Crystallization and Densification of Nano‐Size Amorphous Cordierite Powder Prepared by a PVA Solution‐Polymerization Route

A homogeneous and stable amorphous‐type cordierite (2MgO2Al 2 O 3 5SiO 2 ) powder was prepared by a solution‐polymerization route employing a Pechini resin or a poly(vinyl alcohol) (PVA) solution as the polymeric carrier. After calcination at 800°C for 1 h under atmospheric conditions, the bulky precursor changed into a very soft and porous powder. A 30 nm size, amorphous‐type cordierite powder was prepared by attrition milling the calcined powder, which was made using a PVA precursor solution. The nano‐size powder, which had a high specific surface area of 181 m 2 /g, was obtained after milling for <1 h. The sintered cordierite grains did not show the presence of any amorphous SiO 2 phase and had a dense microstructure with a relative density of 99% and a thermal expansion coefficient of 2.1 10 ‐6 /°C.