Table 1.
The classification of major processing strategies and corresponding compositions of porous ceramics produced from polysiloxane precursors.
| Processing strategy | Composition | Remarks | References | ||||||
|---|---|---|---|---|---|---|---|---|---|
| I. Replica | |||||||||
| SiC | Open cells | [56–60, 62] | |||||||
| Cell size:>150 μm | |||||||||
| Porosity range: 85–96% | |||||||||
| SiC–Si3N4 | [56, 58, 59] | ||||||||
| SiC–TiC | [56] | ||||||||
| SiOC/C | [53] | ||||||||
| II. Sacrificial template | |||||||||
| NaCl compact | SiC | Open cells | [67] | ||||||
| Cell size: 10–100 μm | |||||||||
| LDPE | SiOC | Open or closed cells | [68, 69] | ||||||
| Cell density: >104 cells cm− 3 | |||||||||
| Porosity range: 21–80% | |||||||||
| Expandable or PMMA templates | SiOC | Open, closed or partially interconnected cells | [66, 72–75] | ||||||
| Cell size: 0.5–80 μm | |||||||||
| Cell density: >109 cells cm− 3 | |||||||||
| Porosity range: 56–88% | |||||||||
| SiC | Porosity range: 32–64% | [18] | |||||||
| Expanded (hollow) templates | SiOC | Closed cells | [65] | ||||||
| Cell size: >30 μm. | |||||||||
| Cell density: >109 cells cm−3 | |||||||||
| Porosity range: 70–87% | |||||||||
| III. Direct foaming | |||||||||
| Foaming by chemical agent | SiOC | Open, closed or interconnected cells | [6, 77, 80–84, 86, 138] | ||||||
| Cell size: 80–800 μm | |||||||||
| Porosity range: 75–90% | |||||||||
| SiOC + SiC | Open cells | [81] | |||||||
| Cell size: 100–700 μm | |||||||||
| Foaming using CO2 | |||||||||
| Batch process | SiOC | Closed cells | [78, 89, 91, 95] | ||||||
| Cell size: 2–50 μm | |||||||||
| Cell density: 107–1012 cells cm− 3 | |||||||||
| Porosity: 45% | |||||||||
| SiC | [90] | ||||||||
| Extrusion process | SiOC | Open or closed cells | [92, 93] | ||||||
| Cell density: >107 cells cm− 3 | |||||||||
| Porosity range: 27–90% | |||||||||
| IV. Reaction technique | |||||||||
| SiC | Open cells | [18, 96–101, 103– | |||||||
| Cell size: 10–45 μm | 105] | ||||||||
| Cell density: >109 cells cm− 3 | |||||||||
| Porosity range: 32–94% | |||||||||
| Mullite | Partially interconnected open cells | [106–108] | |||||||
| Cell size: >20 μm | |||||||||
| Cell density: >109 cells cm− 3 | |||||||||
| Porosity range: 32–85% | |||||||||
| Cordierite | Interconnected open cells | [109, 110] | |||||||
| Cell size: 13 μm | |||||||||
| Cell density: 109 cells cm− 3 | |||||||||
| Porosity range: 11–75% | |||||||||