Atom Probe Tomography of Yttrium‐Doped Barium–Cerium–Zirconium Oxide with NiO Addition

Abstract

The perovskite ceramic BaCe0.2Zr0.7Y0.1O3‐δ (BCZY27) with a small addition of NiO has previously been shown to densify at a reasonable sintering temperature while maintaining high protonic conductivity. However, some questions remain regarding the role, location, and resulting phase of the NiO addition. Transmission electron microscopy and atom probe tomography (APT) were used to analyze BCZY27 specimens before and after use as a hydrogen separation membrane. The effects of electrolyte operation on the local chemistry were explored. Grain boundaries were specifically targeted due to their higher energies and importance for overall conductivity. The compositions measured by APT were found to be dependent on the laser energy used for analysis, but conditions were found which gave results reasonably consistent with x‐ray fluorescence results. Specimens before and after electrolytic use showed no measureable difference in the local chemistry. Most grain boundaries exhibited little compositional variation from the bulk material, with only a slight increase in yttrium being apparent. A few grain boundaries had particles 2–15 nm in diameter, which were found by APT to be NiO.

Surface and grain‐boundary excess of ZnO‐doped SnO2 nanopowders by the selective lixiviation method

“…However, it is hard to obtain good images of isolated grain boundaries of agglomerates of nanoparticles with crystallite size lower than 10 nm as far as determining the chemical composition of layers as thin as some 10 of nanometers next to interface. The combination of electronic microscopy with Atomic Probe Tomography (APT) has been successfully used to create a 3D map of chemical distribution of grain‐boundary segregation in dense nanometals and ceramic materials . However, APT analysis of porous ceramic nanomaterials or agglomerate nanopowders is an open issue.…”

“…The combination of electronic microscopy with Atomic Probe Tomography (APT) has been successfully used to create a 3D map of chemical distribution of grain-boundary segregation in dense nanometals 32 and ceramic materials. 33,34 However, APT analysis of porous ceramic nanomaterials or agglomerate nanopowders is an open issue. Tin oxide is an interesting inorganic material for segregation studies because of the high stability: the rutile structure is stable from room temperature to approximately 1300°C, the additive solubility is low, and the water solubility is low.…”

Quantification of grain boundary defect chemistry in a mixed proton‐electron conducting oxide composite

“…NiO has been seen to segregate to grain boundaries in previous studies of BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ . 31 However, SEM imaging of the samples in the present work revealed larger clusters of NiO at triple points as shown in Figure S3. A considerable amount of variation was found between grain boundaries; however, good agreement of concentration quantification between samples from the same grain boundary was discovered.…”

“…Ni and Si impurities were at the detection limit of the APT measurement and no visible segregation can be found. NiO has been seen to segregate to grain boundaries in previous studies of BaZr 0.7 Ce 0.2 Y 0.1 O 3‐δ . However, SEM imaging of the samples in the present work revealed larger clusters of NiO at triple points as shown in Figure .…”

Correlative Atom Probe Tomography and Transmission Electron Microscopy Analysis of Grain Boundaries in Thermally Grown Alumina Scale

“…Correlative analysis has made a tremendous impact in recent years and has already been successfully applied for characterization of many alloys and semiconducting materials (Arslan et al, 2008; Gorman et al, 2008 b ; Schreiber et al, 2013; Herbig et al, 2014; Toji et al, 2014; London et al, 2015; Aguiar et al, 2016; Zhou et al, 2016; Cojocaru-Mirédin et al, 2018). On the other hand, the correlative approach is rarely applied to ionic compounds such as oxides (Diercks et al, 2014; Kirchhofer et al, 2015; Perea et al, 2015) and only a few correlative studies of TGO scales have been published so far (Baik et al, 2013; Chen et al, 2015). One of the obstacles in application of the correlative approach as a routine characterization pathway is a lack of cost-efficient commercial solutions enabling easy, safe, and reliable transfer of specimens between TEM, APT, and focused ion beam (FIB) tools.…”