表面磷化对羰基铁耐蚀及电磁性能的影响分析OA

Carbonyl iron(CI)has been widely used in the field of electromagnetic wave absorption due to its excellent electromagnetic properties.However,CI will be corroded when it is used in harsh environments such as the ocean for a long time,which will affect the electromagnetic characteristics of the material.In recent years,phosphating treatment has been employed as an effective surface modification technique to enhance the corrosion resistance of iron-based materials.By applying phosphating treatment to CI powder,a phosphate passivation layer is formed on the surface of the material.This phosphate layer can significantly inhibit the electrochemical corrosion process of CI,through its physical barrier effect and chemical inertness.After 10 minutes of phosphating,the corrosion current density of CI decreased significantly from 29.4 A·cm-2 to 3.9 A·cm-2,and the corrosion rate dropped from 3.45 mm·a-1 to 0.46 mm·a-1.Simultaneously,this phosphate passivation layer acts as a high-resistance thin film,substantially reducing the leakage conductivity caused by direct contact between CI particles.Consequently,the relative permittivity of the material is modulated,with the real part decreasing from 33.9 to 25.5 and the imaginary part decreasing from 18.5 to 6.1.This adjustment in electromagnetic properties leads to an improvement in the traveling wave attenuation rate at 3 GHz from 17.6 dB·m-1 before phosphating to 34.4 dB·m-1 after phosphating for a coating with thickness of 2 mm.These findings provide a novel approach for corrosion protection and traveling wave suppression in complex environments such as shipboard applications.