hybrid composite. For the sandblasting treatment, samples with higher pyrolysis temperature are more erosion resistant due to the high surface hardness and structure rigidity. Comparing the flexural strength before and after sandblasting treatment, samples prepared with 1300°C pyrolysis temperature have the lowest drop, which means samples with pyrolysis temperature of 1300°C are the most erosion resistant ones out of the five groups. The mass loss caused by sandblasting treatment decreases with increase in preparation temperature. This is also because of the surface hardness and structure stiffness. Influence of CNT ceramic composite thickness CNT ceramic composite thickness is another parameter which could influence the erosion resistance of the hybrid composite. Multiple CNT preforms are used in the preparation process to achieve larger CNT ceramic composite thickness, e.g. 2-layer CNT preforms result in a 40 µm CNT ceramic composite. Three samples are tested for each parameter. Figure 10 shows the flexural strength variations of hybrid composites with different CNT ceramic composite thickness before and after 60 seconds sandblasting treatment. Larger CNT ceramic composite thickness results in smaller flexural strength. This is because the rigid CNT ceramic composite mitigates the flexural properties of CFRP. The thicker the CNT ceramic composite, the higher flexural strength for hybrid composites after sandblasting treatment. Since the sandblasting parameters are fixed, hybrid composite with thicker CNT ceramic composite protects the CFRP better than the hybrid composite with thinner CNT ceramic composite. FIGURE 9. Flexural strength of hybrid composite with CNT ceramic composite prepared at different pyrolysis temperature before and after sandblasting treatment (inset shows the mass loss after 60 seconds sandblasting). CONCLUSIONS A hybrid composite including a CNT ceramic composite layer and a CFRP substrate is successfully developed. The erosion resistance property is characterized by sandblasting test. Mass loss and flexural strength loss increase with the increase of sandblasting duration. The hybrid composite has less flexural strength loss percentage comparing to the pure CFRP due to the protection of the CNT ceramic composite on the surface. The hybrid composite and CFRP have different failure mode. Perorated dents first appear on the hybrid composite before the breaking of carbon fibers in CFRP. Pyrolysis temperature of the CNT ceramic composite influences the erosion resistance performance of the hybrid composite. w w w. s a m p e . o r g FIGURE 10. Flexural strength of hybrid composite with different thicknesses of CNT ceramic composite before and after sandblasting treatment (inset shows the mass loss for three groups of samples). J U LY/AU G U S T 2 0 1 9 | SAMPE JOURNAL | 47http://www.sampe.org