Effect of 0.3% Sc on microstructure, phase composition and hardening of Al-Ca-Si eutectic alloys

The phase composition,microstructure and hardening of aluminum-based experimental alloys containing0.3%Sc,0?14%Si and0?10%Ca(mass fraction)were studied.The experimental study(electron microscopy,thermal analysis and hardnessmeasurements)was combined with Thermo-Calc software simulation for the optimization of the alloy composition.It wasdetermined that the maximum hardening corresponded to the annealing at300?350°С,which was due to the precipitation of Al3Scnanoparticles with their further coarsening.The alloys falling into the phase region(Al)+Al4Ca+Al2Si2Ca have demonstrated asignificant hardening effect.The ternary eutectic(Al)+Al4Ca+Al2Si2Ca had a much finer microstructure as compared to the Al?Sieutectic,which suggests a possibility of reaching higher mechanical properties as compared to commercial alloys of the A356type.Unlike commercial alloys of the A356type,the model alloy does not require quenching,as hardening particles are formed in thecourse of annealing of castings.

Influence evaluation of titania nanotube surface morphology on the performance of bioelectrochemical systems

In order to investigate the effect of the surface morphology and resistance of the TiO2 semiconductor on current output,TiO2 nanotube array bio-anodes(TNA)are synthesized at different electrolyte temperatures,thereby changing the length and surface roughness of the nanotubes.When the anodizing temperature is increased from 30 to 75℃,the length of the nanotubes increases from 1.459 to 4.183μm,which hinders the transfer of extracellular electrons to the electrodes.On the other hand,the surface roughness of TNA is significantly improved at higher temperatures,which is conducive to electron transfer.Therefore,samples processed at 45℃have the best current output performance.Compared with the treatment at 30℃under anodization,samples processed at 45℃can balance the resistance and roughness and have a higher electron transfer rate;the current output density of which is increased by 1.5 times,and the decolorization rate is increased by 0.8 times.Therefore,proper TNA surface morphology can improve the current output and the potential of wastewater treatment.

A dual-electrolyte system for photoelectrochemical hydrogen generation using CuInS_2-In_2O_3-TiO_2 nanotube array thin film

The utilization of Na2S/Na2SO3 mixture as the electrolyte solution to stabilize sulfide anode in a photoelectrochemical cell for hydrogen evolution generally compromises the current-to-hydrogen efficiency（ηcurrent） of the system. Here, the employment of a dual-electrolyte system,that is, Na2S/Na2SO3 mixture and p H-neutral Na2SO4 as the respective electrolyte solutions in the anode and cathode chambers of a water splitting cell is demonstrated to suppress the photocorrosion of CuInS2-In2O3-TiO2 nanotube（CISIn2O3-TNT） heterostructure, while simultaneously boosts theηcurrent. Although n-type CIS and In2O3 nanoparticles can be easily formed on TNT array via facile pulse-assisted electrodeposition method, conformal deposition of the nanoparticles homogeneously on the nanotubes wall with preservation of the TNT hollow structure is shown to be essential for achieving efficient charge generation and separation within the heterostructure. In comparison to Na2S/Na2SO3 solution as the sole electrolyte in both the anode and cathode chambers, introduction of dual electrolyte is shown to not only enhance the photostability of the CIS-In2O3-TNT anode, but also lead to near-unity ηcurrentas opposed to the merely 20% ηcurrentof the single-electrolyte system.