Aluminum hydroxide, bayerite, boehmite, and gibbsite ToF-SIMS spectra in the positive ion mode. II

Abstract

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was performed for boehmite (AOH-60) and its potential products of oxidation including pseudo-boehmite (AOH-180), α- and γ-Al2O3, and α- and γ-Al(OH)3. Since boehmite often forms on cladding materials to prevent corrosion, surface analysis techniques are performed to determine the amount of oxidation present. This ToF-SIMS spectral library is of significance because it includes boehmite and its potential oxidation products (i.e., aluminum oxide and hydroxide), which can be used to compare to spectra obtained for real-world samples containing boehmite. Furthermore, ToF-SIMS is often used as a complementary technique to x-ray photoelectron spectroscopy due to its surface sensitivity and ability to compare spectra via a multivariate analysis, therefore establishing that the molecular signatures of boehmite and relevant compounds are essential for peak identification. The SIMS spectra shown are acquired from commercially available powders, which were deposited onto a silicon wafer substrate via liquid slurry drop casting. This library of SIMS mass spectra will serve as a comparison of boehmite [γ-AlO(OH)], pseudo-boehmite [AlOOH⋅nH2O], α- and γ-aluminum oxide [Al2O3], and α- and γ-aluminum hydroxide [Al(OH)3] in the positive ion mode, which compliments those reported in the negative ion mode {Part I [L. Strange et al., Surf. Sci. Spectra 29(2), 025001 (2022)]}.