en Research Paper Research Paper <div style="text-align: justify;">In this study, Si-modified aluminide coating on nickel-base superalloy IN-738LC was prepared using a pack cementation method with various powder compositions at 1050 &deg;C for 6 h. The cyclic oxidation test was conducted at 1000 &deg;C followed by cooling at room temperature for 200 h and 20 cycles. The effect of powder composition and the way of cooling on the coatings microstructure and oxidation behavior were studied. Investigations carried out using a scanning electron microscope (SEM), EDS analysis, and XRD. Microstructural observations revealed that the coating thickness of 293 and 274 &micro;m was achieved in the case of using pure Al and Si powder and alloyed Al-20wt.%Si one in the packed mixture, respectively. It was also found that utilizing pure Al and Si powder with NH₄Cl as an activator in the pack led to the formation of silicide coating, owing to the higher diffusion of Si, which showed superior cyclic oxidation performance.</div> ,Si-modified aluminide coating,Cyclic oxidation,Pack cementation,Superalloys 92 103 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-71-2&slc_lang=en&sid=1 M. Ghasemian Safaei mandana89ghs@yahoo.com 1800319475328460014659 1800319475328460014659 No Iran University of Science and Technology S. Rastegari rastegari@iust.ac.ir 1800319475328460014660 1800319475328460014660 Yes Iran University of Science and Technology R. Latifi roza.latifi89@gmail.com 1800319475328460014661 1800319475328460014661 No Iran University of Science and Technology