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Hydrophobic silica aerogels were synthesized by an ambient pressure drying method from silicic acid with a different pH value, which was prepared from sodium silicate solution (water glass). In this study we chose various hydrocarbon class solvents such as pentane, hexane, heptane, and toluene, and performed surface modification in TMCS (trimethylchlorosilane)/solvent solutions in order to improve reproducibility in aerogel production. Densities of the aerogels were about 0.1 ~ 0.3 g/cm3 , and apparent porosities were 88 ~ 96 %, depending on the processing conditions. Specific surface area was approximately 730 ~ 950 m2/g, and average pore size around 10 nm.

In this study, a dense strontium‐doped lanthanum chromite (La0.8Sr0.2CrO3, LSC) thin layer was designed to protect a stainless‐steel (SUS430) substrate from carbon deposition. The LSC layer was coated onto an SUS430 substrate by a dipping technique from a precursor solution of La, Sr and Cr nitrates, acetylacetone (acac), and 2‐methoxyethanol. The effect of AcAc on the phase behavior and microstructure evolution of the LSC thin films was investigated. After being heat‐treated at 800°C in air, the thin film was found to consist of perovskite LaCrO3, Mn1.5Cr1.5O4, and Cr2O3 phases. The addition of a chelating agent, acac, to the precursor solution led to a reduction in the formation of the strontium chromite (SrCrO4) phase. As a consequence, a thin film having a dense microstructure could be obtained. It was confirmed by Fourier‐tranform Raman spectroscopic analysis and FESEM observations that the carbon deposited on the uncoated SUS430 substrate was amorphous with a spherical morphology. The LSC thin film thus obtained was found to be very effective at preventing carbon deposition when it was heat‐treated under a dry hydrocarbon atmosphere.

Ceria-coated copper oxide powders were prepared by the precipitation method using cerium nitrate hexahydrate and ammonia as a precipitant. Heterogeneous nucleation and growth of ceria took place on the copper oxide surface by dispersing the copper oxide particles in cerium nitrate aqueous solution and subsequently adding ammonia into it. Process conditions such as the pH of the precursor solution and precipitation temperatures were carefully controlled for the homogeneous precipitation of ceria particles. It was found that copper oxide was homogeneously coated with nano-sized (~20 nm) ceria particles at room temperature. The morphology of ceria and ceria-coated copper oxide powder were examined by field-emission scanning electron microscopy (FE-SEM) as a function of precipitation temperature.