Quantification of grain boundary equilibrium segregation by NanoSIMS analysis of bulk samples

F Christien, C Downing, K L Moore, C R M Grovenor

    Research output: Contribution to journalArticlepeer-review

    Abstract

    A technique for the quantification of equilibrium grain boundary segregation by high resolution secondary ion mass spectroscopy (NanoSIMS) on simple metallographically polished surfaces has been demonstrated for the model system of sulphur segregation to nickel grain boundaries. Samples of nickel containing 5.4 wt ppm of sulphur were annealed at different temperatures to achieve different equilibrium sulphur grain boundary concentrations, ranging from less than 1% to about 50% of a monolayer. Quantification was carried out from sulphur concentration profiles acquired across about 20 grain boundaries in each sample. An internal standard (nickel containing a known concentration of sulphur in solid solution) was used for calibration. It is found that, depending on the annealing temperature, the average grain boundary sulphur concentration ranges from 0.9 to 25.8 ng cm -2 (or 1.7 10 13 to 4.8 10 14 atoms cm -2), i.e. ∼0.015 to ∼0.43 monolayer. Thermodynamic analysis gives a segregation free energy of -97.8 kJ mol -1 and a grain boundary sulphur concentration at saturation of 26.7 ng cm -2 (or 5.0×10 14 atoms cm -2), i.e. ∼0.44 monolayer, in good agreement with previous measurements on this system. The limit of detection of the technique is shown to be as low as 0.24 ng cm -2 (or 4.5×10 12 atoms cm -2), i.e. ∼0.004 monolayer, with a counting time of only 10 min. © 2012 John Wiley & Sons, Ltd.
    Original languageEnglish
    Pages (from-to)377-387
    Number of pages11
    JournalSurface and Interface Analysis
    Volume44
    Issue number3
    DOIs
    Publication statusPublished - 2012

    Keywords

    • Auger electron spectroscopy (AES)
    • microbeam techniques
    • SIMS
    • surface analysis
    • traces
    • Annealing temperatures
    • Boundary equilibrium
    • Bulk samples
    • Counting time
    • Grain boundary segregation
    • Grain-boundary concentration
    • High resolution
    • Internal standards
    • Limit of detection
    • Microbeam technique
    • Model system
    • NanoSIMS
    • Nickel containing
    • Nickel grain boundaries
    • Polished surfaces
    • Secondary ion mass spectroscopy
    • Sulphur concentration
    • Thermo dynamic analysis
    • Atoms
    • Auger electron spectroscopy
    • Grain boundaries
    • Lunar surface analysis
    • Monolayers
    • Nickel
    • Secondary ion mass spectrometry
    • Sulfur
    • Thermoanalysis
    • Segregation (metallography)

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