Effects of surface aluminizing on structure and compressive strength of Fe foam prepared by electrodeposition

摘要

In order to improve the oxidation resistance in air and mechanical properties of Fe foam prepared by electrodeposition on polyurethane foam, a surface aluminizing layer of Fe foam was obtained by a convenient pack cementation method. Phase evolution, microstructure, compressive strength of the as-fabricated Fe foams and surface aluminized Fe foams (SA-Fe foam) were investigated and characterized by XRD, SEM, EDS and compression testing. The SEM results showed that the SA-Fe foams maintain the overall porous architecture inherited from the Fe foam and polyurethane foams. A key factor for enhancing the mechanical properties of the Fe foam was a high temperature heat treatment in H_2 atmosphere. A porous and sponge-like structure appeared on the surface of the strut of SA-Fe foams after surface aluminization. With increasing aluminizing time, main phase on the surface changed from Fe-Fe_2Al_5/FeAl/Fe-FeAl/Fe_3Al. Maximum compressive strength of the SA-Fe foams was obtained for 10 min aluminization and had a value of about 12 MPa, which is more than 2.5 times that of Fe foams. The deformation characteristic of the porous materials changed from ductile to brittle deformation with increasing pack aluminization time.