An Apparatus for Producing Material Foam from a Material and Methods thereof

Category- Advance Material and Manufacturing

Industry Classification:

NIC (2008)- 28230- Manufacture of machinery for metallurgy; 2431 Casting of iron and steel; 2432 Casting of non-ferrous metals.
NAICS (2022)-33351- Metalworking Machinery Manufacturing ; 3315 Foundries
Applications- Metal foams are useful in mechanical and acoustic energy absorption applications, lightweight applications, heat exchangers, CO2 scrubbing, flame arresters, etc.

Market drivers:

The global metal foam market size is predicted to grow from USD 86.21 million in 2023 to USD 128.01 million by 2032 with a CAGR of 4.49%.

Metallic foams can be produced from melts by introducing bubbles in the melt either by injecting gas into the melt through a nozzle or by add-mixing a chemical blowing agent which dissociates at high temperature and releases gas.
Chemical blowing agents can result in high cost, improper distribution of bubbles and brittleness due to use of ceramics as foam stabilizers.
Moreover, It is challenging to keep the bubble size to a small size while injecting gas into a melt. This in turn results in an increase in average bubble/cell size.
There is a need for an efficient, economic and simple apparatus and method to produce material foams from molten metal

Two high temperature crucibles capable of handling molten metal are connected to each other through a pump and nozzle. The nozzle is attached with a valve to allow the molten material to come out as a jet from the first crucible to the second
The nozzle in the first crucible is surrounded by a hollow tube which is connected with a gas inlet and outlet. The gas inlet is connected to a tube which is connected to two types of gases- an inert gas and oxygen or air.
When the nozzle is opened, a metallic jet comes out from the first crucible and impinges on the surface of the molten material kept in the second crucible. The jet entrains gas that is present in the atmosphere surrounding the jet while impinging on the surface of the molten material to create a foam on the surface of the molten metal which can be removed using a metallic scrapper
The quality of the foam can be controlled by changing the inner diameter and length of the nozzle, varying the gas pressure in the first crucible, varying the distance between the first and second crucible, finally varying the atmosphere surrounding the metallic jet.

This apparatus can be used for producing foams from any molten material including metal such as aluminum, zinc, magnesium, and their alloys and composites. This method and apparatus can also be used to produce foam from ceramic slurries and polymer melts.
Unlike the existing methods to produce metal foam, this process neither needs any blowing agent nor any gas injection.
The foams produced by melt injection method are stabilized by a combined action of oxide layer and particles hence there is no need of any ceramic particles used in conventional methods for foam stabilization.
The oxide layer thickness achieved inside the foam bubbles is higher compared to those achievable using conventional processes
The process is cost-effective when compared to conventional processes that use chemical blowing agents.

Prof. Manas Mukherjee

Department of Metallurgical and Materials Engineering

TRL 4

Technology Validated in Lab

Technology Transfer