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

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