Foam metal as a new material, in the field of filtration, heat exchange, structural materials, electromagnetic shielding, etc. has gradually emerged, more material and different requirements, foam metal in terms of its preparation process, there are mainly the following methods: 

1. Molten metal foaming method
After the metal is melted, the foaming agent is added to it, and the gas precipitated from the foaming agent is used to produce bubbles, and after cooling, the foam metal can be made. This method is mainly used for the preparation of low melting point Al, Sn and other foam metals.
2. Metal deposition method
Metal deposition method is to use chemical or physical methods to deposit metals on easily decomposed organic materials (such as: polyurethane sponge), and then use the sintering method to remove the organic materials. There are two main methods: electrodeposition and vapor phase deposition.
3. Electrodeposition method
First, the non-conductive organic material is roughened, activated and chemically plated to conduct electricity, and then plated on it, and then the organic material is removed by heat treatment.
4. Vapor deposition method
Take the preparation of nickel foam as an example: nickel foam can be produced by introducing CO – Ni (CO)4 mixture into the reactor and making it pass through the surface treated polymer organic matter (such as polyurethane, etc.) under the irradiation of infrared light of specific wavelength, which makes Ni (CO)4 decompose into Ni and CO.
5. Sintering method
First, the sponge is cut into the desired shape so that it can fully absorb the slurry containing metal powder, and then dried and subjected to sintering heat treatment to make the sponge decompose. Continue to heat to make the decomposition of organic metal compounds and make the material sintered, and after cooling, you can get the foam metal with high void ratio.