Synthesis, Characterization and Sintering Behavior of Nanocrystalline Cordierite Ceramics
Nanocrystalline cordierite powders were prepared by the polymerized complex method. The synthesized precursor was calcined in air at 600-1200 oC for 1h, and the calcined powders were fully characterized by TG/DTA, BET, XRD, SEM, and TEM. The XRD and selected-area electron diffraction (SAED) analysis confirmed the development of the phase composition of cordierite powders showing amorphous phase after calcination at temperature below 800oC, mixed phases of spinel and μ-cordierite phase after calcination at 800oC and 900oC, and mixed phases of spinel, μ- cordierite and α-cordierite phases after calcination at above 900oC. The BET specific surface areas of the calcined powders varied from 3 to 107 m2/g, depending on calcination temperature. The highest specific surface area of 107 m2/g was found in the powders calcined at 800oC. The average particle sizes evaluated by BET were less than 60 nm, depending on calcination temperature. The powders calcined at 800oC and 1000oC were uniaxially pressed and pressureless-sintered in air at 1250-1350oC for 2h. Densities of the sintered samples evaluated by Archimedes’s method were 87- 91 % of theoretical value. The crystal structure of all the sintered samples, determined by XRD, was mainly α-cordierite, having a small amount of spinel as second phase.
P. Laokul and S. Maensiri, "Synthesis, Characterization and Sintering Behavior of Nanocrystalline Cordierite Ceramics", Advances in Science and Technology, Vol. 45, pp. 242-247, 2006