Fabrication of Open‐Cell, Microcellular Silicon Carbide Ceramics by Carbothermal Reduction

Abstract

A novel processing route for developing open-cell, microcellular SiC ceramics has been developed. The strategy adopted for making microcellular SiC ceramics involved the following: (i) fabricating a formed body from a mixture of polysiloxane, phenol resin (used as a carbon source), polymer microbeads (used as sacrificial templates), and Al 2 O 3 -Y 2 O 3 (an optional sintering additive); (ii) cross-linking the polysiloxane in the formed body; (iii) transforming the polysiloxane and phenol resin by pyrolysis into silicon oxycarbide and C, respectively; and (iv) synthesizing SiC by carbothermal reduction. By controlling the microbead and additive contents, it was possible to adjust the porosity so that it ranged from 60% to 95%.

Processing and properties of polysiloxane-derived porous silicon carbide ceramics using hollow microspheres as templates

“…24 The in situ grown SiC whiskers were also observed in porous SiC ceramics using microbeads as the sacrificial templates. 17 Fig . 4 shows the typical grain morphology of porous SiC ceramics.…”

“…16 The carbothermal reduction techniques involve the carbothermal reduction of SiO 2 or polysiloxane-derived SiOC by carbon. 17,19 There are no reports of the mechanical strength and thermal conductivity of porous SiC ceramics processed by carbothermal reduction.…”

“…Reaction methods involve oxidation bonding techniques, 15 siliciding techniques 16 and carbothermal reduction techniques. 17 Oxidation bonding techniques involve the heating of SiC powder compacts in air so that the SiC particles are bonded to each other by an oxidationderived SiO 2 glass 15 or by oxidation-derived mullite with the addition of Al 2 O 3 addition. 18 Siliciding techniques involve a chemical reaction between wood-derived carbon foams and molten Si.…”

Microstructural designs of spark-plasma sintered silicon carbide ceramic scaffolds

“…Structural macroporous SiC components have been produced by replicating polymer foams [11] or wood templates [12,13], or by using other sacrifi cial organic templates (e.g. PMMA [14] or nylon [15]), and inorganic materials (such as graphite and SiO 2 [14]). Other methods as direct foaming [16] have also been attempted for SiC.…”

Fabrication of Bioactive High Porous Hydroxyapatite Ceramics

“…These processing methods are generally classified into three groups: replica, sacrificial template and reaction techniques [16]. The replica method is one of the most attractive routes to fabricate the micro porous hydroxyapatite structures.…”