The mechanisms of densification and creep were examined during spark plasma sintering (SPS) of alumina doped with a low and high level of zirconia or yttria, over a temperature range of 1173–1573 K and stresses between 25 and 100 MPa. Large additions of yttria led clearly to in situ reactions during SPS and the formation of a yttrium-aluminum garnet phase. Dopants generally lead to a reduction in the densification rate, with substantial reductions noted in samples with ∼5.5 vol% second phase. In contrast to a stress exponent of n ∼ 1 for pure alumina, the doped aluminas displayed n ∼ 2 corresponding to an interface-controlled diffusion process. The higher activation energies in the composites are consistent with previous data on creep and changes in the interfacial energies. The results reveal a compensation effect, such that an increase in the activation energy is accompanied by a corresponding increase in the pre-exponential term for diffusion.

One-dimensional (1D) nanofibers of polypyrrole (PPY) are fabricated on glass substrates in the presence of different dopants, namely, hydrochloric acid (HCl), ferric chloride (FeCl3·6H2O), p-toluene sulfonic acid, camphor sulfonic acid, and polystyrene sulfonic acid using a simple in situ vapor phase chemical oxidative polymerization method. Preliminary morphological details investigated using light microscopic study reveal 1D configuration for all the doped PPY structures, indicating a fibrous/tubular appearance. Furthermore, scanning electron microscopy confirms preferential growth of these PPY structures as fine fibers arranged in a brush-/comb-like pattern, having an average diameter of 70 nm. Such brush-like growing pattern observed for the PPY nanostructures without the aid of nanoporous membranes and/or sophisticated techniques is not very commonly reported in the literature. The undertaken work suggests applications of nanodimensioned fabricated PPY structures in the practical nanodevices and/or functional glass for sensing, optoelectronic, photocatalysis, and solar energy systems.