The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experim...The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich phase.In addition,the primary Al dendrites show significant refinement with an increase in the withdrawal speed.The relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 HV.This is a combined effect of grain refinement and second-phase strengthening.展开更多
Effects of La addition on corrosion resistance of hot-dipped galvalume coating steel wire were investigated.The corrosion resistance of Zn-Al-Si-La alloy coatings containing 0, 0.02wt.%, 0.05wt.%, 0.1wt.% and 0.2wt.% ...Effects of La addition on corrosion resistance of hot-dipped galvalume coating steel wire were investigated.The corrosion resistance of Zn-Al-Si-La alloy coatings containing 0, 0.02wt.%, 0.05wt.%, 0.1wt.% and 0.2wt.% La were evaluated by various tests such as copper-accelerated acetic acid salt spray testing（CASS）, immersion test in 3.5% NaCl solution, electrochemical tests including weak polarization curves and electrochemical impedance spectroscopy（EIS） tests, scanning electron microscope（SEM） test and X-ray diffraction（XRD） test.It was found that the corrosion resistance of galvalume coating could be improved by adding proper amounts of La.Meanwhile, the mechanism of the improvement of corrosion resistance by La addition was discussed.展开更多
To study the effect of free radical photocurable passivation film modified by titanate coupling agent for hot-plated aluminum-zinc plate,trimethylpropane triacrylate(TMPTA)and 2-phenoxyethyl acrylate were used as acti...To study the effect of free radical photocurable passivation film modified by titanate coupling agent for hot-plated aluminum-zinc plate,trimethylpropane triacrylate(TMPTA)and 2-phenoxyethyl acrylate were used as active diluents,a mixture of modified epoxy acrylate and modified polyester acrylate in a certain proportion was used as an oligomer,2-methyl-1-[4-(methylothyl)benzene]-2-morpholine acetone(907)was used as a free radical photoinitiator,isopropyl thioxanthone(ITX)was used as sensitizer,and bis(dioctyl phosphate acyl)titanate ethyltitanate acrylamide chelate(FD-812)was used as corrosion inhibitor modifier.After UV-curing,the passivation film was characterized by neutral salt spray test,electrochemical testing and other methods.The general performance of the passivation film may meet the requirements of downstream users of hot aluminum-zinc steel plate.The neutral salt spray test,electrochemical testing and microscopic surface morphology analysis of passivation film are in agreement.The introduction of titanate components may effectively promote the photocuring of free radicals.There have been few reports on the titanate coupling which is added to UV-curing coating formula.The titanate coupling agent contains acrylamide groups and terminal amine groups,acrylamide group has oligomer and crosslinking monomer,the terminal tertiary amine groups can provide hydrogen protons,reduce oxygen polymerization,and a phosphating film is formed on the surface of the metal substrate to improve the adhesion and corrosion resistance of the coating.展开更多
基金supported by the Key Science and Technology Projects of Gansu Province(Grant No.22ZD6GB019)Gansu Key Research and Development Project(Grant No.23YFGA0003)+2 种基金Gansu Provincial Joint Research Fund(Grant No.23JRRC0004)Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2022-ey15)the State Key Laboratory of Solidification Processing in NPU(Grant No.SKLSP202204).
文摘The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich phase.In addition,the primary Al dendrites show significant refinement with an increase in the withdrawal speed.The relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 HV.This is a combined effect of grain refinement and second-phase strengthening.
文摘Effects of La addition on corrosion resistance of hot-dipped galvalume coating steel wire were investigated.The corrosion resistance of Zn-Al-Si-La alloy coatings containing 0, 0.02wt.%, 0.05wt.%, 0.1wt.% and 0.2wt.% La were evaluated by various tests such as copper-accelerated acetic acid salt spray testing（CASS）, immersion test in 3.5% NaCl solution, electrochemical tests including weak polarization curves and electrochemical impedance spectroscopy（EIS） tests, scanning electron microscope（SEM） test and X-ray diffraction（XRD） test.It was found that the corrosion resistance of galvalume coating could be improved by adding proper amounts of La.Meanwhile, the mechanism of the improvement of corrosion resistance by La addition was discussed.
基金by the National Basic Research Program of China(2009AA03Z529)。
文摘To study the effect of free radical photocurable passivation film modified by titanate coupling agent for hot-plated aluminum-zinc plate,trimethylpropane triacrylate(TMPTA)and 2-phenoxyethyl acrylate were used as active diluents,a mixture of modified epoxy acrylate and modified polyester acrylate in a certain proportion was used as an oligomer,2-methyl-1-[4-(methylothyl)benzene]-2-morpholine acetone(907)was used as a free radical photoinitiator,isopropyl thioxanthone(ITX)was used as sensitizer,and bis(dioctyl phosphate acyl)titanate ethyltitanate acrylamide chelate(FD-812)was used as corrosion inhibitor modifier.After UV-curing,the passivation film was characterized by neutral salt spray test,electrochemical testing and other methods.The general performance of the passivation film may meet the requirements of downstream users of hot aluminum-zinc steel plate.The neutral salt spray test,electrochemical testing and microscopic surface morphology analysis of passivation film are in agreement.The introduction of titanate components may effectively promote the photocuring of free radicals.There have been few reports on the titanate coupling which is added to UV-curing coating formula.The titanate coupling agent contains acrylamide groups and terminal amine groups,acrylamide group has oligomer and crosslinking monomer,the terminal tertiary amine groups can provide hydrogen protons,reduce oxygen polymerization,and a phosphating film is formed on the surface of the metal substrate to improve the adhesion and corrosion resistance of the coating.
