Journal of the American Ceramic Society, Vol.96, No.4, 1032-1034, 2013
Suppressed Reactivity of AlN Powder in Water at 5 degrees C
The hydrolysis behavior of AlN powder suspensions (525wt%) at 5 degrees C has been investigated to explore the impact of low temperatures on the hydrolysis behavior. Throughout the 312-h long experiment, the pH value of the suspensions was below 9, where the hydrolysis remained in the induction period and was eventually suppressed due to the formation of a few-nanometers-thick film of amorphous aluminum hydroxide gel around the AlN particles, acting as a passivation layer. Moreover, the aqueous part of the suspension possessed a remarkably high value of dissolved [Al(III)]aq, being an order of magnitude higher at a given pH value than the aqueous AlCl3 solution.