No abstract

No abstract

No abstract

No abstract

Although granular activated carbon (GAd, fluidizedbed

Open cellular SiC foams with low densities were prepared by thermo‐foaming and setting (130°C–150°C) of silicon powder dispersions in molten sucrose followed by pyrolysis and reaction sintering at 1500°C. The bubbles generated in the dispersion by water vapor produced by the –OH condensation was stabilized by the adsorption of silicon particles on the air‐molten sucrose interface. The composition of a sucrose‐silicon powder mixture for producing SiC foam without considerable unreacted carbon was optimized. The sucrose in the thermo‐foamed silicon powder dispersion leaves 24 wt% carbon during the pyrolysis. The sintering additives such as alumina and yttria promoted the silicon‐carbon reaction. SiC nanowires with diameters in the range of 35–55 nm and length >10 μm observed on the cell walls as well as in the fractured strut region were grown by both vapor–liquid–solid and vapor–solid mechanisms. Large SiC foam bodies without crack could be prepared as the total shrinkage during pyrolysis and reaction sintering was only ~30 vol%. The relatively low compressive strength (0.06–0.41 MPa) and Young's modulus (14.9–24.2 MPa) observed was due to the large cell size (1.1–1.6 mm) and high porosity (93%–96%).

No abstract

Thermally conducting microcellular carbon foams are prepared from sucrose with graphite as a filler using an economical, scalable, and sustainable NaCl particle templating technique. The effect of graphite filler and NaCl template loading on density, porosity, thermal conductivity, and microstructure are carefully investigated. Conducting carbon foams (CCF) exhibit high porosity (76.1 to 93.4%) and adequate compressive strength (0.225 to 14.96 MPa). The high thermal conductivity (0.282 to 5.23 W m À1 K À1 ), interconnected microcellular structure (cell size 2-12 μm), and hydrophobic nature make the foams ideal for hosting wax-based phase change materials for thermal energy storage and management applications. Composites of conducting carbon foam and paraffin wax (PW) are prepared with various wax loadings (50.5 to 82.6 wt%), which exhibit thermal conductivities in the range of 0.65-7.72 W m À1 K À1 . The melting and freezing characteristics and form stability of the composites are also studied. It is established that the microcellular structure is advantageous for easy wax-impregnation and retention during thermal cycling compared to macrocellular (cell size of 600 μm) foams of the similar composition due to the enhanced capillary forces. Differential scanning calorimetry (DSC) study of PW/CCF composites shows the highest melting enthalpy of 110.9 J g À1 .