Oxidation of silicon melt infiltrated SiC/SiC ceramic matrix composites (CMC) was studied in air at 1200–1400 °C for 1, 5, 24 and 48 h. Weight gain and oxide layer thickness measurements revealed the oxidation follows parabolic reaction kinetics with increase in temperature and time. XRD showed the extent of oxide layer (SiO2) formation was greatest after 48 h at 1400 °C: an observation confirmed by X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM) analyses. Oxide layer thickness varied from 1 μm after 48 h at 1200 °C to 8 μm after 48 h at 1400 °C. Oxidation of SiC/SiC composites is both temperature and time dependent with an activation energy of 619 kJ mol−1. BN coatings around SiC fibres showed good resistance to oxidation even after 48 h at 1400 °C

Rare‐earth ( RE ) monosilicates are promising candidates as environmental barrier coating ( EBC ) materials for ceramic matrix composites for aerospace applications. Five rare‐earth monosilicate materials have been investigated: Y ₂ SiO ₅ , Gd ₂ SiO ₅ , Er ₂ SiO ₅ , Yb ₂ SiO ₅ , and Lu ₂ SiO ₅ produced from RE oxides and silica starting materials pressed and sintered at 1580°C under flowing air. Relative densities above 94% were obtained for all samples and ceramics were made containing 85–100 wt% of the RE monosilicate according to X‐ray diffraction ( XRD ) with RE disilicates as the second phase in the Gd, Yb, and Lu silicate systems. Microstructures were characterized using scanning electron microscopy and XRD , and thermal properties measured including specific heat, thermal expansion, and thermal diffusivity. For the first time, specific heat capacity values are reported for the monosilicates [0.45–0.69 J·(g·K) ⁻¹ ]. Thermal expansion coefficients ( TEC s) of the dense samples ranged between 5.9 and 10.3 × 10 ⁻⁶ K ⁻¹ measured for 473 to 1473 K. All EBC s have low thermal conductivities [1.8 W·(m·K) ⁻¹ or less] making them excellent EBC insulators.

We propose a large-area SERS device with efficient fluorescence quenching capability. The substrate is based on anodic porous alumina templates with various pore size and wall thickness as small as 15 and 36 nm, respectively. The nano-patterned SERS substrate, with excellent control and reproducibility of plasmon-polaritons generation, shows very efficient enhanced Raman signal in the presence of intrinsically fluorescent molecules such as cresyl violet, rhodamine, and green fluorescent protein. This work demonstrates that, when the nanostructures are properly designed and fabricated, Raman and fluorescence spectroscopy can be used in combination in order to obtain complementary molecular informations. Theoretical simulation shows excellent agreement with the experimental findings. The enhancement factor is found to be 10³–10⁴, with respect to flat gold surface when the molecules are supposed to be closely packed, with considerable fluorescence suppression, showing a promising disposable biosensor.