Corrosion passivation of plasma nitrided iron

Corrosion passivation of plasma nitrided iron

A403 Surface Science 189/190 (1987) 221-225 North-Holland, Amsterdam CORROSION PASSIVATION M. JUR(~IK-RAJMAN 221 OF PLASMA NITRIDED IRON a n d S...

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A403 Surface Science 189/190 (1987) 221-225 North-Holland, Amsterdam CORROSION

PASSIVATION

M. JUR(~IK-RAJMAN

221 OF PLASMA

NITRIDED

IRON

a n d S. V E P [ 1 . E K

Institute of Inorganic Chernistw, University of Ziirich, Winterthurerstrasse 190, CH-8057 Ziirich, Switzerland Received 31 March 1987; accepted for publication 7 May 1987 Corrosion passivation of iron nitrided in a glow discharge has been studied by means of potentiodynamic and galvanostatic methods in NaC1 water solution. The results show that the corrosion resistance of iron nitride is due to a formation of an anodic passivation layer.

226

Surface Science 189/190 (1987) 226-231 North-Holland, Amsterdam

ADSORPTION OF MONOVALENT ON THE GaAs(ll0) SURFACE C.M. BERTONI

*, C. C A L A N D R A ,

METALS C. M A R I A N I

a n d S. V A L E R I

Dipartimemo di Fisica, Universit~ di Modena, via G. Campi 213/A, 1-41100 Modena, Italy Received 13 April 1987; accepted for publication 15 April 1987 We present a synchrotron radiation investigation on the electronic properties of the GaAs(110) surface covered with alkali metals (Cs, K). As and Ga core level spectra for the clean surface are compared with those obtained after metal deposition. Satellites structures at about 4 and 6 eV from the main peak are found, which can be interpreted in terms of the excitation of overlayer plasma modes. We also study comparatively the effect of K and Cs on the oxidation of the GaAs surface.

232

Surface Science 189/190 (1987) 232-237 North-Holland, Amsterdam

SELF-CONSISTENT CALCULATIONS OF WORK FUNCTIONS AND RELAXATIONS OF METALS UPON ALKALI ADSORPTION P.A, S E R E N A

a n d N, G A R C I A

Departamenw de F&ica de la Materia Condensada C-Ill, Facultad de Ciencias, Universidad Autbnoma de Madrid, Cantoblanco, E-28049 Madrid, Spain Received 30 March 1987; accepted for publication 14 April 1987 We present self-consistent calculations of the work function of the clean aluminum (111), (100) and (110) faces, taking into account the surface relaxation and we study the changes of the substrate work function due to adsorption of alkali atoms. The calculations are done by using the local density approximation and including in a total way the ion pseudopotential in the self-consistent procedure. Our finding shows: (i) the relaxation of metal layers on the work function are not important, (ii) in order to explain the work function dependence on coverage it is necessary to introduce an adsorbate-metal substrate distance that increases with coverage. Our calculations show excellent agreement with experiment on Cs/AI(111).