In this study, the corrosion behavior of pure aluminum and Al-Si alloy in aqueous environments containing Cl⁻ and SO₄²⁻ ions was investigated using ReaxFF reactive molecular dynamics simulations under acidic, neutral, and basic conditions. Simulations were performed under acidic, neutral, and basic conditions at 300 and 500 K. Results showed that the acidic environment induced the highest corrosion severity (IE₁ = -5.67 eV for Al-Si). Cl⁻ exhibited higher mobility (D = 7.0×10⁻⁸ cm²/s), while SO₄²⁻ demonstrated stronger surface interaction (-6.87 eV vs. -5.23 eV), indicating a complementary dual mechanism in passive layer breakdown. Silicon presence increased interaction energy by 62.1%, a behavior consistent with a possible local galvanic mechanism in which Si atoms acquire partial negative charge (-0.15 e) and may act as micro-cathodic sites. Increasing temperature from 300 to 500 K reduced COMZ from 9.6 to 7.1 Å, indicating deeper ion penetration. These findings provide atomic-scale insights for designing corrosion-resistant Al alloys.