Electrochemical Hydrogen Charging on Corrosion Behavior of Ti-6Al-4V Alloy in Artificial Seawater

This study employs advanced electrochemical and surface characterization techniques to investigate the impact of electrochemical hydrogen charging on the corrosion behavior and surface film of the Ti-6Al-4V alloy.The findings revealed the formation ofγ-TiH andδ-TiH_(2) hydrides in the alloy after hydrogen charging.Prolonging hydrogen charging resulted in more significant degradation of the alloy microstructure,leading to deteriorated protectiveness of the surface film.This trend was further confirmed by the electrochemical measurements,which showed that the corrosion resistance of the alloy progressively worsened as the hydrogen charging time was increased.Consequently,this work provides valuable insights into the mechanisms underlying the corrosion of Ti-6Al-4V alloy under hydrogen charging conditions.

Cryoablation Combined with TACE for Treating Large Hepatocellular Carcinoma： Tumor Load and Cellular Immunity

OBJECTIVE To study the effectiveness on the tumor load and cellular immune function of percutaneous cryoablation （argon-helium cryoablative system, AHCS） combined with transarterial chemoembolization （TACE） for treating large hepatocellular carcinomas （HCCs） with diameters over 10 ca. METHODS A total of 48 HCC patients were treated with AHCS after TACE. Tumor sizes ranged from 10 to 14 cm. All cases were a hypervascular type. There were 38 Child A cases and 10 Child B cases. Forty were AFP positive and 8 negative. The patients were randomized with therapy group consisting of 26 cases and the control group 22 cases. The therapy group received AHCS 4 weeks following TACE treatment. Reexamination included pathology, tumor markers, T-lymphocyte subgroup levels and computed tomography or MRI. The necrosis rate of the tumor load was calculated by Cavalieri＇s theory. EORTC QLQ-C30 was used in quality of life evaluation. RESULTS The average tumor-load reduction rate （necrosis rate） was 8.07% after TACE, and 28.65% after AHCS. Coagulation necrosis was produced in the target area. The tumor markers deceased significantly after AHCS. Tumor-load reduction after AHCS was more significant than after TACE. Suppression of cellular immunity after TACE was significant. In contrast, CD3^＋, CD4^＋ and NK increased after AHCS and an abnormal T-lymphocyte distribution was corrected. Quality of life after AHCS increased according to the EORTC QLQ-C30 evaluation. No severe complications occurred. CONCLUSION Percutaneous AHCS cryoablation after TACE reduced the tumor load in the short term. At the same time, cellular immune function was increased after AHCS. TACE was critical in increasing the therapeutic efficacy of AHCS because of its embolisation of blood vessels preventing a Flow Effect. Reduction of the tumor load in the short term may conduce to increase cellular immunity. Percutaneous AHCS cryoablation combined with TACE can reduce the tumor load, improve cellular immunity and increase quality of life of HCC patients. This type of therapy deserves to be studied further research.

Advanced cellulose-based materials toward stabilizing zinc anodes

Rechargeable aqueous zinc metal batteries(RAZMBs) have received extensive attention for large-scale energy storage systems due to the merits of Zn anodes, including moderate volumetric and gravimetric energy density, low redox potential, abundant reserve, low cost and impressive intrinsic safety. However, Zn anodes suffer from a series of adverse reactions(dendrite growth,hydrogen evolution, and surface passivation) resulting in low Coulombic efficiency, large polarization, and unsatisfied cycling performance, which inevitably hinder the wide application of RAZMBs. To address the above issues, cellulose-based materials are widely used for Zn anode protection because of their unique physical and chemical properties and other advantages such as biocompatibility, non-toxicity, degradability and easy extraction. In order to better understand the current progress in cellulosebased materials for the Zn anode protection, we have classified and summarized the relevant literatures. In this review, we summarize and elaborate the causes of poor reversibility for Zn anodes, including dendrite formation, hydrogen evolution, and surface passivation. Subsequently, the effective strategies(anode interfacial engineering, gel electrolyte optimization, and separator modification) of cellulose-based materials toward stabilizing Zn anodes are overviewed. In the end, the existing challenges and prospects of cellulose-based materials in Zn anode protection are summarized to shed light on future work.

Water vapor effects on the oxidation resistance of modified potassium silicate coating at high temperature

An inorganic potassium silicate coating with pigments of alumina,aluminum phosphate,NiCrAlY and copper chromite black was prepared on CB2 stainless steel.Oxidation behavior in either ambient air or O_(2)+H_(2) O mixture at 630℃ for 2000 h was comparatively studied,and the coating exhibited excellent resistance under both test conditions.The water vapor considerably accelerated the oxidation of the uncoated CB2 steel,as the hydroxide,the main constituent of the coating,had a negligible evaporation rate at test temperature,while it had a limited effect on the coated sample.Meanwhile,the existence of coating may prolong or eliminate the incubation period in the O_(2)+H_(2) O mixture at 630℃.After oxidation,the coating matrix is in an amorphous state and fillers as alumina and copper chromite black are stable in the coating.Leucite(KAlSi_(2) O_(6))formed by Al from NiCrAlY and potassium silicate in the coatings was detected after tests either in O_(2) or O_(2)+H_(2) O mixture.

On the rumpling mechanism in nanocrystalline coatings:Improved by reactive magnetron sputtering with oxygen

Surface rumpling is detrimental to high temperature protective coatings as it shortens their lifetime and leads to adhesion losses and unexpected corrosion degradation.The driving force and mass transport mechanism behind of rumpling remains to be clarified.In the present investigation,we subjected two types of nanocrystalline coating systems to avoid the influence of interdiffusion on rumpling study.One group was an ordinary nanocrystalline coating,and the other group was designed and prepared with trace oxygen by reactive magnetron sputtering.Systematic cyclic oxidation test at 1100°C was also car-ried out.Results show the ordinary nanocrystalline coating oxidized rapidly,which leads to the fast consumption of Al and the acceleration of phase transition in the coating.Meanwhile,severe surface rumpling is observed due to the stress release of nanocrystals through plastic deformation.Besides,the reactive doping of oxygen can significantly reduce the consumption process of Al in nanocrystalline coat-ing.The rumpling is controlled due to the improvement of coefficient of thermal expansion and Young’s modulus of the coating.Thereafter,the cyclic oxidation resistance is improved.

Microstructure and composition evolution of a single-crystal superalloy caused by elements interdiffusion with an overlay NiCrAlY coating on oxidation

MCrAlY(M=Ni and/or Co)overlay coating is widely used as a protective coating against high temperature oxidation and corrosion.However,due to its big difference in chemical composition with the underlying superalloy,elements interdiffusion occurs inevitably.One of the direct results is the formation of interdiffusion zone(IDZ)and secondary reaction zone(SRZ)with a high density of fine topological closed-packed phases(TCPs),weakening dramatically the mechanical properties of the alloy substrate.It is by now the main problem of modern high-temperature metallic coatings,but there are still hardly any reports studying the formation,growth and transformation of IDZ and SRZ in deep,as well as the precipitation of TCPs.In this work,a typical NiCrAlY coating is deposited by arc ion plating on a single-crystal superalloy N5.Elements interdiffusion between them and its relationship on microstructure were clarified.Cr rather than Al from the coating diffuses into the alloy at high temperatures and segregates immediately beneath their interface,contributing largely to the formation of IDZ.Simultaneously,diffusion of Ni from the deep alloy to IDZ leads to the formation and continuous expansion of SRZ.

Effect of aging treatment on microstructure and corrosion behavior of a Fe-18Cr-15Mn-0.66N stainless steel

The effect of aging treatment on the microstructure and corrosion behavior of a Fe-18Cr-15Mn-0.66N high-nitrogen stainless steel(HNSS) in 3.5 wt.% Na Cl solution was investigated using a series of electrochemical tests, scanning electronic microscopy(SEM), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). The results showed that the aging treatment led to the precipitation of CrN particles along the grain boundaries and their morphologies changed from dispersive particles to continuous network as the aging time increased up to 60 min. Aging time had minor effects on the corrosion potential and corrosion current density, but resulted in the sharp decrease in the pitting corrosion potential.The passive film behaved as a n-type semiconductor, and the donor density of the passive film increased with the aging time. Meanwhile, the fraction of stable oxide(CrO) in the passive film decreased with the aging time. It demonstrates that the aging treatment deteriorated the protectiveness of the passive film, hence weakened the corrosion resistance of HNSS.