A glass coating for SiC fiber reinforced aluminum phosphate matrix (SiCf/AlPO4) composites for high-temperature absorbing wave applications

A single-layer radar-absorbing structure in the X-band (8.2 GHz to 12.4 GHz) was fabricated by blending conductive carbon black (CB) with the binder matrix of SiCf/AlPO4 composites. An oxidation protective glass coating was prepared on SiCf/AlPO4 composites using a simple and low-cost slurry technique. Oxidation test shows that, after oxidation in air at 1273 K for 50 h, the three-point bending strength of coated SiCf/AlPO4 composites keeps up to 200 MPa, and the complex permittivity has little difference with the as-received sample. By simulating the reflection loss, it was found that − 10 dB absorbing bandwidth can be more than 3 GHz for oxidation test-coated SiCf/AlPO4 composites in the range of 2.8 mm to 3.2 mm thickness.