The use of Raman Spectroscopy for Characterisation of Ceramic Dielectrics

Mechanism of Be-Thermodiffusion in Rutile Inclusions of Fancy Sapphires

“…Since these solid solutions seem to be an intermediate step of the decomposition reaction of Al 2 TiO 5 into Al 2 O 3 and TiO 2 in atmospheric conditions, several studies suggest that these two species cannot be treated as separate stoichiometric phases . Characteristic Raman bands of Ti 3 O 5 (anosovite) are reported at 154, 412, 238, and 605 cm –1 . − Although no peaks associated with Ti 3 O 5 were detected by Raman spectroscopy, the shape and position of the band at 900 cm –1 is in good agreement with the peak previously reported for tialite (Al 2 TiO 5 ) . In fact, the characteristic Raman bands of tialite measured with Raman spectroscopy are at 540 and 900 cm –1 .…”

“…43 In fact, the characteristic Raman bands of tialite measured with Raman spectroscopy are at 540 and 900 cm −1 . 44 According to Webb et al, 43 aluminum titanate (A1 2 TiO 5 ) is detected in Al 2 O 3 doped with TiO 2 after annealing using Raman spectroscopy. 42,43 As the dopant level increases, new bands appear in the Raman spectrum of Al 2 O 3 doped with TiO 2 , with peaks centered at 240, 325, 430, 610, and 900 cm −1 (doping level 5 wt %).…”

“…40−42 Although no peaks associated with Ti 3 O 5 were detected by Raman spectroscopy, the shape and position of the band at 900 cm −1 is in good agreement with the peak previously reported for tialite (Al 2 TiO 5 ). 43 In fact, the characteristic Raman bands of tialite measured with Raman spectroscopy are at 540 and 900 cm −1 . 44 According to Webb et al, 43 aluminum titanate (A1 2 TiO 5 ) is detected in Al 2 O 3 doped with TiO 2 after annealing using Raman spectroscopy.…”

“…44 According to Webb et al, 43 aluminum titanate (A1 2 TiO 5 ) is detected in Al 2 O 3 doped with TiO 2 after annealing using Raman spectroscopy. 42,43 As the dopant level increases, new bands appear in the Raman spectrum of Al 2 O 3 doped with TiO 2 , with peaks centered at 240, 325, 430, 610, and 900 cm −1 (doping level 5 wt %). The bands are broader than the Raman lines of pure corundum, and they are strong bands in the spectrum of Al 2 TiO 5 .…”

“…45 Indeed, we have features around 310 and 900 cm −1 compatible with some tialite-like compounds in many spectra (A1, A3, A4, FR01_5, F1, 546_c), as products of Be-treatment in inclusions. Indeed, the 900 cm −1 broad band can most likely be associated with some high-Ti(IV)-content product (doping level higher than 5 wt %) 43 of the reaction between corundum and rutile, also involving the amorphization of corundum (see below) and eventually of rutile. The high temperature and rutile amorphization in the inclusion upon Fe(II) attack might collaterally make Ti ion diffusion easier to form a blue halo in the surrounding area.…”