SiC nanowire-toughened SiC–MoSi2–CrSi2 oxidation protective coating for carbon/carbon composites

To prevent carbon/carbon (C/C) composites from oxidation, a dense SiC nanowire-toughened SiC–MoSi2–CrSi2 multiphase coating was prepared by the two-step technique composed of chemical vapor deposition (CVD) and pack cementation. The coatings were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). SiC nanowires could decrease the dimension of cracks and improve the oxidation and thermal shock resistance of SiC–MoSi2–CrSi2 multiphase coating. Oxidation test shows that, after introducing SiC nanowires, the weight loss of the coated sample can be reduced from 1.06% to 0.64% after oxidation at 1773 K for 155 h and decreased from 6.92% to 3.42% after thermal cycling between 1773 K and room temperature for 30 times.