Single-Particle Mass Spectrometry of Titanium and Niobium Carbonitride Precipitates in Steels

We introduce a new method for the characterization of particlesextracted from steels. Microalloyed steelswere dissolved to extract niobiumand titanium carbonitride particlesthat are of critical importance for the mechanical properties of the steel. Size distribution and chemical composition of the particleswere analyzed by single particle inductively coupled plasma mass spectrometryand compared to electron microscopy. Mass spectrometryrapidly provided data on a large number of particles(> 2000 in 1 min) and indicated two particlepopulations that differ in size and composition: smaller particlescontained only niobium, while larger particlescontained both niobiumand titanium. Electron microscopy of a much smaller particle numberconfirmed the results and indicated that larger particleshad complex, overgrown structures. The combination of single- particle mass spectrometryand electron microscopy enables a better understanding of the precipitation processes that form the particlesduring steel pr...