Y₂Mo₃O₁₂ modified carbonyl iron powder-boron-phenolic resin coatings for microwave absorption

Carbonyl iron powder–polymer coating is one of the effective microwave absorption systems, which can be widely used as medium temperature structural materials in the aerospace industry. However, the significant mismatch of the coefficient of thermal expansion (CTE) between coatings and the titanium alloy substrates will cause serious cracking and peeling problems in practical applications. Thus, we designed to introduce Y₂Mo₃O₁₂ (YMO) with negative CET into the carbonyl iron powder–boron-modified phenolic (BP) resin coating to reduce the CET of coating. The result showed that the CTE of the coatings is significantly decreased by the addition of Y₂Mo₃O₁₂. The YMO/CIP/BP coating of 8 wt% YMO - 67 wt% CIP - 25 wt% BP shows a CTE of 21.1 × 10^–6 ℃⁻¹, which is 68% smaller than that of CIP/BP coating. The minimum RL (maximum of microwave absorption) of 8 wt% YMO - 67 wt% CIP - 25 wt% BP is – 12.3 dB at the thickness of 1.4 mm, which makes it an excellent candidate for the microwave absorptions applied on the titanium alloy surfaces.