engleski

Corrosion of cold isostatic pressed alumina ceramics

Aluminum oxide (Al2O3) or alumina, like most ceramic materials, can withstand harsh environments. In order to measure the corrosion resistance of cold isostatic pressed (CIP) high purity alumina, its dissolution in aqueous nitric acid (HNO3) solutions was studied as a function of immersion time and acid concentration. The corrosion resistance of CIP Al2O3 was investigated in the following concentrations of HNO3: 0.5, 1.25 and 2 mol dm-3 at temperatures of 25, 40 and 55 °C and with an exposure time of up to 240 h. The number of eluted ions (Al3+, Ca2+, Fe3+, Mg2+, Na+ and Si4+) was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). Furthermore, corrosion rate constants were determined. The corrosion resistance of the investigated highly pure alumina slightly decreased with an increase of nitric acid concentration. Nevertheless, very low dissolution values of Al3+, Ca2+, Fe3+, Mg2+, Na+ and Si4+ions after the corrosion test showed a very good corrosion resistance of alumina ceramics to the HNO3 aqueous solutions.

highly pure alumina ; ion elution ; inductively coupled plasma atomic emission spectrometry ; corrosion kinetics

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