report
3.4.4 Additional demand for research

A remaining item in particular in view of industrial scale production is the metal nanoparticles´ tendency to agglomerate. Within the upcoming years additional effort has to be spent on this issue. Another difficulty concerning the handling of metal nanoparti-cles (except noble metals) is their sensitivity to oxygen, a fact which is currently inten-sively investigated.

Additional demands may be seen in the production cost, which is still quite high for both nanocrystalline metals and nanoparticulate powders. In general there is an increas-ing need for cost efficiency in industrial production, which forces producers to mini-mize their material quantities.

In the area of nanocrystalline metals all fabrication methods still suffer from material problems. Noble-gas condensed samples exhibit residue porosities, electrolytically de-posited metals show impurities or disturbing textures and samples manufactured by plasticity deformation (swaging) have high remaining concentrations of lattice defects. In addition some materials in particular Mg-based ones are prone to corrosion. Besides, some materials such as e. g. titanium require a high purity and exhibit an only low plas-ticita at room temperature, thus making the building of nanocrystallites complex and expensive. Nanocrystalline metals in particular in large scale production are currently still quite expensive. Another issue is the ensurance of the reliability of the material quality in high volume production.