Ceramics-Silikáty 45 (3) 98-104 (2001)

Effects of Host Micas, Interlayer Cations and the Addition of PVA on Formation and Porous Properties of Fluorine Mica - Iron(III) Oxide Composites

T. Yamaguchi, S. Iida, K. Kitajima 

Syntheses of Fe₂O₃-pillared fluorine micas have been undertaken using Na-tetrasilicic fluorine mica [NaMg_2.5Si₄O₁₀F₂], Na-taeniolite series mica [Na_0.5Mg_2.5Li_0.5Si₄O₁₀F₂] and their Li⁺-exchanged forms as host crystals in the presence or absence of PVA as a template agent. The properties and structures of the products depend on the species of host crystals and interlayer cations as well as on the addition of PVA. Fe₂O₃-pillared fluorine micas obtained from the Li-exchanged form of the taeniolite series mica retained pillared structure up to 600°C and had pores with mean diameter around 3.3 nm. On the other hand, the products obtained from the Li-exchanged form of Na-tetrasilicic mica with using PVA had the "house-of-cards" structure consisting of delaminated Fe₂O₃-pillared mica flakes and Fe₂O₃ particles deposited on the external surface of the mica flakes. They can be called "Fe₂O₃ pillared mica - Fe₂O₃" composites which are featured by mesopore distributions in the range of 3.3 - 6.9 nm, depending on the heating temperature. They gave sintered bodies above 500°C and exhibited a maximum BET specific surface area of 110 m²g^-1 at 600°C.

Keywords: Pillared mica, Fe₂O₃, Poly vinyl alcohol, Porous characteristic, Delamination