Fusion Science and Technology / Volume 65 / Number 2 / March 2014 / Pages 282-291
Technical Paper / dx.doi.org/10.13182/FST13-673
Hot dip aluminizing was tried on Indian reduced activation ferritic martensitic steel. This experiment was performed with aluminum (Al) melt, with three different silicon (Si) concentrations (3%, 5%, and 7%). Samples were dipped into the Al-Si melt, at 750°C for 30 s, which produced a hard and brittle Fe2Al5 intermetallic layer on the samples. These samples were subjected to two types of heat treatments: (I) 760°C for 30 h and (II) 980°C for 0.5 h, followed by 760°C for 1.5 h to convert the intermetallic layer into more ductile phases. The width of the Fe2Al5 layer was <10 μm for all the samples with different Si concentrations, and for the pure Al melt, it was ∼35 μm. For both the heat treatments, FeAl and α-Fe(Al) layers were observed. Out of the two heat treatments, heat treatment I gives thinner FeAl and α-Fe(Al) layers compared to heat treatment II. X-ray diffraction measurements confirmed the formation of an α-Al2O3 layer on the surface, for 3% and 5% Si concentrations for heat treatment I and for all Si concentrations for heat treatment II. The hardnesses of the Fe2Al5, FeAl, and α-Fe(Al) layers were found to be 972 to 1089 HV (hardness value)/0.01, 324 to 384 HV/0.01, and ∼200 HV/0.01, respectively.