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We have presented a numerical technique for analyzing onedimensional transient temperature distributions in a circular hollow cylinder that was composed of functionally graded ceramic-metal-based materials, without considering the temperature-dependent material properties. The functionally graded material (FGM) cylinder was assumed to be initially in a steady state of gradient temperature; the ceramic inner surface was exposed to high temperature, and the metallic outer surface, which was associated with its in-service performance, was exposed to low temperature. Then, the FGM cylinder was cooled rapidly on the ceramic surface of the cylinder, using a cold medium. The transient temperature and related thermal stresses in the FGM cylinder were analyzed numerically for a model of the mullite-molybdenum FGM system. The technique for analyzing the temperature distribution is quite simple and widely applicable for various boundary conditions of FGMs, in comparison with methods that have been proposed recently by other researchers.

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Fully dense multiwall carbon nanotubes (MWCNT)/SiO2 nanocomposites with MWCNTs contents of 5 and 10 vol% have been processed by spark plasma sintering, and the electrical conductivities of the nanocomposites were evaluated at temperatures ranging from 5 to 300 K. It has been found that the incorporation of MWCNTs converted an insulating silica nanoceramic into metallically conductive composites. The room‐temperature conductivities of the nanocomposites, with over 14 orders of magnitude compared with pure silica, are in the range of 8 and 65 S/m. Also, it was interestingly found that the conductivity increased linearly with temperature from 5 to 300 K.

Fine b-sialon (Si 6Àz Al z O z N 8Àz , 1ozo4) was prepared by mechanical-activated combustion synthesis (CS) using raw materials such as Si, Al, and SiO 2 in a nitriding atmosphere of 1 MPa. Mechanical activation by planetary milling for only 18 min led to the formation of b-sialon after combustion synthesis. Comparative experiments with ball milling showed that the relative amount of b-sialon was considerably increased to 66% when planetary milled to 18 min after CS. The raw material Si was replaced by waste Si of 94.8 mass% in purity, and was combustion synthesized successfully under the same processing parameters for cost-effective measures.

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