Oxidation resistivity of montmorillonite-α-naphthylamine complex heated under nitrogen

Abstract

A thin film of montmorillonite-α-naphthylamine complex (MNC) was heated to various temperatures below 1473 K for 5 min under nitrogen. The resulting samples were further heated to 1073 to 1473 K for 30 min or 5 h in air to examine their oxidation resistivities. A thin montmorillonite film was also treated in the same manner for reference purposes. The layered structure of MNC was retained up to 1273 K under nitrogen, although it changed gradually to an amorphous state with increase in temperature. MNCs after heating below 1073 K under nitrogen were changed to montmorillonite by subsequent heating to 1073 K for 30 min in air, whereas, MNCs heated to 1173 and 1273 K under nitrogen retained somewhat their layered structures, even after heating to 1173 K for 30 min in air. The causes for such differences are discussed on the basis of the results obtained from X-ray diffraction, thermogravimetry, FT-IR and SEM observation.