Rapid Hydrolysis of Aluminum Nitride by Ultrasonic Wave-Enhanced Process
2013
Hochschulschrift
Zugriff:
101
Due to the high reactivity of aluminum nitride (AlN) powder with water, the product layer will be generated on the surface of powders, resulting in the elevation of diffusion resistance and the difficulty of complete hydrolysis of AlN particles. Therefore, in this study, the rapid hydrolysis of aluminum nitride via the ultrasonic wave-enhanced process by means of the cavitation erosion of ultrasonic wave to decrease the diffusion resistance of product layer has been proposed. The performance of AlN hydrolysis is compared between the traditional heating process (THP) and ultrasonic wave-enhanced process (UWP). Moreover, the effects of initial reaction temperature (25℃, 50℃, 70℃), reaction time (10-1440 min), and initial pH values (pH0 = 3, 6.6, 12) on the performance of AlN hydrolysis has also been discussed The results showed that at 25℃, the conversion of AlN (2 μm) was only 87.2% after hydrolyzing 1440 min, and reached only 92.3% at 70℃ after 360 min of hydrolysis by using the THP. However, by using UWP, AlN was completed after 180 min of hydrolysis at 50℃. The trends for the increase of pH value and the measured NH4 + concentration in solution at 25℃ were consistent with the conversion of AlN for THP and UWP. According to the XRD patterns, a weak and broad peak of amorphous AlOOH was found at a short hydrolysis time, especially for THP, while apparent Al(OH)3 (bayerite) with a middle intensity of AlOOH (boehmite) crystallization phase at a longer reaction time or at a higher hydrolysis temperature had been identified. However, the SEM pictures showed that the morphology of the hydrolyzed-AlN powders was mainly composed by a large amount of lamellas boehmite with little of the columnar of bayerite,indicated that the bayerite crystallize phase was formed mainly in the internal of the AlN powders. Finally, the influences of various starting pH values (pH0) in solution by UWP on the conversion of AlN powder showed that the hydrolysis rate is in the orders: deionized water (pH0 = 6.6) ~ NaOH(aq) (pH0 = 12) > HCl(aq) (pH0 = 3).
Titel: |
Rapid Hydrolysis of Aluminum Nitride by Ultrasonic Wave-Enhanced Process
|
---|---|
Autor/in / Beteiligte Person: | Huang, Yen-Yu ; 黃硯毓 |
Link: | |
Veröffentlichung: | 2013 |
Medientyp: | Hochschulschrift |
Sonstiges: |
|