Direct Laser Synthesis of Fe₂O₃ Modified TiO₂

A very fast, selective CO 2 laser line scan direct synthesis method is presented and has been applied here to study phase and defect formation within an irradiated mixture of powdered oxides, as a proof‐of‐principle. A nominal composition interval of 0<x<0.03 was conveniently chosen for the TiO 2 +xFe 2 O 3 system herein reported. X‐ray diffraction analyses were used to determine the main crystalline phase composition. Thus, for 3 % mol. Fe 2 O 3 , pseudobrookite crystals were found to coexist with rutile‐type MO 2‐δ (M=Ti, Fe) with extended defects. These are composed mainly of (121) r and (132) r crystallographic shear planes (CSP‘s), where r subindex refers to the rutile subcell. For samples with a lower Fe 2 O 3 content (2, 1, 0.5 % mol) only iron‐doped rutile phases were observed, with complex microstructure arising from the presence of multi‐twinned (011) r and (110) r crystals and isolated and/or ordered CSP‘s at short length scale. The diverse microstructures observed in the CO 2 laser produced samples correlate with the conditions imposed during the laser treatment, which include intrinsically high solidification rates and steep temperature gradients.