The effect of a non-chromate deoxidiser (bromate–nitric acid) on AA2024-T3 has been examined by SEM, TEM/EELS and XPS. At low temperatures (20°C) the deoxidiser removed all intermetallics but had little effect on the surface oxide. At 40°C, attack on the intermetallics was again extensive but there was also evidence of attack on the surface oxide covering the matrix after 10min of immersion, leaving a roughened porous oxide. At 60°C, removal of intermetallics was complete and longer immersion times resulted in a characteristic scalloped structure across the surface which became more pronounced with increasing immersion time.