Mesoporous silicon carbide with high specific surface area was successfully synthesised from a MCM-48/polyacrylamide nanocomposite precursor in two temperature ranges of 650-700uC and 800-850uC by a magnesiothermic reduction process. The MCM-48/polyacrylamide precursor nanocomposite was prepared by in situ polymerisation. Heat treatment using low concentrations of acrylamide monomer in the temperature range of 650-700uC and using high concentration of acrylamide monomer was carried in two temperature ranges of 650-700uC and 800-850uC. The products were characterised by X-ray diffraction, TEM and N 2 adsorption-desorption. The results show that synthesised SiC in both temperature ranges of 650-700uC and 800-850uC is mesoporous and has specific surface of 194/60 and 167/84 m 2 g 21 respectively. The results also show that the value of carbon content and the concentration of acrylamide monomer (factor affecting the amount of contact surface of carbon and silica) impress the starting temperature of the reaction.

SiO 2(activated or mesoporous silica) /Mg (magnesiothermic or metal sintering aid) /C (activated or polymeric carbon) / N 2(atmosphere) systems were used in the one-step synthesis of β-SiC and β-Si 3 N 4 whiskers. In this study, a mixture of the active precursors was allowed to react via a self-sustaining reaction (highenergy ball milling process). Scanning electron micrographs and X-ray diffraction (XRD) analysis showed that the rod-like SiC whiskers (~800 μm) were synthesized in situ by the direct carbothermal reduction of silicon nitride (or silicon) with activated carbon in N 2 (or Ar) atmosphere. The results show that β-Si 3 N 4 (without β-SiC) was fully formed after 5 h of milling with four different morphologies, namely whisker tip (droplet/no droplet) and nonuniform whiskers (short hexagonal/ rhombohedral/rod-like) with a length of 0.1-400 μm. By adding metal sintering aids, the liquid phase Mg-Si-O-N and the rate of carbothermal reduction increased (enhanced densification via particle rearrangement) and their hexagonal whiskers tended to assume a rod-like shape. The effect of the concentration of CO (reduction of α-Fe 2 O 3 to Fe by CO) on the whisker synthesis suggests that, in addition to the concentration of CO, the nature of the family of mesoporous silica/carbon template is an important factor in the synthesis of β-SiC and β-Si 3 N 4 whiskers. The possible chemical reactions were investigated by studying the unwanted phases (MgO

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This article investigates the effect of alternating the sequence of variable‐energy repeated low‐velocity impact on the residual strength of carbon fiber reinforced polymer (CFRP) laminates. Quasi‐isotropic CFRP specimens were impacted using three impact energy levels, that is, Low (L), Medium (M), and High (H). Every group, out of three groups in total, was impacted consecutively using one of three sequences: LMH, HML, and MLH. Delamination and its growth after each impact was quantified using a phased‐array ultrasonic probe. The impacted specimens were then subjected to compression after impact loading with in situ acoustic emission (AE) and digital image correlation (DIC) measurement. Mechanical results showed that the residual strength of the specimens was not significantly affected by alternating the impacts sequence. However, the AE, sentry function and DIC results revealed that the impact‐induced damage in HML configuration was activated much earlier than MLH, and the damage induced in LMH configuration was activated later than both.