Nickel-based superalloy was treated with molten zinc for the selective extraction of nickel.The effects of heating temperature,heating time,and the mass ratio of zinc to superalloy on the extraction of metals in the s...Nickel-based superalloy was treated with molten zinc for the selective extraction of nickel.The effects of heating temperature,heating time,and the mass ratio of zinc to superalloy on the extraction of metals in the superalloy were investigated.An extraction rate of 95.2%for nickel,55.4%for iron and 30.4%for chromium,but low extraction rates of the refractory metals(titanium(Ti),molybdenum(Mo),and niobium(Nb))were obtained under the optimal conditions of the heating temperature of 850℃,the heating time of 4 h,and the zinc/superalloy mass ratio of 10:1.In the subsequent vacuum distillation process,the obtained nickel alloy contained nickel with a purity of 73.5 wt.%after zinc removal.Moreover,the recovered zinc after the distillation process had a purity of 99.9 wt.%.The results of the investigated process indicated the possibility of extracting nickel directly from nickel-based superalloy scraps.展开更多
The effects of pulse parameters on the cobalt content, surface morphologies and grain size of Zn-Co alloy deposits were studied using a pulse plating technique with a square-wave current containing reverse pulse. Aver...The effects of pulse parameters on the cobalt content, surface morphologies and grain size of Zn-Co alloy deposits were studied using a pulse plating technique with a square-wave current containing reverse pulse. Average current density and reverse anodic current density amongst the variables investigated have very strong effects on the cobalt content in the Zn-Co alloy deposits. Grain size, surface appearance and internal stress in the deposit were improved significantly by introducing the reverse current. Varieties of Zn-Co alloy compositionally modulated multilayer (CMM) coatings with large differences in cobalt contents for different sublayers were electrodeposited by designing corresponding waveforms using a computer-aided pulse plater and characterized in terms of surface morphologies. Cross-sectional morphologies of the Zn-Co alloy CMM coatings, examined using field emission gun scanning electron microscopy (FEGSEM), confirmed the layered structure.展开更多
The synergistic inhibition effect of poly(ethylene glycol)-400(PEG-400)and cetyltrimethylammonium bromide(CTMAB)on the corrosion of Zn and Zn-Ni alloys in 8 mol/L KOH solution saturated with Zn O was observed by poten...The synergistic inhibition effect of poly(ethylene glycol)-400(PEG-400)and cetyltrimethylammonium bromide(CTMAB)on the corrosion of Zn and Zn-Ni alloys in 8 mol/L KOH solution saturated with Zn O was observed by potentiodynamic anodic/cathodic polarization(PDP),and electrochemical impedance spectroscopy(EIS)measurements.The electrochemical studies confirmed that there was a synergism between PEG-400 and CTMAB on corrosion inhibition of Zn and its alloys.Corrosion inhibition efficiency of the mixed inhibitors,250 mg/L CTMAB+250 mg/L PEG-400,was found to be much higher than that of the single inhibitor,500 mg/L PEG-400 or 500 mg/L CTMAB.Scanning electron microscopic(SEM)investigations before and after the corrosion inhibition process emphasize the synergistic effect of the mixed inhibitors.Accordingly,it was found that the addition of the investigated inhibitors to the alkaline solution enhanced the discharge and capacity of the alkaline battery anodes.The obtained electrochemical data exhibited a good correlation with the computational one.展开更多
基金financial supports from the National Natural Science Foundation of China(Nos.51922108,51874371,51904350)the Hunan Natural Science Foundation,China(No.2019JJ20031)the Hunan Key Research and Development Program,China(No.2019SK2061)。
文摘Nickel-based superalloy was treated with molten zinc for the selective extraction of nickel.The effects of heating temperature,heating time,and the mass ratio of zinc to superalloy on the extraction of metals in the superalloy were investigated.An extraction rate of 95.2%for nickel,55.4%for iron and 30.4%for chromium,but low extraction rates of the refractory metals(titanium(Ti),molybdenum(Mo),and niobium(Nb))were obtained under the optimal conditions of the heating temperature of 850℃,the heating time of 4 h,and the zinc/superalloy mass ratio of 10:1.In the subsequent vacuum distillation process,the obtained nickel alloy contained nickel with a purity of 73.5 wt.%after zinc removal.Moreover,the recovered zinc after the distillation process had a purity of 99.9 wt.%.The results of the investigated process indicated the possibility of extracting nickel directly from nickel-based superalloy scraps.
文摘The effects of pulse parameters on the cobalt content, surface morphologies and grain size of Zn-Co alloy deposits were studied using a pulse plating technique with a square-wave current containing reverse pulse. Average current density and reverse anodic current density amongst the variables investigated have very strong effects on the cobalt content in the Zn-Co alloy deposits. Grain size, surface appearance and internal stress in the deposit were improved significantly by introducing the reverse current. Varieties of Zn-Co alloy compositionally modulated multilayer (CMM) coatings with large differences in cobalt contents for different sublayers were electrodeposited by designing corresponding waveforms using a computer-aided pulse plater and characterized in terms of surface morphologies. Cross-sectional morphologies of the Zn-Co alloy CMM coatings, examined using field emission gun scanning electron microscopy (FEGSEM), confirmed the layered structure.
基金Chemistry Department,Faculty of Science,Sohag University,and the deanship of scientific research,King Faisal University(Project No.1811020)for financing of this work.
文摘The synergistic inhibition effect of poly(ethylene glycol)-400(PEG-400)and cetyltrimethylammonium bromide(CTMAB)on the corrosion of Zn and Zn-Ni alloys in 8 mol/L KOH solution saturated with Zn O was observed by potentiodynamic anodic/cathodic polarization(PDP),and electrochemical impedance spectroscopy(EIS)measurements.The electrochemical studies confirmed that there was a synergism between PEG-400 and CTMAB on corrosion inhibition of Zn and its alloys.Corrosion inhibition efficiency of the mixed inhibitors,250 mg/L CTMAB+250 mg/L PEG-400,was found to be much higher than that of the single inhibitor,500 mg/L PEG-400 or 500 mg/L CTMAB.Scanning electron microscopic(SEM)investigations before and after the corrosion inhibition process emphasize the synergistic effect of the mixed inhibitors.Accordingly,it was found that the addition of the investigated inhibitors to the alkaline solution enhanced the discharge and capacity of the alkaline battery anodes.The obtained electrochemical data exhibited a good correlation with the computational one.
