Analysis of composition and size distribution of inclusions in Fe-10Mass%Ni alloy deoxidized by Al and Mg using laser ablation ICP mass spectrometry

The laser ablation ICP mass spectrometry (LA-ICP-MS) has been applied for the quantitative analysis of the inclusion composition and size distribution in an Fe-10mass%Ni alloy deoxidized by Al and/or Mg. The composition and size distributions of particles in the range of dv<10 μm obtained from LA-ICP-MS are compared with those from SEM with EPMA. It was found that total size distribution of inclusions in the range of dv>1 μm obtained from LA-ICP-MS agrees reasonably well with that on film filter after electrolytic extraction from SEM. The underestimation of particle number density obtained from LA-ICP-MS is found in the range of dv<1 μm and it can be explained by the limit of LA-ICP-MS analysis for small size particles on polished metal surface. The LA-ICP-MS is superior to EPMA for the analysis of nonuniform complex inclusions. The inclusion size obtained by Mg followed by Al addition is smaller than that obtained by Al followed by Mg addition. The total compositions for most of inclusions in these experiments are not spinel composition. (author)