Sintesis dan Karakterisasi Ijuk "Arenga pinnata" dan Pasir Besi Alam sebagai Penyerap Gelombang Mikro

Abstract

This study aims to synthesize and characterize activated carbon-based composites from Arenga pinnata fiber and natural iron sand as microwave absorbing materials. The synthesis was carried out using the solid state reaction method with three variations of Fe₃O₄/C ratios, namely (1:1, 3:5, 5:3) g. Characterization was performed using X-Ray Diffraction (XRD), Scanning Electron Microscopy–Energy Dispersive X-ray (SEM-EDX), and Vector Network Analyzer (VNA). The XRD results showed that all samples had a cubic crystal structure with the Fe₃O₄ (Magnetite) phase, where the largest crystal size was found in the 3:5 composition at 27.77 nm and the highest degree of crystallinity in the 5:3 composition at 78%. SEM-EDX analysis confirmed the presence of the main elements carbon (C), iron (Fe), and oxygen (O), with the highest carbon content of 73.5% in the 5:3 composition. The surface morphology showed that there was particle agglomeration and a more even distribution of Fe₃O₄ particles in a balanced ratio. Testing using VNA in the X-band frequency range (8-12 GHz) showed that the 3:5 composition produced an optimum absorption power of 87% with a Reflection Loss (RL) value of -12.31 Db at a frequency of 10.54 GHz. Although the 1:1 composition has a slightly higher RL value of -12.39 dB, it has an absorption value of 86%. The 5:3 composition produces the lowest performance with an RL of -10.89 dB and an absorption power of 80%. These results show that the 5:3 composition produces an absorptive material that is balanced between carbon and Fe₃O₄.