Anodic Etching Surface Treatment and Antibacterial Properties of Ti-Cu

This study used an anodic etching(AE)method to construct a hierarchical rough surface on the surface of the Cu-bearing antibacterial titanium alloy,Ti-xCu(x=3,5,7 wt%),a three-dimensional structure with nested micro-/submicro-pores and internal cavities,which is conducive to the adhesion and growth of bone cells.After AE treatment,with increase of the Cu content in the alloy,the surface of Ti-Cu alloy became sharper,with more fine micropores and internal cavities,thus increasing the surface area.The results indicated that the AE/Ti-Cu alloy exhibited good antibacterial properties and had the effect of inhibiting bacterial biofilm formation.AE treatment could increase the Cu ions release of Ti-Cu alloy in saline,and the higher the Cu content in the alloy,the more Cu ions release,resulting in stronger antibacterial performance of the alloy.AE/Ti-Cu alloy showed excellent biocompatibility,similar to the pure Ti.Therefore,anodic etching is a safe and effective surface treatment method for Ti-Cu alloy,with good clinical application prospects.

Fabrication and Field Emission of Silicon Nano-Crystalline Film

The silicon nano-crystalline (nc-Si) film is fabricated on <100> orientation,0.01Ω·cm resistivity,and p-type boron-doped silicon wafer by the anodic etching.The microstructure and the orientation of nc-Si are examined by the scanning electron microscopy,transmission electron microscopy,and X-ray diffraction spectroscopy,respectively.The average size of particle is estimated by Raman spectroscopy.The results show that the particle size of nc-Si film is scattered from 10nm to 20nm,the alignment is compact,the orientation is uniform,the expansion of lattice constant is negligible,and mechanical robustness and stability are good.The correlations between film structure and the experiment parameters such as etching time,HF concentration,and etching current density are discussed.As a potential application,efficient field emission is observed from the nc-Si film,and the turn-on field is about 3V/μm at 0.1μA/cm 2 of current density,which is close to carbon nanotube film's.

On-demand production of hydrogen by reacting porous silicon nanowires with water

On-demand hydrogen generation is desired for fuel cells,energy storage,and clean energy applications.Silicon nanowires(SiNWs)and nanoparticles(SiNPs)have been reported to generate hydrogen by reacting with water,but these processes usually require external assistance,such as light,electricity or catalysts.Herein,we demonstrate that a porous SiNWs array,which is fabricated via the metal-assisted anodic etching(MAAE)method,reacts with water under ambient and dark conditions without any energy inputs.The reaction between the SiNWs and water generates hydrogen at a rate that is about ten times faster than the reported rates of other Si nanostructures.Two possible sources of enhancement are discussed:SiNWs maintain their high specific surface area as they don’t agglomerate,and the intrinsic strain of the nanowires promotes the reactivity.Moreover,the porous SiNWs array is portable,reusable,and environmentally friendly,yielding a promising route to produce hydrogen in a distributed manner.