. O aluminato de lítio dopado apresentou elevada intensidade LOE e estabilidade térmica mesmo após 300 °C de tratamento térmico, entretanto, demonstrou alta sensibilidade à exposição óptica. As curvas de LM-LOE foram ajustadas com 4 componentes de elevadas seções de choque de fotoionização o que confere com a alta sensibilidade óptica reportada. / In this work dosimetric proprieties of calcium and lithium aluminates synthetized by solgel technique and codoped/doped with rare earth europium and terbium were studied. Morphological characterization showed Ca12Al14O33 (C12A7) as a predominant phase, with grains size distribution between 150 -270 &#956;m and a porous system between 200-290 nm for the sample calcined at 1100 °C. This calcination revealed the greatest luminescence results. The dopant incorporation phases, observed by XRD patterns, matches to CaEuAl3O7 and CaTbAl3O7 compounds. Luminescence characterization showed intense OSL signal when the samples were codoped with the concentration of 0,8 mol% of Eu,Tb. However, due to low TL-UV intensity, OSL signal could not be correlated with TL-UV glow curve of this aluminate. TL-VIS detection showed peaks at, 92, 216 and 310 °C for pure calcium aluminate and at 92, 135 and 216 °C for the codoped one. The lowest minimum detectable dose (MDD) obtained was 16 mGy in OSL detection from codoped calcium aluminate and the lowest fading was 5% from aluminate for 216 °C TL peak in VIS region. By Tm-Tstop studies and CGCD deconvolution TL-VIS glow curve could be fitted using 6 peaks, with general order kinetic, and CW-OSL decay curve was fitted with 4 components of second order. LMOSL experiments resulted in high photo-ionization cross-sections, which explains the optical response of this sample. For lithium aluminate, morphological characterization showed grains size dispersion between 25- 70 &#956;m, with predominant phase of &#947;-LiAlO2 for pure sample, as well Al2Tb4O9 and TbAlO3 for Tb to doped one. Furthermore, SEM images showed long and longitudinal structures (500 nm) emerging from grain surface after Tb doping process. Luminescence characterization showed intense OSL, TL-UV and TL-VIS signals for sample doped with 0,2 mol% and calcined at 900 °C, which comprehends a complex luminescence system, with overlapping of 6 peaks in TL-VIS for pure aluminate (65, 100, 140, 203, 304 and 370 °C), 7 peaks for TL-VIS of doped one (70, 100, 140, 184, 211, 295 and 340 °C). The MDD obtained was 5 mGy for OSL and 2,2 mGy for 211 °C for TL-VIS peak, both for 0,2 mol% of Tb. The lowest fading was 1,5% for pure lithium aluminate of the 140 °C TL-VIS peak . By Tm-Tstop studies and CGCD deconvolution, TL-VIS glow curves were fitted using 9 peaks and for TLUV region, 8 and 7 peaks for pure and doped samples, respectively. Strictly, lithium aluminate revealed several energetic transfers evolving two possible depth trap explain by a simplified model of luminescence bands. The energetic transfer increments the final luminescence of the sample up to 2 times the initial OSL signal. Besides, even after 300 °C of thermal treatment, OSL signal keep its intense luminescence. However, the samples are highly sensitize by optical stimulation. In LM-OSL deconvolution, 4 components with elevated photo-ionization cross-sections were determined and fitted the experimental curve, which explains the highly optical sensitization.