Abstract
Abstract Analyzing porous (nano)materials via atom probe tomography has been notoriously difficult. Voids and pores act as concentrators of the electrostatic pressure, which results in premature specimen failure, and the electrostatic field distribution near voids leads to aberrations that are difficult to predict. In this study, we propose a new encapsulating method for porous samples using a low melting point Bi–In–Sn alloy, known as Field's metal. As a model material, we used porous iron made by direct-hydrogen reduction of single-crystalline wüstite. The complete encapsulation was performed using in situ heating on the stage of a scanning electron microscope. No visible corrosion nor dissolution of the sample occurred. Subsequently, specimens were shaped by focused ion-beam milling under cryogenic conditions at −190°C. The proposed approach is versatile and can be applied to provide good quality atom probe datasets from micro/nanoporous materials.
Highlights
Atom probe tomography (APT) provides 3D compositional (Miller & Forbes, 2009; Larson et al, 2013; Gault et al, 2021), and sometimes crystallographic information (Gault et al, 2012) from a material’s microstructure with sub-nanometer resolution (De Geuser & Gault, 2020; Jenkins et al, 2020)
We have demonstrated a new method for preparing APT specimens from a sample containing micro- to nanopores
A spongelike iron sample prepared by hydrogen reduction from a single crystal of wüstite was infiltrated and embedded in a fusible Bi– In–Sn alloy
Summary
Atom probe tomography (APT) provides 3D compositional (Miller & Forbes, 2009; Larson et al, 2013; Gault et al, 2021), and sometimes crystallographic information (Gault et al, 2012) from a material’s microstructure with sub-nanometer resolution (De Geuser & Gault, 2020; Jenkins et al, 2020). Many recent studies have sought to apply APT to porous materials (El-Zoka et al, 2017; Mouton et al, 2017; Barroo et al, 2019), nanoparticles (Li et al, 2014; Yang et al, 2019; Lim et al, 2020), and materials with cracks (Meisnar et al, 2015) or voids (Wang et al, 2020) Leaving these pores and cracks open introduces stress concentrators that make specimen preparation difficult and complicate the reconstruction of the analyzed specimens due to trajectory aberrations and premature fractures during analysis (Pfeiffer et al, 2015). To deal with this problem, the APT community has established the elimination of these pores/voids/cracks using foreign chemical methods, for instance, electrodeposition (El-Zoka et al, 2018a; Kim et al, 2020), electron beam-induced deposition (Barroo et al, 2020), atomic layer deposition (Larson et al, 2015), organic polymer resin deposition (Perea et al, 2016), and other
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
