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- Natural alternatives for thermoelectric materials [Resumo]Publication . Santos, Beatriz; Lopes, E.B.; Neves, Filipe; Gonçalves, António Pereira
- Powder sintering of single-phase tetrahedrite materials [Resumo]Publication . Neves, Filipe; Esperto, Luís; Figueira, Isabel; Mascarenhas, João; Correia, J.B.; Ferreira, H.; Lopes, E.B.; Gonçalves, António PereiraABSTRACT: There is a worldwide consensus for the development and implementation of zero global-warming-potential and energy efficient technologies. This energy transition requires more progress in all aspects related with renewable technologies, including the research and innovation on new and improved materials, e.g., materials for converting thermal wasted energy into electricity.
- Thermoelectric Properties of Tetrahedrites Produced from Mixtures of Natural and Synthetic MaterialsPublication . Santos, Beatriz; Esperto, Luís; Figueira Vasques, Isabel; Mascarenhas, João; Lopes, E.B.; Salgueiro, Rute; Silva, Teresa; Correia, Jose B.; de Oliveira, Daniel Pipa Soares; Pereira Gonçalves, Antonio; Neves, FilipeABSTRACT: Thermoelectric materials have considerable potential in the mitigation of the global energy crisis, through their ability to convert heat into electricity. This study aims to valorize natural resources, and potentially reduce production costs, by incorporating tetrahedrite-tennantite (td) ores from the Portuguese Iberian Pyrite Belt into synthetic samples. The ore samples were collected in a mine waste at Barrig & atilde;o and as "dirty-copper" pockets of ore from the Neves Corvo mine. Subsequently, high-energy ball milling and hot pressing were employed in the production of thermoelectric materials. These are characterized by XRD, SEM/EDS, and thermoelectrical properties. The complete dissolution of the dump material sulfides with the synthetic tetrahedrite constituents led to an increase in the amount of the tetrahedrite-tennantite phase, which was made up of a tetrahedrite-tennantite-(Fe) solid solution. The thermoelectric characterization of these materials is provided, revealing that most of the combined synthetic ore samples displayed better results than the pristine tetrahedrite, mostly due to higher Seebeck coefficient values. Furthermore, the best thermoelectric performance is achieved with 10% of ore, where a power factor of 268 mu W.K-2.m-1 is reached at room temperature.