ISSN:
1432-0630
Keywords:
61.70 Wp
;
66.30 Jt
;
79.60 Eq
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract Carbon dissolved in the (100) surface of MgO single crystals, grown by arc-fusion, was studied by x-ray photoelectron spectroscopy, XPS, between 80–920 K. In the complex C 1s spectrum observed the signal due to the carbon species contained in the MgO structure are distinguishable from those due to contamination. The XPS data support the conclusions, derived with a lesser depth resolution, from earlier12C(d, p)13C concentration profile analysis [Wengeler et al.: J. Phys. Chem. Solids43, 59–71 (1982)] that the carbon in MgO strongly segregates into the subsurface zone. A typical bulk C concentration is 300 wt.-ppm, corresponding to about 1000 at.-ppm. The C concentration in the topmost 5–10 nm analyzed by XPS, however, may be as high as one C per two O. With increasing temperature the C concentration decreases. Upon cooling the C concentration rises in a reversible manner. The diffusion coefficient of carbon in MgO was determined by measuring the subsurface C concentration increase at different temperatures after Ar ion sputtering: Dc/Mgo=2×10−9exp(−22.5±2.5/RT)[cm2s−1 and KJ·mole−1].
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00617711
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