Made available in DSpace on 2014-12-17T14:54:55Z (GMT). No. of bitstreams: 1 RanilsonCF_TESE.pdf: 2036029 bytes, checksum: f7ba8fa789f5420decc75fb98f14f807 (MD5) Previous issue date: 2010-07-27 / The main purpose of this work was the development of ceramic dielectric substrates of bismuth niobate (BiNbO4) doped with vanadium pentoxide (V2O5), with high permittivity, used in the construction of microstrip patch antennas with applications in wireless communications systems. The high electrical permittivity of the ceramic substrate provided a reduction of the antenna dimensions. The numerical results obtained in the simulations and the measurements performed with the microstrip patch antennas showed good agreement. These antennas can be used in wireless communication systems in various frequency bands. Results were satisfactory for antennas operating at frequencies in the S band, in the range between 2.5 GHz and 3.0 GHz. / O objetivo principal deste trabalho foi o desenvolvimento de substratos diel?tricos cer?micos de niobato de bismuto (BiNbO4) dopados com pent?xido de van?dio (V2O5), com alta permissividade el?trica, usados na constru??o de antenas patch de microfita com aplica??es em sistemas de comunica??es sem fio. A alta permissividade el?trica do substrato cer?mico proporcionou uma redu??o no tamanho das antenas. Os resultados num?ricos obtidos nas simula??es e medi??es realizadas com as antenas patch de microfita mostraram boa concord?ncia. Essas antenas podem ser usadas em sistemas de comunica??es sem fio em v?rias faixas de freq??ncias. Foram obtidos resultados satisfat?rios em antenas com freq??ncias de opera??o na banda S, na faixa compreendida entre 2,5 GHz e 3,0 GHz.

Made available in DSpace on 2014-12-17T14:54:59Z (GMT). No. of bitstreams: 1 ElderECO_TESE_Capa_ate_pag86.pdf: 3877192 bytes, checksum: d9b068e5eaa76a69d5a1fa1f245dbc5d (MD5) Previous issue date: 2011-09-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The search for ever smaller device and without loss of performance has been increasingly investigated by researchers involving applied electromagnetics. Antennas using ceramics materials with a high dielectric constant, whether acting as a substract element of patch radiating or as the radiant element are in evidence in current research, that due to the numerous advantages offered, such as: low profile, ability to reduce the its dimensions when compared to other devices, high efficiency of ratiation, suitability the microwave range and/or millimeter wave, low temperature coefficient and low cost. The reason for this high efficiency is that the dielectric losses of ceramics are very low when compared to commercially materials sold used in printed circuit boards, such as fiberglass and phenolite. These characteristics make ceramic devices suitable for operation in the microwave band. Combining the design of patch antennas and/or dielectric resonator antenna (DRA) to certain materials and the method of synthesis of these powders in the manufacture of devices, it s possible choose a material with a dielectric constant appropriate for the design of an antenna with the desired size. The main aim of this work is the design of patch antennas and DRA antennas on synthesis of ceramic powders (synthesis by combustion and polymeric precursors - Pe- chini method) nanostructured with applications in the microwave band. The conventional method of mix oxides was also used to obtain nanometric powders for the preparation of tablets and dielectric resonators. The devices manufactured and studied on high dielectric constant materials make them good candidates to have their small size compared to other devices operating at the same frequency band. The structures analyzed are excited by three different techniques: i) microstrip line, ii) aperture coupling and iii) inductive coupling. The efficiency of these techniques have been investigated experimentally and compared with simulations by Ansoft HFSS, used in the accurate analysis of the electromagnetic behavior of antennas over the finite element method (FEM). In this thesis a literature study on the theory of microstrip antennas and DRA antenna is performed. The same study is performed about the materials and methods of synthesis of ceramic powders, which are used in the manufacture of tablets and dielectric cylinders that make up the devices investigated. The dielectric media which were used to support the analysis of the DRA and/or patch antennas are analyzed using accurate simulations using the finite difference time domain (FDTD) based on the relative electrical permittivity (er) and loss tangent of these means (tand). This work also presents a study on artificial neural networks, showing the network architecture used and their characteristics, as well as the training algorithms that were used in training and modeling some parameters associated with the devices investigated / A busca por dispositivos cada vez menores e sem perda de desempenho vem sendo cada dia mais investigada pelos pesquisadores da ?rea envolvendo eletromagnetismo apli- cado. Antenas utilizando materiais cer?micos com uma alta constante diel?trica, sejam elas atuando como substrato do elemento patch radiante ou como sendo o pr?prio ele- mento radiante est?o em evid?ncia nas pesquisas atuais, isso devido ?s in?meras vantagens que apresentam, tais como: baixo perfil, capacidade de redu??o de suas dimens?es (quando comparado a outros dispositivos), alta efici?ncia de radia??o, adequabilidade a faixa de micro-ondas e/ou ondas milim?tricas, baixo coeficiente de temperatura e baixo custo. A raz?o para essa alta efici?ncia ? que as perdas diel?tricas das cer?micas s?o muito baixas, quando comparadas ?s dos materiais comercialmente usados em placas de circuito impresso, tais como: fibra de vidro e fenolite. Essas caracter?sticas tornam os dispositivos cer?micos adequados para operar na faixa de micro-ondas. Aliando o projeto de antenas patch e/ou antenas ressoadoras diel?tricas (DRA) ao uso de certos materiais e ao m?todo de s?ntese desses p?s na fabrica??o dos dispositivos, ? poss?vel escolher um material com uma determinada constante diel?trica para o projeto de uma antena com o tamanho desejado. O objetivo principal deste trabalho consiste no projeto de antenas patches e antenas DRA sob s?ntese de p?s cer?micos (s?ntese por combust?o e por precursores polim?ricos - m?todo Pechini) nanoestruturados para aplica??es na faixa de micro-ondas. O m?todo convencional de mistura de ?xidos tamb?m foi utilizado na obten??o de p?s nanom?tricos para a confec??o das pastilhas e ressoadores diel?tricos. Os dispositivos fabricados e estudados sobre materiais de alta constante diel?trica os tornam bons candidatos ? fabrica??o de dispositivos e circuitos de dimens?es reduzidas quando comparado aos outros dispositivos tradicionais operando na mesma faixa de frequ?ncia. As estruturas analisadas s?o excitadas por tr?s diferentes t?cnicas: i) linha de microfita, ii) acoplamento por abertura e iii) acoplamento indutivo. A efici?ncia dessas t?cnicas de alimenta??o s?o investigadas experimentalmente e comparada com simula??es realizadas pelo Ansoft HFSS, utilizado na an?lise precisa do comportamento eletromagn?tico das antenas atrav?s do m?todo dos elementos finitos (FEM). Nesta tese um estudo bibliogr?fico sobre teoria de antenas de microfita e antenas DRA ? realizado. O mesmo estudo ? realizado a respeito dos materiais e dos m?todos de s?ntese dos p?s cer?micos que s?o utilizados na fabri- ca??o das pastilhas e dos cil?ndros diel?tricos que compor?o os dispositivos investigados. Os meios diel?tricos os quais serviram de suporte na an?lise das antenas patch e/ou DRA s?o analisados atrav?s de simula??es precisas utilizando o m?todo das diferen?as finitas no dom?nio do tempo (FDTD) com base na permissividade el?trica relativa (er) e tangente de perda desses meios (tand). Este trabalho ainda apresenta um estudo em redes neurais artificiais, evidenciando a arquitetura de rede utilizada e suas caracter?sticas, bem como os algoritmos de treinamento que foram usados no treinamento e na modelagem de alguns par?metros associados aos dispositivos investigados

Made available in DSpace on 2014-12-17T14:57:47Z (GMT). No. of bitstreams: 1 JoaoDPV.pdf: 1303151 bytes, checksum: 407305d41d4b24852e57967eeba5cfd5 (MD5) Previous issue date: 2007-08-17 / Companies involved in kaolin mining and treatment represent an important area of industrial development in Brazil, significantly contribution to the worldwide production of such mineral. As a result, large volumes of kaolin residue are constantly generated and abandoned in the environment, negatively contributing to its preservation. In this scenario, the objective of the present study was to characterize the residue generated from kaolin mining as well as to assess its potential use as raw material for the production of ceramic tiles. Ceramic mixtures were prepared from raw materials characterized by X-ray fluorescence, X-ray diffraction, particle size analysis and thermal analysis. Three compositions were prepared using kaolin residue contents of 10%, 20% and 30%. Samples were uniaxially pressed, fired at 1200?C and characterized aiming at establishing their mineralogical composition, water absorption, apparent porosity, specific mass, linear retraction and modulus of rupture. The results showed that the residue basically consisted of kaolinite and successfully replaced raw kaolin in the preparation of ceramic title formulations without significantly affecting the properties of the fired material / As ind?strias de minera??o e beneficiamento de caulim s?o um importante segmento econ?mico do pa?s, com uma produ??o bastante significativa no cen?rio internacional. Em fun??o disso, a produ??o de res?duos ? muito grande, poluindo e agredindo o meio ambiente. Assim, esse trabalho tem por objetivo a caracteriza??o do res?duo do beneficiamento do caulim e a avalia??o de sua aplicabilidade como mat?riaprima alternativa na produ??o de cer?mica de revestimento. As mat?rias-primas utilizadas neste trabalho foram caracterizadas por t?cnicas de: fluoresc?ncia de raios X; difra??o de raios X; analise granulom?trica; an?lise termogravim?trica e an?lise termodiferencial. Foram formuladas tr? s composi??es contendo o res?duo de caulim, em propor??es de 10%, 20%, e 30%. Foram confeccionados corpos-de-prova por prensagem e suas massas foram queimadas a 1200?C e caracterizadas qu?mica e mineralogicamente com o objetivo de identificar suas composi??es, seus elementos e suas fases. Estes corpos-de-prova foram avaliados quanto ? absor??o de ?gua, porosidade aparente, massa espec?fica aparente, retra??o linear, difra??o de raios X e o m?dulo de ruptura ? flex?o. Pode-se concluir que o res?duo de caulim ? constitu?do basicamente por caulinita, e que a incorpora??o nas propor??es estudadas teve resultados altamente satisfat?rios nas formula??es, para a produ??o de cer?micas de revestimento

Made available in DSpace on 2014-12-17T14:57:49Z (GMT). No. of bitstreams: 1 JoseEVC_capa_ate_resumo.pdf: 114113 bytes, checksum: 65c5a81ce8eceb533010608034415ec0 (MD5) Previous issue date: 2009-08-10 / The production of red ceramic is an industrial activity that causes an intense impact. The manufacture of its products considerably increases the demand for natural resources, mainly with the extraction of raw material. The ceramic material produced generates waste, such as ash firewood and chamote. The residue from the beneficiation of kaolin is deposited in a poor, degrades the environment and contaminate water sources and soil, constituting in this manner, ecological disasters. The main objective of this work is to develop the formulation of a ceramic product consisting solely of industrial solid wastes, from ceramic tiles, (chamote) residue of kaolin and ash firewood. It is assumed that this product made in the laboratory can be used in coatings, wall and floor. The aim is to facilitate the replacement of the raw material of original composition of a ceramic body, for waste, while the process of production equal to the conventionally used, so that the properties of the product are reproduced. This work is characterized waste as its chemical composition, analysis of particle size, X-ray diffraction and thermal behavior. Several formulations were studied. The mass of waste was prepared by dry process, pressed to 25 MPa, and then burned in muffle type oven to 850, 950, 1050 and 1150 ?C. The results showed that it is technically possible to produce porous tiles only with waste. It was found that the formulations of bodies play a key role in the properties of the final product, as well as the sintering temperature and heating rates. RN in the waste of kaolin is estimated at 15,000 t/month, about 3,000 gray t/month and chamote with 10 million pieces/month damaged. The presence of carbonates of calcium and magnesium at 1050 ? C results in an appropriate porosity and mechanical strength. The formulation M3JE, composed of 69% waste of kaolin, 7.7% and 23.3% of chamote of gray, became suitable for porous materials with the strength and absorption within the level of national and international standards / A produ??o de cer?mica vermelha ? uma atividade industrial que provoca um intenso impacto ambiental. A confec??o de seus produtos aumenta sobremaneira a demanda por recursos naturais, principalmente com a extra??o da mat?ria prima, argila. O material cer?mico produzido gera res?duo, como o chamote e a cinza vegetal. O res?duo proveniente do beneficiamento do caulim que ? depositado de forma inadequada degrada o meio ambiente e contamina os mananciais da ?gua e do solo, constituindo dessa maneira, desastres ecol?gicos. O principal objetivo deste trabalho ? desenvolver formula??o de um produto cer?mico constitu?do exclusivamente de res?duos s?lidos industriais, oriundos de telhas cer?micas, (chamote), res?duo de caulim e cinza vegetal. Presume-se que este produto confeccionado em laborat?rio possa ser aproveitado em revestimentos de parede e piso. Pretende-se assim viabilizar a substitui??o das mat?rias-primas da composi??o original de uma massa cer?mica, por res?duos, mantendo-se o processo de produ??o igual ao convencionalmente utilizado, a fim de que as propriedades do produto sejam reproduzidas. No presente trabalho caracteriza-se os res?duos quanto a sua composi??o qu?mica, an?lise de tamanho de part?cula, difra??o de raios X e comportamento t?rmico. Diversas formula??es foram estudadas. A massa de res?duos foi preparada pelo processo via seca com corpos de provas prensados a 25 MPa, posteriormente queimados em forno mufla a 850, 950, 1050 e 1150 ?C. Os resultados obtidos evidenciaram tecnicamente que ? poss?vel se produzir placas cer?micas porosos exclusivamente com res?duos. Verificou-se que as formula??es das massas desempenham um papel fundamental nas propriedades do produto final, assim como as temperaturas de sinteriza??o e taxas de aquecimento. No RN os res?duos de caulim s?o estimados em 15000 t/m?s, a cinza com aproximadamente 3000 t/m?s e o chamote com 10 milh?es pe?as/m?s danificadas. A presen?a de carbonatos de c?lcio e magn?sio em 1050 ?C resulta em uma adequada porosidade e resist?ncia mec?nica. A formula??o M3JE, composta de 69% de res?duo de caulim, 7,7% de chamote e 23,3 % de cinza, se tornou adequado aos materiais porosos, com a resist?ncia mec?nica e absor??o dentro do patamar das normas nacionais e internacionais

Made available in DSpace on 2014-12-17T14:57:49Z (GMT). No. of bitstreams: 1 JaniaraFA.pdf: 946913 bytes, checksum: 7a2683c43f2b9a59eaca617cf3e52563 (MD5) Previous issue date: 2008-11-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The production of roof tiles in the state of Rio Grande do Norte accounts for around 60% of the total of ceramic pieces produced. There is a need for investment to improve quality and productivity, thereby promoting technological innovations. Accordingly, the aim of this study is to determine the effect of kaolin, potassium feldspar and quartz in two standard formulations, as well as the effect of sintering temperature on the technological properties of linear firing shrinkage, water absorption and bending rupture stress, by fitting the statistical model and using multiple linear regression to assess the relationship between technological properties and independent variables. The raw materials were characterized using the following techniques: X-ray fluorescence (XRF), X-ray diffraction (XRF), rational analysis (RA), differential thermal analysis (DTA) and granulometric analysis (GA). The test specimens were compacted by uniaxial pressure (25 MPa), dried in a stove at 110 ?C for 24 hours and sinterized at 850 ?C, 950 ?C and 1050 ?C and held isothermal for 30 minutes. The results obtained indicate that the addition of kaolin to two standard formulations (M and R) promoted a reduction in water absorption values and an increase in bending rupture stress values. The sintering temperatures for group M that resulted in the lowest linear firing shrinkage and water absorption values were 850 ?C and 950 ?C, respectively, and the highest bending rupture stress values were reached at a temperature of 950 ?C. In the case of group R, the sintering temperature that obtained the lowest water absorption and linear firing shrinkage values was 850 ?C, and the highest bending rupture stress values were attained at a temperature of 1050 ?C. This work explains the statistical approach used to fit the model that describes the relationship between the technological properties and percentage of kaolin, quartz and feldspar, as well as the models that enable predictions, provided that the lower and upper limits of the percentage of clay minerals, flux and quartz used in this study are respected. Statistica 6 software was used and results were obtained by stepwise forward regression / A produ??o de telha no Estado do Rio Grande do Norte representa cerca de 60 % do total de pe?as cer?micas produzidas. Percebe-se a necessidade de investimento na melhoria da qualidade e da produtividade, promovendo assim inova??es tecnol?gicas. Neste contexto, o objetivo geral deste trabalho ? verificar o efeito da adi??o de caulim, feldspato pot?ssico e quartzo em duas formula??es padr?o, assim como o efeito da temperatura de sinteriza??o nas propriedades tecnol?gicas de retra??o linear de queima, absor??o de ?gua e tens?o de ruptura ? flex?o, atrav?s do ajuste do modelo estat?stico, sendo utilizada a regress?o linear m?ltipla para avaliar a rela??o entre as propriedades tecnol?gicas e as vari?veis independentes. As mat?rias-primas foram caracterizadas atrav?s das seguintes t?cnicas: fluoresc?ncia de raios X (FRX), difra??o de raios X (DRX), an?lise racional (AR), an?lise t?rmica diferencial (DTA) e an?lise granulom?trica (AG). Os corpos-de-prova foram compactados por prensagem uniaxial (25 MPa), e na sequ?ncia secos em estufa a 110 ?C por 24 horas, em seguida sinterizados a 850 ?C, 950 ?C e 1050 ?C, com isoterma de 30 minutos. Os resultadosobtidos indicaram que a adi??o de caulim, em duas formula??es padr?o (M e R) promoveu redu??o nos valores de absor??o de ?gua e aumento nos valores de tens?o de ruptura ? flex?o. As temperaturas de sinteriza??o para o grupo M que proporcionaram os menores valores para a retra??o linear de queima e absor??o de ?gua foram 850 ?C e 950 ?C, respectivamente, e os maiores valores para a tens?o de ruptura ? flex?o foram alcan?ados na temperatura de 950 ?C. No caso do grupo R a temperatura de sinteriza??o que proporcionou os menores valores para absor??o de ?gua e retra??o linear de queima, foi a de 850 ?C, e os maiores valores para a tens?o de ruptura ? flex?o foram atingidosna temperatura de 1050 ?C. Este trabalho descreve a abordagem estat?stica para ajustar o modelo de regress?o linear m?ltipla e apresenta o ajuste do modelo que descreve a rela??o entre as propriedades tecnol?gicas e a porcentagem de caulim, quartzo e feldspato, assim como os modelos que possibilitam a realiza??o de predi??es, desde que n?o sejam ultrapassados os limites inferiores e superiores da porcentagem de argilominerais, fundente e quartzo utilizados neste trabalho. Para isto utilizou-se o software Statistica vers?o 6, obtendo resultados atrav?s da regress?o stepwise forward

Made available in DSpace on 2014-12-17T14:57:51Z (GMT). No. of bitstreams: 1 AndreaSP.pdf: 1820286 bytes, checksum: a1263199151d8fb3f317fa86bacf6014 (MD5) Previous issue date: 2006-05-19 / The State of Rio Grande do Norte, Brazil, possess major deposits of feldspar, clay, kaolin and talc, all raw materials used in the production of porcelainized stoneware tiles. Conversely, state industries manufacture only low added value red ceramics. Porcelainized stoneware tiles is one of the noblest ceramics, depicting low water absorption (typically below of 0,5%), in addition to excellent staining resistance and mechanical strength. The present work aims at investigating the potential of local raw materials for the production of porcelainized stoneware tiles. To that end, these materials were characterized by X-ray fluorescence, X-ray diffraction, particle size analysis, thermal gravimetric analysis and thermal differential analysis. Admixtures containing different compositions were prepared and fired at three temperatures, 1150, 1200 and 1250?C for 30 min. After firing, tests samples were characterized by water absorption tests, linear retraction, dilatometric analysis, apparent porosity, apparent specific mass, flexural strength, and microstructural analysis by XRD and SEM. The results revealed that ceramics with porcelainized stoneware tiles characteristics could be produced from raw materials originated in the State of Rio Grande do Norte / O Rio Grande do Norte possui grandes jazidas de pegmatitos, argilas caulin?ticas e caulim, principais mat?rias-primas para a fabrica??o de gr?s porcelanato. No entanto, o RN produz apenas produtos de baixo valor agregado em rela??o ao porcelanato, uma das mais nobres cer?micas de revestimento, devido a sua baixa absor??o d??gua (tipicamente abaixo de 0,5%), al?m de apresentar excelentes caracter?sticas t?cnicas, destacando-se elevada resist?ncia mec?nica, ao risco e ao manchamento. O presente trabalho tem a finalidade de validar o potencial de mat?rias-primas do RN (feldspato, argila, caulim e talco beneficiado) para a produ??o de gr?s porcelanato. Para isso, foi feita a caracteriza??o das mat?rias primas por FRX, DRX, AG, ATG e ATD, elaborando-se cinco formula??es que foram queimadas em tr?s temperaturas: 1150, 1200 e 1250?C com 30 minutos de patamar. Ap?s a queima, os corpos-de-prova foram submetidos a ensaios de absor??o de ?gua, retra??o linear, porosidade aparente, massa espec?fica aparente, resist?ncia ? flex?o, DRX, MEV e an?lise dilatom?trica. Obteve-se para uma das misturas, propriedades compat?veis com as exigidas para um gr?s porcelanato

Made available in DSpace on 2014-12-17T14:57:52Z (GMT). No. of bitstreams: 1 JoaoMVBSS_TESE.pdf: 1637052 bytes, checksum: 5b9631c974cd41d9288d624c302d0cfb (MD5) Previous issue date: 2011-12-21 / Metal/ceramic interfaces using zirconia have dominated the industrial applications in the last decade, due to the high mechanical strength and fracture toughness of zirconia, especially at temperatures below 300 ?C. Also noteworthy is the good ionic conductivity in high temperatures of this component. In this work joining between ZrO2 Y-TZP and ZrO2 Mg-PSZ with austenitic stainless steel was studied. These joints were brazed at high-vacuum after mechanical metallization with Ti using filler alloys composed by Ag-Cu and Ag-Cu-Ni. The influence of the metallization, and the affinity between the different groups (ceramic / filler alloys) was evaluated, in order to achieve strong metal/ceramic joints. Evaluation of joints and interfaces, also the characterization of base materials was implemented using various techniques, such as: x-ray diffraction, leak test, three-point flexural test and scanning electron microscopy with chemical analysis. The microstructural analysis revealed physical and chemical bonds in the metal/ceramic interfaces, providing superior leak proof joints and stress cracking, in order to a good joint in all brazed samples. Precipitation zones and reaction layers with eutetic characteristics were observed between the steel and the filler metal / As interfaces metal/cer?micas utilizando zirc?nia t?m dominado as aplica??es industriais na ?ltima d?cada, em virtude da alta resist?ncia mec?nica e tenacidade ? fratura da zirc?nia, especialmente em temperaturas abaixo de 300 ?C. Destaca-se tamb?m a boa condutividade i?nica em temperaturas elevadas deste componente. No presente trabalho, estudou-se as uni?es entre ZrO2 Y-TZP e ZrO2 Mg-PSZ com o a?o inox austen?tico 304. Estas jun??es foram produzidas por brasagem a alto-v?cuo ap?s a metaliza??o mec?nica com Ti utilizandose ligas de adi??o compostas por Ag-Cu e Ag-Cu-Ni. Avaliou-se a influ?ncia da metaliza??o, bem como a afinidade entre os diversos grupos (cer?mica / liga de adi??o) com o intuito de se conseguir a melhor uni?o metal/cer?mica. A avalia??o das uni?es e interfaces, bem como a caracteriza??o dos materiais de base foi feita com recurso de diversas t?cnicas, tais como: difra??o de raios-x, ensaios de estanqueidade, flex?o em 3- pontos e microscopia eletr?nica de varredura com microan?lise por espectroscopia de energia dispersiva de raios-x. A an?lise microestrutural revelou liga??es f?sicas e qu?micas na interface metal/cer?mica, proporcionando boa estanqueidade e tens?o de ruptura e, consequentemente, uma boa uni?o em todas as amostras brasadas. Foram observadas zonas de precipita??o e camadas de rea??o com caracter?sticas eut?ticas entre o a?o e o metal de adi??o

Made available in DSpace on 2014-12-17T14:57:53Z (GMT). No. of bitstreams: 1 JorgeFB.pdf: 2466045 bytes, checksum: 390a8dfd299d465779890586b1bd5be1 (MD5) Previous issue date: 2009-10-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The State Bahia, Brazil, presents different geological sites it with a very expressive variety minerals. It is situated among the very important States which produces minerals for industries, such as pointed aggregate, ornamentals stones and ceramics raw materials. Nowadays only four companies producting ceramics tiles. Porcelainized stoneware tiles is one of the noblest ceramics, depicting low water absorption (typically below of 0,5%), in addition to excellent staining resistance and mechanical strength. The present work aims at investigating the potential of local raw materials for the production of porcelainized stoneware tiles. For this purpose, these materials were characterized by X-ray fluorescence, X-ray diffraction, particle size analysis, thermal gravimetric analysis, thermal differential analysis and dilatometric analysis. Admixtures containing different compositions were prepared and fired at four temperatures, 1100 ?C, 1150 ?C, 1200 ?C and 1250 ?C with isotherm for 60 minute and heathing rate of 5 oC/min. After firing the samples, they were characterized by water absorption tests, linear retraction, analysis, apparent porosity, apparent specific mass, flexural strength, and microstructural analysis by X-ray diffraction and scanning electron microscopy . The results revealed three ceramics with porcelainized stoneware tiles characteristics and porcelain tile will be produce from raw materials originated in the State of Bahia / O Estado da Bahia apresenta uma diversidade de terrenos geol?gicos que encerra uma expressiva dota??o mineral e est? situado entre os mais importantes Estados produtores de minerais industriais, ressaltando-se agregados, rochas ornamentais e mat?rias-primas cer?micas. Atualmente somente quatro empresas produzem placas cer?micas. O gr?s porcelanato ? uma das mais nobres cer?micas de revestimento devido a sua baixa absor??o d ?gua (tipicamente abaixo de 0,5%), al?m de apresentar excelentes caracter?sticas t?cnicas, destacando-se pelas elevadas resist?ncias mec?nica, ao risco e ao manchamento. O presente trabalho tem a finalidade de avaliar o potencial das mat?rias-primas, feldspato, argila e caulim, utilizado na produ??o de gr?s porcelanato no estado da Bahia. Para isso, foi feita a caracteriza??o das mat?rias-primas por fluoresc?ncia de raios X (FRX), difra??o de raios X (DRX), an?lise granulom?trica (AG), an?lise t?rmica gravim?trica (TG), an?lise t?rmica diferencial (DTA) e an?lise dilatom?trica, elaborando-se sete formula??es que foram queimadas nas temperaturas: 1100 ?C, 1150 ?C, 1200 ?C e 1250 ?C, com isoterma de 60 minutos e taxa de aquecimento de 5 oC/ min. Ap?s a queima, os corpos-de-prova foram submetidos a ensaios de absor??o de ?gua, retra??o linear, an?lise dilatom?trica, porosidade aparente, massa espec?fica aparente, resist?ncia ? flex?o, difra??o de raios X e microscopia eletr?nica de varredura. Em tr?s formula??es foram obtidas, propriedades compat?veis com as exigidas para a produ??o do gr?s porcelanato com mat?rias-primas oriundas do Estado da Bahia

Made available in DSpace on 2014-12-17T14:57:56Z (GMT). No. of bitstreams: 1 RonaldoFC_DISSERT.pdf: 4616662 bytes, checksum: 0873d4d0b759a28864c474fb890be216 (MD5) Previous issue date: 2010-03-09 / Universidade Federal do Rio Grande do Norte / Companies involved in emerald mining and treatment represent an important area of industrial development in Brazil, with significative contribution to the worldwide production of such mineral. As a result, large volumes of emerald waste are constantly generated and abandoned in the environment, negatively contributing to its preservation. By the other side the interest of the use of mining waste as additive in ceramic products has been growing from researchers in recent years. The ceramic industry is constantly seeking to the marked amplification for the sector and perfecting the quality of the products and to increase the variety of applications. The technology of obtaining of ceramic tiles that uses mining residues assists market niches little explored. In this scenario, the objective of the present study was to characterize the residue generated from emerald mining as well as to assess its potential use as raw material for the production of ceramic tiles. Ceramic mixtures were prepared from raw materials characterized by X-ray fluorescence, X-ray diffraction, particle size analysis and thermal analysis. Five compositions were prepared using emerald residue contents of 0%, 10%, 20%, 30% and 40%. Samples were uniaxially pressed, fired at 1000, 1100 and 1200?C and characterized aiming at establishing their mineralogical composition, water absorption, apparent porosity, specific mass, linear retraction and modulus of rupture. The results shows that the emerald residue, basically consisted of 73% of (SiO2 + Al2O3) and 17,77% of (MgO + Na2O+ K2O) (that facilitates sintering), can be added to the ceramic tile materials with no detrimental effect on the properties of the sintered products / Empresas envolvidas na minera??o de esmeralda e beneficiamento representam uma importante ?rea de desenvolvimento industrial no Brasil, com significativa contribui??o para a produ??o mundial desse min?rio. Como resultado, grandes volumes de res?duos de esmeralda s?o constantemente gerados e abandonados no ambiente, contribuindo negativamente para a sua preserva??o. Por outro lado o interesse no uso do res?duo de minera??o como aditivo na produ??o de material cer?mico tem crescido entre os pesquisadores nos ?ltimos anos. A ind?stria cer?mica est? constantemente buscando a amplia??o do mercado para o setor e tentando aperfei?oar a qualidade dos produtos e aumentar a variedade de aplica??es. A tecnologia de obten??o de cer?mica de revestimento que usa res?duos de minera??o ? um mercado ainda pouco explorado. Neste cen?rio, o objetivo do presente estudo foi caracterizar o res?duo gerado a partir de minera??o de esmeralda, bem como para avaliar seu potencial uso como mat?ria-prima para a produ??o de revestimentos cer?micos. Misturas cer?micas foram preparadas a partir de mat?rias-primas caracterizadas por fluoresc?ncia de raios X, difra??o de raios X, an?lise granulom?trica e an?lise t?rmica. Cinco composi??es foram preparadas utilizando ?ndices de res?duos de esmeraldas de 0%, 10%, 20%, 30% e 40%. As amostras foram prensadas uniaxialmente, sinterizadas em 1000, 1100 e 1200 ? C e caracterizadas visando estabelecer sua composi??o mineral?gica, absor??o de ?gua, porosidade aparente, massa espec?fica, retra??o linear e m?dulo de ruptura. Os resultados mostraram que o res?duo de esmeraldas composto basicamente de 73% de (SiO2 + Al2O3) e 17,77% de (MgO+Na2O+K2O) (que facilitam a sinteriza??o) pode ser incorporado na massa de revestimento cer?mico sem comprometimento das propriedades do produto sinterizado

Made available in DSpace on 2014-12-17T14:57:59Z (GMT). No. of bitstreams: 1 AldemiroJRP_DISSERT.pdf: 1779400 bytes, checksum: 8a5467983a7427bc6b96f7baa7868609 (MD5) Previous issue date: 2010-01-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work presents research into the addition of chamotte obtained from the ceramic isolator of unusable spark plugs in formulations of material mixes for standard white ceramic material with aluminum oxide bases. After the physical chemical characterization of the primary materials, standard clay and the chamotte, three mixtures were prepared with concentrations of 10, 20 and 30% chamotte by weight in relation to the standard clay. The test samples underwent heating at a rate of 30 0C/min to levels that included 100o , 200o , 300o, 400o, 500o e 600 0C and also we submitted to three distinct burn temperatures: 1450o, 1500o e 1550 0C, remaining at these temperatures for 2 hour periods. After sintering, the physical and microstructural properties of the different test samples were measured and analyzed. The results show that the materials obtained present good technical properties and that the chamotte can be reutilized as an additive in the production of white ceramic material with an aluminum oxide base / Neste trabalho estudou-se a influ?ncia da adi??o de chamote obtido do isolador cer?mico de velas de igni??o inserv?veis na formula??o de massas de cer?mica branca a base de alumina. Ap?s caracteriza??o f?sico-qu?mica das mat?rias-primas, argila-padr?o e chamote, foram preparadas tr?s formula??es de concentra??es 10, 20 e 30% em peso de chamote em rela??o ? argila-padr?o. Os corpos-de-prova foram submetidos ao aquecimento numa taxa de 30 0C/min em patamares de 100? , 200? , 300? , 400? , 500? e 600 0C e queimados em tr?s temperaturas distintas a 1450? , 1500? e 1550 0C, permanecendo 2 horas na temperatura de patamar. Ap?s as sinteriza??es, as propriedades f?sicas e a evolu??o microestrutural de fases dos corpos-de-prova foram mensuradas e discutidas. Os resultados mostraram que os materiais obtidos apresentam boas propriedades e que o chamote pode ser reaproveitado como aditivo na produ??o de cer?micas brancas a base de alumina