Effect of Heat Treatment on the Microstructure and Mechanical Properties of FeSi Alloy Powder / Organosilicone Resin Microwave Absorbing Coatings

It is important to study the microstructure and mechanical properties of FeSi alloy powder / silicone resinmicrowave absorbing coatings under the simulated service temperature conditions to optimize the coating performances and predict their service life. In this work,the microwave absorbing coatings were prepared by air-cooled spraying process,and they were subjected to 10,20,30,40 and 50 thermal cycles at 400 ℃. The results of thermogravimetric analysis showed that the mass loss of microwave absorbing coating at 400 ℃ was only 0. 12%. It meant that the coating had good heat resistance and stable morphological structure. With the increase of thermal cycles,the surface hardness of the coating increased from 17. 32HV1±0. 57HV1 at room temperature to 34. 01HV1±0. 75HV1 after 10 cycles. When thermal cycles continued to increase,the surface hardness of the coating stabilized. The bonding strength of the microwave absorbing coating gradually decreased with the increase in thermal cycles,decreasing to (1. 95±0. 60)MPa after 40 thermal cycles. The main reasons may be the oxidative cross-linking reaction of the coating and the accumulated thermal stress due to mismatch,which damaged the mechanical properties of the microwave absorbing coatings during thermal cycling. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.