Propriedades eletroquímicas de compostos intermetálicos e soluções sólidas em ligas de alta entropia do sistema FeNiCuMnTiSn
Data
2023-11-30
Autores
Alvarenga, Matheus Bellot de 
Orientadores
Silva, Ricardo Alexandre Galdino da
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
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Resumo
O desempenho de motores termomagnéticos é fortemente dependente das propriedades do material utilizado e durante muito tempo o desempenho destes dispositivos era baixo devido a falta de materiais magnéticos eficientes, o presente trabalho se propõe a estudar compostos de alta entropia para a obtenção de parâmetros que podem contribuir para o design de materiais termomagnéticos. Resultados preliminares indicaram que as ligas FeNiCuMnSn e FeNiCuMnTiSn apresentam propriedades magnéticas e eletroquímicas promissoras, pensando em sua aplicação em motores termomagnéticos, porém exibiram duas ou mais fases em seu estado bruto de fusão. Com o objetivo de entender a origem destas propriedades foram sintetizados os compostos intermetálicos CuFe0,4Mn0,8Ni0,8Sn e CuMnNiSn presentes nas ligas citadas. A caracterização destas fases foi realizada utilizando-se medidas de microscopia óptica (MO), microscopia eletrônica de varredura (MEV), espectroscopia por dispersão de energia de raios X (EDS), difratometria de raios X (DRX), polarização linear, análise termogravimétrica (TGA) e medidas de dureza. Os resultados obtidos indicam que o composto CuMnNiSn apresentou duas fases com composições iguais, porém com grupos espaciais distintos, o que também ocorreu para o composto CuFe0,4Mn0,8Ni0,8Sn, porém este também apresentou uma terceira fase, rica em ferro. Considerando as propriedades eletroquímicas dos materiais estudados, observou-se que o composto CuMnNiSn atingiu potenciais muito mais nobres e teve uma taxa de corrosão muito menor quando comparado ao CuFe0,4Mn0,8Ni0,8Sn. A partir das curvas TGA foi possível determinar as temperaturas de Curie de cada composto, sendo que para o CuMnNiSn obteve-se um valor de 360 K e para o CuFe0,4Mn0,8Ni0,8Sn um valor de 913 K. Pelos ensaios de dureza observou-se que o composto CuMnNiSn apresentou um valor de dureza de 485 HV, já o composto CuFe0,4Mn0,8Ni0,8Sn apresentou um valor de 609 HV. De uma maneira geral, entre os dois compostos intermetálicos estudados, a fase CuMnNiSn parece ser o composto mais promissor para aplicações em motores termomagnéticos, pois ele apresenta uma boa resistência à corrosão, temperatura de Curie abaixo do ponto de ebulição da água e valor de dureza que sugere melhores propriedades mecânicas.
The performance of thermomagnetic motors is strongly dependent on the properties of the utilized material and for a long time the performance of these devices was low due to the lack of efficient magnetic materials, this work studies high entropy compounds to obtain parameters that can contribute to the design of thermomagnetic materials. Preliminary results indicated that the FeNiCuMnSn and FeNiCuMnTiSn alloys presented promising magnetic and electrochemical properties, considering their application in thermomagnetic motors, but also exhibited two or more phases in their as-casting state. To understand the origin of this properties, the CuFe0.4Mn0.8Ni0.8Sn and CuMnNiSn intermetallic compounds present in the alloys were synthesized. The characterization of these compounds was performed using optical and scanning electron microscopies, X-ray energy dispersion spectroscopy, X-ray diffractometry, linear polarization, thermogravimetry analysis, and hardness measurements. The results obtained indicate that the compound CuMnNiSn presented two phases with equal compositions, but with distinct space groups, which also occurred to the compound CuFe0,4Mn0,8Ni0,8Sn, but this also presented a third phase, rich in iron . Considering the electrochemical properties of the materials studied, it was observed that the CuMnNiSn compound reached the nobler potentials and had a lower corrosion current density when compared to the CuFe0.4Mn0.8Ni0.8Sn. From the TGA curves it was possible to determine the Curie temperatures of each compound, with a value of 360 K for the CuMnNiSn and 913 K for the CuFe0.4Mn0.8Ni0.8Sn phase. From hardness tests it was observed that the CuMnNiSn compound presented a hardness value of 485 HV, and the CuFe0,4Mn0,8Ni0,8Sn compound presented a value of 609 HV. In general, between the two intermetallic compounds studied, the CuMnNiSn phase seems to be the most promising compound for applications in thermomagnetic motors since it presents good corrosion resistance, Curie temperature below the boiling point of water and hardness value that suggests better mechanical properties.
The performance of thermomagnetic motors is strongly dependent on the properties of the utilized material and for a long time the performance of these devices was low due to the lack of efficient magnetic materials, this work studies high entropy compounds to obtain parameters that can contribute to the design of thermomagnetic materials. Preliminary results indicated that the FeNiCuMnSn and FeNiCuMnTiSn alloys presented promising magnetic and electrochemical properties, considering their application in thermomagnetic motors, but also exhibited two or more phases in their as-casting state. To understand the origin of this properties, the CuFe0.4Mn0.8Ni0.8Sn and CuMnNiSn intermetallic compounds present in the alloys were synthesized. The characterization of these compounds was performed using optical and scanning electron microscopies, X-ray energy dispersion spectroscopy, X-ray diffractometry, linear polarization, thermogravimetry analysis, and hardness measurements. The results obtained indicate that the compound CuMnNiSn presented two phases with equal compositions, but with distinct space groups, which also occurred to the compound CuFe0,4Mn0,8Ni0,8Sn, but this also presented a third phase, rich in iron . Considering the electrochemical properties of the materials studied, it was observed that the CuMnNiSn compound reached the nobler potentials and had a lower corrosion current density when compared to the CuFe0.4Mn0.8Ni0.8Sn. From the TGA curves it was possible to determine the Curie temperatures of each compound, with a value of 360 K for the CuMnNiSn and 913 K for the CuFe0.4Mn0.8Ni0.8Sn phase. From hardness tests it was observed that the CuMnNiSn compound presented a hardness value of 485 HV, and the CuFe0,4Mn0,8Ni0,8Sn compound presented a value of 609 HV. In general, between the two intermetallic compounds studied, the CuMnNiSn phase seems to be the most promising compound for applications in thermomagnetic motors since it presents good corrosion resistance, Curie temperature below the boiling point of water and hardness value that suggests better mechanical properties.