Structures and properties of Al₂O₃/Fe composite honeycombs fabricated by plasticizing powder extrusion

In order to fabricate Al₂O₃/Fe composite honeycombs with high-performances, 316L alloy powder, Al₂O₃ powder and binder were used as raw materials, Al₂O₃/Fe composite honeycombs were obtained by plasticizing powder extrusion and sintering at 1 200℃ for 2 h in argon atmosphere firstly. Then, the effects of adding Al₂O₃ on the structures and properties of Al₂O₃/Fe composite honeycombs were investigated by SEM, XRD and universal testing machine. The results show that metal powder particles bind together to form γ-Fe matrix network structure during sintering process, and Cr₂O₃ with polygon geometric shape is formed on the surface. Adding a small amount of Al₂O₃ can inhibit the precipitation of Cr from matrix and reduce the amount of Cr₂O₃ on the surface, which makes the sintering combination of metal powder particles more compact and the surface of structure more smooth. With Al₂O₃ content increasing, the bonding capacity for the surface of honeycomb materials with catalytic activity coating enhances, compressive strength of the composite honeycomb increases at first and then decreases, and when Al₂O₃ content is 5.0wt%, the compressive strength reaches 26 MPa. The conclusions obtained show that the mechanical properties of 5.0wt% Al₂O₃/Fe composite honeycomb are the best, and the surface paintability is preferable.