A novel approach to fabricate porous magnesia materials with excellent properties via pore-forming agent

Abstract

Abstract

A creative approach for fabricating porous magnesia materials with improved mechanical and thermal properties using walnut shell powders as pore-forming agent combined with self-created porous magnesia aggregates is reported in the present work. The work focused on the microstructure and binding mechanism of the novel walnut shell powders (WSP), which treated by silica sol, aluminum sol, and oleic acid, and the properties and microstructure of porous magnesia materials. The results showed that the surface of the sols-treated walnut shell powders was spherical and significantly dispersed. The oleic acid-treated walnut shell powder (OWS) did not differ much from the original state; the surface was rough and agglomeration. The porous magnesia material with the addition of SWS has excellent properties, forms closed pores and low conductivity. When the SWS was added at 10%, the bulk density, porosity, compressive strength, and thermal conductivity of samples were 1.64 g·cm⁻³, 53.97%, 22 MPa, and 0.447 W/(m·K), respectively.