Effect of red mud and cenosphere reinforcements on the structural and emi shielding performance of open-cell aluminum foams

The Open-cell Al foam (OCAF) with an average density of 0.12 g/cc were synthesized successfully through reticulation technique, using polyurethane (PU) foam as a precursor. For further enhancing the multifunctional properties of OCAF, here in this work it is reinforced with red mud and cenospheres. The addition of red mud and cenosphere reinforcements in OCAF at 10% by weight is studied to analyze their effect on microstructure, mechanical strength and electromagnetic wave (EMW) absorption of the foam. The EMW absorption was evaluated using a Vector network analyzer in X-Band (i.e. 8.2 -12.4 GHz) frequency range. OCAF with cenosphere shows the highest total shielding effectiveness (~28 dB) which is then followed by red mud reinforcement and bare OCAF. In cenosphere, absorption component dominates the total shielding. Whereas in red mud, reflection and absorption contribute almost equally in total shielding. This reinforcement also enhances the compressive strength and energy absorption of the OCAF structure. The result demonstrated the use of cenosphere and red mud to tailor the properties of OCAF in terms of EMW absorption and structure application for the development of new material for electromagnetic shielding.