The Advanced Pore Morphology (APM) process, a new method for production of aluminum foam-polymer hybrid materials, is described. Small volume aluminum foam spheres are produced first and then adhesively joined in a separate process step to realize an APM foam part. Detailed information on mechanical properties of this new hybrid material is given. Results of uniaxial and hydrostatic compression tests are summarized and evaluated to show how typical parameters characterizing material and process such as spatial arrangement, size and density of the foam elements influence the global properties. Two levels of the hierarchical architecture of the material are evaluated-namely the individual foam spheres and the hybrid structure. Variation of adhesives and adhesive coating thickness used in bonding the spheres in conjunction with study of unbonded specimens provides additional insight in the influence of this bond. First estimates on density dependence of mechanical properties are derived from the experimental data. Distinctive differences between APM and conventional aluminum foams are qualitatively explained. Throughout the study, AlSi7 aluminum foam produced from chemically identical precursor material according to the powder metallurgical FOAMINAL® process is included as reference material. © 2008 Elsevier Ltd. All rights reserved

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The work described in this paper demonstrates that very small protein and DNA structures can be applied to various substrates without denaturation using aerosol printing technology. This technology allows high-resolution deposition of various nanoscaled metal and biological suspensions. Before printing, metal and biological suspensions were formulated and then nebulized to form an aerosol which is aerodynamically focused on the printing module of the system in order to achieve precise structuring of the nanoscale material on a substrate. In this way, it is possible to focus the aerosol stream at a distance of about 5 mm from the printhead to the surface. This technology is useful for printing fluorescence-marked proteins and printing enzymes without affecting their biological activity. Furthermore, higher molecular weight DNA can be printed without shearing. The advantages, such as printing on complex, non-planar 3D structured surfaces, and disadvantages of the aerosol printing technology are also discussed and are compared with other printing technologies. In addition, miniaturized sensor structures with line thicknesses in the range of a few micrometers are fabricated by applying a silver sensor structure to glass. After sintering using an integrated laser or in an oven process, electrical conductivity is achieved within the sensor structure. Finally, we printed BSA in small micrometre-sized areas within the sensor structure using the same deposition system. The aerosol printing technology combined with material development offers great advantages for future-oriented applications involving biological surface functionalization on small areas. This is important for innovative biomedical micro-device development and for production solutions which bridge the disciplines of biology and electronics.

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Li7La3Zr2O12 (LLZO) and related compounds are considered as promising candidates for future all-solid-state Li-ion battery applications. Still, the processing of those materials into thin membranes with the right stoichiometry and crystal structure is difficult and laborious. The sensitivity of the Li-ion conductive garnets against moisture and the associated Li+/H+ cation exchange makes their processing even more difficult. Formulation of suitable polymer/ceramic hybrid solid state electrolytes could be a prosperous way to reach the future large scale production of solid state Li-ion batteries. In fact, solvent mediated and/or slurry based wet-processing of the LLZO, e.g., tape-casting, could result in irreversible Li-ion loss of the pristine material due to Li+/H+ cation exchange. The concomitant structural changes and loss in functionality in terms of Li-ion conductivity are the results of the above process. Therefore, in the present work a systematic study on the chemical stability and structural retention of Al-substituted LLZO in different solvents is reported. It was found that Li+/H+ exchange in LLZO occurs upon solvent immersion, and its magnitude is dependent on the availability of −OH functional groups of the solvent molecules. As a result, a larger degree of Li+/H+ exchange causes higher increase of the lattice parameter of the LLZO, determined by synchrotron diffraction analyses. The expansion of the cubic unit cell was ascertained, when Li+ was replaced by H+ in the host lattice, by ab initio computational studies. The application of the most common solvent as dispersion medium, i.e., high purity water, causes the most significant Li+/H+ exchange and, therefore, structural change, while acetonitrile was proven to be the best suitable solvent for wet postprocessing of LLZO. Finally, computational calculations suggested that the Li+/H+ exchange could result in diminished ionic, i.e., mixed Li+–H+, conductivity due to the insertion of protons with lower mobility than that of Li-ions.

Using hollow particles as reinforcement, syntactic foams are a unique class of materials with features of conventional foams as well as composites. Usually, the main role of the filler is to introduce porosity, and thus also change specifically the compressive response to that of a typical foam or cellular material. However, depending on which of the many variants of such syntactic foams is considered, hollow particles can also have a strengthening effect. In the way this is achieved, however, they are distinguished from the many kinds of metal foams that use ceramic particles first for stabilization during processing and secondly for some strengthening effect: [1][2][3] In syntactic foams, the reinforcement provides a stable inner lining of each pore, while in conventional particle-reinforced metal foams, the distribution of ceramic particles in the matrix effectively allows them to be understood as cellular MMCs in which matrix ductility is adversely affected by the otherwise strengthening addition. In syntactic foams of the type discussed here, the matrix is unaltered and can thus maintain considerable levels of ductility.So far, numerous materials differing in the size of structural elements, nature of filler, etc. have been realized, featuring both polymer [4,5] and metal [6] matrices. In the case of metals, reinforcing particles can be millimeter sized steel hollow spheres, [7] or, on another, micrometer length scale, cenospheres [8] as well as glass microspheres. [9] The present study concentrates on the latter variant. Main production methods for such materials are melt stirring, melt infiltration [9][10][11][12] or powder metallurgy processes. [13,14] When contrasted to metal foams based on the powder compact melting or the APM process [15][16][17] iron matrix syntactic foams combine lower maximum porosity and thus higher density with greatly improved performance under both quasi-static compressive and tensile load while showing the typical deformation characteristics of foams. [14] In comparison to other types of iron-based foams, such as the so-called lotus-type porous metals recently discussed in detail by Song et al. and Tane et al.,[18][19][20] the present materials combine still higher strength with isotropic behavior and greater ease in manufacture of theSyntactic iron foams are produced by metal injection moulding from pure Fe powder and two grades of commercial glass microspheres. Mechanical performance of samples containing 5/10/13 wt% of microspheres is compared to unfilled reference material properties at strain-rates covering 6 orders of magnitude, including Split Hopkinson Pressure Bar (SHPB) experiments. Complex mechanical behavior including strengthening effects of microspheres leading to a plateau strength level which is nearly independent of porosity as well as strain-rate sensitivity of compressive properties are observed. Typical plateau onset stress levels exceed equivalent characteristics of most comparable cellular metallic materials, reaching between approximately 220 and 270 MPa...

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