Diffuse-Reflectance Fourier Transform Infrared Spectroscopic Studies of the Stability of Aluminum Nitride Powder in an Aqueous Environment

Abstract

Diffuse-reflectance Infrared Fourier-transform spectroscopy (DRIFT) 1s applied to monitor the degradation process that occurs when AIN ceramic powders are suspended In water at 25 °C. By virtue of Its ability to obtain optical absorption data from amorphous and bulk materials, DRIFT has certain advantages over alternative techniques such as X-ray photoelectron spectroscopy and X-ray diffraction In this case. An amorphous oxy-hydroxide shell, of probable formula AIO(OH), Initially forms and grows on a shrinking AIN core. Later, the shell crystallizes to bayerite, AI(OH)3. The quantitative capability of DRIFT Is demonstrated by good linear calibration of OH stretch band area vs O content, before crystallization, with a correlation coefficient of 0.995 and a standard error on the slope of ±7% at the 95% confidence level. The method appears Insensitive to the Inhomogeneous (shell/ core) structure of the samples. © 1989, American Chemical Society. All rights reserved.