Manufacturing metal membranes by sintering

Porous metal membranes are frequently used in coal and petrochemical industries for two-phase separation and purification.

Such membranes are often made from Fe-Al based intermetallic compounds. They have high wear, heat, and corrosion resistance.

Below, we present some processes of manufacturing metal membranes with enhanced properties.

Making metal membranes with high strength & toughness

To create a metal membrane with high strength and toughness, the following steps are followed:

1. A slurry is prepared by mixing a Fe₃Al or FeAl powder and stainless steel fiber powder (to avoid cracking and peeling) into an organic solvent such as polyvinyl alcohol.
2. The slurry is cast into a membrane green body on a wire mesh. The green body is then left to dry at room temperature.
3. The dried membrane body then undergoes sintering in a furnace at ramping temperatures from ~300°C till 1300°C. This process takes around 12 hours. During this step, the organic additives are removed due to heat, leaving behind a porous structure.
4. The metal membrane thus formed is then cut to suitable size by a shearing machine.
5. A tube-forming machine then shapes the membrane as a cylinder and resistance welding is used to join the edges.

Now a filter membrane with smooth surface, uniform pore-size distribution, and high toughness is obtained.

The process is detailed further in this patent.