Metallization of 3D Printed Polymers and Their Application as a Fully Functional Water-Splitting System.

In this work, the plating of high-quality amorphous nickel-phosphorous coating with low resistivity of 0.45 µΩ m (298 K) on complex 3D printed polymeric structures with high uniformity is reported. Such a polymer metallization results in an effective conductivity of 4.7 × 104 S m-1. This process also allows flexible structures to maintain their flexibility along with the conductivity. Octet-truss structures with nickel-iron-(oxo) hydroxide nanosheets electrodeposited onto further displays excellent water-splitting performance as catalytic electrodes, i.e., in KOH (1 m, aq), a low oxygen evolution reaction (OER) overpotential of 197 mV at 10 mA cm-2 and Tafel slope of 51 mV dec-1. Using this light-weight electrode with high specific area, strength, and corrosion resistance properties, a fully functional water-splitting system is designed and fabricated through the concentric integration of 3D printed components. A dense polymeric mesh implemented is also demonstrated as an effective separator of hydrogen and oxygen bubbles in this system.

Microstructure, elastic deformation behavior and mechanical properties of biomedical ß-type titanium alloy thin-tube used for stents.

Cold-deformability and mechanical compatibility of the biomedical ß-type titanium alloy are the foremost considerations for their application in stents, because the lower ductility restricts the cold-forming of thin-tube and unsatisfactory mechanical performance causes a failed tissue repair. In this paper, ß-type titanium alloy (Ti-25Nb-3Zr-3Mo-2Sn, wt%) thin-tube fabricated by routine cold rolling is reported for the first time, and its elastic behavior and mechanical properties are discussed for the various microstructures. The as cold-rolled tube exhibits nonlinear elastic behavior with large recoverable strain of 2.3%. After annealing and aging, a nonlinear elasticity, considered as the intermediate stage between "double yielding" and normal linear elasticity, is attributable to a moderate precipitation of α phase. Quantitive relationships are established between volume fraction of α phase (Vα) and elastic modulus, strength as well as maximal recoverable strain (εmax-R), where the εmax-R of above 2.0% corresponds to the Vα range of 3-10%. It is considered that the "mechanical" stabilization of the (α+ß) microstructure is a possible elastic mechanism for explaining the nonlinear elastic behavior.