A SiC-ZrB2-ZrC coating toughened by electrophoretically-deposited SiC nanowires to protect C/C composites against thermal shock and oxidation

SiC nanowire toughened ZrB2–SiC ablative coating for SiC coated C/C composites

“…Qiang reported that after introducing SiC nanowires, the size of cracks in SiC outer layer decreased and the weight loss of coated carbon/carbon samples decreased from 127.7 g/m 2 to 76.2 g/m 2 after 40 times thermal cycling between 1500 ℃ ℃ ℃ ℃ and room temperature [17]. Previous studies on SiC nanowire toughened coatings were mainly focus on its oxidation behavior [18,19]. After introducing the SiC nanowires into the coating, the hardness and elastic modulus of the coating were increased and the number and the size of microcrack of the coating were decreased.…”

High temperature anti‐oxidation behavior of in situ and ex situ nanostructured C/SiC/ZrB2‐SiC gradient coatings: Thermodynamical evolution, microstructural characterization, and residual stress analysis

“…Therefore, SiC nanowhiskers with different diameters and lengths are formed in different pores. The formation of SiC nanowhiskers facilitates the improvement of the oxidation resistance due to an increase in fracture toughness of the coatings by the toughening mechanisms of nanowhiskers, such as pullout, crack deflection, and bridging . Generally, ceramic coatings tend to cracking due to their inherent brittleness, especially during thermal stress loading.…”

Preparation of a nanostructured SiC-ZrO2 coating to improve the oxidation resistance of graphite

“…Moreover, regarding the presence of the SiC phase in the coatings, it could be concluded that oxygen reacted with the SiC according to Eqs. (9) and (10), to form the SiO 2 phase. Because the SiO 2 glass phase has a melting point in the range of 1373-1923 K and a low vaporizing rate [28], the liquid SiO 2 phase could fill the coating pores and since the coefficient of oxygen diffusion to the SiO 2 glass phase at 1773 K is very low [29], the SiO 2 liquid phase could prevent the diffusion of oxygen to the coating.…”

“…The ZrO 2 produced by oxidation of ZrB 2 can react with SiO 2 to form ZrSiO 4 , which is beneficial to oxidation resistance ability due to its low permeability for oxygen and high thermal stability at high temperature. The high-thermally stable ZrSiO 4 can be expected to reduce the consumption of SiO 2 and improve the oxidation resistance of SiC coating at high temperature [9][10][11]. Wang et al [12] used a two-step pack cementation method with ZrB 2 , Si and graphite powders at 2273 K to prepare ZrB 2 -SiC coating on graphite, which showed (ZrB 2 -SiC)/SiC coatings can better protect the graphite matrix than SiC coating from oxidation.…”