Effect of yttria on crystallization and microstructure of an alumina–YAG fiber prepared by aqueous sol–gel process

Phase and microstructural evolution of yttrium-doped nanocrystalline alumina: A contribution of advanced microscopy techniques

“…This result is in partial agreement with some literature data 23,24,27 in which the formation of intermediate hexagonal and orthorhombic YAlO 3 phases is observed in alumina-YAG composite powders and fibres produced by sol-gel process. In these works, however, YAM crystallization was never observed, so that differences in phase evolution can be also reasonably imputed to the synthesis route.…”

“…Secondly, the crystallization temperature of yttrium-aluminates decreases by increasing the dopant amount. This result agrees with previous works by Shojaie-Bahaabad et al 23 and Towata et al 24 , whereas Al-Yassir et al 25 determined the same crystallization temperature of YAlO 3 phase in 2.5-20 wt.% yttria-doped alumina powders.…”

“…DTA results clearly evidence the role of yttrium in delaying the metastable to ␣-alumina crystallization temperature, as already reported in literature [23][24][25] ; however, despite the numerous investigations, there is not yet a clear understanding of the mechanism responsible for transition alumina thermal stabilization. According to our microstructural observations, we can consider the stabilizing effect of rare-earth cations on the surface of transition Al 2 O 3 .…”

Nanoindentation of melt-extracted amorphous YAG and YAG:Eu, Nd micrometric fibers synthesized by the citrate precursor method

“…Different methods to prepare doped-and undoped-YAG and Al 2 O 3 -Y 2 O 3 fibers have been also reported in the literature such as sol-gel, 17,18 melt growth techniques such as micro-pulling-down (-PD) method [19][20][21] and the internal crys- tallization method, 22,23 the levitation technique, 24 and melt extraction. 25,26 The melt-extraction method was developed initially by Maringer and Mobley 27 in 1974.…”

Spinnablity and structure characterization of mullite fibers via sol–gel-ceramic route

“…Fiber formation from metal alkoxide solutions in the sol-gel process is an attractive technique for making glass and ceramic fibers [1][2][3][4][5][6][7]. This method provides oxide glass or ceramic fibers which are difficult to prepare by the conventional fiber formation technique such as melt spinning, wet spinning or dry-spinning.…”