Preparation of porous MgAl2O4 ceramics by a novel pectin gel-casting process

摘要

In this paper, a novel pectin gel-casting method was developed to prepare porous MgAl2O4 ceramics using MgO and Al2O3 powders as raw materials and ficus pumila seeds as the gel source. The effects of pectin content on the properties of MgAl2O4 porous ceramics, such as phase composition, microstructural characteristics, apparent porosity, bulk density, compressive strength, and thermal conductivity, were investigated. The results showed that the linear shrinkage of the samples was about 5%, indicating a near-net shape method. With the increase of pectin content, the porosity of porous MgAl2O4 ceramics increased significantly. The prepared MgAl2O4 porous ceramics with different pectin contents showed high apparent porosity of 58.7-70.1%, low thermal conductivity of 0.328-0.840 W/(mK), and relatively high compressive strength of 0.27-2.45 MPa. The proposed method as a near-net shape forming method provided a novel feasible gel-casting method to fabricate other porous ceramics.