Bis-3-(triethoxysilyl)propyltetrasulfide(BTESPT) silane-rare earth cerium composite coatings on aluminum-tube were prepared at 60 °C by immersion method.The performance of composite coatings to protect the alumin...Bis-3-(triethoxysilyl)propyltetrasulfide(BTESPT) silane-rare earth cerium composite coatings on aluminum-tube were prepared at 60 °C by immersion method.The performance of composite coatings to protect the aluminum-tube against corrosion was investigated with potentiodynamic polarization curves,electrochemical impedance spectroscopy(EIS),and salt spray test(SST).The results of potentiodynamic polarization curves and EIS indicated that the self-corrosion current decreased by two orders of magnitude and the i...展开更多
The feasibility of forming pollution-free and environmentally benign Ce-based rare earth conversion coatings （short for RECCs） on AZ91 magnesium alloy to enhance corrosion resistance was studied. The effect of optim...The feasibility of forming pollution-free and environmentally benign Ce-based rare earth conversion coatings （short for RECCs） on AZ91 magnesium alloy to enhance corrosion resistance was studied. The effect of optimum processing parameters on corrosion resistance of RECCs, such as density of treating solution, temperature and time of coating formation were discussed. Protective performance of conversion coatings on magnesium alloy was evaluated by moisture/heating test, anodic polarization, etc. The results show that Ce-based RECCs under moisture/heating condition can remain intact, with high coverage and no obvious corrosion phenomenon. Corrosion potential increases and passive phenomenon occurs while current density decreases, therefore Ce-based RECCs can improve corrosion resistance of AZ91 magnesium alloy. The morphology of Ce-based RECCs prepared under optimum process through SEM observation is found to be a few particles coherent to the base coating, and the coating has no cracks and exhibits apparent corrosion resistance during corrosion courses of AZ91 magnesium alloy.展开更多
The effect of rare earth elements on quenching crack resistance of steel 9Cr2Mo was investigated by means of scanning electron microscopy (SEM) and optical microscopy. Experimental results show that, by adding RE elem...The effect of rare earth elements on quenching crack resistance of steel 9Cr2Mo was investigated by means of scanning electron microscopy (SEM) and optical microscopy. Experimental results show that, by adding RE elements to steel 9Cr2Mo, the number of quenching for crack initiation is increased. Meanwhile the propagation of quenching cracks is postponed and the paths of crack propagation are changed. Therefore, quenching crack resistance can be improved by adding RE elements to steel 9Cr2Mo.展开更多
The effects of rare earths on electric conductivity fusion welding-resistance and erosion-resistance by electric arc of copper-based compound material by adding different amount of rare earths to copper base to get co...The effects of rare earths on electric conductivity fusion welding-resistance and erosion-resistance by electric arc of copper-based compound material by adding different amount of rare earths to copper base to get copper based compound materials were studied. Rare earths improve active ability among interfaces and optimize organizational structures. The conductivity of samples with rare earths is obviously better than that of materials without them. Moreover, wear ability and oxidization resistance of materials with rare earths can be improved greatly. For copper contact head with rare earths, electric arc corrosion resistance and welding-melting resistance are improved. Such alloys also decrease resistance change with increasing temperature. But the adding quantity of rare earths should be appropriate and formed handicraft should be properly regulated.展开更多
By adding rare earth alloy and cerium oxide, the effect of rare earths on tribological properties of nickel base alloy layer was studied to approach the possibility of applying rare earths to Ni base thermal spray ...By adding rare earth alloy and cerium oxide, the effect of rare earths on tribological properties of nickel base alloy layer was studied to approach the possibility of applying rare earths to Ni base thermal spray welding coating. Wear test results showed that the wear rates of the nickel base coating without rare earths were quite high, and the load bearing capacity of coating was low, in contrast, the wear rates of the coating with rare earths were low and the coating had higher load bearing capacity. The results show that rare earths can refine the structure of nickel base alloy, improve the interface of the coating and substrate.展开更多
The corrosion behavior of BFe10-1-1 alloy with different rare earth （RE） contents in simulated flowing marine water was investigated by X-ray diffractometer and scanning electron microscope （SEM）. It was demonstra...The corrosion behavior of BFe10-1-1 alloy with different rare earth （RE） contents in simulated flowing marine water was investigated by X-ray diffractometer and scanning electron microscope （SEM）. It was demonstrated that the corrosion rate of BFel0-1-1 alloy with the same chemical compositions in faster flow velocity of marine water was higher than that in a lower flow velocity of marine water. Fixing the flow velocity, BFe 10-1-1 alloy had the best flushing corrosion resistance when the RE content was 0.04wt.%. The consequence of such good corrosion resistance was attributed to the formation of compact protective film on alloy surface containing RE phase such as CeNis. The RE-contained film combines with other corrosion products firmly, which was difficult to fall off from the alloy surface in the flowing marine water. Additionally, SEM analysis confirmed that pitting mechanism, which would be transformed to spalling mechanism gradually with further increasing RE content, was the prevalent mechanism when the alloy contained 0.04wt.%RE.展开更多
The effect of adding RE to plating bath on microstructure and corrosion resistance of Ni-Co alloy coatings prepared by pulse reversal current electrodeposition was studied by means of SEM/EDS, electrochemical analysis...The effect of adding RE to plating bath on microstructure and corrosion resistance of Ni-Co alloy coatings prepared by pulse reversal current electrodeposition was studied by means of SEM/EDS, electrochemical analysis and corrosion mass loss etc. The results show that adding proper RE to plating solution can promote the microstructure of coatings compacter, the surface smoother and the crystal finer, and improve the corrosion resistance. The coatings exhibite the highest corrosion resistance when the concentration of RE reaches 0.25 g·L -1. The reason of increasing corrosion resistance by adding RE was also investigated.展开更多
The samples of pure Fe were treated by surface gas phase RE permeation plus laser melting solidification (LMS). The microstructures were observed by Scanning Electron Microscope (SEM) and X ray Photoelectron Spectro...The samples of pure Fe were treated by surface gas phase RE permeation plus laser melting solidification (LMS). The microstructures were observed by Scanning Electron Microscope (SEM) and X ray Photoelectron Spectroscopy (XPS), meanwhile the corrosion resistance was investigated by electrochemical impedance spectroscopy (EIS) and anodic polarization. The results show that this treatment can remarkably improve the density and uniformity of microstructure, and enhance corrosion resistance of the pure Fe surface.展开更多
The microstructure and corrosion resistance of the RE-doped electrodeposition Ni coatings fabricated with direct current electrodeposition (DC), pulse current electrodeposition (PC), and pulse reversal current electro...The microstructure and corrosion resistance of the RE-doped electrodeposition Ni coatings fabricated with direct current electrodeposition (DC), pulse current electrodeposition (PC), and pulse reversal current electrodeposition (PRC) were investigated by means of SEM, electrochemical analysis and corrosion mass loss, etc. The results show that the Ni coatings produced with PRC exhibit the highest corrosion resistance among the three kinds of coatings, and the corrosion resistance of the PC coatings is higher than that of the DC coatings. The reason is that the surface of the PRC coatings is compacter, crystal finer compared with the coarse surface of DC and PC coatings.展开更多
The rare earth-containing composite elastomer was obtained by the reaction of vinyl pyridine-SBR (PSBR) latex with rare earth alkoxides, and its thermal oxidation resistance was studied. After aging test, it is found ...The rare earth-containing composite elastomer was obtained by the reaction of vinyl pyridine-SBR (PSBR) latex with rare earth alkoxides, and its thermal oxidation resistance was studied. After aging test, it is found that its retention rate of mechanical properties is far higher than that of the control sample. The results of thermogravimetric analysis show that its thermal-decomposing temperature rises largely. The analysis of oxidation mechanisms indicates that the main reasons for thermal oxidation resistance are that rare earth elements are of the utility to discontinue autoxidation chain reaction and that the formed complex structure has steric hindrance effect on oxidation.展开更多
The Influence of RE on wear resistance of wear resistant cast iron containing low alloy was studied by means of slide wear and impact wear test. Moreover, its microstructure and characteristics of wearing surface was ...The Influence of RE on wear resistance of wear resistant cast iron containing low alloy was studied by means of slide wear and impact wear test. Moreover, its microstructure and characteristics of wearing surface was analyzed. The experimental results show that RE can improve the wear resistance of wear resistant cast iron containing low alloy, especially for impact wear resistance. The optimum wear resistance of wear resistant cast iron containing low alloy modified by RE of 0.046% can be obtained by normalization at 950 ℃ for 3 h. Moreover, the coordinated effect of rare earths and heat treatment was also revealed in this paper.展开更多
The surface of carbon fiber reinforced Mg matrix (Cf/Mg) composites was modified by treatment of rare earth conversion coating, and nontoxic, non-pollution Ce conversion coatings were prepared. The effect of the coati...The surface of carbon fiber reinforced Mg matrix (Cf/Mg) composites was modified by treatment of rare earth conversion coating, and nontoxic, non-pollution Ce conversion coatings were prepared. The effect of the coatings on corrosion behaviors of composites was investigated by electrochemical polarization technology and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The higher Ecorr and lower icorr were obtained by Ce conversion coatings. EIS results showed that the higher values of R2 were obtained by treatment containing CeCl3, the high corrosion resistance occured in treatment containing CeCl3, the low corrosion resistance in uncoating sample, the coating of treatment containing Ce(NO3)3 was medium. The microstructure of Ce conversion coatings was observed by scanning electron microscopy (SEM), and the elements of corresponding for coatings was characterized by energy dispersive spectrometer (EDS). The micro-cracks and Ce-riched spherical particles were characteristics of these coatings.展开更多
To protect humans, devices and maintain high reliability of electrical equipments, efficient earthing system has to be provided for residential and commercial buildings. The use of chemical elements around the electro...To protect humans, devices and maintain high reliability of electrical equipments, efficient earthing system has to be provided for residential and commercial buildings. The use of chemical elements around the electrode of earthing systems reduces the earth resistance which improves the efficiency of these systems. However, the use of these elements can’t achieve very small earth resistance especially in the case of dry clay. In addition, they are expensive and not available all the time. This paper presents a method that treats the soil with adding the Dead Sea water instead of the chemical elements to further reduce the earth resistance and to avoid the expenses of these elements. In our approach, the Dead Sea water is added to a hole around the electrode with a distance not exceeding 10 cm to avoid the corrosion layer on the electrode. Practical measurements are demonstrated to show the efficiency of the proposed approach.展开更多
The low-energy multi-impact fracture resistance of the cross rolled low chromium cast semi-steel containing RE grinding balls was studied. Moreover, its damage mode was analyzed by means of metallographic examination,...The low-energy multi-impact fracture resistance of the cross rolled low chromium cast semi-steel containing RE grinding balls was studied. Moreover, its damage mode was analyzed by means of metallographic examination, scanning electron microscopic examination and drop ball test. The results show that it can obtain extractive impact fracture resistance after proper heat treatment. More advantages were obtained for the ball worked in the condition of low-imp ductility act. The main reasons are the function of RE and the change in morphology of eutectic carbide network.展开更多
Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 3...Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 38CrMoAl steel by introducing RE during nitrocarburizing processing as compared with conventional nitrocarburizing processing. Results of mechanical testing show that both hardness and impact toughness of RE-nitrocarburizing layer of 38CrMoAl steel increase as compared with the conventional one. Optical microscopy reveals that there is improvement in the nitrocarburized layer attributed to the introduction of RE, which results in improvement in erosion resistance. Surface morphology observation of tested samples reveals that predominantly furrow-like peelings from plastic deformation are observed for RE nitrocarburizied 38CrMoAl steel, while the furrow-like peeling with initial cross crack and large grinding peelings were observed for conventionally nitrocarburized samples.展开更多
Magnesium(Mg)alloys have received an increasing interest in the past two decades for their tremendous application potential.The strength and corrosion resistance levels of common Mg alloys are still relativity low,and...Magnesium(Mg)alloys have received an increasing interest in the past two decades for their tremendous application potential.The strength and corrosion resistance levels of common Mg alloys are still relativity low,and especially they are to be improved simultaneously.The addition of rare earth(RE)to Mg alloys is believed to be beneficial for both the strength and corrosion resistance,and some RE-modified traditional Mg alloys have been studied and some new RE-containing Mg alloys have been developed by now.However,further simultaneous improvements in both strength and anti-corrosion require a better understanding of the behavior and mechanism of RE in Mg alloys.In this review,the common influence mechanisms of RE on mechanical and anti-corrosion properties of Mg alloys are summarized,and the latest research progress of RE-containing Mg alloys with simultaneously improved strength and corrosion resistance are introduced.It is demonstrated that the research on high-strength and high corrosion resistant RE-containing Mg alloys is still immature,and some opinions and suggestions are put forward for the synergetic improvement of the strength and corrosion resistance of Mg alloys,so as to contribute to the further development of Mg alloys with higher performance.展开更多
Cu-30Ni-xRE(x=0–0.213 wt.%) alloy was prepared by adding rare earths(RE) in melted Cu-30Ni alloy using metal mould casting method.The effects of RE on corrosion resistance of the alloy in simulated seawater were inve...Cu-30Ni-xRE(x=0–0.213 wt.%) alloy was prepared by adding rare earths(RE) in melted Cu-30Ni alloy using metal mould casting method.The effects of RE on corrosion resistance of the alloy in simulated seawater were investigated using optical microscope,scanning electronic microscope with energy-dispersive spectrometer and electrochemical measurement system.The results showed that the corrosion resistance of Cu-30Ni alloy was greatly improved by adding proper amount of RE,whereas excess addition of RE worsened ...展开更多
The age-hardening behavior and mechanical properties of the extruded Mg-2Gd-1.2Y-0.5Zn(at.%)alloy with Zr or Mn additions were investigated.The results show that Mn added alloy exhibits more remarkable age-hardening r...The age-hardening behavior and mechanical properties of the extruded Mg-2Gd-1.2Y-0.5Zn(at.%)alloy with Zr or Mn additions were investigated.The results show that Mn added alloy exhibits more remarkable age-hardening response than Zr added alloy,which is attributed to the fact that partitioning of Mn into the β'phases,β'precipitates and long period stacking ordered(LPSO)phases leads to the decrement in(G d+Y)concentrations in the second phases,facilitating the precipitation during aging treatment.Both peak-aged alloys show bimodal microstructure comprising the fine DRXed grains with nano-sized β phases pinned at DRXed grain boundaries as well as coarse worked grains with strong fiber texture.High strength and good thermal stability were obtained in both peak-aged Mn and Zr added alloys.While the peak-aged Mn added alloy shows higher strength and superior creep resistance due to its denser β'precipitates,thin LPSO phases and γ'precipitates and higher area fraction of worked grains with strong fiber texture.The 0.2% tensile proof stress and ultimate tensile strength of peak-aged Mn added alloy reach up to 454 MPa and 508 MPa,respectively,with elongation of 3.2%at room temperature.The minimum creep rate of the peak-aged Mn added alloy at 250℃/150 MPa is 2.4 × 10^-8 s^-1,which is superior than previously reported extruded Mg-Gd based alloys.展开更多
The effect of rare earth elements on thermal shock resistance of cold roller steel 9Cr2Mo was investigated by means of X-ray diffractometry and optical microscopy. Experimental results show that the process of carbide...The effect of rare earth elements on thermal shock resistance of cold roller steel 9Cr2Mo was investigated by means of X-ray diffractometry and optical microscopy. Experimental results show that the process of carbide precipitation of heat effect zone is restrained by adding RE elements in steel 9Cr2Mo. Therefore, thermal shock resistance of this steel can be improved.展开更多
Steel H13 was put in non toxic salt bath with addition of CeO 2 for co diffusion of sulfur, nitrogen and carbon and followed by oxidation treatment. The effect of rare earths on the improvement of wear resistance a...Steel H13 was put in non toxic salt bath with addition of CeO 2 for co diffusion of sulfur, nitrogen and carbon and followed by oxidation treatment. The effect of rare earths on the improvement of wear resistance and high temperature oxidation resistance of steel H13 was studied using scanning electron microscope, energy dispersive spectrometry and X ray diffraction. The results show that compared to the surface treatment without rare earth addition, the treatment with addition of rare earths improves the wear resistance and high temperature resistance to oxidation of steel H13. Under the conditions of 30 N and 2 h, the wear weight loss was decreased by 40%, and the friction coefficient was reduced from 0 25 to 0 22; whereas for 150 N and 0 2 h, the wear weight loss was decreased by 24%, and the friction coefficient was reduced from 0 35 to 0 32. For the oxidation at 700 ℃ and 4 h, the rate of weight gain decreased to only about 1/30 of that without rare earths.展开更多
基金supported by the Provincial Natural Science Foundation of Hunan Province (04JJ30817)
文摘Bis-3-(triethoxysilyl)propyltetrasulfide(BTESPT) silane-rare earth cerium composite coatings on aluminum-tube were prepared at 60 °C by immersion method.The performance of composite coatings to protect the aluminum-tube against corrosion was investigated with potentiodynamic polarization curves,electrochemical impedance spectroscopy(EIS),and salt spray test(SST).The results of potentiodynamic polarization curves and EIS indicated that the self-corrosion current decreased by two orders of magnitude and the i...
文摘The feasibility of forming pollution-free and environmentally benign Ce-based rare earth conversion coatings （short for RECCs） on AZ91 magnesium alloy to enhance corrosion resistance was studied. The effect of optimum processing parameters on corrosion resistance of RECCs, such as density of treating solution, temperature and time of coating formation were discussed. Protective performance of conversion coatings on magnesium alloy was evaluated by moisture/heating test, anodic polarization, etc. The results show that Ce-based RECCs under moisture/heating condition can remain intact, with high coverage and no obvious corrosion phenomenon. Corrosion potential increases and passive phenomenon occurs while current density decreases, therefore Ce-based RECCs can improve corrosion resistance of AZ91 magnesium alloy. The morphology of Ce-based RECCs prepared under optimum process through SEM observation is found to be a few particles coherent to the base coating, and the coating has no cracks and exhibits apparent corrosion resistance during corrosion courses of AZ91 magnesium alloy.
文摘The effect of rare earth elements on quenching crack resistance of steel 9Cr2Mo was investigated by means of scanning electron microscopy (SEM) and optical microscopy. Experimental results show that, by adding RE elements to steel 9Cr2Mo, the number of quenching for crack initiation is increased. Meanwhile the propagation of quenching cracks is postponed and the paths of crack propagation are changed. Therefore, quenching crack resistance can be improved by adding RE elements to steel 9Cr2Mo.
文摘The effects of rare earths on electric conductivity fusion welding-resistance and erosion-resistance by electric arc of copper-based compound material by adding different amount of rare earths to copper base to get copper based compound materials were studied. Rare earths improve active ability among interfaces and optimize organizational structures. The conductivity of samples with rare earths is obviously better than that of materials without them. Moreover, wear ability and oxidization resistance of materials with rare earths can be improved greatly. For copper contact head with rare earths, electric arc corrosion resistance and welding-melting resistance are improved. Such alloys also decrease resistance change with increasing temperature. But the adding quantity of rare earths should be appropriate and formed handicraft should be properly regulated.
文摘By adding rare earth alloy and cerium oxide, the effect of rare earths on tribological properties of nickel base alloy layer was studied to approach the possibility of applying rare earths to Ni base thermal spray welding coating. Wear test results showed that the wear rates of the nickel base coating without rare earths were quite high, and the load bearing capacity of coating was low, in contrast, the wear rates of the coating with rare earths were low and the coating had higher load bearing capacity. The results show that rare earths can refine the structure of nickel base alloy, improve the interface of the coating and substrate.
基金supported by the Science and Technology Payoffs Transformation Program of Jiangsu Province (DA2006034)the Program of National College Student Creative Experiment (081053309)
文摘The corrosion behavior of BFe10-1-1 alloy with different rare earth （RE） contents in simulated flowing marine water was investigated by X-ray diffractometer and scanning electron microscope （SEM）. It was demonstrated that the corrosion rate of BFel0-1-1 alloy with the same chemical compositions in faster flow velocity of marine water was higher than that in a lower flow velocity of marine water. Fixing the flow velocity, BFe 10-1-1 alloy had the best flushing corrosion resistance when the RE content was 0.04wt.%. The consequence of such good corrosion resistance was attributed to the formation of compact protective film on alloy surface containing RE phase such as CeNis. The RE-contained film combines with other corrosion products firmly, which was difficult to fall off from the alloy surface in the flowing marine water. Additionally, SEM analysis confirmed that pitting mechanism, which would be transformed to spalling mechanism gradually with further increasing RE content, was the prevalent mechanism when the alloy contained 0.04wt.%RE.
文摘The effect of adding RE to plating bath on microstructure and corrosion resistance of Ni-Co alloy coatings prepared by pulse reversal current electrodeposition was studied by means of SEM/EDS, electrochemical analysis and corrosion mass loss etc. The results show that adding proper RE to plating solution can promote the microstructure of coatings compacter, the surface smoother and the crystal finer, and improve the corrosion resistance. The coatings exhibite the highest corrosion resistance when the concentration of RE reaches 0.25 g·L -1. The reason of increasing corrosion resistance by adding RE was also investigated.
文摘The samples of pure Fe were treated by surface gas phase RE permeation plus laser melting solidification (LMS). The microstructures were observed by Scanning Electron Microscope (SEM) and X ray Photoelectron Spectroscopy (XPS), meanwhile the corrosion resistance was investigated by electrochemical impedance spectroscopy (EIS) and anodic polarization. The results show that this treatment can remarkably improve the density and uniformity of microstructure, and enhance corrosion resistance of the pure Fe surface.
文摘The microstructure and corrosion resistance of the RE-doped electrodeposition Ni coatings fabricated with direct current electrodeposition (DC), pulse current electrodeposition (PC), and pulse reversal current electrodeposition (PRC) were investigated by means of SEM, electrochemical analysis and corrosion mass loss, etc. The results show that the Ni coatings produced with PRC exhibit the highest corrosion resistance among the three kinds of coatings, and the corrosion resistance of the PC coatings is higher than that of the DC coatings. The reason is that the surface of the PRC coatings is compacter, crystal finer compared with the coarse surface of DC and PC coatings.
文摘The rare earth-containing composite elastomer was obtained by the reaction of vinyl pyridine-SBR (PSBR) latex with rare earth alkoxides, and its thermal oxidation resistance was studied. After aging test, it is found that its retention rate of mechanical properties is far higher than that of the control sample. The results of thermogravimetric analysis show that its thermal-decomposing temperature rises largely. The analysis of oxidation mechanisms indicates that the main reasons for thermal oxidation resistance are that rare earth elements are of the utility to discontinue autoxidation chain reaction and that the formed complex structure has steric hindrance effect on oxidation.
文摘The Influence of RE on wear resistance of wear resistant cast iron containing low alloy was studied by means of slide wear and impact wear test. Moreover, its microstructure and characteristics of wearing surface was analyzed. The experimental results show that RE can improve the wear resistance of wear resistant cast iron containing low alloy, especially for impact wear resistance. The optimum wear resistance of wear resistant cast iron containing low alloy modified by RE of 0.046% can be obtained by normalization at 950 ℃ for 3 h. Moreover, the coordinated effect of rare earths and heat treatment was also revealed in this paper.
文摘The surface of carbon fiber reinforced Mg matrix (Cf/Mg) composites was modified by treatment of rare earth conversion coating, and nontoxic, non-pollution Ce conversion coatings were prepared. The effect of the coatings on corrosion behaviors of composites was investigated by electrochemical polarization technology and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The higher Ecorr and lower icorr were obtained by Ce conversion coatings. EIS results showed that the higher values of R2 were obtained by treatment containing CeCl3, the high corrosion resistance occured in treatment containing CeCl3, the low corrosion resistance in uncoating sample, the coating of treatment containing Ce(NO3)3 was medium. The microstructure of Ce conversion coatings was observed by scanning electron microscopy (SEM), and the elements of corresponding for coatings was characterized by energy dispersive spectrometer (EDS). The micro-cracks and Ce-riched spherical particles were characteristics of these coatings.
文摘To protect humans, devices and maintain high reliability of electrical equipments, efficient earthing system has to be provided for residential and commercial buildings. The use of chemical elements around the electrode of earthing systems reduces the earth resistance which improves the efficiency of these systems. However, the use of these elements can’t achieve very small earth resistance especially in the case of dry clay. In addition, they are expensive and not available all the time. This paper presents a method that treats the soil with adding the Dead Sea water instead of the chemical elements to further reduce the earth resistance and to avoid the expenses of these elements. In our approach, the Dead Sea water is added to a hole around the electrode with a distance not exceeding 10 cm to avoid the corrosion layer on the electrode. Practical measurements are demonstrated to show the efficiency of the proposed approach.
文摘The low-energy multi-impact fracture resistance of the cross rolled low chromium cast semi-steel containing RE grinding balls was studied. Moreover, its damage mode was analyzed by means of metallographic examination, scanning electron microscopic examination and drop ball test. The results show that it can obtain extractive impact fracture resistance after proper heat treatment. More advantages were obtained for the ball worked in the condition of low-imp ductility act. The main reasons are the function of RE and the change in morphology of eutectic carbide network.
文摘Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 38CrMoAl steel by introducing RE during nitrocarburizing processing as compared with conventional nitrocarburizing processing. Results of mechanical testing show that both hardness and impact toughness of RE-nitrocarburizing layer of 38CrMoAl steel increase as compared with the conventional one. Optical microscopy reveals that there is improvement in the nitrocarburized layer attributed to the introduction of RE, which results in improvement in erosion resistance. Surface morphology observation of tested samples reveals that predominantly furrow-like peelings from plastic deformation are observed for RE nitrocarburizied 38CrMoAl steel, while the furrow-like peeling with initial cross crack and large grinding peelings were observed for conventionally nitrocarburized samples.
基金This work was supported by National Natural Sci-ence Foundation of China(51871069)Domain Foundation of Equipment Advance Research of 13th Five-year Plan(61409220118)Science and technology innovation ma-jor project of Ningbo City(2019B10103).
文摘Magnesium(Mg)alloys have received an increasing interest in the past two decades for their tremendous application potential.The strength and corrosion resistance levels of common Mg alloys are still relativity low,and especially they are to be improved simultaneously.The addition of rare earth(RE)to Mg alloys is believed to be beneficial for both the strength and corrosion resistance,and some RE-modified traditional Mg alloys have been studied and some new RE-containing Mg alloys have been developed by now.However,further simultaneous improvements in both strength and anti-corrosion require a better understanding of the behavior and mechanism of RE in Mg alloys.In this review,the common influence mechanisms of RE on mechanical and anti-corrosion properties of Mg alloys are summarized,and the latest research progress of RE-containing Mg alloys with simultaneously improved strength and corrosion resistance are introduced.It is demonstrated that the research on high-strength and high corrosion resistant RE-containing Mg alloys is still immature,and some opinions and suggestions are put forward for the synergetic improvement of the strength and corrosion resistance of Mg alloys,so as to contribute to the further development of Mg alloys with higher performance.
基金Project Financially supported by Major State Basic Research Development Program of China (2007CB616903)
文摘Cu-30Ni-xRE(x=0–0.213 wt.%) alloy was prepared by adding rare earths(RE) in melted Cu-30Ni alloy using metal mould casting method.The effects of RE on corrosion resistance of the alloy in simulated seawater were investigated using optical microscope,scanning electronic microscope with energy-dispersive spectrometer and electrochemical measurement system.The results showed that the corrosion resistance of Cu-30Ni alloy was greatly improved by adding proper amount of RE,whereas excess addition of RE worsened ...
基金This work was supported by National Natural Science Foundation for Young Scientists of China,Grant No.51801042 and 51704088Fundamental Research Funds for the Central Universities,National Natural Science Foundation,Grant No.51775150JSPS KAKENHI Grant-in-Aid for Young Scientists,Grant No.JP 16K18266,and JST,Advanced Low Carbon Technology Research and Development Program(ALCA),Grant No.12102886.
文摘The age-hardening behavior and mechanical properties of the extruded Mg-2Gd-1.2Y-0.5Zn(at.%)alloy with Zr or Mn additions were investigated.The results show that Mn added alloy exhibits more remarkable age-hardening response than Zr added alloy,which is attributed to the fact that partitioning of Mn into the β'phases,β'precipitates and long period stacking ordered(LPSO)phases leads to the decrement in(G d+Y)concentrations in the second phases,facilitating the precipitation during aging treatment.Both peak-aged alloys show bimodal microstructure comprising the fine DRXed grains with nano-sized β phases pinned at DRXed grain boundaries as well as coarse worked grains with strong fiber texture.High strength and good thermal stability were obtained in both peak-aged Mn and Zr added alloys.While the peak-aged Mn added alloy shows higher strength and superior creep resistance due to its denser β'precipitates,thin LPSO phases and γ'precipitates and higher area fraction of worked grains with strong fiber texture.The 0.2% tensile proof stress and ultimate tensile strength of peak-aged Mn added alloy reach up to 454 MPa and 508 MPa,respectively,with elongation of 3.2%at room temperature.The minimum creep rate of the peak-aged Mn added alloy at 250℃/150 MPa is 2.4 × 10^-8 s^-1,which is superior than previously reported extruded Mg-Gd based alloys.
文摘The effect of rare earth elements on thermal shock resistance of cold roller steel 9Cr2Mo was investigated by means of X-ray diffractometry and optical microscopy. Experimental results show that the process of carbide precipitation of heat effect zone is restrained by adding RE elements in steel 9Cr2Mo. Therefore, thermal shock resistance of this steel can be improved.
文摘Steel H13 was put in non toxic salt bath with addition of CeO 2 for co diffusion of sulfur, nitrogen and carbon and followed by oxidation treatment. The effect of rare earths on the improvement of wear resistance and high temperature oxidation resistance of steel H13 was studied using scanning electron microscope, energy dispersive spectrometry and X ray diffraction. The results show that compared to the surface treatment without rare earth addition, the treatment with addition of rare earths improves the wear resistance and high temperature resistance to oxidation of steel H13. Under the conditions of 30 N and 2 h, the wear weight loss was decreased by 40%, and the friction coefficient was reduced from 0 25 to 0 22; whereas for 150 N and 0 2 h, the wear weight loss was decreased by 24%, and the friction coefficient was reduced from 0 35 to 0 32. For the oxidation at 700 ℃ and 4 h, the rate of weight gain decreased to only about 1/30 of that without rare earths.
