Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-10T20:12:53Z No. of bitstreams: 1 LarissaBezerraDaSilva_DISSERT.pdf: 3671939 bytes, checksum: 0ded2fa22f6e277a6bf0acd3e16b0455 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-05-12T00:26:21Z (GMT) No. of bitstreams: 1 LarissaBezerraDaSilva_DISSERT.pdf: 3671939 bytes, checksum: 0ded2fa22f6e277a6bf0acd3e16b0455 (MD5) / Made available in DSpace on 2016-05-12T00:26:21Z (GMT). No. of bitstreams: 1 LarissaBezerraDaSilva_DISSERT.pdf: 3671939 bytes, checksum: 0ded2fa22f6e277a6bf0acd3e16b0455 (MD5) Previous issue date: 2014-08-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A efetiva utiliza??o dos recursos naturais diante o acelerado crescimento econ?mico resulta no aumento cont?nuo de res?duos industriais, e para suprimir estes res?duos, um processo de reciclagem ? de prefer?ncia uma solu??o atraente. Durante a usinagem dos blocos de zirc?nia para diversos tipos de implantes odontol?gicos, grande parte do material ? desprendida na forma de p?, que posteriormente ? descartado. A zirc?nia tetragonal estabilizada com 3% em mol de ?tria (Y-TZP) possui uma variedade de aplica??es na ?rea de engenharia e biom?dica devido ? sua ?tima combina??o de resist?ncia, tenacidade ? fratura, condutividade i?nica e baixa condutividade t?rmica. Al?m do dano para o meio ambiente, o desperd?cio deste material resulta em preju?zo financeiro, refletindo em elevado custo final no tratamento para os pacientes. Os materiais de partida utilizados neste trabalho foram dois diferentes p?s do sistema cer?mico ZrO3-Y2O3: zirc?nia comercial nanoparticulada e res?duo de zirc?nia microparticulado. Os p?s foram conformados por prensagem uniaxial e isost?tica e em seguida sinterizadas a 1500, 1550 e 1600 ?C, durante 1 hora. As t?cnicas de granulometria a laser, difra??o de raios X (DRX), e dilatometria foram utilizadas para caracteriza??o do p?. Ap?s sinterizados, foram realizados ensaios de densidade e porosidade, difra??o de raios X (DRX), resist?ncia mec?nica ? flex?o, microdureza Vickers e an?lise de tenacidade ? fratura, e microscopia eletr?nica de varredura (MEV). As amostras compactadas via prensagem isost?tica apresentaram valores de porosidade inferiores a 0,78% e demostraram maior efetividade de compacta??o comparada ? via uniaxial. Foi observado nos difratogramas de raios X, com o aumento da temperatura, a intensidade dos picos da fase monocl?nica diminuiu. A temperatura de sinteriza??o influenciou de forma moderada a microdureza das amostras, demostrando pequenos acr?scimos da dureza at? a temperatura de 1600?C. A resist?ncia ? flex?o do res?duo de zirc?nia aumenta com o aumento da temperatura de sinteriza??o, para ambas as vias de compacta??o, apresentando melhores valores por via isost?tica. / The actual use of natural resources on accelerated economic growth, resulting in continuous increase of industrial waste, and to remove these residues, a recycling process is preferably na attractive solution. During the machining of blocks of zirconia to several types of dental implants, most of the material is loosened as a powder, which is subsequently discarded. The stabilized tetragonal zirconia with 3% yttria (Y-TZP) mol boasts a variety of applications in engineering, and biomedical, because of its great combination of strength, fracture toughness, ionic conductivity and low thermal conductivity. Besides the damage to the environment wasting of the material resulting in financial loss, reflecting the high final cost of medical treatment for patients. The starting materials used in this work were two different powders ZrO3-Y2O3ceramic system: commercial zirconia nanoparticulate and microparticulate zirc?nia residue. The powder was uniaxially and isostatically pressed and then sintered at 1500, 1550 and 1600 ? C for 1 hour. The techniques of laser granulometry, X-ray diffraction (XRD) and dilatometry were used for powder characterization. After sintering were performed density and porosity tests, X-ray diffraction (XRD), Flexural strength, microhardness and fracture toughness analysis, and scanning electron microscopy (SEM). Samples compacted via isostatic pressing showed values less than 0.78% porosity and demonstrated greater effectiveness compared to uniaxial compression. Was observed in X-ray diffra ction, that with increasing temperature, the intensity of the peaks of monoclinic phase is decreased. The sintering temperature moderately has influenced on the microhardness of samples, showing small increases in hardness to temperature of 1600 ? C. The flexural strength of zirconia residue increases with increasing sintering temperature for both routes of compression, showing the best values for isostatic compression.

Made available in DSpace on 2014-12-17T14:07:21Z (GMT). No. of bitstreams: 1 YankelBFS_TESE.pdf: 4090438 bytes, checksum: fb7a52b044d1b89e50309a0eea67270d (MD5) Previous issue date: 2014-03-17 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / At present, the material of choice for performing aesthetic dental prosthetic work is in the ceramic. Among them, the ceramic base of stabilized zirconia with 3% yttria (3Y - TZP) stand out for having excellent physical and mechanical properties. During the machining of blocks of zirconia in the laboratory to prepare the various types of prostheses, much of the material is given off in the form of powder, which is subsequently discarded. The waste of this material results in financial loss, reflecting higher final cost treatment for patients, as well as damage to the environment, thanks to the processes involved in the manufacture and disposal of the ceramic. This research, pioneered the recycling of zirconium oxide powder obtained during milling of dental crowns and bridges, we highlight the social and environmental aspects and aims to establish a protocol for the reuse of waste (powder of zirconia Zirkonzahn? system) discarded to obtain a new block of compacted zirconia to maintain the same mechanical and microstructural properties of commercial high-cost imported material. To compare with the commercial material, samples were uniaxially (20 MPa) and isostatically (100 MPa), and its mechanical and microstructural characterization was performed through tests of density, porosity, dilatometry, X-ray diffraction (XRD), hardness, fracture toughness, resistance to fracture electron microscopy (SEM) and analysis of grain size. The results observed in the samples were isostatically pressed similiares those obtained with samples from the commercial material demonstrating the viability of the process / Na atualidade, o material de escolha para execu??o de trabalhos prot?ticos est?ticos em odontologia ? o cer?mico. Dentre eles, as cer?micas a base de zirc?nia estabilizada com 3% de ?tria (3Y-TZP) se destacam por apresentarem excelentes propriedades f?sicas e mec?nicas. Durante a usinagem dos blocos de zirc?nia em laborat?rio para preparo dos diversos tipos de pr?tese, grande parte do material ? desprendida na forma de p?, que posteriormente ? descartado. O desperd?cio deste material resulta em preju?zo financeiro, refletindo em elevado custo final no tratamento para os pacientes, al?m de preju?zo para o meio ambiente, devido aos processos envolvidos na fabrica??o e descarte da cer?mica. Esta pesquisa, pioneira na reciclagem do p? de ?xido de zirc?nia obtido durante a fresagem de coroas e pontes dent?rias, destaca-se nos aspectos social e ambiental e tem como objetivo, estabelecer um protocolo de reaproveitamento de res?duos (p? de zirc?nia do sistema Zirkonzahn?) descartados para a obten??o de um novo bloco de zirc?nia compactado que mantenha as mesmas propriedades mec?nicas e microestruturais do material comercial importado de alto custo. Para comparar com o material comercial, as amostras foram prensadas uniaxialmente (20 MPa) e isostaticamente (100 MPa), e sua caracteriza??o mec?nica e microestrutural foi realizada atrav?s dos ensaios de densidade, porosidade aparente, dilatometria, difra??o de raios X (DRX), microdureza, tenacidade a fratura, resist?ncia a fratura, microscopia eletr?nica de varredura (MEV) e an?lise de tamanho de gr?o. Os resultados constatados nas amostras prensadas isostaticamente foram similiares ?queles obtidos com as amostras do material comercial demostrando a viabilidade do processo