High temperature behaviour of AlN based ceramics in water vapor.
Comportement dans la vapeur d'eau à haute température du nitrure d'aluminium fritté.
Résumé
Fully dense (97%) aluminium nitride obtained by pressureless sintering with CaO additive (1wt%) has been studied in water vapour in the range 1300-1450°C. The oxidation resistance is similar to that in oxygen, though the hydrogen produced at the inner interface (AlN-oxide) during the reaction opens the microstructure of the scale products. As a consequence, kinetics are controlled by a linear mechanism with an activation energy of 55 Kcal/Mole probably in connection with the break of Al-N bonds (54 Kcal/Mole).