# Nanocrystalline Macroporous Wollastonite Ceramics - A Spectroscopic View

UNSPECIFIED (2005) Nanocrystalline Macroporous Wollastonite Ceramics - A Spectroscopic View. In: 50th DAE Solid State Physics Symposium, Dec. 5 - 9, 2005., Bhabha Atomic Research Centre, Mumbai.

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Nanocrystalline macroporous $CaSiO_{3}$ ceramic powders have been synthesized by a novel low temperature initiated self-propagating, gas producing solution combustion process. The effects of temperature on crystalline phase formation, amount of porogens and particle size of porous $CaSiO_{3}$ have been investigated. Single phase \beta-$CaSiO_{3}$ and \alpha-$CaSiO_{3}$ are formed at much lower temperatures to the powders obtained via solid state reaction method. On calcination the samples becoming more porous and the pore diameter increases from 2 to 8 \mu m. The samples calcined at 950 degree C has 17.5 % porosity, and the porosity increases to 31.6 % at 1200 degree C. The surface area of as formed and calcined at 950 and 1200 degree C of $CaSiO_{3}$ samples were found to be 31.93 $m^{2}$/g, 0.585 $m^{2}$/g and 3.48 $m^{2}$/g respectively. The TL intensity in powdered sample is more when compared to the pelletized $CaSiO_{3}$ and it is further observed that there is a shift in glow peak temperatures in pelletized sample. This is attributed to the inter particle spacing and pressure-induced defects. The structure of $CaSiO_{3}$ has been investigated by $^{29}Si$ MAS NMR.