Abstract: Aluminum nitride (AlN) ceramics exhibit exceptional thermal and electrical properties, making them highly promising candidates for electronic packaging applications and integrated circuits. Nevertheless, the hydrolysis of AlN powder results in the formation of Al(OH)₃, which subsequently decomposes into Al₂O₃ during the subsequent sintering process. This reaction increases oxygen content, thereby degrading the thermal conductivity of AlN ceramics and further imposing significant limitations on their processing and utilization. Consequently, surface modification of AlN powder is imperative to improve its hydrolysis resistance. In this work, a dual-agent modification strategy utilizing polyethylene glycol (PEG) and lauric acid (LA) was implemented through a straightforward wet ball-milling protocol, successfully forming a chemically bonded encapsulation layer on AlN particles. FT-IR and XPS analyses verified that carboxyl groups (-COOH) of LA engaged in esterification reactions with hydroxyl groups on the oxidized AlN surface, leading to the formation of robust ester linkages. TEM images revealed a continuous encapsulation layer with a thickness ranging from 12.2 nm to 16.1 nm. Remarkably, the modified powder maintained a solution pH below 9 after 72 h immersion in water at 40 ℃, with no discernible alterations in phase composition and microscopic morphology. This chemically stable, low-solubility encapsulation layer effectively obstructs water diffusion pathways, thereby suppressing hydrolysis kinetics. Enhanced hydrolysis resistance was positively correlated with LA dosage. Our findings propose an innovative encapsulation-based paradigm for developing hydrolysis-resistant AlN powders and advancing high-performance ceramic fabrication.

Key words: lauric acid, aluminum nitride powder, hydrolysis resistance, surface modification