Li–CO_(2) batteries,which integrate CO_(2) utilization and electrochemical energy storage,offer the prospect of utilizing a greenhouse gas and providing an alternative to the well-established lithium-ion batteries.Ho...Li–CO_(2) batteries,which integrate CO_(2) utilization and electrochemical energy storage,offer the prospect of utilizing a greenhouse gas and providing an alternative to the well-established lithium-ion batteries.However,they still suffer from rather limited reversibility,low energy efficiency,and sluggish CO_(2) redox reaction kinetics.To address these key issues,a nanoporous Ni_(3)Al intermetallic/Ni heterojunction(NP–Ni_(3) Al/Ni)is purposely engi-neered here via an alloying–etching protocol,whereby the unique interactions between Al and Ni in Ni_(3)Al endow NP-Ni_(3)Al/Ni with optimum reactant/product adsorption and thus unique catalytic performance for the CO_(2) redox reaction.Furthermore,the nanoporous spongy structure benefits mass transport as well as discharge product storage and enables a rich multiphase reaction interface.In situ Raman studies and theoretical simulations reveal that both CO_(2) reduction and the co-decomposition of Li_(2)CO_(3) and C are distinctly promoted by NP-Ni_(3)Al/Ni,thereby greatly improving catalytic activity and stability.NP-Ni_(3)Al/Ni offers promising application potential in Li–CO_(2) batteries,with its scalable fabrication,low production cost,and superior catalytic performance.展开更多
The Ni_(3)Al-based alloy has been considered as a robust catalyst for oxygen evolution reaction(OER)due to its long-term durability and acceptable activity.However,related reports about understanding the catalytic mec...The Ni_(3)Al-based alloy has been considered as a robust catalyst for oxygen evolution reaction(OER)due to its long-term durability and acceptable activity.However,related reports about understanding the catalytic mechanism are rare and desirable.Herein,the effect of γ/γ’phase lattice mismatch on the catalytic performance caused by various cooling rates after solution heat treatment was investigated.With decreasing cooling rate,the morphologies of γ' precipitates transformed from sphere to cube and the lattice mismatch increased from-0.172%to-0.409%.The increased lattice mismatch facilitated the formation of the active β-NiOOH phase and enhanced the intrinsic catalytic activity,resulting in the optimized OER overpotential of 240 mV at a current density of 10 mA cm^(−2) with a Tafel slope of 66.1 mV dec^(−1) and a stability of 200 h in 1 M KOH.This work reveals the lattice mismatch effect on OER and provides a potential candidate for OER.展开更多
In this study,the cyclic oxidation tests of the Ni3Al-based single-crystal super alloy IC21 were carried out at 800,900,950,1000,1050 and 1100℃in air.The present study shows that the complex oxide scale on the surfac...In this study,the cyclic oxidation tests of the Ni3Al-based single-crystal super alloy IC21 were carried out at 800,900,950,1000,1050 and 1100℃in air.The present study shows that the complex oxide scale on the surface of the alloy is made up of an outer columnar NiO layer,an intermediate mixture of NiO and NiAl2O4layer with a small amount of Mo oxides and an inner continuous layer ofα-Al_(2)O_(3).The cyclic oxidation kinetics curves show that oxidation resistance at 800,900,950,1000 and1050℃seems to follow a similar law and is better than that at 1100℃.The overall weight changes at 1100℃follows a parabolic law.Spallation and severe rumpling of the oxide scale are observed on the surface of the alloy at1100℃,revealing the occurrence of disastrous oxidation.展开更多
Antiphase boundaries(APBs)are planar defects that play a critical role in strengthening Ni-based superalloys,and their sensitivity to alloy composition offers a flexible tuning parameter for alloy design.Here,we repor...Antiphase boundaries(APBs)are planar defects that play a critical role in strengthening Ni-based superalloys,and their sensitivity to alloy composition offers a flexible tuning parameter for alloy design.Here,we report a computational workflow to enable the development of sufficient data to train machine-learning(ML)models to automate the study of the effect of composition on the(111)APB energy in Ni_(3)Al-based alloys.We employ ML to leverage this wealth of data and identify several physical properties that are used to build predictive models for the APB energy that achieve a cross-validation error of 0.033 J m^(−2).We demonstrate the transferability of these models by predicting APB energies in commercial superalloys.Moreover,our use of physically motivated features such as the ordering energy and stoichiometry-based features opens the way to using existing materials properties databases to guide superalloy design strategies to maximize the APB energy.展开更多
Heavy elements(X=Ta/W/Re)play an important role in the performance of superalloys,which enhance the strength,anti-oxidation,creep resistance,and anti-corrosiveness of alloy materials in a high-temperature environment....Heavy elements(X=Ta/W/Re)play an important role in the performance of superalloys,which enhance the strength,anti-oxidation,creep resistance,and anti-corrosiveness of alloy materials in a high-temperature environment.In the present research,the heavy element doping effects in FCC-Ni(γ)and Ni_(3)Al(γ')systems are investigated in terms of their thermodynamic and mechanical properties,as well as electronic structures.The lattice constant,bulk modulus,elastic constant,and dopant formation energy in non-spin,spin polarized,and spin-orbit coupling(SOC)calculations are compared.The results show that the SOC effects are important in accurate electronic structure calculations for alloys with heavy elements.We find that including spin for bothγandγ'phases is necessary and sufficient for most cases,but the dopant formation energy is sensitive to different spin effects,for instance,in the absence of SOC,even spin-polarized calculations give 1%to 9%variance in the dopant formation energy in our model.Electronic structures calculations indicate that spin polarization causes a split in the metal d states,and SOC introduces a variance in the spin-up and spin-down states of the d states of heavy metals and reduces the magnetic moment of the system.展开更多
A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatm...A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatments,wherein the electroplating procedures consisted of the composite deposition of Ni-Re followed by electroplating of Pt.In order to perform a comparison with conventional Ni Al and(Ni,Pt)Al coatings,the cyclic oxidation performance of the Ni Re Pt Al coating was evaluated at 1100 and 1150℃.We observed that the oxidation resistance of the Ni Re Pt Al coating was significantly improved by the greater presence of the residualβ-Ni Al phase in the outer layer and the lesser outward-diffusion of Mo from the substrate.In addition,the coating with the Re-rich diffusion barrier demonstrated a lower extent of interdiffusion into the substrate,where the thickness of the second reaction zone(SRZ)in the substrate alloy decreased by 25%.The mechanisms responsible for improving the oxidation resistance and decreasing the extent of SRZ formation are discussed,in which a particular attention is paid to the inhibition of the outward diffusion of Mo by the Re-based diffusion barrier.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(52201254)the Natural Science Foundation of Shandong Province(ZR2020QE012,ZR2020MB090)+2 种基金the project of“20 Items of University”of Jinan(202228046)the Taishan Scholar Project of Shandong ProvinceJ.W.acknowledges the support of the Singapore Ministry of Education,for research conducted at the National University of Singapore(Tier 1,A-8000186-01-00).
文摘Li–CO_(2) batteries,which integrate CO_(2) utilization and electrochemical energy storage,offer the prospect of utilizing a greenhouse gas and providing an alternative to the well-established lithium-ion batteries.However,they still suffer from rather limited reversibility,low energy efficiency,and sluggish CO_(2) redox reaction kinetics.To address these key issues,a nanoporous Ni_(3)Al intermetallic/Ni heterojunction(NP–Ni_(3) Al/Ni)is purposely engi-neered here via an alloying–etching protocol,whereby the unique interactions between Al and Ni in Ni_(3)Al endow NP-Ni_(3)Al/Ni with optimum reactant/product adsorption and thus unique catalytic performance for the CO_(2) redox reaction.Furthermore,the nanoporous spongy structure benefits mass transport as well as discharge product storage and enables a rich multiphase reaction interface.In situ Raman studies and theoretical simulations reveal that both CO_(2) reduction and the co-decomposition of Li_(2)CO_(3) and C are distinctly promoted by NP-Ni_(3)Al/Ni,thereby greatly improving catalytic activity and stability.NP-Ni_(3)Al/Ni offers promising application potential in Li–CO_(2) batteries,with its scalable fabrication,low production cost,and superior catalytic performance.
基金financially supported by the National Natural Science Foundation of China (Nos.52034004 and 52075373)。
文摘The Ni_(3)Al-based alloy has been considered as a robust catalyst for oxygen evolution reaction(OER)due to its long-term durability and acceptable activity.However,related reports about understanding the catalytic mechanism are rare and desirable.Herein,the effect of γ/γ’phase lattice mismatch on the catalytic performance caused by various cooling rates after solution heat treatment was investigated.With decreasing cooling rate,the morphologies of γ' precipitates transformed from sphere to cube and the lattice mismatch increased from-0.172%to-0.409%.The increased lattice mismatch facilitated the formation of the active β-NiOOH phase and enhanced the intrinsic catalytic activity,resulting in the optimized OER overpotential of 240 mV at a current density of 10 mA cm^(−2) with a Tafel slope of 66.1 mV dec^(−1) and a stability of 200 h in 1 M KOH.This work reveals the lattice mismatch effect on OER and provides a potential candidate for OER.
基金financially supported by the National Natural Science Foundation of China(No.51371014)。
文摘In this study,the cyclic oxidation tests of the Ni3Al-based single-crystal super alloy IC21 were carried out at 800,900,950,1000,1050 and 1100℃in air.The present study shows that the complex oxide scale on the surface of the alloy is made up of an outer columnar NiO layer,an intermediate mixture of NiO and NiAl2O4layer with a small amount of Mo oxides and an inner continuous layer ofα-Al_(2)O_(3).The cyclic oxidation kinetics curves show that oxidation resistance at 800,900,950,1000 and1050℃seems to follow a similar law and is better than that at 1100℃.The overall weight changes at 1100℃follows a parabolic law.Spallation and severe rumpling of the oxide scale are observed on the surface of the alloy at1100℃,revealing the occurrence of disastrous oxidation.
基金This work is partly performed under the auspices of the U.S.Department of Energy(DOE)by the Lawrence Livermore National Laboratory(LLNL)under Contract No.DE-AC52-07NA27344The authors are grateful for project funding from the High-Performance Computing for Materials(HPC4Mtls)Program of the DOE Vehicle Technologies Office under Cooperative Research and Development Agreement(CRADA)No.TC02309+2 种基金Computing support for this work comes from the LLNL Institutional Computing facilities,and the National Energy Research Scientific Computing Center(NERSC),a DOE Office of Science User Facility operated under Contract No.DE-AC02-05-CH11231E.C.acknowledges a fellowship through the National Science Foundation Graduate Research Fellowship Program under Grant No.DGE-1752814M.A.acknowledges support for his contributions by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division,under Contract No.DE-AC02-05-CH11231 within the Materials Project program(KC23MP).All figures are produced using matplotlib79.
文摘Antiphase boundaries(APBs)are planar defects that play a critical role in strengthening Ni-based superalloys,and their sensitivity to alloy composition offers a flexible tuning parameter for alloy design.Here,we report a computational workflow to enable the development of sufficient data to train machine-learning(ML)models to automate the study of the effect of composition on the(111)APB energy in Ni_(3)Al-based alloys.We employ ML to leverage this wealth of data and identify several physical properties that are used to build predictive models for the APB energy that achieve a cross-validation error of 0.033 J m^(−2).We demonstrate the transferability of these models by predicting APB energies in commercial superalloys.Moreover,our use of physically motivated features such as the ordering energy and stoichiometry-based features opens the way to using existing materials properties databases to guide superalloy design strategies to maximize the APB energy.
基金the National Key Research and Development Program of China(Grant Nos.2017YFB0701603 and 2017YFB0701502).
文摘Heavy elements(X=Ta/W/Re)play an important role in the performance of superalloys,which enhance the strength,anti-oxidation,creep resistance,and anti-corrosiveness of alloy materials in a high-temperature environment.In the present research,the heavy element doping effects in FCC-Ni(γ)and Ni_(3)Al(γ')systems are investigated in terms of their thermodynamic and mechanical properties,as well as electronic structures.The lattice constant,bulk modulus,elastic constant,and dopant formation energy in non-spin,spin polarized,and spin-orbit coupling(SOC)calculations are compared.The results show that the SOC effects are important in accurate electronic structure calculations for alloys with heavy elements.We find that including spin for bothγandγ'phases is necessary and sufficient for most cases,but the dopant formation energy is sensitive to different spin effects,for instance,in the absence of SOC,even spin-polarized calculations give 1%to 9%variance in the dopant formation energy in our model.Electronic structures calculations indicate that spin polarization causes a split in the metal d states,and SOC introduces a variance in the spin-up and spin-down states of the d states of heavy metals and reduces the magnetic moment of the system.
基金the Key-Area Research and Development Program of Guangdong Province(2019B010936001)financially supported by the National Natural Science Foundation of China(Grant Nos.51671202 and 51301184)。
文摘A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatments,wherein the electroplating procedures consisted of the composite deposition of Ni-Re followed by electroplating of Pt.In order to perform a comparison with conventional Ni Al and(Ni,Pt)Al coatings,the cyclic oxidation performance of the Ni Re Pt Al coating was evaluated at 1100 and 1150℃.We observed that the oxidation resistance of the Ni Re Pt Al coating was significantly improved by the greater presence of the residualβ-Ni Al phase in the outer layer and the lesser outward-diffusion of Mo from the substrate.In addition,the coating with the Re-rich diffusion barrier demonstrated a lower extent of interdiffusion into the substrate,where the thickness of the second reaction zone(SRZ)in the substrate alloy decreased by 25%.The mechanisms responsible for improving the oxidation resistance and decreasing the extent of SRZ formation are discussed,in which a particular attention is paid to the inhibition of the outward diffusion of Mo by the Re-based diffusion barrier.