In-depth compositional analysis of ceramic (Bi2O3)0.75(Er2O3)0.25 by AES and XPS

Abstract

Abstract. The chemical composition of dense ceramics of erbia-stabilized 6-Bi203 was analyzed by Auger electron spectroscopy (AES) depth profiling using Ar + ion sputtering. The relative sensitivity factors (rsI) and sputter rates of bismuth and erbium in this material have been determined by electron probe microanalysis (EPMA) and chemical analysis. These results, supplemented by data from angle resolved X-ray photoelectron spectroscopy (ARXPS), shows a bismuth enrichment at the surface. Evidence has been found for reduction of the bismuth-oxide at the outermost part of the surface layer.Key words: AES, ceramic, sputtering, XPS.As discussed by Burggraaf and Winnubst [1] the chemical composition of grain boundaries and surfaces of ceramic materials controls sintering behaviour, grain growth and related properties such as fracture strength, toughness, wear resistance and also electrochemical and catalytic properties. Ceramic erbia stabilized 6-Bi203 may find commercial use in oxygen pumps, sensors and solid oxide fuel cells because of its high oxide ion conductivity. The aim of our research is to elucidate a possible segregation at the surface of this type of material.Auger electron spectroscopy (AES) can be applied for quantitative analysis of surfaces, provided that the relative sensitivity factors (rst) are known. The rsf values of the elements are known from literature [2] but often not applicable for composite materials, as for example shown by Keim and Aite [3] for silicon nitride. Experi-

Surface Modification of Multiferroic BiFeO<sub>3</sub> Ceramic by Argon Sputtering

“…The peak heights of Fe 2p, O 1s, and Ba 3d signals increased, but the Bi 4f signal increased, then decreased, and then leveled off as the sputter time increased in Figure 1. This surface segregation of Bi has been observed and reported by other studies, for example, in the (Bi 2 O 3 ) 0.75 (Er 2 O 3 ) 0.25 ceramic, titania films, and bismuthiron-garnet films [18]- [20]. In order to reconfirm this trend and understand how the surface composition/bonding environment changed as a function of sputter time, the multiplex spectra of C 1s (from 290 to 280 eV), Bi 4f 5/2 and 4f 7/2 (from 170 to 153 eV), Fe 2p 1/2 and 2p 3/2 (from to 736.2 to 700 eV), O 1s (from 535 to 525 eV), Ti 2p 3/2 (from 470 to 450 eV), and Ba 3d 3/2 and 3d 5/2 (from 803 to 775 eV) were collected.…”