Abstract:A new three-step method for preparing aluminum rich coating on HR-2 stainless steel was proposed, i.e. ambient temperature chloroaluminate melts electroplating followed by heat treating and artificial oxidation. In the electroplating process, aluminum deposition from AlCl3/MEIC to the surface of HR-2 steel was performed with a deposition rate of 15 μm/h. Within the aluminizing temperature range from 650 to 750 oC, aluminizing time from 1 to 30 h, the aluminized coating with thickness of 3-27 μm can be prepared, which is homogeneous and free of porosity or crack, and have good metallographic adherence to the substrate; the coating cross section exhibits a three-layer or two-layer structure. A simple Arrhenius relationship can be used to describe the effect of temperature on the coating growth rate, which gives activation energy of 116.9 kJ/mol. The relationship between the coating thickness against time1/2 is approximately linear, which is a typical feature of the diffusion controlled coating growth mechanism. To form Al2O3 film on surface, the aluminized coating treated for 4 h was oxidized in 10-2 Pa O2 for 80 h and observed by X-ray photoelectron spectroscopy (XPS) and Reflection spectrum. The finally fabricated coating shows a double-layer structure consisting of an outer γ-A12O3 layer with thickness of 110 nm and inner (Fe,Cr,Mn and Ni)Al/(Fe,Cr,Mn and Ni)3Al layer of 30 μm thickness, and is homogeneous without any defects. The deuterium permeation rate through the coated HR-2 steel is reduced by 3 orders of magnitude at 600 oC. The coating remains a perfect surface for 20 thermal cycles between 750 oC and room temperature. The method is a potential candidate for preparation of TPB on the tritium container surface in ITER.