X-ray and Neutron Diffraction Study of Nanocrystalline Ti−Ru−Fe−O Compounds

Abstract

The effect of adding oxygen on the structure of nanocrystalline Ti-Ru-Fe compounds obtained by high-energy ball-milling has been studied by X-ray and neutron diffraction using a Rietveld refinement analysis. It is shown that oxygen atoms readily oxidize Ti to form various types of titanium oxides depending on the oxygen content. In each case, a simple cubic structure (cP2-CsCl) is also formed during milling but with a concentration higher than expected on the basis of various reaction schemes. Through a detailed analysis of the neutron and X-ray diffraction peaks, it is shown that the 1a site of the CsCl-type unit cell is depleted from Ti atoms by preferential substitution with Fe. At high oxygen concentration, the alloy is a multiphase material containing Ti 2-x Ru 1+y Fe 1+z , Ti oxides, Ru, and Fe.

Neutron and in Situ X-ray Investigation of Hydrogen Intake in Titanium-Based Cubic Alloys

“…This was shown through a detailed analysis of both X-ray and neutron diffraction data of a series of nanocrystalline Ti:Ru:Fe:O (2:1:1:w), where w was varied from 0 to 2. 7 In that study, it was demonstrated that the presence of oxygen in the powder mixture leads to the formation of a Ti-depleted B2 cubic phase, Ti 2-x Ru 1+y Fe 1+z , with x being as large as 0.74 when w ) 1.5. On the basis of these structural differences, it was hypothesized 4,7 that the improved stability of the nanocrystalline Ti:Ru:Fe:O (2:1:1:2) materials could arise as a consequence of a modification of the intrinsic hydrogen absorption properties of the Ti-depleted B2 cubic phase.…”

Surface modification of co-evaporated thin films upon oxygen and air exposure

“…Obviously, oxygen has a beneficial effect on the stability of the electrode. As clearly depicted by these examples, the corrosion and catalytic properties depend on the composition and structure of the electrode surface [10,[12][13][14][15][16][17][18] and is affected by the whole sample history or treatment.…”

“…For example, the cathodic overpotential of electrodes made from nanocrystalline materials obtained through milling of Ti:Ru:Fe:O (2:1:1:2) does not vary over a period of 1000 h, nor does the electrode show any sign of degradation after this prolonged test [11]. In comparison, the cathodic overpotential of an electrode made from the O-free material starts to increase (becoming more cathodic) after only $100 h [12]. Obviously, oxygen has a beneficial effect on the stability of the electrode.…”

A new family of high performance nanostructured catalysts for the electrosynthesis of sodium chlorate

“…Most of the energy losses in the present technology come from the high overpotential associated with the iron cathodes. The nanocrystalline Ti 2 RuFe alloy prepared by high energy ball milling (HEBM) has been identified as a potential alternative but the material absorbs hydrogen and decrepitates during electrolysis [1][2][3][4][5][6][7][8][9][10]. Oxidizing the material into Ti 2 RuFeO 2 helps reducing the hydrogen absorption but long term electrolysis experiments conducted on coatings of this material prepared by thermal spray have not been successful [10].…”