Wancheng Zhou
Northwestern Polytechnical University, China
Title: Improvement of oxidation resistance of carbonyl iron powder through cobalt-coating
Biography
Biography: Wancheng Zhou
Abstract
Carbonyl iron powder is commonly used as an absorber in microwave absorbing coatings. However, the resistances of carbonyl iron powder to oxidation and corrosion are not good. In this work, carbonyl iron powder is coated with cobalt through electroless plating to increase the resistance to oxidation and corrosion. Original and cobalt-coated carbonyl iron powders were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), vibrating sample magnetometer (VSM), thermogravimetric (TG) and microwave network analyzer, respectively. The original and cobalt-coated carbonyl iron powders were embedded in polyimide to form coatings to study the complex permeability and permittivity before and after heat treatment in air at different temperatures and different time. The results show that the cobalt-coating slightly decreases both the real part and the imaginary part of the permeability of the carbonyl iron powder, and remarkably increase both the real part and the imaginary part of the permittivity of the carbonyl iron powder. After heat treatment at 250oC and 300oC, respectively, the permeability of both coated and non-coated carbonyl iron powders decreases and the permittivity of both coated and non-coated carbonyl iron powders increases. However, the degree of decrease in permeability and increase in permittivity of the cobalt-coated carbonyl iron powder is smaller than those of the non-coated carbonyl iron powder. The cobalt-coating increases the oxidization resistance of the carbonyl iron powder.