Sintered TiO2 powder containing metallic Co binder prepared via mechanical carbonization, and its mechanical properties

A TiO2-Co-a composite powder was prepared via carbonizing and selective oxidation processing of a Ti-Co alloy. The conventionally mixed TiO2-Co-c composite powder and pure TiO2 were sintered at 1100, 1200, 1300, 1400 °C, respectively. The structural characterization was performed using X-ray diffraction, field emission scattering electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The sintered samples were more densified, and melted bonding occurred at temperature higher than 1300 °C. The flexural strength and fracture toughness of the TiO2-Co-a sample were higher than those of the TiO2 and TiO2-Co-c sintered at temperature higher than 1300 °C, while the Vickers hardness of TiO2-Co-a was the lowest at all sintering temperatures. The sintered TiO2-Co-a sample was more ductile and strengthened than the TiO2-Co-c sample with added metallic Co binder via mechanical mixing. The enhanced mechanical properties of the TiO2-Co-a sample were due to the fine dispersion of the metallic Co binder wetted with a TiO2 matrix.