Evolving surface properties of stirred wet milled aluminum-doped titanium dioxide: A discretely heterogeneous system

The stirred wet milling of aluminum-doped TiO 2 was considered. At speeds 2500–6000 rpm, the pH i.e.p. shifted from 5.7 to ~8, while at 8000 rpm shift in smaller. Milling reduced performance attributed a change predominant mechanism. XPS revealed an approximate linear correlation between relative surface alumina content (at.%) and particle specific area, with shifting corresponding alumina. lower rationalized by high resolution TEM image analysis. Samples milled (beyond mill energies used pigment production) produced significant quantity ultra-fines (d 50 ≪ nm) which coated larger particles. These were predominately titania-like suppressed . study confirmed particles initially titania surface-rich bulk increasingly exposed during milling. • Surface chemistry Al-doped sensitive regime. Particle Al increased ca. linearly SSA. High shear led formation rich ultra-fines. Ultra-fines base screened properties.