Effects of process parameters and annealing on microstructure and properties of CoCrFeMnNi high-entropy alloy coating prepared by plasma cladding

Plasma cladding was used to prepare a CoCrFeMnNi high-entropy alloy(HEA)coating under different conditions.The process parameters were optimized using an orthogonal experiment design based on surface morphology quality characteristics,dilution rate,and hardness.The optimal process parameters were determined through range and variance analysis to be a cladding current of 70 A,a cladding speed of 7 cm·min^(-1),and a powder gas flow rate of 8 L·s^(-1).During the optimized experiments,both the cladded and annealed CoCrFeMnNi HEA coatings exhibit some pores,micro-voids,and a small amount of aggregation.However,the aggregation in the annealed coating is more dispersed than that in the cladded coating.The cladded CoCrFeMnNi HEA coating consists of simple FCC phases,while a new Cr-rich phase precipitates from the FCC matrix after annealing the coating at a temperature range of 550°C-950°C.After annealing at 850°C,the proportion of the FCC phase decreases compared to the cladded coating,and the number of large-angle grain boundaries is significantly reduced.However,the proportion of grains with sizes below 50μm increases from 61.7%to 74.3%.The micro-hardness and wear resistance of the cladded coating initially increases but then decreases with an increase in annealing temperature,indicating that appropriate annealing can significantly improve the mechanical properties of the CoCrFeMnNi HEA coatings by plasma cladding.The micro-hardness of the CoCrFeMnNi HEA coatings after annealing at 650°C increases to 274.82 HV_(0.2),while the friction coefficient decreases to below 0.595.

Treatment outcomes and cognitive function following electroconvulsive therapy in patients with severe depression

BACKGROUND Traditional treatments for major depressive disorder(MDD),including medication and therapy,often fail and have undesirable side effects.Electroconvulsive therapy(ECT)uses electrical currents to induce brief seizures in the brain,resulting in rapid and potent antidepressant effects.However,owing to misconceptions and controversies,ECT is not as widely used as it could and often faces stigmatization.AIM To evaluate the efficacy and safety of ECT compared to those of medication and/or therapy in patients with severe MDD.METHODS This prospective cohort study included 220 individuals with severe MDD who were divided into the ECT and non-ECT groups.The patients in the ECT group underwent bilateral ECT three times a wk until they either achieved remission or reached a maximum of 12 sessions.The non-ECT group received medication and/or therapy according to clinical guidelines for MDD.The primary outcome was the variation in the hamilton depression rating scale(HDRS)score from treatment/ECT initiation to week 12.In addition,patients’quality of life,cognitive abilities,and biomarkers were measured throughout the study.RESULTS Although both groups showed significant improvements in their HDRS scores over time,the improvement was more pronounced in the ECT group than in the non-ECT group.Additionally,the ECT group exhibited a more substantial improvement in the quality of life and cognitive function than those of the non-ECT group.Compared with the non-ECT group,the ECT group exhibited evidently lower variations in the brain-derived neurotrophic factor(BDNF)and cytokine interleukin-6(IL-6)levels.The side effects were generally mild and comparable between the two groups.ECT is safer and more potent than medication and/or therapy in mitigating depressive symptoms,enhancing wellbeing,and bolstering cognitive capabilities in individuals with severe MDD.ECT may also affect the levels of BDNF and IL-6,which are indicators of neuroplasticity and inflammation,respectively.CONCLUSION ECT has emerged as a potentially advantageous therapeutic approach for patients with MDD who are unresponsive to alternative treatments.