High energy ball-mill behavior of titania + hydroxyapatite composite nano-powders

Ribbons of the Zn–Al eutectoid alloy obtained by melt-spinning, were heat treated at 350 °C during 30 min in a free atmosphere furnace, and then quenched in liquid nitrogen. The temperature correspond to β phase zone, which has a triclinic crystalline structure [1, 2]. Some evidence, obtained by X-ray diffraction, show that the structures present in the just quenched material are both close-packed hexagonal (η-phase) and rhombohedral (R-phase). X-ray diffractograms taken in the same ribbons after annealed 500 h at room temperature, show that the R phase its transform to α and η phases.