S. Subaer, H. Husain, N. Nurhasmi, M. Misdayanti, R. Irfanita, H. Ismayanti, I. Nayla Sari, Annisa Nur, F.H. Al Fiqhi
In this study, a geopolymer–graphene–Fe3O4 nanoparticle composite (Geo-G-Fe3O4NPs) was synthesized and characterized for its potential application in electromagnetic shielding. The geopolymer paste was produced via alkali activation of dehydroxylated laterite, with fly ash progressively incorporated as a partial replacement to improve mechanical performance. Graphene–Fe3O4 nanoparticles were uniformly dispersed into the paste to fabricate the Geo-G-Fe3O4NPs composite, with Fe3O4NPs content systematically varied from 0 to 2.0 g to optimize magnetic properties. Phase analysis and microstructural characterization of the raw materials and composites were performed using XRF, XRD, Raman spectroscopy, SEM-EDS, and HRTEM-SAED. Compressive and flexural strength tests confirmed that the composites are suitable for structural applications. Magnetic characterization using a vibrating sample magnetometer (VSM) at constant temperature revealed a monotonic increase in magnetic moment with increasing Fe3O4NPs content, affirming the material's potential for electromagnetic shielding. XRD analysis indicates formation of a sodium poly(ferro-silico-aluminate) geopolymer network, driven by the high iron-oxide content of the laterite. The incorporation of graphene sheets and Fe3O4NPs resulted in a dense, compact microstructure, with nanoparticles distributed throughout the geopolymer matrix. This synergistic interaction among the geopolymer, graphene, and Fe3O4NPs significantly enhanced both mechanical integrity and electromagnetic shielding performance. © 2026 Elsevier Ltd
Material Physics Lab, Physics Department, Universitas Negeri Makassar, Indonesia; Geopolymer and Advanced Materials Group (Ge, MA, Universitas Negeri Makassar, Indonesia; Metallurgical Engineering Technology, Politeknik Dewantara, Indonesia
