The polymer‐based synthesis of ceramics such as SiCO (and SiCN) leads to the incorporation of significant amounts of carbon into their molecular structure. A key feature of the nanostructure of these polymer‐derived ceramics is the revelation of persistent, 1–5 nm size domains by small‐angle X‐ray scattering. Here we present a model for these nanodomains, which is consistent with the nuclear magnetic resonance (NMR) data and with the phenomenological properties of SiCO (high resistance to creep and viscoelastic behavior). The model consists of clusters of silica tetrahedra encased within an interdomain wall constituted from mixed bonds of SiCO, and from a network of sp2 carbon. The model predicts the domain size as a function of the carbon content. These predictions are in reasonable agreement with the measurements of the nanodomains in SiCO synthesized with varying carbon contents (the domain size decreases with higher carbon). Simple maps are developed for easy reading of the domain size and the width of the interdomain boundary in the composition diagrams.

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Quenching and partitioning (Q&P) produces steel microstructures with martensite and austenite that exhibit promising property combinations for third generation advanced high strength steels. Understanding kinetics of reactions that compete for the available carbon, such as carbide formation, is critical for alloying and processing design and achieving austenite enrichment and retention during Q&P. Mössbauer effect spectroscopy (MES) was used to characterize Q&P microstructures in a 0.38C-1.54Mn-1.48Si wt. pct. steel after quenching to 225 °C and partitioning at 400 °C for 10 or 300 s, with an emphasis on transition carbides. The recoilless fraction for η-carbide was calculated and a correction for saturation of the MES absorption spectrum was applied, making quantitative measurements of small amounts of η-carbide, including non-stoichiometric η-carbide, possible in Q&P microstructures. Complementary transmission electron microscopy confirmed the presence of η-carbides, and MES and x-ray

High-hydrogen-diluted films of hydrogenated amorphous Si (a-Si:H) 0.5 μm in thickness and optimized for solar cell efficiency and stability, are found to be partially microcrystalline (μc) if deposited directly on stainless steel (SS) substrates but are fully amorphous if a thin n layer of a-Si:H or μc-Si:H is first deposited on the SS. In these latter cases, partial microcrystallinity develops as the films are grown thicker (1.5–2.5 μm) and this is accompanied by sharp drops in solar cell open circuit voltage. For the fully amorphous films, x-ray diffraction (XRD) shows improved medium-range order compared to undiluted films and this correlates with better light stability. Capacitance profiling shows a decrease in deep defect density as growth proceeds further from the substrate, consistent with the XRD evidence of improved order for thicker films.