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Master's Dissertation
DOI
10.11606/D.88.2003.tde-14112014-111451
Document
Author
Full name
Rosangela Bocutti
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2003
Supervisor
Committee
Angelo, Antonio Carlos Dias (President)
Bocchi, Nerilso
Tremiliosi Filho, Germano
Title in Portuguese
Modificação superficial de ligas armazenadoras de hidrogênio por óxidos metálicos a partir do método sol-gel
Keywords in Portuguese
Hidretos metálicos
Ligas armazenadoras
Método sol-gel
Óxidos metálicos
Abstract in Portuguese
Este trabalho consiste na análise da modificação superficial da liga armazenadora de hidrogênio, MmNi3,4Co0,8Al0,8, através de óxidos de Cobre, Níquel e Cobalto, utilizando-se para tanto o método sol-gel. As técnicas de caracterização usadas para o recobrimento obtido, Microscopia Eletrônica de Varredura (MEV) e Redução Térmica Programada (RTP), permitiram a observação de uma "rede" formada pelos óxidos presentes nos recobrimentos que proporcionam a aglomeração das partículas da liga, sem contudo, impedir a interação de hidrogênio com o material. O estudo do comportamento eletroquímico do recobrimento foi realizado pelas técnicas de Voltametria Cíclica , Ciclos Galvanostáticos de Carga e Descarga e Espectroscopia de Impedância. Foi possível verificar que a camada de óxidos formada pelo recobrimento através do método sol-gel melhora o desempenho da liga: em relação a sua capacidade de descarga que é significativamente aumentada, principalmente no recobrimento por óxido de cobalto e também em relação a proteção contra a pulverização do material, que proporciona maiores números de ciclos de carga e descarga
Title in English
Surface modification on hydrogen storage alloys by metal oxides via sol-gel route
Keywords in English
Hydrogen storage alloys
Metal
Metal oxides
Sol-gel route
Abstract in English
This work consists in the analysis of the surface modification of the hydrogen storage alloy, MmNi3,4Co0,8Al0,8, threugh Copper, Nickel and Cobalt oxides, using for this the sol-gel method. The characterization techniques used for the obtained surfase modification (SEM and TPR) allowed the observation of a " net " formed by the presents oxides in the surface modification that provides the gathering of the alloys particles, without however, to harm the hydrogen interaction with the material. The study of the electrochemical behavior of the surface modification was carried out by the techniques of Cyclic Voltammetry, Charge/Discharge cycles and Electrochemical Impedance. It was possible to verify that the oxides of layer formed by the surface modification for the sol-gel method improves the alloy performance: in relation to its discharge capacity that is significantly increased, mainly in the surface modification by oxide of cobalt, and also in relation to the protection against the deterioration of the material, that provides higher numbers of cycles charge and discharge
 
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Publishing Date
2014-11-21
 
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