Low Cost Porous Alumina with Tailored Microstructure and Thermal Conductivity Prepared using Rice Husk and Sucrose

This study demonstrates a cost-effective way to fabricate porous ceramics with tailored porosity and pore microstructure using 5-40wt% rice husk (RH) in <75m, 75-180m, 180-355m, 355-420m, and 420-600m size, as pore former. Sucrose, used as binder, also acted as a pore former. Porous alumina compacts with 20%-66% volume fraction porosity and 50-516m pore size (length) were successfully fabricated. Microstructure of samples reveal randomly oriented elongated coarse pores and fine pores (avg. size 4m), created during burnout of RH and sucrose, respectively. Samples with isolated and/or interconnected pores were fabricated using this process. Thermal conductivity of the samples prepared was measured using Transient Plane Source (TPS) technique. Thermal conductivity ranges from 1.2 to 24W/mK. Experimental results agree closely with predictions made based on Effective Medium Theory (EMT) for a two-phase system.