Porous SiC ceramics were successfully fabricated by silica bonding of SiC compacts and porogen burnout technique. Silica coating on SiC particle was carried out using TEOS hydrolysis and crystallizes during the sintering process at 1200°C, which forms a well-developed neck growth between the SiC particles. Different volume fractions of sodium chloride porogen were used to obtain varied porosity content in porous SiC ceramics from 36 to 62.47 % leading to wide-ranging compressive strength from 8.11 to 0.69 MPa. Interconnected bimodal pores were created throughout the sample due to the burnt out of salt and stacking of SiC particles. The pore size distribution of porous SiC measured using mercury intrusion porosimetry shows that average pore size due to the salt particle is around 74-110 lm and stacking of SiC particle result 4-10 lm. Direct squeeze infiltration method is successfully adopted for infiltration of 6061 aluminium molten alloy into SiC preforms with the controlled process parameters of initial preform temperature, liquid metal superheating, squeezed pressure and its rate of application and die temperature. Microstructures have shown complete infiltration of Al alloy into the pores of the SiC preform forming Al composite with good interfacial bonding aided by the presence of MgAl 2 O 4 spinel. The silica coating on SiC surface have a multifunctional role of acting as a binder for the porous preform, enhances the wettability of SiC particle with molten metal during infiltration and prevention of deleterious Al 4 C 3 interfacial reaction product.
We report the formation of breath-figure (BF) patterns with amino-functionalized cavities in a BF incompatible polystyrene (PS) by incorporating functionalized alumina nanoparticles. The particles were amphiphilic-modified and the modifier ratio was regulated to achieve a specific hydrophobic/hydrophilic balance of the particles. The influence of the physical and chemical properties of the particles like particle concentration, the hydrophobic/hydrophilic balance, etc., on particle dispersion in solvents having different polarity and the corresponding changes in the BF patterns have been studied. The amphiphilic-modified alumina particles could successfully assist the BF mechanism, generating uniform patterns in polystyrene films with the cavity walls decorated with the functionalized alumina particles, even from water-miscible solvents like THF. The possibility of fabricating free-standing micropatterned films by casting and drying the suspension under ambient conditions was also demonstrated. The present method opens up a simple route for producing functionalized BF cavities, which can be post-modified by a chemical route for various biological applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.