Aluminum nitride (AlN) ceramics are being increasingly used as substrate materials for electronic packaging and as refractories [1, 2] amongst other applications due to their excellent thermal conductivity and the electrical resistivity. Although AlN can be consolidated by hot pressing or hot isostatic pressing, pressureless sintering at temperatures of 1600–2000 ◦C is increasingly used [3, 4]. Common fabrication processes for pressureless sintering are injection molding, slip casting and tape casting. These techniques rely on the formation of dispersed suspensions and this offers advantages for dispersing small quantities of sintering aids, such as SiO2, Y2O3 and Al2O3 [5, 6] homogeneously. However, due to economic and environmental concerns, the processing of AlN powders into components via the use of aqueous, rather than organic-based, suspensions is attracting increasing interest. Unfortunately, AlN powders are easily hydrolyzed by water. X-ray photoelectron spectroscopy (XPS) [7, 8] and diffuse-reflectance Fourier transform infrared spectroscopy [9] have all been used to characterize the surface of untreated AlN particles. When in contact with moisture the powder surface becomes hydrolyzed and hence covered by γ -AlOOH, Al(OH)3 or γ -Al2O3 species [10, 11]. Thus in order to process them by aqueous colloidal routes, modification of the powder surfaces with organic chemicals to make them hydrophobic is usually performed [12–15]. The chemically treated AlN powder through surface modification will have organic species on its surface that will then affect the interactions between the particles and any dispersants used once they are contacted with water. In this paper, the hydrolysis process of a hydrophobic treated AlN powder (later denoted as treated AlN powder, ART20, Advanced Refractory Technologies (ART), Buffalo, New York, USA) was studied under different conditions, i.e. hydrolysis time, dispersant concentration (Emphos 1316, a polyoxyalkylated aldylaryl phosphate ester sodium salt supplied by ART, USA). The water-contacted powders were then characterized using a Fourier transform infrared spectroscopy (FTIR) (5DXB, Nicolet Instrument Corporation, USA). FTIR spectra for samples hydrolyzed (20 ◦C) without addition of the surfactant for different time periods and an FTIR spectrum from a reference sample of Al(OH)3 are presented in Fig. 1. The exact peak positions can be seen in Table I. The spectrum for the AlN powder before hydrolysis (0 h) exhibited a strong absorption peak at 710 cm−1 and a few much weaker peaks at higher frequencies; the peaks centered at 710 and 1326 cm−1 may be assigned to the vibration of the AlN bond [16]. The figure shows that there was a gradual increase in the intensity of the peaks positioned at about 1398, 1457, 1635 and 3400 cm−1 with increasing hydrolysis time up to 192 h. The latter three peaks are all clearly attributable to amorphous Al(OH)3. It is interesting to note, however, that the largest two peaks, 3400 and 1635 cm−1, were both detectable in the sample that had not been hydrolyzed at all indicating a degree of hydrolysis in the as-received powder. The broad peak at around 3400 cm−1 has been attributed to the O–H stretching vibration of AlOH species that undergo hydrogen bonding with neighboring hydroxyl groups [17, 18]. In addition, the O–H stretching vibration of molecular H2O may also contribute to this band. The presence of physisorbed