In this thesis, a systematic study has been carried out on the synthesis, characterization and applications of microcrystalline diamond (MCD) and nanocrystalline diamond (NCD) thin films deposited by the chemical vapor deposition (CVD) method. Firstly, an overview of diamond films synthesized from carbon-containing gas plasmas is presented. A parameter study was performed to grow diamond thin films. The transition from micro- to nanocrystallinity of diamond grains was achieved by controlling the Ar/Hydrogen gas ratio. The nanocrystallinity is the result of a new growth mechanism which involves the insertion of carbon dimmer into carbon-carbon and carbon-hydrogen bonds. Secondly, characterization of diamond films has been carried out by different techniques including electron microscopy, near edge X-ray absorption fine structure (NEXAFS), nanoindentation, and Raman spectroscopy. Unique properties of NCD, compared to those of MCD grown by conventional hydrogen rich plasma, have been observed and investigated. Thirdly, various applications of diamond films are discussed: a). Well-adhered MCD coatings have been deposited on WC-Co substrates with proper surface pretreatment. A diffusion barrier Cr/CrN/Cr was deposited on the cemented carbide substrate and the substrate was short peened with 150 micron friable diamond powders to achieve higher nucleation density and stronger adhesion strength; b). A nitrogen doped NCD based biosensor was fabricated for glucose sensing. Carboxyl functional group and conducting polymer (polyaniline) have been utilized respectively to electrochemically functionalize the diamond surface. A linear response to glucose concentration has been obtained from the electrode with good sensitivity and stability; c). A novel approach to synthesize NCD wires has been developed for the first time. The NCD coating was successfully coated on Si nanowires (SiNWs) to form NCD wire with diameter around a few microns. This study opens a whole new area for applications based on diamond wires such as neural transmission electrodes, field emission emitters, and electrochemical electrodes with improved properties

No description available.

Objectives: The aim of this study was to determine the prevalence of MetS among different African populations using the new Joint Statement Criteria. Hereafter we aimed to determine whether waist or neck circumference is the best predictor of MetS risk after ethnic, gender and age-specific cut-points were developed. Lastly, we aimed to determine whether afore-mentioned cut-point can predict albumin:creatinine ratio as a marker of target organ damage. Methods: The study sample (N=409) comprised of urban African (men, N=101; women, N=99) and Caucasian (men, N=101; women, N=108) teachers from the Dr. Kenneth Kaunda Education district in the North-West Province, South Africa. Participants were aged between 25 and 65 years. Anthropometric measurements, albumin:creatinine ratio and other markers of the metabolic syndrome (MetS) (systolic and diastolic blood pressure [SBP and DBP], glucose, triglycerides [TG] and high density lipoprotein [HDL]) were determined. Results: Africans (65 and 63 % for men and women) and Caucasian men (73%) showed high prevalence of MetS; ROC analysis determined neck circumference (NC) cut-points of 39 and 35 cm for young and older African men, 32 and 35 cm for young and older African women, 40 and 41 cm for Caucasian men and 34 and 33 cm for Caucasian women. This NC cut-point can be used to determine metabolic syndrome risk in all groups, except in African women; ROC developed waist circumference (WC) cut-points were 91 cm for all African male groups, 84, 81 and 84 cm for young, older and total group of African women. Suggested WC cut-points for Caucasian men were 93 cm for the young group and 97 cm for older as well as total Caucasian male groups, while cut-points for Caucasian women were 87 cm, 79 cm and 84 cm for young, older and total Caucasian women. These WC cut-points were good measures of metabolic syndrome risk in all groups; neither cut-point of WC nor NC could increase the risk of albumin:creatinine ratio. Conclusion: African women as a group present with few MetS risk factors and glucose is associated with renal function risk in Africans; NC cut-points may be used as an additional anthropometric marker to predict the metabolic syndrome in a South African cohort, but not in African women; WC cutpoints demonstrated to be good predictors of the metabolic syndrome in the same South African cohort, especially among men; WC would seem to be the best measure of MetS risk in all African populations, although NC can also be used for this purpose in all African populations, except in African women. / Thesis (PhD (Human Movement Science))--North-West University, Potchefstroom Campus, 2012

O metal duro é um material compósito utilizado em diversas áreas de usinagem, mineração e construção civil, podendo ser aplicado diretamente em componentes de equipamentos de perfuração de petróleo e gás. O presente trabalho teve como objetivo principal a aplicação da técnica de moagem de alta energia visando produzir o compósito WC-Ni e estudar os efeitos do tempo de moagem nas propriedades do material. A moagem do metal duro WC-20Ni, partindo dos pós de WC e Ni, foi realizada para tempos de moagem de 1, 2, 4, 8, 16, 32 e 64 horas. Os pós de partida foram caracterizados por granulometria à laser, MEV e EDS. Nas amostras sinterizadas foi realizada análise microestrutural por microscopia ótica, medição de microdureza e medida de densidade pelo método de Arquimedes. Os melhores resultados para o compósito WC-20%Ni, foram conseguidos para o tempo de 8 horas de moagem, onde a densificação e dureza alcançaram após a sinterização 97,09% e 1058 ± 54 HV respectivamente. Tempos de moagem maiores que 8 horas foram prejudiciais nas propriedades do material. / The hard metal is a composite material used in several areas of machining, mining and construction, it can be applied directly in components of the drilling equipment for oil and gas. This work had as main objective the application of high energy milling technique to produce the composite WC-Ni and studying the effects of time milling in the material properties. The milling of hard metal WC-20Ni, from the WC and Ni powders, was performed for milling times of 1, 2, 4, 8, 16, 32 and 64 hours. The starting powders were characterized by laser granulometry, SEM and EDS. Microstrutural analysis of the sintered samples was performed by optical microscopy, microhardness and density by Archimedes. The best results for the composite WC-20%Ni, was achieved for 8 hours milling, where the density and hardness reached after sintering 97.09% and 1058 ± 54 HV respectively. Longer times of milling, after 8 hours milling, provided a detrimental effect on the properties of the material.

O presente trabalho tem como objetivo o estudo das propriedades mecânicas do metal duro nas composições WC-6Co, WC-10Co, WC-20Co, WC-6Co-6Ni, WC-6Co-12Ni, obtidos por metalurgia do pó convencional para aplicação em anéis de selos mecânicos. Estes compósitos foram obtidos a partir de uma composição comercial de WC-6Co, e adicionado cobalto e níquel para realização do balanço de massa. Determinou-se um procedimento de obtenção das composições, através de cálculos de balanceamento adicionando-se a quantidade de cobalto e níquel necessária para transformar um compósito comercial 94WC-6Co nos metais duros mencionados. Após este procedimento adicionou-se 1,5% de lubrificante, em um misturador em “Y”. Analisou-se no Microscópio eletrônico de varredura a homogeneidade das composições. Determinou-se a densidade aparente, a curva de compressibilidade e compactaram-se as amostras de metal duro obtendo-se as densidades a verde. Realizou-se a pré-sinterização e determinaram-se as densidades das peças présinterizadas, executou-se ensaio de compressão e obtiveram-se parâmetros de usinagem na operação de faceamento e furação dos corpos de prova pré-sinterizados. A sinterização foi realizada em diversas vezes, nos dois fornos resistivos e em três atmosferas de controle diferentes. Determinaram-se curvas rápidas de sinterização e utilizou as temperaturas de 1360, 1400, 1420, e 1450ºC para as várias composições de metal duro. Para analisar-se a eficiência da mistura foi realizado ensaio de densidade das amostras sinterizadas, dureza, microdureza, metalografia, micrografia, EDS, contração linear e contração volumétrica e compressão. Após a caracterização dos materiais foi projetado e fabricado um ferramental de compactação. Compactou-se, sinterizou-se e retificou-se um anel de selo mecânico. / The aim of this work is to characterize to study the mechanical properties of carbide in the composition WC-6Co, WC-10Co, WC-20Co, WC-6Co-6Ni, WC-6Co-12Ni obtained by conventional powder metallurgy for application to rings of mechanical seals. These composites were obtained from a commercial composition of WC-6Co, and added cobalt and nickel to perform the mass balance. It was determined a procedure for obtaining the compositions, by calculation of balancing resulting in the amount of cobalt and nickel needed to transform a composite commercial 94WC-6Co in hard metals mentioned. After this procedure was added to 1.5% of lubricant, in a blender "Y". Analyzed in a scanning electron microscope the homogeneity of the compositions. It was determined the density, the compressibility curve and compress the samples carbide yielding green densities. We calculated the pre-sintering and determined the densities of pre-sintered parts, performed in compression test and it was obtained machining parameters in milling operation and drilling of the specimens pre-sintered. The sintering was performed at various times in the two resistive furnaces and atmospheres in three different control. Were determined fast corners and used sintering temperatures of 1360, 1400, 1420, and 1450 º C for various compositions of carbide. To analyze the efficiency of mixing was performed to test the samples sintered density, hardness, hardness, metallography, electron micrograph, EDS, linear and volumetric shrinkage and compression. After the characterization of materials was designed and manufactured tools of compaction, compacted, sintered and ground a ring of mechanical seal.

O metal duro é um material compósito utilizado em diversas áreas de usinagem, mineração e construção civil, podendo ser aplicado diretamente em componentes de equipamentos de perfuração de petróleo e gás. O presente trabalho teve como objetivo principal a aplicação da técnica de moagem de alta energia visando produzir o compósito WC-Ni e estudar os efeitos do tempo de moagem nas propriedades do material. A moagem do metal duro WC-20Ni, partindo dos pós de WC e Ni, foi realizada para tempos de moagem de 1, 2, 4, 8, 16, 32 e 64 horas. Os pós de partida foram caracterizados por granulometria à laser, MEV e EDS. Nas amostras sinterizadas foi realizada análise microestrutural por microscopia ótica, medição de microdureza e medida de densidade pelo método de Arquimedes. Os melhores resultados para o compósito WC-20%Ni, foram conseguidos para o tempo de 8 horas de moagem, onde a densificação e dureza alcançaram após a sinterização 97,09% e 1058 ± 54 HV respectivamente. Tempos de moagem maiores que 8 horas foram prejudiciais nas propriedades do material. / The hard metal is a composite material used in several areas of machining, mining and construction, it can be applied directly in components of the drilling equipment for oil and gas. This work had as main objective the application of high energy milling technique to produce the composite WC-Ni and studying the effects of time milling in the material properties. The milling of hard metal WC-20Ni, from the WC and Ni powders, was performed for milling times of 1, 2, 4, 8, 16, 32 and 64 hours. The starting powders were characterized by laser granulometry, SEM and EDS. Microstrutural analysis of the sintered samples was performed by optical microscopy, microhardness and density by Archimedes. The best results for the composite WC-20%Ni, was achieved for 8 hours milling, where the density and hardness reached after sintering 97.09% and 1058 ± 54 HV respectively. Longer times of milling, after 8 hours milling, provided a detrimental effect on the properties of the material.

O presente trabalho tem como objetivo o estudo das propriedades mecânicas do metal duro nas composições WC-6Co, WC-10Co, WC-20Co, WC-6Co-6Ni, WC-6Co-12Ni, obtidos por metalurgia do pó convencional para aplicação em anéis de selos mecânicos. Estes compósitos foram obtidos a partir de uma composição comercial de WC-6Co, e adicionado cobalto e níquel para realização do balanço de massa. Determinou-se um procedimento de obtenção das composições, através de cálculos de balanceamento adicionando-se a quantidade de cobalto e níquel necessária para transformar um compósito comercial 94WC-6Co nos metais duros mencionados. Após este procedimento adicionou-se 1,5% de lubrificante, em um misturador em “Y”. Analisou-se no Microscópio eletrônico de varredura a homogeneidade das composições. Determinou-se a densidade aparente, a curva de compressibilidade e compactaram-se as amostras de metal duro obtendo-se as densidades a verde. Realizou-se a pré-sinterização e determinaram-se as densidades das peças présinterizadas, executou-se ensaio de compressão e obtiveram-se parâmetros de usinagem na operação de faceamento e furação dos corpos de prova pré-sinterizados. A sinterização foi realizada em diversas vezes, nos dois fornos resistivos e em três atmosferas de controle diferentes. Determinaram-se curvas rápidas de sinterização e utilizou as temperaturas de 1360, 1400, 1420, e 1450ºC para as várias composições de metal duro. Para analisar-se a eficiência da mistura foi realizado ensaio de densidade das amostras sinterizadas, dureza, microdureza, metalografia, micrografia, EDS, contração linear e contração volumétrica e compressão. Após a caracterização dos materiais foi projetado e fabricado um ferramental de compactação. Compactou-se, sinterizou-se e retificou-se um anel de selo mecânico. / The aim of this work is to characterize to study the mechanical properties of carbide in the composition WC-6Co, WC-10Co, WC-20Co, WC-6Co-6Ni, WC-6Co-12Ni obtained by conventional powder metallurgy for application to rings of mechanical seals. These composites were obtained from a commercial composition of WC-6Co, and added cobalt and nickel to perform the mass balance. It was determined a procedure for obtaining the compositions, by calculation of balancing resulting in the amount of cobalt and nickel needed to transform a composite commercial 94WC-6Co in hard metals mentioned. After this procedure was added to 1.5% of lubricant, in a blender "Y". Analyzed in a scanning electron microscope the homogeneity of the compositions. It was determined the density, the compressibility curve and compress the samples carbide yielding green densities. We calculated the pre-sintering and determined the densities of pre-sintered parts, performed in compression test and it was obtained machining parameters in milling operation and drilling of the specimens pre-sintered. The sintering was performed at various times in the two resistive furnaces and atmospheres in three different control. Were determined fast corners and used sintering temperatures of 1360, 1400, 1420, and 1450 º C for various compositions of carbide. To analyze the efficiency of mixing was performed to test the samples sintered density, hardness, hardness, metallography, electron micrograph, EDS, linear and volumetric shrinkage and compression. After the characterization of materials was designed and manufactured tools of compaction, compacted, sintered and ground a ring of mechanical seal.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-12T13:28:19Z No. of bitstreams: 1 RenanSavioDeAlmeidaCoelho_DISSERT.pdf: 6989070 bytes, checksum: 02ffff122848bc43e7d1a9ef1bef5171 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-14T19:12:58Z (GMT) No. of bitstreams: 1 RenanSavioDeAlmeidaCoelho_DISSERT.pdf: 6989070 bytes, checksum: 02ffff122848bc43e7d1a9ef1bef5171 (MD5) / Made available in DSpace on 2018-03-14T19:12:58Z (GMT). No. of bitstreams: 1 RenanSavioDeAlmeidaCoelho_DISSERT.pdf: 6989070 bytes, checksum: 02ffff122848bc43e7d1a9ef1bef5171 (MD5) Previous issue date: 2017-07-28 / As propriedades ?nicas do comp?sito de matriz met?lica de cobre (Cu) refor?ada por dispers?o de part?culas de carboneto de tungst?nio (WC) s?o de grande import?ncia para v?rias aplica??es industriais, devido a sua excelente resist?ncia sob alta temperatura, boa resist?ncia ? corros?o e ? fratura. O comp?sito Cu-WC ? quimicamente e termicamente est?vel, al?m de possuir excelentes propriedades de condutividade t?rmica e el?trica. Tais caracter?sticas o tornam um promissor material para fabrica??o de contato el?trico de alta pot?ncia, eletrodos para soldagem, condutores de campo magn?tico pulsado, dispositivos de gerenciamento t?rmico e el?trico. Este trabalho investiga o efeito da moagem de alta energia na densifica??o e microestrutura dos comp?sitos WC-20%Cu e WC-18%Cu-2%Nb, bem como a influ?ncia da adi??o do ni?bio como inibidor de crescimento de gr?o. O efeito da press?o de compacta??o e da temperatura de sinteriza??o dos p?s preparados por moagem e mistura mec?nica na densidade tamb?m foram estudados. P?s de WC, Cu e Nb, na raz?o de 80, 20 e 2 por cento em massa, respectivamente, foram preparados por moagem e, tamb?m, por mistura mec?nica. A moagem dos p?s comp?sitos foi realizada a seco sob atmosfera ambiente com um recipiente e bolas de metal duro em um moinho attritor. Os p?s foram mo?dos a 900 rpm durante 90 minutos e sob uma raz?o de massa p? para bolas de 1:100. Compactos de p?s com forma cil?ndricas foram prensados a 200, 400 e 600 MPa em uma matriz de a?o uniaxial de 8 mm de di?metro. Os corpos verdes foram sinterizados nas temperaturas de 1030 ?C e 1150 ?C por 60 min. em forno tubular resistivo sob atmosfera de nitrog?nio. A microestrutura dos corpos sinterizados foi analisada por microscopia eletr?nica de varredura. Para analisar a presen?a de impurezas nos p?s elementares e mo?dos, an?lises qu?micas de FRX e EDS foram realizadas. A an?lise de DRX foi usada para detectar as fases presentes. Uma significativa diminui??o dos cristalinos e amorfiza??o das fases Cu e WC foi exibida pelos p?s mo?dos. Assim como, um menor tamanho de gr?o foi alcan?ado pelas microestruturas sinterizadas dos p?s comp?sitos Cu-WC com adi??o de Nb. Os compactos de p?s submetidos a maior press?o de compacta??o e temperatura de sinteriza??o tamb?m alcan?aram as maiores densifica??es. / The unique properties of copper metal matrix composite reinforced by dispersion tungsten carbide particles (WC) are of great importance for several industrial applications, due to their excellent high temperature strength and good corrosion and fracture resistance. This composite is chemically and thermally very stable at high temperatures, as well as having excellent thermal and electrical conductivity properties. These promising features make for the manufacture of high-power electrical contact parts, welding electrodes, magnetic field conductors, thermal and electrical management devices. This work investigates the effect of high energy milling on the densification and microstructure of the composites WC-20% Cu and WC-18% Cu-2% Nb as well as an influence of the addition of niobium as a grain growth inhibitor. The effect of the compacting pressure and the sintering temperature of the powders prepared by milling and mechanical mixing in the density were also studied. WC, Cu and Nb powders in the ratio of 80, 20 and 2 percent by mass, respectively, were prepared by milling and also mechanical mixing. The powder mixture were mechanically alloyed in a attritor ball mil in a dry environment. The powders were milled at 900 rpm, with a mass to powder ratio of 1: 100 balls for 1.5 hours, and pressed at 200, 400 and 600 MPa in a uniaxial matrix with 8mm diameter. The green bodies were sintered at temperatures of 1030 ?C and 1150 ? C for 60 min in a resistive tubular oven under a nitrogen atmosphere. A microstructure of sintered bodies for analysis by scanning electron microscopy. To analyze a presence of impurities in the initial powder and the as-milled powders, chemical analyzes of XRF and EDS were performed. A XRD analysis was used to detect as structure of crystalline. Amortization of the Cu and WC phases occurred, with a decrease in the crystalline phase due to milling, and inhibition of grain growth, both at temperatures, in the samples with Nb. Higher compaction pressure and higher sintering temperature show better results for densification of the material.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-14T20:59:53Z No. of bitstreams: 1 GerlaneaSilvaDeOliveira_DISSERT.pdf: 3478391 bytes, checksum: 594895a6c6a847cb2a39bb6ce51e2b62 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-15T20:06:06Z (GMT) No. of bitstreams: 1 GerlaneaSilvaDeOliveira_DISSERT.pdf: 3478391 bytes, checksum: 594895a6c6a847cb2a39bb6ce51e2b62 (MD5) / Made available in DSpace on 2017-03-15T20:06:06Z (GMT). No. of bitstreams: 1 GerlaneaSilvaDeOliveira_DISSERT.pdf: 3478391 bytes, checksum: 594895a6c6a847cb2a39bb6ce51e2b62 (MD5) Previous issue date: 2016-07-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O n?quel tem sido bastante utilizado, em estudos, como substituto do cobalto no metal duro - WC-Co, devido apresentar maior resist?ncia ? corros?o e ? oxida??o, al?m das propriedades mec?nicas e de aspectos econ?micos. Atualmente, carbetos e metais s?o adicionados ao metal duro, para aumentar a sinterabilidade do material, e, consequentemente, as suas propriedades de dureza e tenacidade. Neste trabalho, foram estudados os efeitos da varia??o percentual de Ni e dos par?metros de sinteriza??o (temperaturas de sinteriza??o e isotermas) nas propriedades do sinterizado WC-Ni. Os produtos sinterizados foram obtidos atrav?s das etapas de processamento da metalurgia do p?, no qual p?s de carbeto de tungst?nio ? WC com adi??o de 5 e 15%p. de N?quel ? Ni foram mo?dos em um moinho planet?rio de alta energia durante 8 horas. Em seguida, os p?s particulados foram compactados em uma prensa uniaxial sob carga de 300 Mpa numa matriz cil?ndrica de 5 mm de di?metro. A sinteriza??o dos compactados a verde foi realizada nas temperaturas de 1350 ?C e 1450?C, com isotermas de 30 e 90 minutos, no dilat?metro; e, na temperatura de 1350? C, com isotermas de 30 e 90 minutos, em forno ? v?cuo. Os p?s de partida (WC e Ni) e os mo?dos foram caracterizados por difra??o de raios ? X (DRX), microscopia eletr?nica de varredura (MEV) e espectroscopia de energia dispersiva (EDS); e as amostras sinterizadas foram caracterizadas por MEV, EDS e medidas de microdureza. Os valores de microdureza Vickers foram maiores para as amostras de WC-5%p.Ni sinterizadas a 1450?C, com isotermas de 30 e 90 minutos no dilat?metro (1078,6 HV e 1246,1 HV, respectivemente). No forno a v?cuo, o melhor resultado de microdureza, tamb?m, foi para as amostras WC-5%p.Ni sinterizadas a 1350?C com isoterma de 30 e 90 minutos (849,6 HV e 914,7 HV, respectivemente). As amostras de WC-5%p.Ni sinterizadas no forno a v?cuo a 1350?C com isotermas de 30 e 90 minutos mostraram maiores valores de microdureza comparados aos das amostras WC-5%pNi sinterizadas no dilat?metro a 1350?C com isoterma de 30 e 90 minutos. / Nickel has been widely used as a substitute for cobalt in WC-Co hardmetal studies due to greater corrosion and oxidation resistance as well as mechanical properties and economic aspect. Currently, carbides and metals are added to hard metal in order to increase the sinterability of the material, and consequently their hardness and toughness. In this study, the effects of different amount of Ni and sintering parameters (sintering temperatures and holding time) on properties of sintered WC-Ni were studied. The sintered products were obtained via powder metallurgy processing steps, in which powders of tungsten carbide (WC) with 5 and 15 wt% Nickel (Ni) were milled in a planetary high energy ball milling for 8 hours. Then, the particulate powders were compacted into a cylindrical die with 5 mm in diameter under a uniaxial load of 300 MPa. Sintering of the green samples was carried out at 1350 and 1450?C with holding time of 30 and 90 minutes, in resistance furnace and at 1350? C, with 30 and 90 minutes holding time in vacuum furnace. Starting (WC and Ni) and milled powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Sintered samples were also characterized by SEM, EDS and microhardness measurements. Hardness results were higher for WC-5 wt% Ni sintered in the resistance furnace at 1450 ? C with 30 and 90 minutes holding time (1078.6 and 1246.1 Hv respectively). WC-5wt% Ni Samples sintered in vacuum furnace at 1350 ?C with 30 to 90 minutes holding time obtained a higher microhardness compared to ones sintered in the resistance furnace at 1350 ?C with holding time of 30 and 90 minutes.

O presente trabalho tem como objetivo o estudo das propriedades mecânicas do metal duro nas composições WC-6Co, WC-10Co, WC-20Co, WC-6Co-6Ni, WC-6Co-12Ni, obtidos por metalurgia do pó convencional para aplicação em anéis de selos mecânicos. Estes compósitos foram obtidos a partir de uma composição comercial de WC-6Co, e adicionado cobalto e níquel para realização do balanço de massa. Determinou-se um procedimento de obtenção das composições, através de cálculos de balanceamento adicionando-se a quantidade de cobalto e níquel necessária para transformar um compósito comercial 94WC-6Co nos metais duros mencionados. Após este procedimento adicionou-se 1,5% de lubrificante, em um misturador em “Y”. Analisou-se no Microscópio eletrônico de varredura a homogeneidade das composições. Determinou-se a densidade aparente, a curva de compressibilidade e compactaram-se as amostras de metal duro obtendo-se as densidades a verde. Realizou-se a pré-sinterização e determinaram-se as densidades das peças présinterizadas, executou-se ensaio de compressão e obtiveram-se parâmetros de usinagem na operação de faceamento e furação dos corpos de prova pré-sinterizados. A sinterização foi realizada em diversas vezes, nos dois fornos resistivos e em três atmosferas de controle diferentes. Determinaram-se curvas rápidas de sinterização e utilizou as temperaturas de 1360, 1400, 1420, e 1450ºC para as várias composições de metal duro. Para analisar-se a eficiência da mistura foi realizado ensaio de densidade das amostras sinterizadas, dureza, microdureza, metalografia, micrografia, EDS, contração linear e contração volumétrica e compressão. Após a caracterização dos materiais foi projetado e fabricado um ferramental de compactação. Compactou-se, sinterizou-se e retificou-se um anel de selo mecânico. / The aim of this work is to characterize to study the mechanical properties of carbide in the composition WC-6Co, WC-10Co, WC-20Co, WC-6Co-6Ni, WC-6Co-12Ni obtained by conventional powder metallurgy for application to rings of mechanical seals. These composites were obtained from a commercial composition of WC-6Co, and added cobalt and nickel to perform the mass balance. It was determined a procedure for obtaining the compositions, by calculation of balancing resulting in the amount of cobalt and nickel needed to transform a composite commercial 94WC-6Co in hard metals mentioned. After this procedure was added to 1.5% of lubricant, in a blender "Y". Analyzed in a scanning electron microscope the homogeneity of the compositions. It was determined the density, the compressibility curve and compress the samples carbide yielding green densities. We calculated the pre-sintering and determined the densities of pre-sintered parts, performed in compression test and it was obtained machining parameters in milling operation and drilling of the specimens pre-sintered. The sintering was performed at various times in the two resistive furnaces and atmospheres in three different control. Were determined fast corners and used sintering temperatures of 1360, 1400, 1420, and 1450 º C for various compositions of carbide. To analyze the efficiency of mixing was performed to test the samples sintered density, hardness, hardness, metallography, electron micrograph, EDS, linear and volumetric shrinkage and compression. After the characterization of materials was designed and manufactured tools of compaction, compacted, sintered and ground a ring of mechanical seal.