Leaching of Al2O3 in double-destilled water

Al2O3 material has been leached at 90 deg C in pure double-distilled water and in double-distilled water buffered to pH 9.3 with sodium carbonate. The corrosion rate of Al2O3 has been calculated after determination of the Al-content of the leaching solution by atomic absorption spectrometry. The corrosion rate in the pure water was 10.10-6 mm.year-1 all through the investigation, 184 days hitherto. The corrosion rate in the solution at pH 9.3 was approximately 230.10-6 mm.year-1 during the first days and then steadily decreasing to 10-12.10-6 mm.year-1 after 120 days and stabilising there during the leaching period 120 to 184 days. The leached material has been sent to other laboratores for further investigations. (author)