Artigo de peri??dico
Synthesis by high-energy ball milling of MgH2-TiFe composites for hydrogen storage
Registro en:
1662-9752
899
10.4028/www.scientific.net/MSF.899.13
Autor
LEAL NETO, RICARDO M.
SILVA, RAFAEL de A.
FLORIANO, RICARDO
COUTINHO, GRAZIELE C.S.
FALCAO, RAILSON B.
LEIVA, DANIEL R.
BOTTA, WALTER J.
Resumen
The aim of this work is to investigate the influence of some processes variables on the
microstructure and hydrogen absorption kinetics of MgH2 - X wt.% TiFe composites. Samples were
synthesized by high-energy ball milling in a planetary (X = 40, 50, 60) and shaker mill (X = 40)
under high-purity argon atmosphere. Commercial MgH2 instead of Mg powder was used in order to
reduce adherence on the vial and balls. TiFe powder was previously produced by ball milling a
mixture of TiH2 and Fe powders followed by a reaction synthesis at 600??C. Milled composites
samples were characterized by XRD and SEM analysis. Milling time was preliminary investigated
(X = 40) in the planetary ball mill (6 to 36h). TiFe particle size reduction was shown to be difficult
since they are surrounded by MgH2 matrix. Strong particle reduction was obtained by using a
shaker mill only for 2 hours and adding cyclohexane as process control agent. No reaction between
MgH2 and TiFe compound was observed in any milled sample. Hydrogen absorption kinetics
measurements of the as-milled samples were conducted on an Sieverts' type apparatus at room
temperature after hydrogen desorption at 350??C under vacuum. The best hydrogen kinetics (3 wt%
at the first hour) was attained by the planetary milled sample (36 h). Higher hydrogen capacity was
observed for the sample milled in the shaker mill (4.0 wt.%), but only after 13h. Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP) Conselho Nacional de Desenvolvimento Cient??fico e Tecnol??gico (CNPq) Coordena????o de Aperfei??oamento de Pessoal de N??vel Superior (CAPES) FAPESP: 01/03961-4; 07/50018-2