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Characterization of Cu2ZnSn(SSe)4 monograin powders by FE-SEM
Neves, Filipe; Livramento, Vanessa; Martins, Isabel M.; Esperto, Luís; Santos, Mário J. G.; Correia, J. Brito; Muska, K.; Holopainen, T.The design and synthesis of high-efficiency materials to convert solar to electrical energy is an increasingly important research field. Within the photovoltaic technologies, crystalline Si have an 80% share while the remaining 20% are mostly thin film solar cells based on Cu(In,Ga)(S,Se)2 (CIGSSe) and CdTe [1,2]. However,the cost, the abundance and the environmental impact of the elemental components cannot be...
Novel two-step processing route combining mechanical alloying and microwave hyb...
Santos, Mário J. G.; Alves, Cátia; Oliveira, F. A. Costa; Marcelo, Teresa; Mascarenhas, João; Cavaleiro, A.; Trindade, B.In this work, microwave hybrid sintering at 1300 and 1350 °C was carried out for densification of La9.33Si2Ge4O26 mechanically alloyed powder with apatite structure. The pellets sintered at these two temperatures present the same structure (apatite) with relative densities of 92 and 96%, respectively. Mechanical analysis performed on sintered materials revealed the following results: hardness of 7.1 and 8.0 GPa...
Exhaled breath condensate as a biomonitor for metal exposure: a new analytical ...
Barreiros, Maria Alexandra; Pinheiro, Teresa; Félix, P. M.; Franco, C.; Santos, Mário J. G.; Araújo, F.; Freitas, Maria do Carmo; Almeida, S. M.The study of exhaled breath condensate (EBC) obtained by cooling exhaled air under conditions of spontaneous breathing is considered one of the areas with higher interest in respiratory health research. The use of EBC for elemental determination in occupational exposure requires a standard methodological procedure to implement its practice in occupational studies. EBC is an inhomogeneous sample with organic and...
Effect of the sintering conditions on the morphology of La9.33Si2Ge4O26 oxyapat...
Macatrão, Mafalda; Santos, Mário J. G.; Alves, Cátia; Oliveira, F. A. Costa; Marcelo, Teresa; Mascarenhas, João; Trindade, B.Solid oxide fuel cells (SOFCs) are devices that allow direct conversion of chemical to electrical energy through an electrochemical reaction in a cleaner and more efficient way than conventional processes (eg. gas turbines). They are characterized by the use of a solid oxide material as the electrolyte. Yttria-stabilised zirconia (YSZ) has traditionally been used in SOFCs electrolytes at temperatures in the ra...
Characterization of Cu2ZnSn(SSe)4 monograin powders by FE-SEM
Neves, Filipe; Livramento, Vanessa; Martins, Isabel M.; Esperto, Luís; Santos, Mário J. G.; Correia, J. Brito; Muska, K.; Holopainen, T.The design and synthesis of high-efficiency materials to convert solar to electrical energy is an increasingly important research field. Within the photovoltaic technologies, crystalline Si have an 80% share while the remaining 20% are mostly thin film solar cells based on Cu(In,Ga)(S,Se)2 (CIGSSe) and CdTe [1,2].
Avaliação estrutural do aço rápido M3/2 sinterizado através da tecnologia DMLS
Esperto, Luís; Martins, Isabel M.; Santos, Mário J. G.O estudo da sinterização do pó de aço rápido M3/2 pela tecnologia DMLS baseou-se na utilização de diferentes parâmetros de processo e na optimização da respectiva distribuição granulométrica e densidade aparente. O material foi sinterizado em linha, área e volume utilizando uma distância entre linhas de varrimento constante (0.30mm), três velocidades de varrimento do laser (50, 150, 250mm/s) e duas potências de...
Metallurgical evaluation of laser sintered M3/2 HSS powder
Martins, Isabel M.; Esperto, Luís; Domingues, Joaquim Resina; Santos, Mário J. G.Direct Metal Laser Sintering (DMLS) is one of the leading commercial rapid tooling (RT) technologies that produce 3D fully functional parts and tools directly from a CAD model. High Speed Steels (HSS) have the desired combination of hot hardness, wear resistance and toughness needed for applications such as cutting tools, special tools, inserts and dies that can be successfully developed in a near net shape by ...
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