Semnan University Press Mechanics of Advanced Composite Structures 2423-4826 14 1 2027 04 01 EExperimental Evaluation of the Effect of Combining a Two-Phase Nano-Composite Containing AL2O3 and NbC in a Surface-Coated Resin Matrix: a Study Based on Dielectric Losses and Radar Reflectance 135 150 10472 10.22075/macs.2026.38962.1918 EN Mohammad Khakbaz Department of Aerospace Engineering, Faculty of Graduate Education, Shahid Sattari University of Aeronautical Sciences and Technology, Tehran, Iran Mehrdad Motavasselolhagh School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran Masoud Javadi Department of Aerospace Engineering, Shahid Sattari University of Aeronautical Sciences and Technology, Tehran, Iran Reza Sarkhosh Department of Aerospace Engineering, Shahid Sattari University of Aeronautical Sciences and Technology, Tehran, Iran Journal Article 2025 09 08 Electromagnetic wave-absorbing polymer nano-coatings are recognized as important for advanced electromagnetic shielding and wave management applications. In this study, a novel two-phase Al₂O₃/NbC polymer nano-composite within an epoxy resin matrix is introduced, incorporating dual silane surface treatments (APTMS and GPTMS) to enhance interfacial bonding and ensure uniform dispersion of the reinforcing materials. A designed experimental (DOE) plan was implemented before the fabrication process to determine the optimal weight fractions of aluminum oxide (Al₂O₃) and niobium carbide (NbC). Subsequently, chemical bonding, particle surface modification, and matrix homogenization were performed, and the samples were prepared in rectangular molds suitable for electromagnetic rectangular wave guide measurements in the 8.2–12.5 GHz range. The structural and chemical characteristics were analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results obtained from electromagnetic absorption and reflection measurements within the 8.2–12.5 GHz frequency range show that sample No.1, with a higher NbC content, demonstrates stronger absorption near 9.5 GHz but reduced performance at higher frequencies. Sample No.2, containing a balanced ratio of Al₂O₃ and NbC, exhibits a more uniform response across the frequency range, while sample No.3, with a higher Al₂O₃ fraction, presents improved impedance matching, enhanced dielectric loss, and absorption exceeding 80% throughout 8.2–12.5 GHz, accompanied by a reflection reduction of approximately 6%. These results indicate that tuning the weight fraction of the two phases allows optimization of broadband absorption performance. Overall, the dual-phase Al₂O₃/NbC system with surface-modified particles can achieve efficient, broadband electromagnetic absorption, offering potential for advanced shielding and wave control applications for aerospace industries. https://macs.semnan.ac.ir/article_10472_a61491cc64ad3d19839d69d8e3163744.pdf