| abstract |
A plurality of crystalline ceramic oxide beads in nanocrystalline volume percent, the nanocrystalline ceramic oxide beads having an average crystallite size of up to 250 nm, each bead collectively comprising, on a theoretical oxide basis, at least one of A12O3, SiO2, TiO2, or ZrO2; at least 40 percent by weight, and at least 1 percent by weight of at least one of a transition metal oxide or at least one Bi2O3 or CeO2, based on the total weight of the nanocrystalline ceramic oxide, and being visibly dark and transmitting infrared. The balls are useful, for example, for pavement marking. |