Inorganic/Organic Bilayer Of Silica/Acrylic Polyurethane Decorating Fesial For Enhanced Anti-Corrosive Microwave Absorption

Corrosive ions with immense penetrating ability often invalidate the traditional microwave absorber as well as cause severe corrosion. Herein, an inorganic/organic bilayer structure of silicon dioxide/polyurethane-acrylic (SiO2@PUA) is developed layer by layer on FeSiAl surface for addressing the dual-function of microwave absorption and anti-corrosion properties. The bilayer structure possesses the inorganic SiO2 layer with physical barrier function and organic outer layer (PUA) of hydrophobic nature. The as-prepared FeSiAl@SiO2@PUA composite structure filled with 20 wt% of paraffin wax displays a maximum reflection loss of -49 dB at 5.8 GHz, and a broad effective absorption bandwidth reaches 7.8 GHz (10.2-18 GHz) at 2.5 mm thickness. Besides, the corrosion behavior of FeSiAl, FeSiAl@SiO2, and FeSiAl@SiO2@PUA is investigated by immersing in a corrosive environment and electrochemical testing. Due to the multi-level protection of SiO2/PUA bilayer, the FeSiAl@SiO2@PUA is immersed in an alkaline salty environment (pH = 12) for 3930 h and the corresponding corrosion potential significantly increases from -0.166 to -0.047 V, indicating the enhanced anti-corrosion with relatively low corrosion current 2.16 x 10(-6) A/cm(2) and corrosion rate (6.94 x 10(-13) m/s). The designing inorganic/organic hybrid structure provides an effective strategy to enhance the dual-function of microwave absorption and anticorrosion and its application at the commercial level.