Corrosion of reinforced concrete structures is a serious problem in ocean engineering. As an orientation of study, anticorrosion coating technique is developed and widely applied, but many problems need to be solved. ...Corrosion of reinforced concrete structures is a serious problem in ocean engineering. As an orientation of study, anticorrosion coating technique is developed and widely applied, but many problems need to be solved. LSW-2 type anticorrosion coating for maritime reinforced concrete structures is characterized by sea water resistance, salt fog resistance, moisture and heal resistance as well as impermeability to chlorions. The new type coating can be applied to wet concrete surface by conventional construction technique. It is a breakthrough in solving the above mentioned problem. The paper mainly introduces the test results, the property indices, coating procedure, construction technique and economic benefit of Ihe coating.展开更多
The effect of arc sprayed times, which are quantitatively described by the volume fraction of coatings, on the mechanical properties of type 316 steel, have been undertaken in the present work. Al wires were utilized ...The effect of arc sprayed times, which are quantitatively described by the volume fraction of coatings, on the mechanical properties of type 316 steel, have been undertaken in the present work. Al wires were utilized as coatings materials. Tensile tests were carried out in the temperature range of Portevin-Le Chatelier (PLC) effect It has been found that grains at edges and corners of the 316 steel specimens have been dramatically constricted by grit blasting and spraying. Grit blasting has been found to exert a shot-peening effect on the mechanical properties of 316 steel specimens. Coatings with lower values of coating volume fraction strengthen the coated specimens in the very similar way as blasting. While if the volume fraction of coating, (Vv)c, exceeds a critical value, (VV)K, softens the specimens. Specimens with low values of (Vv)c, have high values of flow stress, as well as higher values of work-hardening coefficient, Calculations based on the experimental results show that the high thickness coatings have relatively lower contribution to the mechanical properties of specimens.展开更多
The aim of this work is to understand the effect of a thin coating on the compressive properties of the porous metal.In our work,the uniaxial compressive behavior and the energy absorption properties of the lotus-type...The aim of this work is to understand the effect of a thin coating on the compressive properties of the porous metal.In our work,the uniaxial compressive behavior and the energy absorption properties of the lotus-type porous copper deposited with Ni coatings with thickness from 3.9 to 4.8μm on pore walls were investigated.It is found that the Ni coating on pore walls shows a clear enhancement effect on compressive properties of the lotus-type porous copper,in which the specific yield strength and the energy absorption per unit mass at densification strain increase from 5.27 to 7.31 MPa cm3 g-1 and from 11.50 to 18.21 J g-1 with the Ni coating,respectively.Furthermore,the enhancement appears to be insensitive to the coating thickness.It is considered that the resistance of the interface between the nickel coating and the pore walls to the dislocation slip plays an important role in the improvement on compressive properties of the lotus-type porous copper.展开更多
In this paper, we describe the synthesis of gold coated spindle-type iron nanoparticles and its surface modification by a thiolated fluorescently-labelled polyethylene glycol (PEG) polymer. A forced hydrolysis of ferr...In this paper, we describe the synthesis of gold coated spindle-type iron nanoparticles and its surface modification by a thiolated fluorescently-labelled polyethylene glycol (PEG) polymer. A forced hydrolysis of ferric salts in the presence of phosphate ions was used to produce α-Fe2O3 spindle-type particles. The oxide powders were first reduced to α-iron under high temperature and controlled dihydrogen atmosphere. Then, the resulting magnetic spindle-type particles were covered by a shell of gold. The formation of the core@shell structure was driven by a redox-transmetalation reaction between iron(0) at the surface of particles and a gold(III) salt. Protected against oxidation, the Fe@Au core@shell nanoparticles were then grafted with a water soluble fluorescent-PEG-thiol. TEM, XRD, EDX and measurements of magnetic properties of particles confirm 1) the conversion of hematite into iron and 2) their subsequent surface protection with a gold shell. Furthermore, the functionalization of the gold nanoparticle surface with a PEG carrying a fluorescent dye was unambiguously attested by confocal laser scanning microscopy.展开更多
In this paper,acoustic emission（AE） and digital image correlation methods were applied to monitor interface cracking in thermal barrier coatings under compression.The interface failure process can be identifie via i...In this paper,acoustic emission（AE） and digital image correlation methods were applied to monitor interface cracking in thermal barrier coatings under compression.The interface failure process can be identifie via its AE features,including buckling,delamination incubation and spallation.According to the Fourier transformation of AE signals,there arefourdifferentfailuremodes：surfaceverticalcracks,opening and sliding interface cracks,and substrate deformation.The characteristic frequency of AE signals from surface vertical cracks is 0.21 MHz,whilst that of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.The energy released of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.Based on the energy released from cracking and the AE signals,a relationship is established between the interface crack length and AE parameters,which is in good agreement with experimental results.展开更多
The thermomechanical fatigue behaviour of different high temperature alloys has been investigated and is under investigation respectively. The creep-fatigue behaviour of heat resistant steels was investigated by long-...The thermomechanical fatigue behaviour of different high temperature alloys has been investigated and is under investigation respectively. The creep-fatigue behaviour of heat resistant steels was investigated by long-term service-type strain cycling tests simulating thermomechanical fatigue (TMF-) loading conditions at the heated surface of e.g. turbine rotors. Single-stage as well as three-stage cycles leads to similar results at the application of the damage accumulation rule. Life prediction which simulates typical combinations of cold starts, warm starts and hot starts has been established successfully for isothermal service-type loading and will be exceeded for thermomechanical loading. Long-term thermomechanical fatigue testing of Thermal Barrier Coating systems show typical delamination damage. An advanced TMF cruciform testing system enables complex multiaxial loading.展开更多
文摘Corrosion of reinforced concrete structures is a serious problem in ocean engineering. As an orientation of study, anticorrosion coating technique is developed and widely applied, but many problems need to be solved. LSW-2 type anticorrosion coating for maritime reinforced concrete structures is characterized by sea water resistance, salt fog resistance, moisture and heal resistance as well as impermeability to chlorions. The new type coating can be applied to wet concrete surface by conventional construction technique. It is a breakthrough in solving the above mentioned problem. The paper mainly introduces the test results, the property indices, coating procedure, construction technique and economic benefit of Ihe coating.
文摘The effect of arc sprayed times, which are quantitatively described by the volume fraction of coatings, on the mechanical properties of type 316 steel, have been undertaken in the present work. Al wires were utilized as coatings materials. Tensile tests were carried out in the temperature range of Portevin-Le Chatelier (PLC) effect It has been found that grains at edges and corners of the 316 steel specimens have been dramatically constricted by grit blasting and spraying. Grit blasting has been found to exert a shot-peening effect on the mechanical properties of 316 steel specimens. Coatings with lower values of coating volume fraction strengthen the coated specimens in the very similar way as blasting. While if the volume fraction of coating, (Vv)c, exceeds a critical value, (VV)K, softens the specimens. Specimens with low values of (Vv)c, have high values of flow stress, as well as higher values of work-hardening coefficient, Calculations based on the experimental results show that the high thickness coatings have relatively lower contribution to the mechanical properties of specimens.
基金supported financially by the National Science and Technology Project(No.2017ZX02201001)the National Natural Science Foundation of China(No.51772193).
文摘The aim of this work is to understand the effect of a thin coating on the compressive properties of the porous metal.In our work,the uniaxial compressive behavior and the energy absorption properties of the lotus-type porous copper deposited with Ni coatings with thickness from 3.9 to 4.8μm on pore walls were investigated.It is found that the Ni coating on pore walls shows a clear enhancement effect on compressive properties of the lotus-type porous copper,in which the specific yield strength and the energy absorption per unit mass at densification strain increase from 5.27 to 7.31 MPa cm3 g-1 and from 11.50 to 18.21 J g-1 with the Ni coating,respectively.Furthermore,the enhancement appears to be insensitive to the coating thickness.It is considered that the resistance of the interface between the nickel coating and the pore walls to the dislocation slip plays an important role in the improvement on compressive properties of the lotus-type porous copper.
文摘In this paper, we describe the synthesis of gold coated spindle-type iron nanoparticles and its surface modification by a thiolated fluorescently-labelled polyethylene glycol (PEG) polymer. A forced hydrolysis of ferric salts in the presence of phosphate ions was used to produce α-Fe2O3 spindle-type particles. The oxide powders were first reduced to α-iron under high temperature and controlled dihydrogen atmosphere. Then, the resulting magnetic spindle-type particles were covered by a shell of gold. The formation of the core@shell structure was driven by a redox-transmetalation reaction between iron(0) at the surface of particles and a gold(III) salt. Protected against oxidation, the Fe@Au core@shell nanoparticles were then grafted with a water soluble fluorescent-PEG-thiol. TEM, XRD, EDX and measurements of magnetic properties of particles confirm 1) the conversion of hematite into iron and 2) their subsequent surface protection with a gold shell. Furthermore, the functionalization of the gold nanoparticle surface with a PEG carrying a fluorescent dye was unambiguously attested by confocal laser scanning microscopy.
基金supported by the National Natural Science Foundation of China (Grants 11472237,11002122,51172192,and 11272275)
文摘In this paper,acoustic emission（AE） and digital image correlation methods were applied to monitor interface cracking in thermal barrier coatings under compression.The interface failure process can be identifie via its AE features,including buckling,delamination incubation and spallation.According to the Fourier transformation of AE signals,there arefourdifferentfailuremodes：surfaceverticalcracks,opening and sliding interface cracks,and substrate deformation.The characteristic frequency of AE signals from surface vertical cracks is 0.21 MHz,whilst that of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.The energy released of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.Based on the energy released from cracking and the AE signals,a relationship is established between the interface crack length and AE parameters,which is in good agreement with experimental results.
基金supported by the Deutsche Forschungsgemeinschaft(DFG),Project No.BE1890,16-1the Forschungs-vereinigung der Arbeitsgemeinschaften der Eisen und Metall verarbeitenden Industrie e.V.(AVIF),Project No.A166+1 种基金the FKM Forschungskuratorium Maschinenbau e.V.Project No.052510the Arbeitsgemeinschaft industrieller Forschungsvereinigungen(AiF)and the VDEh-Gesellschaft zur Forderung der Eisenforschung mbH,Project No.11200 N.
文摘The thermomechanical fatigue behaviour of different high temperature alloys has been investigated and is under investigation respectively. The creep-fatigue behaviour of heat resistant steels was investigated by long-term service-type strain cycling tests simulating thermomechanical fatigue (TMF-) loading conditions at the heated surface of e.g. turbine rotors. Single-stage as well as three-stage cycles leads to similar results at the application of the damage accumulation rule. Life prediction which simulates typical combinations of cold starts, warm starts and hot starts has been established successfully for isothermal service-type loading and will be exceeded for thermomechanical loading. Long-term thermomechanical fatigue testing of Thermal Barrier Coating systems show typical delamination damage. An advanced TMF cruciform testing system enables complex multiaxial loading.
