Study of Atomic Layer Deposition Nano-Oxide Films on Corrosion Protection of Al-SiC Composites

In recent years, aluminum matrix composites (AMCs) have attracted attention due to their promising properties. However, the presence of ceramic particles in the aluminum matrix renders AMCs a high corrosion rate and makes it challenging to use traditional corrosion protection methods. In this study, atomic layer deposition (ALD) techniques were used to deposit HfO₂, ZrO₂, TiO₂, and Al₂O₃ thin films on AMC reinforced with 20 vol.% SiC particles. Our results indicate that the presence of micro-cracks between the Al matrix and SiC particles leads to severe micro-crack-induced corrosion in Al-SiC composites. The ALD-deposited films effectively enhance the corrosion resistance of these composites by mitigating this micro-crack-induced corrosion. Among these four atomic-layer deposited films, the HfO₂ film exhibits the most effective reduction in the corrosion current density of Al-SiC composites in a 1.5 wt% NaCl solution from 1.27 × 10^-6 A/cm² to 5.89 × 10^-11 A/cm². The electrochemical impedance spectroscopy (EIS) investigation shows that HfO₂ deposited on Al-SiC composites has the largest R_p value of 2.0 × 10¹⁶. The HfO₂ film on Al-SiC composites also exhibits effective inhibition of pitting corrosion, remaining at grade 10 even after 96 h of a salt spray test.