Effects of laser pulsing on analysis of steels by atom probe tomography

When performing atom probe tomography analysis, laser pulsing was found very helpful for some types of steels, which are prone to premature sample failure under voltage pulsing. Rather accurate chemical compositions for both matrix and precipitates were obtained by voltage- and laser-pulsed mode. Some special issues on the effects of laser are discussed. A simple correction based on the 13Cn+ and 10Bn+ peak was used to quantify C in the carbide (M23C6, M=Fe, Cr, Mo) and B in the boride (M3B2, M=Mo, Fe, Cr, V). The mass resolution in laser mode is sufficient to resolve 56Fe2+ and 14N21+ at 28 Da. Small peak shifts were found in the spectrum due to reflectron aberrations.