New concentration data for Ru, Rh, Pd, Re, Os, Ir and Pt are presented for three chromitite reference materials. A simple and very effective procedure was applied for the measurements. Samples were spiked with enriched isotopes and digested in a HNO3/HCl (5+2) acid mixture at 300 °C and 125 bar (1.25 × 107 Pa) pressure in a high pressure asher (HPA‐S, Anton Paar). The programme settings were changed as a function of mass (0.5, 1, 2 and 4 g) and time (5 and 15 hours). Complete chromitite dissolutions for three digestions at each setting were monitored using XRD analyses of the amorphous residue after digestion. The osmium concentration was determined by sparging the OsO4 that was formed during digestion into a quadrupole ICP‐MS. After drying and re‐dissolution of the remaining residue, the other PGEs were separated on‐line from their matrix in a simple cation‐exchange column that was coupled to the ICP‐MS. The concentrations were determined through isotope dilution and external calibration (Rh). By using the on‐line separation, we were able to control interference effects (isobaric and molecular), which resulted in highly reproducible data. Replicate measurements of the reference material CHR‐Bkg (SARM CRPG‐CNRS) with sample masses ranging from 0.5 to 4 g showed very small standard deviations compared to the results from the initial collaborative trials and published data (e.g., 3.2% RSD vs. 32% RSD for Ru). Results for platinum showed the largest scatter, which is currently attributed to the small size of the test portion. In addition to CHR‐Bkg, the first results for two chromitite reference materials “platinumore” GAN Pt‐1 and “chromiumore” HHH issued by the Central Geological Laboratory of Mongolia are presented.
Chromium nitride layers produced by reactive sputtering with different process parameters were characterized with EPMA, SIMS depth profiling, and three-dimensional SIMS imaging. EPMA results are used to quantify the major components of the films while SIMS is used to gather information about the distribution of the elements chromium, silicon, nitrogen, and oxygen. For all measurements a Cs+ primary ion beam was applied to sputter the sample. Positive MCs+ (M represents the element to be analyzed) secondary ions were detected. SIMS depth profiling shows an even distribution of all major elements except oxygen, which shows significant differences in concentration and distribution depending on the process parameters. CrN layers produced at low sputter power have much higher concentration of oxygen than layers produced with high sputter power. Heating the silicon substrate during the process results in an enrichment of oxygen at the interface.
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