Atomic layer deposited Al2O3 coatings on SUS 310S stainless steel

Abstract

Atomic layer deposition (ALD) is a technique capable of forming ultra-thin, uniform, and high-quality films on the surface of various materials. The Al₂O₃ coatings are an ideal choice for protecting stainless steel from high-temperature oxidation and chemical corrosion. In this work, Al₂O₃ coatings with a thickness of approximately 150 nm were prepared on the surface of 310S stainless steel using improved ALD technology. The results found that, firstly, the oxidation rate of Al₂O₃ coating samples (3.03×10⁻¹² g²·cm⁻⁴·s⁻¹) decreased by an order of magnitude compared with the matrix (1.55 × 10⁻¹¹ g²·cm⁻⁴·s⁻¹). Secondly, after oxidation in air at 1200 °C for 50 h, the Cr element content on the surface of the matrix and the Al₂O₃ coating samples is 40.27 % and 9.67 %, respectively. Finally, the corrosion current density corroded in 3.5 wt% NaCl solution and 0.1 mol·L⁻¹ H₂SO₄ solution of Al₂O₃ coating samples (1 × 10⁻⁵ and 5 × 10⁻⁴ mA/cm², respectively) was significantly decreased compared with the matrix (1 × 10⁻⁴ and 1 × 10⁻² mA/cm², respectively). The above results concluded that the Al₂O₃ coatings prepared by ALD technology can significantly enhance the high-temperature oxidation resistance, Cr resistance, and corrosion resistance of the 310S matrix.