Structural, electrical and thermodynamical aspects of hydrogenated La-Ni-Si alloy
- 49 Downloads
The structural, electrical and thermodynamic properties of a La-Ni-Si [La = 28.9%, Ni = 67.5%, Si = 3.6%] alloy have been investigated. Powder XRD results show that the lattice constants and unit cell volume of the alloy increase after hydrogen storage. It was also found that the resistance of the alloy increased with dissolved hydrogen concentration. Hydrogen absorption pressure composition isotherms have also been investigated which show the presence of two single a and β regions and one mixed (α + β) phase. The thermo-dynamic parameters viz. the relative partial molar enthalpy (ΔH) and relative partial molar entropy (ΔS) of dissolved hydrogen, are found to be in the range 8–18 kJ (mol H)-1 and 25–63 JK-1 (mol H)-1. From the dependence of ΔH on the hydrogen concentration,X, the different phases [α, α + β, β] and phase boundaries of the alloy-H system are identified. Thermal conductivity and diffusivity of La-Ni-Si and its hydride have been measured at room temperature by using TPS technique. Thermal conductivity was found to decrease due to absorbed hydrogen in the alloy.
KeywordsPCT isotherms hydrogen storage materials TPS thermodynamics thermal properties electrical properties
Unable to display preview. Download preview PDF.
- Bououdina A M and Guo Z X 2000Mater. Technol. 15 269Google Scholar
- Mebed M M 1983High Temperature High Pressure 15 113Google Scholar
- Nakamura Y, Bowman R C and Akiba E 2004J. Alloys and Compounds 373 183Google Scholar
- Sato A and Yartys V A 2004J. Alloys and Compounds 373 161Google Scholar
- Schlapbach L (ed.) 1988Hydrogen in intermetallic compounds I/II. Topics in applied physics (Berlin: Springer-Verlag) p. 63Google Scholar
- Schlapbach L (ed.) 1992Hydrogen in intermetallic compounds I/II. Topics in applied physics (Berlin: Springer Verlag) p. 67Google Scholar
- Singh K, Saxena N S and Maharajan N B 2002Phys. Status Solidi (a)189 197Google Scholar
- Viswanathan B, Sastry M V C and Murthy S S (eds) 1998Metal hydrides (New Delhi: Narosa Publishing Company)Google Scholar
- Wipf H (ed.) 1997Hydrogen in metals III. Topics in applied physics (Berlin: Springer)Vol. 73 Google Scholar
- Wiswall R 1978Hydrogen storage in metals (eds) G Alefeld and J Volkl (Berlin: Springer Verlag) Ch. 5Google Scholar
- Yamaguchi M and Akiba E 1994Ternary alloys in material science and technology (eds) R W Cahnet al (Weinheim, Germany: VCH, Verlagessellschaff),Vol. 3B Google Scholar