Copper/liquid microcapsule composite coatings with polyvinyl alcohol （PVA）, gelatin or methyl cellulose （MC） as shell materials were prepared by electrodeposition. The influence of shell materials on the corrosion...Copper/liquid microcapsule composite coatings with polyvinyl alcohol （PVA）, gelatin or methyl cellulose （MC） as shell materials were prepared by electrodeposition. The influence of shell materials on the corrosion resistance of the composite coatings in 0.1 M H2SO4 was investigated by means of electrochemical techniques, scanning electron microscopy （SEM）, and energy dispersion spectrometry （EDS）. The results show that the participation of microcapsules can enhance the corrosion resistance of the composite coatings compared with the traditional copper layer. Based on the analysis of electrochemical test results, the release ways of microcapsules were deduced. Gelatin and MC as the shell materials of microcapsules are easy to release quickly in the composite coating. On the contrary, the releasing speed of PVA microcapsules is relatively slow due to their characteristics.展开更多
Tungsten was plated on the surface of diamond by using thermal diffusion method.Different process parameters were employed to prepare the composites with tungsten,diamond and copper.The micro morphology of different s...Tungsten was plated on the surface of diamond by using thermal diffusion method.Different process parameters were employed to prepare the composites with tungsten,diamond and copper.The micro morphology of different samples was observed,and the thermal conductivity of samples was measured by laser flash method.The optimal process parameters for preparing diamond/copper composites with high thermal conductivity were investigated.The results indicated that plating tungsten on diamond could modify the interface bonding.When the diamond was plated for 60 min,the coating appeared intact,uniform and flat,and the thermal conductivity of the sample could reach as high as 486 W/(m·K).The integrity and uniformity were more important than thickness for the coating.When the tungsten-plated diamond was further annealed,the metallurgical bonding between the coating and the diamond was enhanced,and the thermal conductivity rose to 559 W/(m·K).展开更多
Copper coating was deposited on the surface of aluminum borate whisker by an electroless plating method.This method was used to modify the interfacial property of squeeze-casting aluminum borate whisker reinforced 606...Copper coating was deposited on the surface of aluminum borate whisker by an electroless plating method.This method was used to modify the interfacial property of squeeze-casting aluminum borate whisker reinforced 6061Al matrix composite.Interface observation indicates that the spinel reaction(MgAl2O4) is hindered by the copper coating,and the difference in interfacial reaction degree affects the tensile property and aging behavior of the composite.For the composite with less spinel reaction(MgAl2O4),its peak-aging process are postponed due to less depletion of magnesium.On the fracture surface of copper-coated composite dimples and fractures of whiskers are more,but on the fracture surface of uncoated composite pull-out of whiskers are more than that on the coated one.In uncoated composite the fracture generally originates from the near-interface-region.展开更多
The different copper coatings with thickness varying from 0.3μm to 1.5μm were deposited on carbon fibers using either electroless plating or electroplating method. The coated fibers were chopped and composites were ...The different copper coatings with thickness varying from 0.3μm to 1.5μm were deposited on carbon fibers using either electroless plating or electroplating method. The coated fibers were chopped and composites were fabricated with melting aluminum at 700℃. The effect of the copper layer on the microstructure in the system was discussed. The results show that the copper layer has fully reacted with aluminum matrix, and the intermetallic compound CuAl2 forms through SEM observation and XRD, EDX analysis. The results of tensile tests indicate that composites fabricated using carbon fibers with 0.7-1.1μm copper coating perform best and the composites turn to more brittle as the thickness of copper coating increases. The fracture surface observation exhibits good interface bonding and ductility of the matrix alloy when the thickness of copper coating is about 0.7-1.1μm.展开更多
Molybdenum powders with a diameter of approximately 3 μn were coated with copper using the electroless plating technique in the pH 12.5-13 and temperature range of 55-75℃. The optimization of the electroless copper ...Molybdenum powders with a diameter of approximately 3 μn were coated with copper using the electroless plating technique in the pH 12.5-13 and temperature range of 55-75℃. The optimization of the electroless copper bath was evaluated through the combination of process parameters like pH and temperature. The optimized values ofpH and temperature were found to be 12.5 and 60℃, respectively, which attributes to the bright maroon color of the coating with an increase in weight of 46%. The uncoated and coated powders were subjected to microstructural studies using scanning electron microscope （SEM） and the phases were analyzed using X-my diffrction （XRD）. An attempt was made to understand the growth mechanism of the coating. The diffusion-shrinkage autocatalytic model was suggested for copper growth on the molybdenum surface.展开更多
Copper-coated aluminum wires exhibit good electrical conductivity, high thermal conductivity, low contact resistance of copper and low density, and provide economic advantages over aluminum. However, there are some pr...Copper-coated aluminum wires exhibit good electrical conductivity, high thermal conductivity, low contact resistance of copper and low density, and provide economic advantages over aluminum. However, there are some problems in the manufacring processes of hot-dip copper-coated aluminum wires, such as the difficulties in controlling coating process. In this work, the hot-dip copper-coating method of aluminum wires was investigated for producing copper-coated aluminum wire composites. The interface microstructure between the aluminum wire and the copper coating layer was analyzed by scanning electron microscopy （SEM） and energy-dispersive X-ray spec- trometry （EDS）. Five different fluxing agents were tested. Experimental results show that appropriate conditions for the hot-dip process are determined as the liquid copper temperature of 1085℃ and the treatment time less than 1 s. A success in hot-dip copper-coated aluminum wires is achieved by hot-dipping a low-melting-point metal into a high-melting-point metal liquid, which is significant for the further devel- opment and application of copper-coated aluminum wire composites.展开更多
Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the s...Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the shape of copper grains transformed from oval or round to polyhedron, the growth mode of copper grains transformed from columnar growth to gradual change in size, and the preferred ori- entation of copper grains transformed from （220） to （200）. Analyzing the variation of cathodic overpotential, it was found that the cathodic overpotential tended to remain tmchanged when copper plane （220） grew in the process of electrodepositing pure copper, while it tended to decrease with time when copper plane （200） grew in the process of co-deposition. It was inferred that copper plane （200） was propitious to the deposition of submicron diamonds.展开更多
基金supported by the National Natural Science Foundation of China (No. 50771010)
文摘Copper/liquid microcapsule composite coatings with polyvinyl alcohol （PVA）, gelatin or methyl cellulose （MC） as shell materials were prepared by electrodeposition. The influence of shell materials on the corrosion resistance of the composite coatings in 0.1 M H2SO4 was investigated by means of electrochemical techniques, scanning electron microscopy （SEM）, and energy dispersion spectrometry （EDS）. The results show that the participation of microcapsules can enhance the corrosion resistance of the composite coatings compared with the traditional copper layer. Based on the analysis of electrochemical test results, the release ways of microcapsules were deduced. Gelatin and MC as the shell materials of microcapsules are easy to release quickly in the composite coating. On the contrary, the releasing speed of PVA microcapsules is relatively slow due to their characteristics.
基金supported by the National Natural Science Foundation of China(No.11802125)。
文摘Tungsten was plated on the surface of diamond by using thermal diffusion method.Different process parameters were employed to prepare the composites with tungsten,diamond and copper.The micro morphology of different samples was observed,and the thermal conductivity of samples was measured by laser flash method.The optimal process parameters for preparing diamond/copper composites with high thermal conductivity were investigated.The results indicated that plating tungsten on diamond could modify the interface bonding.When the diamond was plated for 60 min,the coating appeared intact,uniform and flat,and the thermal conductivity of the sample could reach as high as 486 W/(m·K).The integrity and uniformity were more important than thickness for the coating.When the tungsten-plated diamond was further annealed,the metallurgical bonding between the coating and the diamond was enhanced,and the thermal conductivity rose to 559 W/(m·K).
文摘Copper coating was deposited on the surface of aluminum borate whisker by an electroless plating method.This method was used to modify the interfacial property of squeeze-casting aluminum borate whisker reinforced 6061Al matrix composite.Interface observation indicates that the spinel reaction(MgAl2O4) is hindered by the copper coating,and the difference in interfacial reaction degree affects the tensile property and aging behavior of the composite.For the composite with less spinel reaction(MgAl2O4),its peak-aging process are postponed due to less depletion of magnesium.On the fracture surface of copper-coated composite dimples and fractures of whiskers are more,but on the fracture surface of uncoated composite pull-out of whiskers are more than that on the coated one.In uncoated composite the fracture generally originates from the near-interface-region.
基金Project(204AA335010) supported by the National High-Tech Research and Development Program of China
文摘The different copper coatings with thickness varying from 0.3μm to 1.5μm were deposited on carbon fibers using either electroless plating or electroplating method. The coated fibers were chopped and composites were fabricated with melting aluminum at 700℃. The effect of the copper layer on the microstructure in the system was discussed. The results show that the copper layer has fully reacted with aluminum matrix, and the intermetallic compound CuAl2 forms through SEM observation and XRD, EDX analysis. The results of tensile tests indicate that composites fabricated using carbon fibers with 0.7-1.1μm copper coating perform best and the composites turn to more brittle as the thickness of copper coating increases. The fracture surface observation exhibits good interface bonding and ductility of the matrix alloy when the thickness of copper coating is about 0.7-1.1μm.
文摘Molybdenum powders with a diameter of approximately 3 μn were coated with copper using the electroless plating technique in the pH 12.5-13 and temperature range of 55-75℃. The optimization of the electroless copper bath was evaluated through the combination of process parameters like pH and temperature. The optimized values ofpH and temperature were found to be 12.5 and 60℃, respectively, which attributes to the bright maroon color of the coating with an increase in weight of 46%. The uncoated and coated powders were subjected to microstructural studies using scanning electron microscope （SEM） and the phases were analyzed using X-my diffrction （XRD）. An attempt was made to understand the growth mechanism of the coating. The diffusion-shrinkage autocatalytic model was suggested for copper growth on the molybdenum surface.
基金financially supported by the Research Fund for the Doctoral Program of Higher Education of China(No.20100006120020)
文摘Copper-coated aluminum wires exhibit good electrical conductivity, high thermal conductivity, low contact resistance of copper and low density, and provide economic advantages over aluminum. However, there are some problems in the manufacring processes of hot-dip copper-coated aluminum wires, such as the difficulties in controlling coating process. In this work, the hot-dip copper-coating method of aluminum wires was investigated for producing copper-coated aluminum wire composites. The interface microstructure between the aluminum wire and the copper coating layer was analyzed by scanning electron microscopy （SEM） and energy-dispersive X-ray spec- trometry （EDS）. Five different fluxing agents were tested. Experimental results show that appropriate conditions for the hot-dip process are determined as the liquid copper temperature of 1085℃ and the treatment time less than 1 s. A success in hot-dip copper-coated aluminum wires is achieved by hot-dipping a low-melting-point metal into a high-melting-point metal liquid, which is significant for the further devel- opment and application of copper-coated aluminum wire composites.
文摘Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the shape of copper grains transformed from oval or round to polyhedron, the growth mode of copper grains transformed from columnar growth to gradual change in size, and the preferred ori- entation of copper grains transformed from （220） to （200）. Analyzing the variation of cathodic overpotential, it was found that the cathodic overpotential tended to remain tmchanged when copper plane （220） grew in the process of electrodepositing pure copper, while it tended to decrease with time when copper plane （200） grew in the process of co-deposition. It was inferred that copper plane （200） was propitious to the deposition of submicron diamonds.
