Abstract In the present work, a novel technique has been introduced to obtain an aluminide coating by casting process and subsequent heat treatment. To do so, the aluminum sheet was placed at the bottom of a copper mold, then HH309 SS melt was poured into the mold. This technique was named Cast-Aluminizing (CA). The CA samples were heat-treated at the temperature range of 900–1050 °C for 0.5–5 h. The FE-SEM, XRD, and EDS were utilized to characterize the microstructure, phase analysis and chemical composition of cast-aluminized samples, respectively. Results showed that (Fe,Cr,Ni)Al3 and (Fe,Cr,Ni)2Al5 layers were formed at the Al/HH309 interface. FE-SEM analysis demonstrated a multi-layer aluminide coating on the heat-treated specimens. This coating consisted of (Fe,Cr,Ni)2Al5+(Fe,Cr,Ni)Al2, (Fe,Cr,Ni)Al and α-Fe,Cr,Ni(Al) sub-layers. The growth kinetics investigation showed that the thickness of layers increased with the increase of the annealing temperature and time. The growth rate of layers obeyed a parabolic law. The activation energies for the growth of (Fe,Cr,Ni)2Al5+(Fe,Cr,Ni)Al2, (Fe,Cr,Ni)Al and α-Fe,Cr,Ni(Al) layers were about 203, 250 and 247 kJ/mol, respectively. Microhardness measurements revealed that (Fe,Cr,Ni)2Al5+(Fe,Cr,Ni)Al2, (Fe,Cr,Ni)Al and α-Fe,Cr,Ni(Al) layers had a hardness of about 820–1040, 580–710 and 380–470 HV, respectively. The resistance to oxidation of cast-aluminized and heat-treated (CA + HT) samples in the air at 1000 °C was studied. The CA + HT samples exhibited higher oxidation resistance than uncoated samples due to the formation of a protective Al2O3 layer on the surface.

中文翻译：

---

HH309不锈钢铸造和后续热处理形成的铝化物涂层的表征、生长动力学和高温氧化行为

摘要 在目前的工作中，引入了一种通过铸造工艺和后续热处理获得铝化物涂层的新技术。为此，将铝板放置在铜模具的底部，然后将 HH309 SS 熔体倒入模具中。这种技术被命名为铸铝 (CA)。CA 样品在 900-1050°C 的温度范围内热处理 0.5-5 小时。FE-SEM、XRD 和 EDS 分别用于表征铸铝样品的微观结构、物相分析和化学成分。结果表明(Fe,Cr,Ni)Al3和(Fe,Cr,Ni)2Al5层在Al/HH3O9界面形成。FE-SEM 分析表明热处理样品上有多层铝化物涂层。该涂层由 (Fe,Cr,Ni)2Al5+(Fe,Cr,Ni)Al2、(Fe,Cr,Ni)Al 和 α-Fe,Cr,Ni(Al) 亚层组成。生长动力学研究表明，层厚随着退火温度和时间的增加而增加。层的增长率服从抛物线规律。(Fe,Cr,Ni)2Al5+(Fe,Cr,Ni)Al2, (Fe,Cr,Ni)Al 和 α-Fe,Cr,Ni(Al) 层生长的活化能约为 203、250 和分别为 247 kJ/mol。显微硬度测量表明 (Fe,Cr,Ni)2Al5+(Fe,Cr,Ni)Al2, (Fe,Cr,Ni)Al 和 α-Fe,Cr,Ni(Al) 层的硬度约为 820-1040，分别为 580-710 和 380-470 HV。研究了铸铝和热处理 (CA + HT) 样品在 1000 °C 空气中的抗氧化性。由于在表面形成了保护性的 Al2O3 层，CA + HT 样品表现出比未涂层样品更高的抗氧化性。