Evaluation of the mechanical properties of a porous alumina ceramic obtained from the rice husk as a porogenic agent

Reference	Presenter	Authors (Institution)	Abstract
17-046	Giseli Cristina Ribeiro	Ribeiro, G.C.(Universidade Federal Fluminense); Fortes, B.d.(Universidade Federal Fluminense); da Silva, L.(Universidade Federal Fluminense); Castro, J.A.(Universidade Federal Fluminense); Ribeiro, S.(Escola de Engenharia de Lorena);	The objective of this work was to evaluate the mechanical properties of porous alumina ceramics, using the rice husk as a porogenic element. Rice husk is an agricultural waste produced in large quantity and contains about 20% of silica in its composition, which when in contact with the alumina, at high temperature, promotes the formation of mullite, which contributes to the improvement of mechanical properties of ceramics. The rice husk was milled and graded granulometrically in 2 bands (150 ?m and 65 ?m) in order to obtain different pore sizes. For each chosen range, the rice husk was added in the proportions of 5, 15 and 30 wt% of calcined alumina, and mixed manually until complete homogenization. The samples were pressed by uniaxial pressing, in cylindrical format and prismatic plates, and sintered at 1450ºC for one hour. The compressive strength results varied between 128MPa, for the addition of 5%, and 4 MPa, for the addition of 30%. The results of modulus of elasticity and rupture also showed a decrease with the increase of the content of rice husk. Samples were also prepared without addition of rice husk in order to compare the porosity increase with the loss of mechanical strength.
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