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La expansión térmica negativa gigante en los compuestos de tipo NaZn13 La(Fe, Si, Co) 13 de tipo NaZn13
Rongjin Huang1, Yanying Liu, Wei Fan
1Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
Journal of the American Chemical Society
|July 27, 2013
Resumen
Los compuestos La(Fe, Si) 13 exhiben una expansión térmica negativa (NTE) útil para aplicaciones industriales. La optimización de la composición, particularmente con cobalto, amplía la ventana de NTE y mejora su potencial para aplicaciones a temperatura ambiente.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física del estado sólido Física del estado sólido
Sus antecedentes:
- Los compuestos a base de La ((Fe, Si) 13) son conocidos como materiales magnetocalóricos.
- Estos materiales muestran una expansión térmica negativa significativa (NTE) cerca de su temperatura de Curie.
- Su potencial para aplicaciones NTE industriales no se ha explorado completamente.
Objetivo del estudio:
- Sintetizar e investigar las propiedades lineales de NTE de los compuestos LaFe13-xSix y LaFe11.5-xCoxSi1.5 del tipo NaZn13.
- Para optimizar la composición química para mejorar las propiedades de NTE.
- Evaluar el potencial de estos compuestos como materiales NTE para uso industrial.
Principales métodos:
- Síntesis de los compuestos LaFe13-xSix y LaFe11.5-xCoxSi1.5 del tipo NaZn13.
- Investigación de las propiedades de la expansión térmica negativa lineal (NTE) a través de la optimización de la composición.
- Ajuste de las características de NTE mediante el ajuste de los niveles de dopaje de cobalto (Co).
Principales resultados:
- La composición química optimizada modificó con éxito los cambios bruscos de volumen en una expansión continua.
- El aumento del contenido de cobalto (Co) desplazó el NTE hacia temperaturas más altas y amplió la ventana operativa.
- El compuesto LaFe10.5Co1.0Si1.5 exhibió un coeficiente NTE lineal de -26.1 × 10(-6) K(-1) en un rango de 110 K (240350 K), incluida la temperatura ambiente.
Conclusiones:
- La composición controlada de los compuestos a base de La (Fe, Si) 13 permite propiedades sintonizables de NTE.
- El significativo NTE y la amplia ventana operativa sugieren potenciales aplicaciones industriales.
- Estos materiales son prometedores como materiales NTE efectivos, especialmente para aplicaciones a temperatura ambiente.
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