Surface Characterization of Gamma-Iron Oxides for Magnetic Memory Media Using Fourier Transform Infrared Photoacoustic Spectroscopy

Abstract

The interaction of gamma-iron oxide powder with several substances (silica, stearic acid, stearylamine, and polyurethane resin) was investigated with the use of Fourier transform infrared photoacoustic spectroscopy. The stearic acid was found to be chemisorbed onto the gammairon oxide surface through the carboxyl group and then dissociated the proton of the carboxyl group. It was also suggested that the stearylamine was chemisorbed onto the surface of the gamma-iron oxides through the NH2 group. In the case of polyurethane, a lower shift of the C=O stretching band and a decreasing of the relative absorption intensity of the NH deformation band were observed, indicating that a chemical interaction between the polyurethane resin and the oxides had occurred. The adsorption sites of these substances on the gamma-iron oxide were also considered.