Showing papers by "Stefan Hüfner published in 2013"

Increasing the wear resistance by interstitial alloying with boron via chemical vapor deposition.

Abstract: The wear resistance of a Rh(111) surface can be strongly increased by interstitial alloying with boron atoms via chemical vapor deposition of trimethylborate [B(OCH3)3] at moderate temperatures of about 800 K. The fragmentation of the precursor results in single boron atoms that are incorporated in the fcc lattice of the substrate, as displayed by X-ray photoelectron diffraction. The penetration depth of the boron atoms is in the range of at least 100 nm with the boron distribution displaying a nearly homogeneous depth profile, as examined by combined X-ray photoelectron spectroscopy and Ar ion etching experiments. Compared to the bare Rh(111) surface, the wear resistance of the boron-doped Rh surface is increased to about 400%, as probed by the scratching experiments with atomic force microscopy. The presented synthesis route provides an easy method for case hardening of micro- or nanoelectromechanical devices (MEMS and NEMS, respectively) at moderate temperatures.

Comment on “Electrochemical behavior of different structural states of the alloy Ti60Ni40” by S. Mathur et al. and related works

Abstract: In the recent studies by Shubhra Mathur et al. [1] , [2] , [3] , Ti60Ni40 alloys (metallic glasses) were investigated in terms of their corrosion behavior in dependence on ion beam irradiation [1] and in dependence on their crystalline state, i.e. crystalline, amorphous and nanocrystalline, [2] or “nanocrystalline I”, “nanocrystalline II” and “nanocrystalline III” [3] . Differences in corrosion behavior result in the formation of oxide films with different amounts of Ti0, Ti2 +, Ti3 +and Ti4 +, as deduced from the analysis of the spectral line shapes of Ti-2p spectra and O-1s spectra in X-ray photoelectron spectroscopy (XPS). Unfortunately, the authors' analysis of data from photoemission does not meet the physics of photoemission, and therefore, some statements from Ref. [1] , [2] , [3] are not beyond any doubt.