TY - THES

T1 - Advancements in elemental analysis of Ti(C,N) coatings using atom probe tomography

AU - Schiester, Maximilian

N1 - no embargo

PY - 2024

Y1 - 2024

N2 - Atom probe tomography (APT) has emerged as a crucial tool in materials science, offering near-atomic resolution and enabling to investigate the three-dimensional distribution of elements. However, the accuracy of elemental composition observed via APT is significantly influenced by acquisition parameters, in particular the effective electric field and laser pulse energy (LPE). Within this study, the impact of these parameters on compositional biases is systematically investigated using a series of Ti(C,N) coatings, ranging from TiN to TiC. Advanced acquisition parameters, available in modern atom probes were utilized, revealing improved evaporation conditions and a higher specimen survival rate. For this purpose, measurements were carried out with active constant field control, auto pulse rate control and auto pulse energy control. The subsequent comparison with the results obtained with the conventional standard parameters made it possible to analyze the advantages of the advanced acquisition parameters. Customized software scripts were developed to enhance data analysis, including peak decomposition for accurate elemental composition determination. The investigation illuminated various compositional biases dependent on the C/(C+N) ratio and LPE. At low LPEs, preferential retention of carbon and nitrogen was observed. Carbides exhibited tendencies to evaporate as adjacent groups or large molecules, with dissociation effects becoming pronounced at very high LPEs. These findings highlight the significance of optimized electric field strength for achieving a high elemental accuracy. In conclusion, this work provides comprehensive insights into the evaporation behavior of nitrides and carbides in atom probe tomography, facilitating improved elemental analysis for future investigations. Utilization of advanced acquisition parameters is recommended for enhanced measurement efficiency and accuracy. By understanding and controlling acquisition parameters, researchers can mitigate compositional biases and advance the capabilities of atom probe tomography in materials science research.

AB - Atom probe tomography (APT) has emerged as a crucial tool in materials science, offering near-atomic resolution and enabling to investigate the three-dimensional distribution of elements. However, the accuracy of elemental composition observed via APT is significantly influenced by acquisition parameters, in particular the effective electric field and laser pulse energy (LPE). Within this study, the impact of these parameters on compositional biases is systematically investigated using a series of Ti(C,N) coatings, ranging from TiN to TiC. Advanced acquisition parameters, available in modern atom probes were utilized, revealing improved evaporation conditions and a higher specimen survival rate. For this purpose, measurements were carried out with active constant field control, auto pulse rate control and auto pulse energy control. The subsequent comparison with the results obtained with the conventional standard parameters made it possible to analyze the advantages of the advanced acquisition parameters. Customized software scripts were developed to enhance data analysis, including peak decomposition for accurate elemental composition determination. The investigation illuminated various compositional biases dependent on the C/(C+N) ratio and LPE. At low LPEs, preferential retention of carbon and nitrogen was observed. Carbides exhibited tendencies to evaporate as adjacent groups or large molecules, with dissociation effects becoming pronounced at very high LPEs. These findings highlight the significance of optimized electric field strength for achieving a high elemental accuracy. In conclusion, this work provides comprehensive insights into the evaporation behavior of nitrides and carbides in atom probe tomography, facilitating improved elemental analysis for future investigations. Utilization of advanced acquisition parameters is recommended for enhanced measurement efficiency and accuracy. By understanding and controlling acquisition parameters, researchers can mitigate compositional biases and advance the capabilities of atom probe tomography in materials science research.

KW - Atomsondentomographie

KW - Elementanalyse

KW - Elektrische Feldstärke

KW - Chemische Zusammensetzung

KW - Atom probe tomography

KW - Elemental accuracy

KW - Electric field strength

KW - Compositional biases

M3 - Master's Thesis

ER -