Coprecipitation of yttrium and aluminium hydroxide for preparation of yttrium aluminium garnet

Fabrication of Nd:YAG transparent ceramics with TEOS, MgO and compound additives as sintering aids

“…The beneficial role of silica in sintering kinetics, which was linked to the solid solution formation by substitution of Al 3+ by Si 4+ [11], has been reported for many times by an increase of the grain-boundary diffusion coefficient and the decrease of grain-boundary surface energy in the presence of secondary phases [8,10]. Simultaneously, the negative influence of the lattice expansion caused by Nd 3+ , which has a larger ionic radius (0.112 nm) than the replaced Y 3+ (0.102 nm), will be effectively eliminated by introducing the Si 4+ , of which the ionic radius (0.04 nm) is smaller than the replaced Al 3+ (0.054 nm).…”

“…Simultaneously, the negative influence of the lattice expansion caused by Nd 3+ , which has a larger ionic radius (0.112 nm) than the replaced Y 3+ (0.102 nm), will be effectively eliminated by introducing the Si 4+ , of which the ionic radius (0.04 nm) is smaller than the replaced Al 3+ (0.054 nm). Meanwhile the positive effect of adding MgO has also been studied [10,12]. MgO acts as sintering aid and not only substitute Al 3+ to form (V o ) • [13,8], but also segregate at the grain boundaries to impede the continuous grain growth at the final stage of vacuum sintering [12].…”

“…Many previous studies [7][8][9][10] have explained the beneficial role and function mechanism of SiO 2 (usually from the pyrolysis of TEOS) as sintering aid. The beneficial role of silica in sintering kinetics, which was linked to the solid solution formation by substitution of Al 3+ by Si 4+ [11], has been reported for many times by an increase of the grain-boundary diffusion coefficient and the decrease of grain-boundary surface energy in the presence of secondary phases [8,10].…”

Vacuum sintering of Tb3Al5O12 transparent ceramics with combined TEOS+MgO sintering aids

“…Sintering aids have the function of increasing the diffusion coefficient of the grain boundary [16][17][18] which is conducive to removing pores, preventing abnormal grain growth and so on [19,20]. In this case, optimizing the sintering aids is an effective way to reduce the optical scattering of transparent ceramics.…”

Co-precipitation Synthesis and Spectroscopic Studies of YAG and Yb:YAG Nanopowder for Opto-Electronic Applications

“…YAG powders was traditionally produced via solid state reaction [10] by milling the component oxides under repeated mechanical mixing and require extensive heat (\1400°C) to eliminate the intermediate phases of YAG. To overcome this various methods like co-precipitation [11][12][13][14][15], Hydrothermal synthesis [16,17], sol-gel process [18,19], Spray pyrolysis [20,21] and Combustion synthesis [22,23] was adopted. It is recognized that wet chemical processing of multi-cation oxides provides considerable advantages like molecular level mixing; less effort more powder yield and excellent homogeneity of the final product [24].…”