Zhuang medicine shallow needling has a long history and plays a significant role in Chinese medicine.With the development of medical treatment in China,there is a constant improvement in the use of needles.Bone needle...Zhuang medicine shallow needling has a long history and plays a significant role in Chinese medicine.With the development of medical treatment in China,there is a constant improvement in the use of needles.Bone needles have been modified to pottery needles,bronze needles,and electroacupuncture.From this long development history,there are some improvements in terms of material and technology.By analyzing and comparing the primitive and current acupuncture instruments used in China and their therapeutic effects,it can be seen that China’s medical treatment is constantly improving and will continue to improve with technology.展开更多
A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma spray...A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma sprayed on the 45# medium carbon steel substrate. The effect of rare earth Ce on the microstructures and Vickers hardness of the cast alloy and coatings were characterized by scanning electron microscopy, X-ray diffraction, electronic probe microanalysis, transmission electron microscopy and microhardness measurements. The results indicate that the hardness of both as-cast alloy and coating are enhanced by the addition of 0.6% Ce due to the refinement of κ phases which are well distributed in the matrix. The rapid solidification in the plasma spray processing retains Fe-supersaturated in the Al-bronze alloy coatings, which avoids the formation of eutectoid (α+γ2) phase and stacking faults are found in the coatings with Ce added, accordingly improves the mechanical properties.展开更多
The atmospheric corrosion behavior of bronze under thin electrolyte layer (TEL) with different thicknesses was monitored using cathodic polarization curves, open circuit potential (OCP) and electrochemical impedan...The atmospheric corrosion behavior of bronze under thin electrolyte layer (TEL) with different thicknesses was monitored using cathodic polarization curves, open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). Cathodic polarization result indicates that the cathodic limiting current density increases with decreasing the TEL thickness. EIS result shows that the corrosion rate increases with decreasing the TEL thickness at the initial stage because the corrosion is dominated by the cathodic process, whereas after long immersion time, the corrosion degree with the TEL thickness is in the sequence of 150 μm 〉 310 μm〉 10μm ≈ bulk solution 〉 57 μm. The measurements of OCP and EIS present in-situ electrochemical corrosion information and their results are in good agreement with that of physical characterizations.展开更多
X-ray diffaction analysis(XRDA)data of the black or brown patina on the surfaces of eight kinds of bronze mirror samples show 4 or 5 broad diffuse peaks which corresponding to almost the same 20 angle, while their mat...X-ray diffaction analysis(XRDA)data of the black or brown patina on the surfaces of eight kinds of bronze mirror samples show 4 or 5 broad diffuse peaks which corresponding to almost the same 20 angle, while their matixes does not.These results indicate that those diffuse peaks were produced by the SnO2, microcrystals of 3  ̄5 nm size contained in the black or brown patina.The matrix of unearthed black patina bronze mirror numbered 223, gives strong XRDA diffraction peaks, indicating that there are a large amounts of non-oxidized bronze alloy particles surrounded by SnO2,which shows that the black patinas are not wholly metallic oxides (mainly SnO2),there are also a lot of original alloys of different sizes in grain in the patina.The bright-field image of the black patina sample gives the same result.展开更多
The material of nickel aluminum bronze (NAB) presents superior properties such as high strength, excellent wear resistance and stress corrosion resistance and is extensively used for marine propellers. In order to est...The material of nickel aluminum bronze (NAB) presents superior properties such as high strength, excellent wear resistance and stress corrosion resistance and is extensively used for marine propellers. In order to establish the constitutive relation of NAB under high strain rate condition, a new methodology was proposed to accurately identify the constitutive parameters of Johnson?Cook model in machining, combining SHPB tests, predictive cutting force model and orthogonal cutting experiment. Firstly, SHPB tests were carried out to obtain the true stress?strain curves at various temperatures and strain rates. Then, an objective function of the predictive and experimental flow stresses was set up, which put the identified parameters of SHPB tests as the initial value, and utilized the PSO algorithm to identify the constitutive parameters of NAB in machining. Finally, the identified parameters were verified to be sufficiently accurate by comparing the values of cutting forces calculated from the predictive model and FEM simulation.展开更多
With the development of society and the prosperity of Chinese literature,as a part of China’s soft power,Chinese chil dren literature is faced with the problem of international dissemination.The English version of Ca...With the development of society and the prosperity of Chinese literature,as a part of China’s soft power,Chinese chil dren literature is faced with the problem of international dissemination.The English version of Cao Wenxuan’s Bronze and Sunflow er won Hans Christian Andersen Award,the top award of children’s literature,which is a successful example of such dissemina tion.Therefore,the Chinese-English translation skills employed are worth studying.This paper aims to analyze the skills used to in the translation of short clauses,reiterative locution,simile,parallelism and dingzhen from the perspective of reception theory.It is found that by using such translation skills as omission,alliteration,repetition of prepositions and pronouns,and literal translation,the translator preserves and recreates the effect of the original text in ways that are more acceptable and idiomatic for the target reader.展开更多
To investigate the effects of thickness and grain size on mechanical and deformation properties of C5210 phosphor bronze thin sheets, samples with different grain sizes were obtained through annealing heat treatment a...To investigate the effects of thickness and grain size on mechanical and deformation properties of C5210 phosphor bronze thin sheets, samples with different grain sizes were obtained through annealing heat treatment at different temperatures; and then tensile tests of samples with different thicknesses and grain sizes were conducted at room temperature. The results show that yield strength increases with decreasing thickness from 800 to 50 μm, but work hardening exponent and total elongation decrease, and a modified model was proposed to describe the relation between yield strength and thickness; yield strength decreases as the grain size increases, but work hardening exponent shows an increasing trend, total elongation increases to a peak and then decreases. Fracture morphology of tensile specimens was observed by SEM, which indicates that all tensile specimens are ductile fracture. The dimple intensity increases as the specimen thickness increases but reduces with the specimen grain size increasing.展开更多
The corrosion behaviour of bronze alloy prepared by equal channel angular pressing(ECAP) was investigated in 3.5 wt. % Na Cl solution.Immersion corrosion tests and different electrochemical techniques were carried out...The corrosion behaviour of bronze alloy prepared by equal channel angular pressing(ECAP) was investigated in 3.5 wt. % Na Cl solution.Immersion corrosion tests and different electrochemical techniques were carried out. The results showed that ECAPed bronze samples exhibited higher corrosion resistance compared with the as-cast alloy and the passive current density decreased with increasing number of passes. Moreover,the morphology of alloys indicated that the corrosion damage on the surface of ECAPed bronze was smooth and uniform while the as-cast alloy suffered from selective corrosion.展开更多
Hydrogen molybdenum bronze (HxMoO3) can be electrodeposited on platinum and oxidized in two steps to the hydrogen molybdenum bronze with less amount of hydrogen HyMoO3 (y<x) and MoO3 when platinum electrode is cycl...Hydrogen molybdenum bronze (HxMoO3) can be electrodeposited on platinum and oxidized in two steps to the hydrogen molybdenum bronze with less amount of hydrogen HyMoO3 (y<x) and MoO3 when platinum electrode is cycled from -0.2 to 1.3V (vs. SCE) in 0.05 mol/L Na2MoO4 + 0.5 mol/L H2SO4 solution. During the formation of HxMoO3, the electrochemical reduction of molybdate existing in the form of polymolydate is reversible and is about a five-electron transfer reaction.展开更多
The effects of various amount of Y and La on the cast structure.the fluidity,the wearability and corrosion resistance of the high manganese aluminium bronze have been investigated.The results have shown that a proper ...The effects of various amount of Y and La on the cast structure.the fluidity,the wearability and corrosion resistance of the high manganese aluminium bronze have been investigated.The results have shown that a proper content of rare earth elements is able to refine the cast structure of the alloy,and furthermore to enhance its wearability and corrosion resistance.The reasons for these phenomena have also been discussed.展开更多
By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and t...By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and the bonding strength between the coating and the substrate were tested with a HV-1000 microhardness tester and a mechanical universal testing machine. The surface microstructure, cross-section and tensile fracture surface of the coating were observed with a scanning electron microscope(SEM). Correspondingly, the influences of the preheat treatment temperature of the bronze powder and the Al_2O_3 content on the coating performance were investigated. The results indicate that the hardness of bronze powders decreased and the coating deposition rate increased after the preheating treatment of the bronze powder. The Al_2O_3 content in the mixed powders contributed to the deformation of bronze powders during the spraying process. This trend resulted in varied performance of the coating.展开更多
Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 h...Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.展开更多
New polyoxometalate α-K 12H 3[Y(BW 11O 39) 2]·25H 2O was synthesized and treated by high temperature gaseous rare earth permeation to prepare tungsten bronze K 0.475WO 3. XRD, TG-DTA, XPS, ...New polyoxometalate α-K 12H 3[Y(BW 11O 39) 2]·25H 2O was synthesized and treated by high temperature gaseous rare earth permeation to prepare tungsten bronze K 0.475WO 3. XRD, TG-DTA, XPS, 183W-NMR,CV and AC impedance spectra were used to characterize the resulting material. The results of XPS indicate that La has permeated and diffused into the body of the sample and exists in the forms of binding with other components. The crystal structure parameters of K 0.475WO 3 were obtained by the analysis of XRD, which shows tetragonal crystal system with lattice parameters: a=12 28 nm, c=3.833 nm, V=578.48 nm -3. The conductivities calculated from the results of AC impedance spectra of the material increase with the increasing of temperature, which shows a semiconductor character.展开更多
The element diffusion process of Nb_3Sn superconductors by bronze route was studied using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The critical current of superconductors was...The element diffusion process of Nb_3Sn superconductors by bronze route was studied using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The critical current of superconductors was measured by four-point method. The results show that a diffusion layer has formed around the boundaries between the filaments and bronze matrix after 15 h heat treatment. The diffusion layer thickness keeps stable after heat treatment duration of 50~75 h. The stable and solid Nb 3 Sn layer is obtained in the sample after 100 h heat treatment. Excessive heat treatment would induce superconductivity degeneration because of superconductor grain coarsening. The characteristics of the element diffusion process were discussed. The diffusion of tin atom is the governing factor in diffusion. In this study, Nb_3_Sn superconductors with good superconducting property were fabricated successfully at 670 °C after 100h heat treatment.展开更多
Copper patinas are generally regarded as aesthetically pleasing and are supposed to protect copper against further corrosion. The preparation of artificial sulphate patina on bronzes has been realized by immersing the...Copper patinas are generally regarded as aesthetically pleasing and are supposed to protect copper against further corrosion. The preparation of artificial sulphate patina on bronzes has been realized by immersing the bronze into CuSO4 solution. The effect of immersion time on the formation of the patina has been investigated. The sulphate patina obtained with immersion time of 500 h in CuSO4 solution consists of fiat area and crystals. The flat area in the patina is mainly made of cuprite, whereas the crystals are mainly composed of brochantite. The electrochemical measurement of sulphate patina in simulated acid rain with pH 3.1 shows that the protective effectiveness of patina decreases with time and the dissolution of patina is the key factor leading to the degradation of patina. The investigation of the formation mechanism of sulphate patina shows that the cuprite layer forms on the surface of bronze in the initial patination. Then, crystal brochantite grows on the surface of cuprite by the oxidation of cuprite and the incorporation of CuSO4 solution.展开更多
The aim of the present investigation was to model the experimental conditions of tin bronze patination using full factorial experimental design. In this sense, a full factorial design approach was developed to model t...The aim of the present investigation was to model the experimental conditions of tin bronze patination using full factorial experimental design. In this sense, a full factorial design approach was developed to model the corrosion behavior of patinated tin bronze alloy in sulfate electrolyte. Three experimental factors (the immersion time in the chloride electrolyte, the potential limit for the anodic sweep Elim, and the potential scan rate) were chosen to identify the significant factor on the patina growth process at the bronze substrate. The experimental responses were the kinetic parameters extracted from the electro-chemical spectra (EIS) for eight different experiments. An equivalent electrical circuit containing an electrolyte resistance (Re), a double layer capacitance (CPEdl), a charge transfer resistance (Rt) and Gerischer element (G), was developed to model the patinated bronze corrosion process. The electro-chemical spectra (EIS) show that the corrosion process of the patinated bronze alloy occurred from a chemical reaction is followed by an electrochemical one. Analysis of the experimental responses showed that while the scan rate is the most influent factor for the corrosion potential (Ecorr), the electrolyte resistance (Re), and the double layer capacitance CPEdl variation, the potential limit is the significant factor for charge transfer resistance Rt, reciprocal of the admittance parameter Y0 and the effective transfer rate of the chemical reaction k variation.展开更多
The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness...The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness and pin-on-plate test showed that DLC coating had a greater hardness compared with NAB alloy.Besides,the decrease in friction coefficient from 0.2 for NAB substrate to 0.13 for the DLC-coated sample was observed.Potentiodynamic polarization and EIS results showed that the corrosion current density decreased from 2.5μA/cm2 for bare NAB alloy to 0.14μA/cm2 for DLC-coated sample in 3.5 wt.%NaCl solution.Moreover,the charge transfer resistance at the substrate−electrolyte interface increased from 3.3 kΩ·cm2 for NAB alloy to 120.8 kΩ·cm2 for DLC-coated alloy,which indicated an increase in corrosion resistance due to the DLC coating.展开更多
Electron beam welding experiment of titanium alloy to chromium bronze with a vanadium filler metal was carried out. Microstructure of the joint was observed by optical microscopy and scanning electron microscopy. Tens...Electron beam welding experiment of titanium alloy to chromium bronze with a vanadium filler metal was carried out. Microstructure of the joint was observed by optical microscopy and scanning electron microscopy. Tensile strength of the joint was evaluated. The fracture surface of the joint was also analyzed. The results showed that the addition of vanadium filler metal reduced the brittleness of joint by increasing the amount of vanadium-based solid solution in the weld. But the melting point of vanadium.filler metal was so high that large heat input was needed to completely melt the filler metal. Thus, a large amount of interfacial compounds were produced. The tensile strength of joint was 280 MPa with a brittle fracture mode.展开更多
The effect of microstructure of nickel-aluminum bronze alloy (NAB) on the corrosion behavior in artificial seawater is studied using linear polarization, impedance and electrochemical noise tests. The alloy was heat t...The effect of microstructure of nickel-aluminum bronze alloy (NAB) on the corrosion behavior in artificial seawater is studied using linear polarization, impedance and electrochemical noise tests. The alloy was heat treated in different heating cycles including quenching, normalizing and annealing. Microstructure of the specimens was characterized before and after heat treatment by optical microscopy and scanning electron microscopy. Results showed that the value of pearlite phase in the normalized alloy is much more than other specimens, leading to higher corrosion resistance. Polarization test showed that starting point of passivation in the polarization of the normalized alloy is lower than other specimens. The dissolution of Mn and Fe rich phases increased the Mn and Fe contents in solid solution, and this enhanced the passivation power of the surface of the alloy. The effect of the alloying elements was seen by a lower corrosion potential and an inflexion at around 280 mV (SCE) in the polarization curve, indicating the preferential dissolution of some elements beyond that potential. The polarization curve showed that the anodic polarization behavior of the alloy in the solution was essentially controlled by the intermetallic phases, mainly containing Cu. Two types of corrosion, pitting and selective corrosion, were observed in the specimens after being exposed to artificial seawater.展开更多
基金The National Ministry of Science and Technology Key Research and Development Program Funding Project(No.2017YFC1703903)Self-funded scientific research project of Guangxi Zhuang Autonomous Region Administration of Traditional Chinese Medicine(No.GZZC2020076)+3 种基金Key Laboratory of Guangxi Zhuang Autonomous Region,DNA Barcode Identification of Zhuang Medicine Dripping Avalokitesvara(No.GXZYKF2020-10)Guangxi Education Department Guangxi College Young and Middle-Aged Teachers Basic Ability Improvement Project(No.2023KY0301)General Project of First-Class Discipline Construction Project of Guangxi University of Traditional Chinese Medicine(No.GJKY2019XK043)Guangxi University of Traditional Chinese Medicine,Guangxi School of Traditional Chinese Medicine Inheritance and Innovation Team funded project-Traditional Chinese Medicine Master Huang Jinming Academic Thought and Clinical Treatment Inheritance and Development Research Center(No.04B22058V2).
文摘Zhuang medicine shallow needling has a long history and plays a significant role in Chinese medicine.With the development of medical treatment in China,there is a constant improvement in the use of needles.Bone needles have been modified to pottery needles,bronze needles,and electroacupuncture.From this long development history,there are some improvements in terms of material and technology.By analyzing and comparing the primitive and current acupuncture instruments used in China and their therapeutic effects,it can be seen that China’s medical treatment is constantly improving and will continue to improve with technology.
基金Projects (50804019, 51165021) supported by the National Natural Science Foundation of ChinaProject (0901ZTB009) supported by the Super Tutor Foundation from the Education Department of Gansu Province, China
文摘A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma sprayed on the 45# medium carbon steel substrate. The effect of rare earth Ce on the microstructures and Vickers hardness of the cast alloy and coatings were characterized by scanning electron microscopy, X-ray diffraction, electronic probe microanalysis, transmission electron microscopy and microhardness measurements. The results indicate that the hardness of both as-cast alloy and coating are enhanced by the addition of 0.6% Ce due to the refinement of κ phases which are well distributed in the matrix. The rapid solidification in the plasma spray processing retains Fe-supersaturated in the Al-bronze alloy coatings, which avoids the formation of eutectoid (α+γ2) phase and stacking faults are found in the coatings with Ce added, accordingly improves the mechanical properties.
基金Projects (51131005, 51171172, 50801056) supported by the National Natural Science Foundation of ChinaProject (Y4110074) supported by Natural Science Foundation of Zhejiang Province, China
文摘The atmospheric corrosion behavior of bronze under thin electrolyte layer (TEL) with different thicknesses was monitored using cathodic polarization curves, open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). Cathodic polarization result indicates that the cathodic limiting current density increases with decreasing the TEL thickness. EIS result shows that the corrosion rate increases with decreasing the TEL thickness at the initial stage because the corrosion is dominated by the cathodic process, whereas after long immersion time, the corrosion degree with the TEL thickness is in the sequence of 150 μm 〉 310 μm〉 10μm ≈ bulk solution 〉 57 μm. The measurements of OCP and EIS present in-situ electrochemical corrosion information and their results are in good agreement with that of physical characterizations.
文摘X-ray diffaction analysis(XRDA)data of the black or brown patina on the surfaces of eight kinds of bronze mirror samples show 4 or 5 broad diffuse peaks which corresponding to almost the same 20 angle, while their matixes does not.These results indicate that those diffuse peaks were produced by the SnO2, microcrystals of 3  ̄5 nm size contained in the black or brown patina.The matrix of unearthed black patina bronze mirror numbered 223, gives strong XRDA diffraction peaks, indicating that there are a large amounts of non-oxidized bronze alloy particles surrounded by SnO2,which shows that the black patinas are not wholly metallic oxides (mainly SnO2),there are also a lot of original alloys of different sizes in grain in the patina.The bright-field image of the black patina sample gives the same result.
基金Project(2014CB046704)supported by the National Basic Research Program of ChinaProject(2014BAB13B01)supported by the National Science and Technology Pillar Program of China
文摘The material of nickel aluminum bronze (NAB) presents superior properties such as high strength, excellent wear resistance and stress corrosion resistance and is extensively used for marine propellers. In order to establish the constitutive relation of NAB under high strain rate condition, a new methodology was proposed to accurately identify the constitutive parameters of Johnson?Cook model in machining, combining SHPB tests, predictive cutting force model and orthogonal cutting experiment. Firstly, SHPB tests were carried out to obtain the true stress?strain curves at various temperatures and strain rates. Then, an objective function of the predictive and experimental flow stresses was set up, which put the identified parameters of SHPB tests as the initial value, and utilized the PSO algorithm to identify the constitutive parameters of NAB in machining. Finally, the identified parameters were verified to be sufficiently accurate by comparing the values of cutting forces calculated from the predictive model and FEM simulation.
文摘With the development of society and the prosperity of Chinese literature,as a part of China’s soft power,Chinese chil dren literature is faced with the problem of international dissemination.The English version of Cao Wenxuan’s Bronze and Sunflow er won Hans Christian Andersen Award,the top award of children’s literature,which is a successful example of such dissemina tion.Therefore,the Chinese-English translation skills employed are worth studying.This paper aims to analyze the skills used to in the translation of short clauses,reiterative locution,simile,parallelism and dingzhen from the perspective of reception theory.It is found that by using such translation skills as omission,alliteration,repetition of prepositions and pronouns,and literal translation,the translator preserves and recreates the effect of the original text in ways that are more acceptable and idiomatic for the target reader.
文摘To investigate the effects of thickness and grain size on mechanical and deformation properties of C5210 phosphor bronze thin sheets, samples with different grain sizes were obtained through annealing heat treatment at different temperatures; and then tensile tests of samples with different thicknesses and grain sizes were conducted at room temperature. The results show that yield strength increases with decreasing thickness from 800 to 50 μm, but work hardening exponent and total elongation decrease, and a modified model was proposed to describe the relation between yield strength and thickness; yield strength decreases as the grain size increases, but work hardening exponent shows an increasing trend, total elongation increases to a peak and then decreases. Fracture morphology of tensile specimens was observed by SEM, which indicates that all tensile specimens are ductile fracture. The dimple intensity increases as the specimen thickness increases but reduces with the specimen grain size increasing.
文摘The corrosion behaviour of bronze alloy prepared by equal channel angular pressing(ECAP) was investigated in 3.5 wt. % Na Cl solution.Immersion corrosion tests and different electrochemical techniques were carried out. The results showed that ECAPed bronze samples exhibited higher corrosion resistance compared with the as-cast alloy and the passive current density decreased with increasing number of passes. Moreover,the morphology of alloys indicated that the corrosion damage on the surface of ECAPed bronze was smooth and uniform while the as-cast alloy suffered from selective corrosion.
文摘Hydrogen molybdenum bronze (HxMoO3) can be electrodeposited on platinum and oxidized in two steps to the hydrogen molybdenum bronze with less amount of hydrogen HyMoO3 (y<x) and MoO3 when platinum electrode is cycled from -0.2 to 1.3V (vs. SCE) in 0.05 mol/L Na2MoO4 + 0.5 mol/L H2SO4 solution. During the formation of HxMoO3, the electrochemical reduction of molybdate existing in the form of polymolydate is reversible and is about a five-electron transfer reaction.
文摘The effects of various amount of Y and La on the cast structure.the fluidity,the wearability and corrosion resistance of the high manganese aluminium bronze have been investigated.The results have shown that a proper content of rare earth elements is able to refine the cast structure of the alloy,and furthermore to enhance its wearability and corrosion resistance.The reasons for these phenomena have also been discussed.
基金financially supported by the National Key Research and Development Program of China(No.2016YFE0111400)the Program on Key Research Project of Gansu Province(No.17YF1WA159)the National High-end Foreign Experts Program of China(No.GTD20156200088)
文摘By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and the bonding strength between the coating and the substrate were tested with a HV-1000 microhardness tester and a mechanical universal testing machine. The surface microstructure, cross-section and tensile fracture surface of the coating were observed with a scanning electron microscope(SEM). Correspondingly, the influences of the preheat treatment temperature of the bronze powder and the Al_2O_3 content on the coating performance were investigated. The results indicate that the hardness of bronze powders decreased and the coating deposition rate increased after the preheating treatment of the bronze powder. The Al_2O_3 content in the mixed powders contributed to the deformation of bronze powders during the spraying process. This trend resulted in varied performance of the coating.
基金This work was financially supported by National Nature Science Foundation of China (No.50075026)and Education Ministry of China (No.[2000]65)and research funding from Guangdong Provincial High Education Department (Thousand, Hundred Ten Project).]
文摘Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.
文摘New polyoxometalate α-K 12H 3[Y(BW 11O 39) 2]·25H 2O was synthesized and treated by high temperature gaseous rare earth permeation to prepare tungsten bronze K 0.475WO 3. XRD, TG-DTA, XPS, 183W-NMR,CV and AC impedance spectra were used to characterize the resulting material. The results of XPS indicate that La has permeated and diffused into the body of the sample and exists in the forms of binding with other components. The crystal structure parameters of K 0.475WO 3 were obtained by the analysis of XRD, which shows tetragonal crystal system with lattice parameters: a=12 28 nm, c=3.833 nm, V=578.48 nm -3. The conductivities calculated from the results of AC impedance spectra of the material increase with the increasing of temperature, which shows a semiconductor character.
基金supported by the National Natural Science Foundation of China(No.50925726)
文摘The element diffusion process of Nb_3Sn superconductors by bronze route was studied using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The critical current of superconductors was measured by four-point method. The results show that a diffusion layer has formed around the boundaries between the filaments and bronze matrix after 15 h heat treatment. The diffusion layer thickness keeps stable after heat treatment duration of 50~75 h. The stable and solid Nb 3 Sn layer is obtained in the sample after 100 h heat treatment. Excessive heat treatment would induce superconductivity degeneration because of superconductor grain coarsening. The characteristics of the element diffusion process were discussed. The diffusion of tin atom is the governing factor in diffusion. In this study, Nb_3_Sn superconductors with good superconducting property were fabricated successfully at 670 °C after 100h heat treatment.
基金Funded by the Special Fund for Talent of Wuhan Instituteof Technologythe Fellowship for Junior Researchers fromPolitecnico di Torino and Regione Piemonte,Italy
文摘Copper patinas are generally regarded as aesthetically pleasing and are supposed to protect copper against further corrosion. The preparation of artificial sulphate patina on bronzes has been realized by immersing the bronze into CuSO4 solution. The effect of immersion time on the formation of the patina has been investigated. The sulphate patina obtained with immersion time of 500 h in CuSO4 solution consists of fiat area and crystals. The flat area in the patina is mainly made of cuprite, whereas the crystals are mainly composed of brochantite. The electrochemical measurement of sulphate patina in simulated acid rain with pH 3.1 shows that the protective effectiveness of patina decreases with time and the dissolution of patina is the key factor leading to the degradation of patina. The investigation of the formation mechanism of sulphate patina shows that the cuprite layer forms on the surface of bronze in the initial patination. Then, crystal brochantite grows on the surface of cuprite by the oxidation of cuprite and the incorporation of CuSO4 solution.
文摘The aim of the present investigation was to model the experimental conditions of tin bronze patination using full factorial experimental design. In this sense, a full factorial design approach was developed to model the corrosion behavior of patinated tin bronze alloy in sulfate electrolyte. Three experimental factors (the immersion time in the chloride electrolyte, the potential limit for the anodic sweep Elim, and the potential scan rate) were chosen to identify the significant factor on the patina growth process at the bronze substrate. The experimental responses were the kinetic parameters extracted from the electro-chemical spectra (EIS) for eight different experiments. An equivalent electrical circuit containing an electrolyte resistance (Re), a double layer capacitance (CPEdl), a charge transfer resistance (Rt) and Gerischer element (G), was developed to model the patinated bronze corrosion process. The electro-chemical spectra (EIS) show that the corrosion process of the patinated bronze alloy occurred from a chemical reaction is followed by an electrochemical one. Analysis of the experimental responses showed that while the scan rate is the most influent factor for the corrosion potential (Ecorr), the electrolyte resistance (Re), and the double layer capacitance CPEdl variation, the potential limit is the significant factor for charge transfer resistance Rt, reciprocal of the admittance parameter Y0 and the effective transfer rate of the chemical reaction k variation.
文摘The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness and pin-on-plate test showed that DLC coating had a greater hardness compared with NAB alloy.Besides,the decrease in friction coefficient from 0.2 for NAB substrate to 0.13 for the DLC-coated sample was observed.Potentiodynamic polarization and EIS results showed that the corrosion current density decreased from 2.5μA/cm2 for bare NAB alloy to 0.14μA/cm2 for DLC-coated sample in 3.5 wt.%NaCl solution.Moreover,the charge transfer resistance at the substrate−electrolyte interface increased from 3.3 kΩ·cm2 for NAB alloy to 120.8 kΩ·cm2 for DLC-coated alloy,which indicated an increase in corrosion resistance due to the DLC coating.
文摘Electron beam welding experiment of titanium alloy to chromium bronze with a vanadium filler metal was carried out. Microstructure of the joint was observed by optical microscopy and scanning electron microscopy. Tensile strength of the joint was evaluated. The fracture surface of the joint was also analyzed. The results showed that the addition of vanadium filler metal reduced the brittleness of joint by increasing the amount of vanadium-based solid solution in the weld. But the melting point of vanadium.filler metal was so high that large heat input was needed to completely melt the filler metal. Thus, a large amount of interfacial compounds were produced. The tensile strength of joint was 280 MPa with a brittle fracture mode.
文摘The effect of microstructure of nickel-aluminum bronze alloy (NAB) on the corrosion behavior in artificial seawater is studied using linear polarization, impedance and electrochemical noise tests. The alloy was heat treated in different heating cycles including quenching, normalizing and annealing. Microstructure of the specimens was characterized before and after heat treatment by optical microscopy and scanning electron microscopy. Results showed that the value of pearlite phase in the normalized alloy is much more than other specimens, leading to higher corrosion resistance. Polarization test showed that starting point of passivation in the polarization of the normalized alloy is lower than other specimens. The dissolution of Mn and Fe rich phases increased the Mn and Fe contents in solid solution, and this enhanced the passivation power of the surface of the alloy. The effect of the alloying elements was seen by a lower corrosion potential and an inflexion at around 280 mV (SCE) in the polarization curve, indicating the preferential dissolution of some elements beyond that potential. The polarization curve showed that the anodic polarization behavior of the alloy in the solution was essentially controlled by the intermetallic phases, mainly containing Cu. Two types of corrosion, pitting and selective corrosion, were observed in the specimens after being exposed to artificial seawater.