Infrared spectroscopic characterization of the α-alumina surface

Abstract

Several α-Al₂O₃ specimens were prepared by thermal treatment of pure transition aluminas, already in the form of i.r. pellets. When the starting material is a high external area phase, the resulting sample is still suitable for i.r. work. In particular two preparations are considered, which only differ in the number of hours of treatment at 1150°C. Although the X-ray pattern is the same in both cases, great differences are revealed by the i.r. spectra, especially in the stretching region of the surface hydroxyl groups. It is suggested that the sample treated for the shorter time either maintains or simulates some surface characteristics of the starting transition phase.