Development of a New Method for Manufacturing Iron Foam Using Gases Generated by Reduction of Iron Oxide

Abstract

A new method for manufacturing iron foam using CO and CO 2 as foaming gases was studied. This method consists of three stages: (1) mixing powders of pure iron, graphite, and hematite; (2) preparing the precursor by cold pressing the mixed powders; and (3) foaming by heating the precursor at temperatures between the liquidus and solidus in the Fe-C binary system. Molten iron containing carbon is foamed by gases generated by a reduction reaction. Optimizations of both the composition of the precursor and the heating conditions are required to produce the iron foam with high porosity. It was found that the content and powder size of hematite in the precursor significantly affect the porosity and pore diameter of the iron foam. Iron foam with a porosity of 55% and average pore diameter of around 500 mm is obtained by heating the precursor of Fe-3.1 mass%C-1.0 mass%Fe 2 O 3 at 1543 K.

Microstructural and mechanical properties of biodegradable iron foam prepared by powder metallurgy

“…Therefore, new foaming processes have been suggested for iron-based materials. One was introduced in 2007 by Murakami and consists of foaming by CO and CO 2 , which are formed by reactions between carbon and Fe 2 O 3 in a heated Fe-Fe 2 O 3 -C mixture [41]. Another process was published in 2014 by Murakami and consists of foaming of a FeO-Fe 2 O 3 -CaO-Al 2 O 3 slug and a subsequent reduction of the obtained porous oxide [40].…”

Porous Metals and Metallic Foams: Current Status and Recent Developments

“…Foaming is driven by the CO and CO 2 generated by the reduction of the iron oxide by carbon. [37] Iron foams with porosity of approximately 55 % were obtained using the process. An alternative method uses less expensive powder (i.e., water atomized powders) and a slip reaction sintering process to produce steel foams with compressive strength significantly higher than that of aluminum foams.…”

Processing, Microstructure, and Oxidation Behavior of Iron Foams

“…in the form of three-dimensional (3-D) Fe-based foam, which is expected to offer particular advantages as an advanced structural and functional material owing to its 3-D structure, low cost, low weight, large specific surface area, and high impact absorbability, along with high mechanical strength and high stiffness-to-weight ratio. [8][9][10] Only during recent years, several studies have been reported on the processing and properties of Fe foam manufactured by a variety of processes, such as powder metallurgy, [6,11] gas foaming, [12] slag foaming, [13] hollow spheres, [14] and lotus-type [15,16] most likely for structural applications. Therefore, there still exists considerable demand for developing Fe foams with controlled porosity, pore size, and strut width to be potentially applied as a 'platform' material for various functional fields described above.…”