Dry vs. wet testing: quasi-static tensile experiment setup for polymer based biomaterials

Polymer materials can be manufactured with high reproducibility and do offer the potential for chemical modification. This enables matrix property modification and fine-tuning of several material characteristics, such as tissue-implant interaction, inflammatory potential or susceptibility to biofilm formation. Whereas manufacturing protocols are crucial for the resulting material properties, also the evaluation in terms of performance and safety has to be considered. Regarding this, both, temperature and composition of test medium may affect the physicochemical properties of implant materials. The present study addresses the influence of test medium compared to dry test conditions, each at two different temperatures, on the mechanical properties of elastomeric film and nonwoven materials.

Microstructure and Property Modification of Cold Sprayed Coatings Using Different Grain Sizes of Cr3C2-25(Ni20Cr) Composite Powder

This article describes the microstructure and mechanical properties of Cr3C2-25(Ni20Cr) cermet coatings cold sprayed on Al 7075 alloy substrates. The aim of the study was to determine the effect of three different powder grain sizes and three different standoff distances on the microstructure (phase composition, surface topography, volume fraction and distribution of the Cr3C2 phase in the Ni20Cr matrix and porosity) and the mechanical properties (hardness and abrasive wear resistance) of the Cr3C2-25(Ni20Cr) coatings. The examinations revealed that the thickness of the coatings obtained with same duration and feed rate decreased with increasing powder grain size and standoff distance. The coatings produced from powders with smaller particles had higher hardness and more compact structures than the coatings obtained from powders where the particles were larger (more than 40 μm). The coatings produced from finer powders were also more resistant to abrasive wear.