Refractory metal silicides reinforced by in-situ formed Nb2O5 fibers and mullite nanoclusters

Microstructural Characterization and Anti‐Oxidation Properties of Molybdenum Disilicide Coating on Niobium by Spent MoSi2‐Based Materials

“…[ 55–61 ] Moreover, SiO 2 has low coefficient of oxygen diffusion at elevated temperature, and it plays the role of oxygen barrier for inhibiting further oxidation inside the coatings. [ 12 ] During initial oxidation, SiO 2 oxide scale will be quickly formed due to the oxidation of MoSi 2 that exposed in air. [ 54 ] As the oxidation process moves to slow oxidation stage, the diffusion path of oxygen is blocked by the formed SiO 2 oxide scale, thus the rate of the mass gain slows down.…”

“…MoSi 2 , considering as an excellent high‐temperature material, possesses lots of advantages such as high melting temperature (2030 °C), low thermal expansion coefficient (CTE, 8.1 × 10 −6 K −1 ), and low density (6.24 g cm −3 ). [ 10,11 ] It is widely used as anti‐oxidation coating because SiO 2 oxide scale with low oxygen diffusion coefficient (10 −13 cm 2 s −1 at 1200 °C) [ 12 ] can be formed on the coating surface by the oxidation of MoSi 2 at high temperature, and this prevents further oxidation of the coating. [ 13–16 ] As one of the most popular applications of molybdenum disilicide, MoSi 2 ‐based materials can work at the temperature of 1850 °C, and it is extensively applied in hot section components of aircraft engines and industrial heating elements.…”

Preparation and high‐temperature oxidation resistance of multilayer MoSi2/MoB coating by spent MoSi2‐based materials

“…The thickness of SiO 2 scale is increased during isothermal oxidation, and the low oxygen The oxidation resistance of coatings can be effectively ameliorated by SiO 2 because good high-temperature flowability is possessed by SiO 2 , which is conducive to filling voids and microcracks on the coating surface for preventing the oxidation corrosion. 5,[8][9][10][11] Moreover, SiO 2 has relatively low diffusion coefficient of O 2 at high temperature (10 −13 g/cm s), 45 and it plays the role of oxygen barrier to prevent further oxidation in the coating and substrate. However, some cracks, the width of which is about 15 μm, are still found in the silica layer of MoSi 2 coating (Figure 8A,B) while only small-sized crack (2 μm) can be found in the multilayer coating.…”