Erhard Grallath

Comparative investigation on copper oxides by depth profiling using XPS, RBS and GDOES

Depth profiling has been performed by using X-ray photoelectron spectrometry (XPS) in combination with Ar-ion sputtering, Rutherford backscattering spectrometry (RBS) and glow discharge optical emission spectrometry (GDOES). The data obtained by XPS have been subjected to factor analysis in order to determine the compositional layering of the copper oxides. This leads to two or three relevant components within the oxide layers consisting of Cu2O or CuO dependent on the sample preparation. GDOES measurements show sputtering profiles which are seriously influenced by a varying sputter rate. To ensure the results obtained so far, RBS measurements of the oxide layers have been carried out in order to discover artefacts of the other methods used and to demonstrate the excellent suitability of RBS for quantitative analysis of these layers. Chemical analysis consisting of (1) carrier-gas fusion analysis (CGFA) and (2) selective dissolution of Cu2O/CuO allows the determination of the total amount of oxygen and copper, respectively, and can serve as a cornerstone of quantitative analysis.

Application of factor analysis in electron spectroscopic depth profiling on copper oxide

Depth profiles were taken by x-ray photoelectron spectrometry/Ar-ion sputtering from copper sheets oxidized during 30 min in air at 200 or 300°C, respectively. The data of the depth profiles were subjected to factor analysis in order to determine the relevant components of the copper oxide layers. Factor analysis shows the existence of a cuprous oxide layer (Cu2O) on both specimens under bombardment with 2 keV argon ions during depth profiling. Rutherford backscattering measurements and carrier gas fusion analysis were successfully applied to determine the oxygen content of the oxide layers. Results corroborate the identification of Cu2O in both layers.

Bestimmung von Argon neben Stickstoff und Sauerstoff in pulvermetallurgisch hergestellten Werkstoffen mit einem modifizierten Trägergas-Heißextraktionsgerät

SummaryThe modification of a commercial carrier-gas fusion instrument for the simultaneous determination of argon is described. In order to separate argon from nitrogen, a gas-chromatographic column with molecular sieve was incorporated between the absorption traps for H2O and CO2 and the thermal conductivity detector. A computing integrator was used for the evaluation of the detector signals. The calibration was done by introduction of defined volumes of dry air into the carrier-gas line. The conditions for the liberation of argon from samples of ODS-alloys and the separation from the other extracted gases were optimized. Results of analysis of powders and compact samples were compared with the results obtained by means of a vacuum-fusion instrument. In the concentration range 25 to 50 μg/g argon the relative standard deviations were 1.5 to 3% (six determinations). With powders of 3 to 5 μg/g relative standard deviations of about 8% were achieved. The limit of detection for 1 g samples was found to be ca. 0.5 μg/g.

Determination of carbon in high-purity iron by a modified combustion method

SummaryA newly developed apparatus was used for the determination of carbon in pure and high-purity iron samples. It enables the differentiation between the carbon content of the surface and the bulk by temperature-controlled heating in an oxygen flow. The carbon dioxide formed was measured by an IR-gas analyzer, type BINOS. At sample weights of about 0.1 g with surface areas of about 0.5 cm2, carbon concentrations of ≥0.04 Μg/cm2 of the surface and of ≥0.2 Μg/g of the bulk can be determined. By means of the results on 6 certified reference materials with low carbon concentrations and on 7 high-purity iron samples, the influence of sample form, treatment and storage on surface and bulk carbon is demonstrated. The findings confirm the already formerly stated tendency to too high values in the certificates of reference samples with carbon concentrations in the lower Μg/g range.