ریز ساختار و ساختار هیدراسیون اولیه آلیاژ TiFe
Abstract
Introduction
Result and discussion Conclusion
Acknowledgment
Appendix A. Supplementary data
References
Abstract
In this paper, the effect of Zr and Mn on the microstructure and first hydrogenation kinetic of TiFe alloy is reported. TiFe alloy to which Zr, Mn or a combination of both have been added were synthesized by induction melting. First hydrogenation of all alloys was performed at room temperature under 20 bar of hydrogen. We found that addition of manganese makes possible activation at room temperature, but kinetics was very sluggish. Alloy with 2 wt% Zr did not absorb hydrogen. However, with addition of 4 wt% Zr, the alloy absorbed 1.2 wt% of hydrogen. A synergetic effect was found when zirconium was added along with manganese. Alloy with 1 wt% Mn and 2 wt% Zr had better kinetics than the alloy having only Mn or only Zr. The maximum hydrogen capacity was also greater at ~1.8 wt% after 7 h. Combination of 4 wt% Zr and 2 wt% Mn absorbed 2 wt% of hydrogen in 5 h. The rate limiting step for each activated alloy was found to be diffusion controlled with decreasing interface velocity.
Introduction
Emission of greenhouse gases due to the intensive use of fossils fuel demands the development of alternative fuels [1,2]. Hydrogen fulfills the criteria as an alternative energy carrier due to its high energy density, availability and less impact on the environment when produced by renewable resources such as solar and wind energies [3,4]. One of the major challenges in the development of hydrogen economy is to store hydrogen safely and at low cost [5]. The solid-state hydrogen storage in metal hydrides presents some advantages over the conventional high-pressure cylinders and liquid hydrogen because of its high volumetric capacity, low pressure, and low temperature of operation [6-10]. Metal hydrides can also be used as a negative electrode in rechargeable batteries such as Ni-MH [11-13]. Two of the major characteristics of metal hydrides should have in order to fulfill the requirements for mobile and stationary applications are low cost and utilization in a practical range of temperature and pressure (0e100 C, 1-10 atm) [14-16].