材料期刊网

为避免制备温度过高引起基体性能退化, 采用了室温熔盐电镀与热处理复合技术在HR-2不锈钢上进行了渗Al涂层制备研究, 并对涂层的形貌、结构和成分进行了表征. 结果表明, 利用该技术制备渗Al涂层是可行的; 经500 ℃和700 ℃两种温度下热处理, 成功制得成分渐变、冶金结合且无缝隙和裂纹的10-15 μm厚渗Al涂层. 经700℃下2 h热处理后, 渗Al涂层与基体无明显界面, 依次由(Fe, Cr, Mn, Ni)₂Al₅, (Fe, Cr, Mn, Ni)Al和(Fe, Cr, Mn, Ni)₃Al3层组成; 与700 ℃热处理后不同, 经500 ℃下10 h热处理后, 渗Al涂层与基体间界面明显, 由内外两层组成.

The aluminized coating has been widely applied on structural materials in fusion reactors as a tritium permeation barrier (TPB). In present study, we proposed a new two-step method for preparing an aluminized coating on HR-2 stainless steel: room temperature molten salt electroplating followed by heat treating at 500 and 700 ℃ in air. In the electroplating process, aluminum deposition from AlCl₃/EMIC to the surface of HR-2 stainless steel was performed with a deposition rate of\linebreak 15 μm/h at 25 ℃ under the protection of argon gas. This method permits coating of large complex shapes that have few blind areas. The coating microstructure has been characterized by optical microscope (OM), scanning electronic microscope (SEM), energy dispersive spectroscope (EDS) and X-ray diffraction (XRD). These results show that after heat treated at 500 ℃ for 10 h, the coating thickness is about 10-15 μm consisting of two distinct layers with a clear interface between the coating and substrate. however, after heat treated at 700 ℃ for 2 h, the coating thickness is changed to about 10-13 μm and it consists of an external (Fe, Cr, Mn and Ni)₂Al₅ layer, inner (Fe, Cr, Mn and Ni)Al layer and transitional (Fe, Cr, Mn and Ni)₃Al layer. No clear interface between the coating and substrate and defects and cracks in the coating were observed.