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When analyzing an alloy composition of a RAM alloy with oxide dispersions of a specific element, how would one quantify the amount of that element that is bound as an oxide and the amount that is free, especially when the element is present in trace concentrations (<0.5%)?  At this point I assume we need to look at bonding information. Could this problem be solved by ICP-MS, or would one have to rely on TOF-SIMS or some other type of characterization method?

Thanks in advance for your input.

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Christopher Crouse
Senior Materials Engineer
Woodward Inc.
Fort Collins CO
9703023451
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Presuming you have a decent sized metallographic sample, use image analysis with either optical microscope or SEM to quantify the oxide dispersion in terms of volume and, a basic idea of size distribution, e.g. are there any abnormally large particles, and if so, why? Then use SEM/EDS or EPMA/WDS to analyse both the matrix for alloy content and homogeneity and the oxide particles to make sure they are what you think they are. If you can find a friendly microprobe operator that is a good way to go as the detection limits and spectral resolution are so much better. I have had the good fortune to spend my working life as a metallurgist associated with a lab with a microprobe and, several years into nominal retriement, I am still buying EPMA data from the same lab. 

One other note, if your particle dispersion is really distinctive in dark field or under crossed polars the image anal;ysis is that much easier.

Regards,

Peter Northover

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Peter Northover
Retired
University of Oxford
+44 1865 820543
peter.northover@retired.ox.ac.uk
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