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Syntactic metal foams, i.e., foams which are composed of a metal matrix with integrated hollow elements, offer a unique spectrum of properties, like pressure-tightness, high capacity for crash energy absorption and comparably low densities. The production techniques are mostly based on the pressureassisted infiltration of solid structures or loose bulks of hollow elements like, e.g., ceramic hollow spheres and microglass bubbles (mGBs) by metal melts. [1][2][3] For higher-melting alloys like iron or steel this approach is, however, very difficult to realize because only few pressure-assisted techniques like gas-pressure infiltration are available. Moreover, the combined impact of high pressures and temperatures during the filling stage might lead to the destruction of the hollow elements.Therefore, tests have recently been performed in order to examine the feasibility of the production of syntactic foams based on iron matrices and mGBs by metal powder injection moulding (MIM), a process, which is closely related to polymer injection moulding. [4] After proving the feasibility of this approach a more systematic investigation was done with Fe99.7% as most simple matrix in order to better understand the process limits, the material structure, and its mechanical behavior. Furthermore, the corrosion behavior of the foam material was investigated not only as it is important for the material application but also as it can give indications of interactions between the mGBs and the matrix during the MIM-process. Experimental ProceduresFor the experiments blends of 50 vol% Fe powder (d 50 ¼ 1.4 mm, Fritsch) were mixed with polymers and waxes (binder). Then up to 13 wt% 3 M-S60HS (d 50 ¼ 35 mm) and 3 M-IM30 K (d 50 ¼ 17 mm) borosilicate glass bubbles were added and the mixture was injection moulded. For the injection a mould with tensile test specimen geometry was used. After moulding the binder was removed from the samples by a solvent (hexane, 12 h at 35 8C) and a thermal debinding step (0.

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