Nickel substituted FeTi hydrides: A critical study of the β-region

• Published in: Journal of the less-common metals 1986-09, Vol.123 (1), p.145-151
• Main Authors: Raj, P., Sathyamoorthy, A., Suryanarayana, P., Iyer, R.M.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Hydrides, borides, nitrides, etc., and metalloidal compounds; Inorganic compounds; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0022-5088
• DOI: 10.1016/0022-5088(86)90124-4

Mössbauer and X-ray diffraction studies are reported on the gaseous and acid hydrided samples of nickel substituted FeTi system. It has been shown that the β-hydride region does not consist of just two discrete β 1 and β 2 phases, as reported earlier for the FeTi hydrides. Instead, β 1 and β 2 represent the two extreme composition limits of a single β region and there is a continuous transformation of cell parameters between the two limits. In this report, which encompasses the first Mössbauer results covering the complete β region, it is shown that in the region of transformation from the β 1 to β 2 composition, quadrupole interaction remains almost unaltered and that the change of chemical isomeric shift can be completely explained in terms of volume expansion alone. The implications of these observations, in relation to the Fe-H bonding, proposed charge transfer, the charge on the interstitial species etc., are discussed.