A new method called sol-gel method was studied to add refractory metals into C/ C composites. Zir
conium acetate sol was used to infuse C/ C composites whose densities were 1. 39 and 1. 59 g/ cm3 respectively. The
effect of weight gain was apparently, and finally, the densities of C/ C composites reached 1. 88 and 1. 86g/ cm3. With
the use of back scattered electron, we studied the distribution of zirconium in the C/ C composites, finding that a zir
conium coating layer was formed on the surface of the material. But inside the material, the distribution of zirconium
mainly depended on the distribution of holes with in the material itself. After the testing of wind tunnel ablation on the
Zr-containing C/ C composites, a uniform ZrO2 film was found on the surface of material, which can cut off osculation
of oxygen and C/ C composites, and reduce the ablation rate of materials.