Micro-Powder Injection Moulding (Micro-PIM) technology is one of the key technologies that permit to fit with the increasing demands for smaller parts associated to miniaturization and functionalization in different application fields. The thesis focuses first on the elaboration and characterization of polymer-powder mixtures based on 316L stainless steel powders, and then on the identification of physical and material parameters related to the sintering stage and to the numerical simulations of the sintering process. Mixtures formulation with new binder systems based on different polymeric components have been developed for 316L stainless steel powders (5 µm and 16 µm). The characterization of the resulting mixtures for each group is carried out using mixing torque tests and viscosity tests. The mixture associated to the formulation comprising polypropylene + paraffin wax + stearic acid is well adapted for both powders and has been retained in the subsequent tests, due to the low value of the mixing torque and shear viscosity. The critical powder volume loading with 316L stainless steel powder (5 µm) according to the retained formulation has been established to 68% using four different methods. Micro mono-material injection (with 316L stainless steel mélange) and bi-material injection (with 316L stainless steel mélange and Cu mélange) are properly investigated. Homogeneity tests are observed for mixtures before and after injection. A physical model well suited for sintering stage is proposed for the simulation of sintering stage. The identification of physical parameters associated to proposed model are defined from the sintering stages in considering 316L stainless steel (5 µm)mixtures with various powder volume loadings (62%, 64% and 66%). Beam-bending tests and free sintering tests and thermo-Mechanical-Analyses (TMA) have also investigated. Three sintering stages corresponding to heating rates at 5 °C/min, 10 °C/min and 15 °C/min are used during both beam-bending tests and free sintering tests. On basis of the results obtained from dilatometry measurements, the shear viscosity module G, the bulk viscosity module K and the sintering stress σs are identified using Matlab® software. Afterwards, the sintering model is implemented in the Abaqus® finite element code, and appropriate finite elements have been used for the support and micro-specimens, respectively. The physical material parameters resulting from the identification experiments are used to establish the proper 316L stainless steel mixture, in combination with G, K and σs parameters. Finally, the sintering stages up to 1200 °C with three heating rates (5 °C/min, 10 °C/min and 15 °C/min) are also simulated corresponding to the four micro-specimen types (powder volume loading of 62%, 64% and 66%). The simulated shrinkages and relative densities of the sintered micro-specimens are compared to the experimental results indicating a proper agreement

O processo tradicional de fabricação de ímãs de terras raras – TR – é a metalurgia do pó convencional. Este processo inclui etapas de preparação da liga, moagem, compactação sob campo e sinterização. Atualmente, ímãs obtidos pelo processo de injeção tem como resultado os ímãs conhecidos como bonded, que são compósitos de resina e ligas magnéticas. O processo de obtenção proposto neste trabalho é a moldagem de pós por injeção – MPI, o que implica novos desafios uma vez que ligas de terras raras são altamente reativas. A obtenção de ímãs de Nd-Fe-B por esse processo fornece a oportunidade de diversificar ainda mais os setores, potencialmente lucrativos, que trabalham com materiais magnéticos. As dificuldades desse processo foram encontradas em cada etapa, desde a mistura da liga com os polímeros à eliminação destes polímeros depois de as peças serem injetadas, essa etapa se tornou crítica dado que está diretamente relacionada às propriedades finais do material. Assim, propuseram-se novos ciclos de extração dos polímeros com solventes orgânicos e degradação térmica. Além disso, modelou-se ferramental para o processo de injeção, uma vez que o material deve ser orientado magneticamente durante a injeção. Finalmente usou-se o MAXWELL 14® (software para análises por elementos finitos para resolução em 3D) para incluir propriedades no banco de dados do software e assim predizer o comportamento do material quando aplicado nas máquinas elétricas de núcleos com de formato complexo. / The typical magnets production process of Rare Earths – RE is the conventional powder metallurgy. This process includes preparation stages of alloys, grind, pressing under field and sintering. Nowadays, magnet obtained by the injection process has as result the magnets known as bonded, that is a resin composite and magnetic alloys. The proposed process to obtainment, in this work, is the Metal Injection Molding- MIM, what involve new challenges once alloys of RE are highly reactive. The magnets obtainment of ND-Fe-B for this process supplies even opportunity of diversifying the sectors, potentially lucrative, that work with magnetic materials. The difficulties of this process were found in each stage, since the alloy mixture with the polymers to the elimination of these polymers after the pieces are injected, this stage became criticizes given it is directly related to final properties of the material. This way if it propose to polymers extraction new cycles with organic solvents and thermal degradation. Moreover, it modeled die for the injection process, once the material should be guided magnetically during the injection. It finally used MAXWELL 14 ® (Software for analyses by finite elements for resolution in 3D) to include properties on the bench of data of the software and thus predict the material behavior when applied in cores of electrical machines with complex shape.

O processo tradicional de fabricação de ímãs de terras raras – TR – é a metalurgia do pó convencional. Este processo inclui etapas de preparação da liga, moagem, compactação sob campo e sinterização. Atualmente, ímãs obtidos pelo processo de injeção tem como resultado os ímãs conhecidos como bonded, que são compósitos de resina e ligas magnéticas. O processo de obtenção proposto neste trabalho é a moldagem de pós por injeção – MPI, o que implica novos desafios uma vez que ligas de terras raras são altamente reativas. A obtenção de ímãs de Nd-Fe-B por esse processo fornece a oportunidade de diversificar ainda mais os setores, potencialmente lucrativos, que trabalham com materiais magnéticos. As dificuldades desse processo foram encontradas em cada etapa, desde a mistura da liga com os polímeros à eliminação destes polímeros depois de as peças serem injetadas, essa etapa se tornou crítica dado que está diretamente relacionada às propriedades finais do material. Assim, propuseram-se novos ciclos de extração dos polímeros com solventes orgânicos e degradação térmica. Além disso, modelou-se ferramental para o processo de injeção, uma vez que o material deve ser orientado magneticamente durante a injeção. Finalmente usou-se o MAXWELL 14® (software para análises por elementos finitos para resolução em 3D) para incluir propriedades no banco de dados do software e assim predizer o comportamento do material quando aplicado nas máquinas elétricas de núcleos com de formato complexo. / The typical magnets production process of Rare Earths – RE is the conventional powder metallurgy. This process includes preparation stages of alloys, grind, pressing under field and sintering. Nowadays, magnet obtained by the injection process has as result the magnets known as bonded, that is a resin composite and magnetic alloys. The proposed process to obtainment, in this work, is the Metal Injection Molding- MIM, what involve new challenges once alloys of RE are highly reactive. The magnets obtainment of ND-Fe-B for this process supplies even opportunity of diversifying the sectors, potentially lucrative, that work with magnetic materials. The difficulties of this process were found in each stage, since the alloy mixture with the polymers to the elimination of these polymers after the pieces are injected, this stage became criticizes given it is directly related to final properties of the material. This way if it propose to polymers extraction new cycles with organic solvents and thermal degradation. Moreover, it modeled die for the injection process, once the material should be guided magnetically during the injection. It finally used MAXWELL 14 ® (Software for analyses by finite elements for resolution in 3D) to include properties on the bench of data of the software and thus predict the material behavior when applied in cores of electrical machines with complex shape.

O processo tradicional de fabricação de ímãs de terras raras – TR – é a metalurgia do pó convencional. Este processo inclui etapas de preparação da liga, moagem, compactação sob campo e sinterização. Atualmente, ímãs obtidos pelo processo de injeção tem como resultado os ímãs conhecidos como bonded, que são compósitos de resina e ligas magnéticas. O processo de obtenção proposto neste trabalho é a moldagem de pós por injeção – MPI, o que implica novos desafios uma vez que ligas de terras raras são altamente reativas. A obtenção de ímãs de Nd-Fe-B por esse processo fornece a oportunidade de diversificar ainda mais os setores, potencialmente lucrativos, que trabalham com materiais magnéticos. As dificuldades desse processo foram encontradas em cada etapa, desde a mistura da liga com os polímeros à eliminação destes polímeros depois de as peças serem injetadas, essa etapa se tornou crítica dado que está diretamente relacionada às propriedades finais do material. Assim, propuseram-se novos ciclos de extração dos polímeros com solventes orgânicos e degradação térmica. Além disso, modelou-se ferramental para o processo de injeção, uma vez que o material deve ser orientado magneticamente durante a injeção. Finalmente usou-se o MAXWELL 14® (software para análises por elementos finitos para resolução em 3D) para incluir propriedades no banco de dados do software e assim predizer o comportamento do material quando aplicado nas máquinas elétricas de núcleos com de formato complexo. / The typical magnets production process of Rare Earths – RE is the conventional powder metallurgy. This process includes preparation stages of alloys, grind, pressing under field and sintering. Nowadays, magnet obtained by the injection process has as result the magnets known as bonded, that is a resin composite and magnetic alloys. The proposed process to obtainment, in this work, is the Metal Injection Molding- MIM, what involve new challenges once alloys of RE are highly reactive. The magnets obtainment of ND-Fe-B for this process supplies even opportunity of diversifying the sectors, potentially lucrative, that work with magnetic materials. The difficulties of this process were found in each stage, since the alloy mixture with the polymers to the elimination of these polymers after the pieces are injected, this stage became criticizes given it is directly related to final properties of the material. This way if it propose to polymers extraction new cycles with organic solvents and thermal degradation. Moreover, it modeled die for the injection process, once the material should be guided magnetically during the injection. It finally used MAXWELL 14 ® (Software for analyses by finite elements for resolution in 3D) to include properties on the bench of data of the software and thus predict the material behavior when applied in cores of electrical machines with complex shape.

The purpose of this research is to investigate the mechanical, microstructural and corrosion performance of the ferritic stainless steel coarse powders, used in Metal Injection Molding (MIM) process. Three coarser powders made by Höganäs AB, were examined along with a commercially available fine MIM powder and samples from sheet metal. The studied powders were individually mixed with binders and then injection molded in the shape of dog bone shaped tensile bars. These green samples were then debinded and sintered to examine under different characterization methods. The methods used for examining the samples were tensile test, hardness test, metallography, SEM, chemical analysis, and salt spray test. After a comparative study of these different materials, it turns out that the chemical composition and the process parameters have more effect on materials properties compared to only particle size distribution in studied materials. After this study, 434 coarse powder was preferred upon the PolyMIM 430 fine powder, because of its lower price and same performance as that of PolyMIM 430.

Le micro-moulage par Injection de Poudres (Micro-PIM) est l’une des technologies permettant de réaliser des micro-composants de très petites dimensions, associés à la miniaturisation et la fonctionnalisation dans différents domaines d’applications. La thèse concerne l’élaboration et la caractérisation de mélanges basés sur des poudres d’acier inoxydable de type 316L, l’identification des paramètres physiques associés à l’étape de densification est traitée. Des modélisations physiques et des simulations numériques de l’étape de densification par diffusion à l’état solide, sont ensuite proposées.De nouvelles formulations de mélanges à base de liants polymériques ont été développées pour différentes granulométries de poudres d’acier inoxydable de type 316L (5 µm et 16 µm). Les différents mélanges élaborés ont été élaborés et validés grâce à des comparatifs entre couples de mélangeages et courbes de viscosité de cisaillement. Les mélanges élaborés avec une formulation de base composée de polypropylène, de cire paraffine et d’acide stéarique, sont adaptés pour les deux types de poudre, et conduisent à des résultats significatifs pour les différents tests réalisés, conduisant à un couple de mélangeage et à une viscosité de cisaillement relativement faibles par rapport aux autres formulations. Le taux de charge critique obtenu pour l’acier inoxydable 316L (5 µm), avec la formulation optimale, est de 68% et a été déterminé par différentes méthodes. Les essais de micro-injection pour le mono-matériau (316L mélange) et les bi-matériaux (mélange de 316 L et Cu) ont été analysés en détail. Des tests d’homogénéité ont été réalisés avant et après l’étape d’injection.Un modèle thermo-élasto-viscoplastique approprié pour modéliser l’étape de densification a été utilisé pour la simulation de la densification des micro-composants. Les paramètres d’identification du modèle physique ont été identifiés pour des mélanges de poudres d’acier 316L (5 µm), pour différents taux de charge (62%, 64% et 66%). Des essais de flexion 3 points et de compression ont été réalisé à l’intérieur d’un dilatomètre vertical avec trois cinétiques de densification (5 °C/min, 10 °C/min et 15 °C/min). Les résultats obtenus par dilatométrie, ont permis l’identification du module de viscosité de cisaillement G, du module de compressibilité K, et de la contrainte de densification σs, Le modèle de comportement associé à la densification, incluant les paramètres identifiés a été implémenté dans le code éléments finis Abaqus©. Des éléments finis adaptés ont été utilisés, tant pour le support, que les quatre micro-éprouvettes de référence. Les simulations de l’étape de densification pour trois différentes cinétiques (5 °C/min, 10 °C/min et 15 °C/min) à 1200°C, ont été réalisées pour l’ensemble des micro-composants dont les taux de charge correspondent respectivement à 62%, 64% et 66%. Les retraits et densités relatives des micro-composants obtenus par simulation sont en très bonne corrélation avec les résultats expérimentaux / Micro-Powder Injection Moulding (Micro-PIM) technology is one of the key technologies that permit to fit with the increasing demands for smaller parts associated to miniaturization and functionalization in different application fields. The thesis focuses first on the elaboration and characterization of polymer-powder mixtures based on 316L stainless steel powders, and then on the identification of physical and material parameters related to the sintering stage and to the numerical simulations of the sintering process. Mixtures formulation with new binder systems based on different polymeric components have been developed for 316L stainless steel powders (5 µm and 16 µm). The characterization of the resulting mixtures for each group is carried out using mixing torque tests and viscosity tests. The mixture associated to the formulation comprising polypropylene + paraffin wax + stearic acid is well adapted for both powders and has been retained in the subsequent tests, due to the low value of the mixing torque and shear viscosity. The critical powder volume loading with 316L stainless steel powder (5 µm) according to the retained formulation has been established to 68% using four different methods. Micro mono-material injection (with 316L stainless steel mélange) and bi-material injection (with 316L stainless steel mélange and Cu mélange) are properly investigated. Homogeneity tests are observed for mixtures before and after injection. A physical model well suited for sintering stage is proposed for the simulation of sintering stage. The identification of physical parameters associated to proposed model are defined from the sintering stages in considering 316L stainless steel (5 µm)mixtures with various powder volume loadings (62%, 64% and 66%). Beam-bending tests and free sintering tests and thermo-Mechanical-Analyses (TMA) have also investigated. Three sintering stages corresponding to heating rates at 5 °C/min, 10 °C/min and 15 °C/min are used during both beam-bending tests and free sintering tests. On basis of the results obtained from dilatometry measurements, the shear viscosity module G, the bulk viscosity module K and the sintering stress σs are identified using Matlab® software. Afterwards, the sintering model is implemented in the Abaqus® finite element code, and appropriate finite elements have been used for the support and micro-specimens, respectively. The physical material parameters resulting from the identification experiments are used to establish the proper 316L stainless steel mixture, in combination with G, K and σs parameters. Finally, the sintering stages up to 1200 °C with three heating rates (5 °C/min, 10 °C/min and 15 °C/min) are also simulated corresponding to the four micro-specimen types (powder volume loading of 62%, 64% and 66%). The simulated shrinkages and relative densities of the sintered micro-specimens are compared to the experimental results indicating a proper agreement

Ces travaux de thèse concernent l’étude du comportement thermo-physique de mélanges de polymères biosourcés chargés de poudre d’Inconel 718 mis en forme par Moulage par Injection de poudre Métallique. Des matériaux et procédés innovants pouvant permettre une amélioration du procédé ont été étudiés. L’utilisation de polyéthylène glycol (PEG), choisi pour ses propriétés de solubilité dans l’eau, et de polymères biosourcés, pour diminuer l’impact environnemental, ont été choisi. Les nuances de polymères biosourcés ont été choisies adaptées aux conditions du procédé de moulage par injection, il s’agit d’acide polylactique et de polyhydroalcanoates. De même, l’utilisation du CO2 à l’état supercritique comme solvant, a pour objectif de diminuer le temps de déliantage ainsi que d’augmenter la qualité des composants réalisés. Les résultats obtenus ont montré une dégradation du PEG et de l’acide stéarique lors des cycles de mélangeage de de moulage par injection dans les conditions d’utilisation des polymères biosourcés. L’utilisation des mélanges chargés composés de polymères biosourcés ont permis d’améliorer l’homogénéité des composants injectés, mais ont engendré des défauts lors de l’étape de déliantage. Ces défauts ont pu être éliminés par l’utilisation de CO2 à l’état supercritique comme solvant du PEG. Ce dernier procédé a permis une diminution importante du temps de déliantage ainsi qu’une amélioration de la qualité des composants finaux. Les composants densifiés possèdent les propriétés mécaniques correspondantes à l’Inconel 718. / The works done during this PhD focuses on the study of the thermo-physical behavior of bio sourced polymer blends loaded with Inconel 718 powder (feedstock) to be shaped by the Metal Injection Molding process (MIM). First, a review of the researches related to the MIM process was conducted to identify innovative materials and processes that can improve the MIM process. Thus, the use of polyethylene glycol (PEG), selected for its properties of solubility in water, and bio sourced polymers, in order to reduce the environmental impact, were selected. The bio sourced polymers have been selected in accordance with the conditions of the injection molding process, and the choice was made to use polylactic acid (PLA) and polyhydroalkanoates (PHA and PHBV). Similarly, the supercritical CO2 as solvent was chosen to reduce the time of binder removal as well as increasing the quality of components produced. Thermo-physical, mechanical and rheological characterizations were made to determine the behavior of the different feedstock formulations. The results showed a degradation of the PEG and of the stearic acid under the conditions of use of the biopolymers, during the mixing and the injection stages. The use of feedstock made of bio sourced polymers have improved the homogeneity of the injected components, but they have generated defects during the debinding step. These defects have been eliminated by the use of CO2 in the supercritical state as solvent of the PEG. This method has significantly decrease the time of binder removal and improved the quality of the final components. Finally, densified components have the mechanical properties corresponding to Inconel 718.

La réduction de l’impact des activités humaines sur l’environnement est au sujet de nombreux programmes de recherche. Ainsi, dans le domaine du transport aérien a été créé le projet Clean-Sky, regroupant les thèmes de recherche associés. La thèse, partie de ce dernier, a pour objectif de réduire l’impact environnemental de la production de composants en alliages avancés à base de Titane. La production actuelle ayant une empreinte écologique non négligeable, un procédé de fabrication alternatif est étudié, il s’agit du moulage par injection de poudres métalliques. La première partie de cette consiste donc en la recherche d’une formulation de mélange optimale parmi les solutions classiques et innovantes. Elles sont triées en fonction de leurs aptitudes, déterminées par caractérisations physico-chimiques, à assurer le bon déroulement de chaque étape du procédé. Un nombre réduit de solution étant ainsi dégagé, il s’agit de passer aux étapes d’injection, de déliantage et de frittage. Plusieurs géométries de pièces sont testées dans chacun de ces cas, afin de valider l’adaptation aux différentes contraintes imposées. Lors de ces trois phases, des analyses physico-chimiques complètes permettent de mettre en avant la ou les formulations les plus aptes à permettre la production de ces composants. Une fois la solution fixée, chaque étape du procédé est optimisées, afin de faciliter le transfert industriel et d’assurer la rentabilité du nouveau processus de fabrication. Ces travaux de doctorat ont permis de mettre en avant deux formulations, répondant aux critères définis en début de thèse. Les étapes de mélange, injection, déliantage et frittage ont été optimisées et le transfert industriel est possible. / Reducing the ecological footprint of human activities is, today, the aim of most of the research programs. In Europe, the « Clean Sky » project funds research activities to make air transport « greener ». This PhD, being part of it, is about improving production of Titanium Aluminide based components. Nowadays production having a strong environmental impact, an alternative way has been investigated: metal injection molding. The first step of this work was focused on a bibliographic study, to select relevant, common and innovative mixtures to be used in the process. Throughout the process, these mixtures have been tested, physically and chemically analyzed, to get data about the optimal mixture. Several components geometries have been tested, during injection, debinding, and sintering steps. Once the mixture(s) chosen, process’ parameters have been optimized to make industrial transfer easier, and lower its overall cost. The developments achieved during this PhD led to two qualified mixtures, and optimized mixing, molding, debinding and sintering steps.

O processo de moldagem de pós injeção é utilizado para a fabricação de peças de geometrias complexas e com alto volume de produção. Em aplicações ortodônticas e médicas, nas quais são requeridas elevadas durezas e resistências à corrosão, o aço inoxidável 17-4 PH é utilizado aplicando-se aquela técnica de conformação. A atmosfera de sinterização é responsável pelo controle das reações químicas que ocorrem durante a densificação do material e são fundamentais para a qualidade final do produto. O objetivo deste trabalho foi avaliar a influência da atmosfera de sinterização na dureza e resistência à corrosão deste tipo de aço. A remoção dos ligantes primários foi realizada por meio de extração química utilizando-se um solvente com menor impacto ambiental, que se mostrou adequado a tal fim. A extração térmica posterior dos ligantes foi realizada pelo aquecimento nas temperaturas de 250°C e 450°C sendo, posteriormente, a temperatura elevada a 900°C, para o início da sinterização. Utilizou-se atmosferas de Nitrogênio, Vácuo e Hidrogênio, com temperaturas de sinterização de 1250°C e 1330°, com tempos de patamares de 30 e 60 minutos. Verificou-se que as densidades atingidas nas atmosferas de Hidrogênio e Vácuo são semelhantes e se adequaram às especificações requeridas pela norma, enquanto a atmosfera de Nitrogênio resultou em características inferiores. As durezas e as resistências à corrosão obtidas com o uso das atmosferas de Hidrogênio e Vácuo foram também superiores as das amostras sinterizadas em atmosfera de Nitrogênio. / The powder injection molding process is used to manufacture parts with complex shapes, with high production demand. In orthodontic and medical applications, in which high hardness and corrosion resistance are required, 17-4 PH stainless steel is used by applying this forming technique. The sintering atmosphere is responsible for controlling the chemical reactions that occur during material densification and is critical to the ultimate product quality. This research study aims at evaluating the influence of the sintering atmosphere on the hardness and corrosion resistance of this type of steel. The removal of the primary binder was carried out by chemical extraction applying a solvent with less environmental impact, which has proved to be suitable for this purpose. The subsequent binder thermal extraction was held by heating at temperatures of 250°C and 450°C and, therefore, at temperature of 900°C, to initiate sintering. Nitrogen, vacuum and hydrogen atmospheres were used with sintering temperatures at 1250°C and 1330°, with 30 and 60 minute-step time. It was verified that the densities achieved in hydrogen and vacuum atmospheres are similar and suitable by the regulations, whereas the nitrogen atmosphere resulted in lower performance. The hardness and corrosion resistance obtained with the use of hydrogen and vacuum atmospheres were also higher than those obtained for samples sintered in the nitrogen atmosphere.

O processo de moldagem de pós injeção é utilizado para a fabricação de peças de geometrias complexas e com alto volume de produção. Em aplicações ortodônticas e médicas, nas quais são requeridas elevadas durezas e resistências à corrosão, o aço inoxidável 17-4 PH é utilizado aplicando-se aquela técnica de conformação. A atmosfera de sinterização é responsável pelo controle das reações químicas que ocorrem durante a densificação do material e são fundamentais para a qualidade final do produto. O objetivo deste trabalho foi avaliar a influência da atmosfera de sinterização na dureza e resistência à corrosão deste tipo de aço. A remoção dos ligantes primários foi realizada por meio de extração química utilizando-se um solvente com menor impacto ambiental, que se mostrou adequado a tal fim. A extração térmica posterior dos ligantes foi realizada pelo aquecimento nas temperaturas de 250°C e 450°C sendo, posteriormente, a temperatura elevada a 900°C, para o início da sinterização. Utilizou-se atmosferas de Nitrogênio, Vácuo e Hidrogênio, com temperaturas de sinterização de 1250°C e 1330°, com tempos de patamares de 30 e 60 minutos. Verificou-se que as densidades atingidas nas atmosferas de Hidrogênio e Vácuo são semelhantes e se adequaram às especificações requeridas pela norma, enquanto a atmosfera de Nitrogênio resultou em características inferiores. As durezas e as resistências à corrosão obtidas com o uso das atmosferas de Hidrogênio e Vácuo foram também superiores as das amostras sinterizadas em atmosfera de Nitrogênio. / The powder injection molding process is used to manufacture parts with complex shapes, with high production demand. In orthodontic and medical applications, in which high hardness and corrosion resistance are required, 17-4 PH stainless steel is used by applying this forming technique. The sintering atmosphere is responsible for controlling the chemical reactions that occur during material densification and is critical to the ultimate product quality. This research study aims at evaluating the influence of the sintering atmosphere on the hardness and corrosion resistance of this type of steel. The removal of the primary binder was carried out by chemical extraction applying a solvent with less environmental impact, which has proved to be suitable for this purpose. The subsequent binder thermal extraction was held by heating at temperatures of 250°C and 450°C and, therefore, at temperature of 900°C, to initiate sintering. Nitrogen, vacuum and hydrogen atmospheres were used with sintering temperatures at 1250°C and 1330°, with 30 and 60 minute-step time. It was verified that the densities achieved in hydrogen and vacuum atmospheres are similar and suitable by the regulations, whereas the nitrogen atmosphere resulted in lower performance. The hardness and corrosion resistance obtained with the use of hydrogen and vacuum atmospheres were also higher than those obtained for samples sintered in the nitrogen atmosphere.