Static SIMS studies of coated TiO2 pigments

In this study we report on an applied SIMS investigation on Al2O3–SiO2 coated TiO2 pigments. The samples were measured using a quadrupole SIMS instrument with Xe+ ions. SIMS spectra were recorded both from undamaged surface and after light sputtering. The aim of the study was to evaluate the surface composition and the coating coverage of the TiO2 cores. Eight Al2O3–SiO2 coated TiO2 pigments were chosen. This type of pigment is typically used as white pigments in weather durable paints. The material consisted of polycrystalline TiO2 cores, typically 0.2–0.4 μm in diameter, which were coated with aluminium and silicon oxides and/or hydroxides. The SIMS results showed that the surface composition of the precipitation layers varied with the precipitation process, not with the quantity of the coating material. The results were in good correlation with results from reported XPS analyses and zeta potential measurements. To determine the coating quality, SIMS coating‐to‐core atomic ratios were calculated and compared with similar ratios from XRF and XPS and also from XPS Tougaard ratios D for the substrate Ti 2p emission. The variations in the results between the three independent surface techniques were mainly due to different analysis volumes of the methods.