SIMS measurement of oxygen content in gamma-TiAl single crystals and polycrystalline alloys with Nb addition

The oxygen content of binary Ti₄₅Al₅₅ and ternary Ti₄₄Al₅₂Nb₄ single crystals and polycrystalline alloys
was quantified with secondary ion mass spectrometry (SIMS) using Cs⁺ primary ions. The SIMS measurements
were calibrated with respect to concentration and depth scale using oxygen implanted samples.
The measurements revealed considerably lower oxygen content in the ternary alloy indicating a protecting
impact of the Nb addition in grain boundaries against oxygen contamination. The relative strong
surface oxide layer thickness of the investigated samples was determined to about 1µm.