Over the past years, great achievements have been made in the development of coating technologies for surface improvement of aluminum alloys. Despite these achievements, the role in the market strongly depends on the ...Over the past years, great achievements have been made in the development of coating technologies for surface improvement of aluminum alloys. Despite these achievements, the role in the market strongly depends on the ability of surface coating technology under technical and economic considerations to meet the increased demands for heavy tribological applications of aluminum alloys. Microplasma oxidation (MPO) technology has recently been studied as a novel and effective means to provide thick and hard ceramic coating with improved properties such as excellent load-bearing and wear resistance properties on aluminum alloys. The present work covers the evaluation of the performances of current single and duplex coatings combining MPO, physical vapor deposition (PVD), and plasma assisted chemical vapor deposition (PACVD) coatings on aluminum alloys. It suggests that the MPO coating is a promising candidate for design engineers to apply aluminum alloys to heavy load-bearing applications. The prospective future for the research on MPO coatings is introduced as well.展开更多
Aluminum foils having thicknesses of 10-20 μm are commonly employed as current collectors for cathode electrodes in Li-ion batteries. The effects of the surface morphology of the foil on battery performance were inve...Aluminum foils having thicknesses of 10-20 μm are commonly employed as current collectors for cathode electrodes in Li-ion batteries. The effects of the surface morphology of the foil on battery performance were investigated by using a foil with roughened surface by chemical etching and a plain foil with smooth surface on both sides. For high-conductivity LiCoO2 active materials with large particle size, there are no significant differences in battery performance between the two types of foils. But for low-conductivity LiFePO4 active materials with small particle size, high-rate discharge properties are significantly different. The possibility shows that optimizing both the surface morphology of the aluminum foil and particle size of active material leads to improvement of the battery performance.展开更多
In order to improve the bonding strength between piston alloys and cast iron ring of aluminum piston with reinforced cast iron ring,the different methods of the surface treatments(shot blasting and sand blasting) to t...In order to improve the bonding strength between piston alloys and cast iron ring of aluminum piston with reinforced cast iron ring,the different methods of the surface treatments(shot blasting and sand blasting) to the cast iron ring are experimented.The optical micrograph shows that an intermetallic layer and a ligulate shaped structure are formed between piston alloys and cast iron base ring.After sand blasting treatment,the ring surface is non-metal shiny,matte-like and has no obvious pits.The intermetallic layer thickness formed between piston alloys and cast iron is thinner and more equally distributed after sand blasting to the ring.The content of the graphite distributed the interfacial zone after the shot blasting treatment is little.With the increase of time by sand blasting,the hardness starts to slightly descend.The bonding strength of the sample by sand blasting is obviously higher than that by shot blasting and increases from 9.32 MPa to 19.53 MPa.展开更多
The process of laser cladding procedure has a closely relation with properties of composite cladding layers. When the input power of laser is certain, the low scanning velocity makes substrate with ahead of laser beam...The process of laser cladding procedure has a closely relation with properties of composite cladding layers. When the input power of laser is certain, the low scanning velocity makes substrate with ahead of laser beam heat for a long time, which worsens interface bonding from surface oxidized; much higher scanning velocity makes the powder’s synthesis near substrate uncompleted fully, the remained powder in interface worsens interface bonding as well. Otherwise, the input specific energy of laser influences on in-situ synthesis courses. If the input energy is lower, the synthesis is not completed fully. In addition, the low temperature effects not only restrict the dispersion of particle leading uneven distribution of TiC, but also form some regions consisting of Al and Al 3Ti.展开更多
The effect of different surface treatments on the bonding strength of composite plates was investigated under the conditions of 400℃ and reduction ratio of 45%.Results show that the wire brush grinding treatment can ...The effect of different surface treatments on the bonding strength of composite plates was investigated under the conditions of 400℃ and reduction ratio of 45%.Results show that the wire brush grinding treatment can only eliminate the oxide film on the plate surface,but it can hardly produce a hard layer on the plate surface.The bonding effect depends on the element diffusion promoted by the close contact between the metals on both sides of the interface.After anodic oxidation,there is a hard layer on the metal surface,and the hard layer broken during the rolling process forms a mechanical occlusion at the bonding interface.However,the hard layer cannot form an effective combination with the metal at the interface,and the bonding can only occur in the fresh metal bonding area at the crack of the hard layer.The acid-alkali washing treatment can completely remove the hard layer on the surface of both alloys without increasing the surface roughness of the plate,and the metal on both sides of the interface is more closely bonded during the rolling process.The optimal bonding strength can be obtained by surface treatment of acid-alkali washing for the aluminum-magnesium hot-rolled bonding.展开更多
文摘Over the past years, great achievements have been made in the development of coating technologies for surface improvement of aluminum alloys. Despite these achievements, the role in the market strongly depends on the ability of surface coating technology under technical and economic considerations to meet the increased demands for heavy tribological applications of aluminum alloys. Microplasma oxidation (MPO) technology has recently been studied as a novel and effective means to provide thick and hard ceramic coating with improved properties such as excellent load-bearing and wear resistance properties on aluminum alloys. The present work covers the evaluation of the performances of current single and duplex coatings combining MPO, physical vapor deposition (PVD), and plasma assisted chemical vapor deposition (PACVD) coatings on aluminum alloys. It suggests that the MPO coating is a promising candidate for design engineers to apply aluminum alloys to heavy load-bearing applications. The prospective future for the research on MPO coatings is introduced as well.
文摘Aluminum foils having thicknesses of 10-20 μm are commonly employed as current collectors for cathode electrodes in Li-ion batteries. The effects of the surface morphology of the foil on battery performance were investigated by using a foil with roughened surface by chemical etching and a plain foil with smooth surface on both sides. For high-conductivity LiCoO2 active materials with large particle size, there are no significant differences in battery performance between the two types of foils. But for low-conductivity LiFePO4 active materials with small particle size, high-rate discharge properties are significantly different. The possibility shows that optimizing both the surface morphology of the aluminum foil and particle size of active material leads to improvement of the battery performance.
基金Project(51101109)supported by the National Natural Science Foundation of China
文摘In order to improve the bonding strength between piston alloys and cast iron ring of aluminum piston with reinforced cast iron ring,the different methods of the surface treatments(shot blasting and sand blasting) to the cast iron ring are experimented.The optical micrograph shows that an intermetallic layer and a ligulate shaped structure are formed between piston alloys and cast iron base ring.After sand blasting treatment,the ring surface is non-metal shiny,matte-like and has no obvious pits.The intermetallic layer thickness formed between piston alloys and cast iron is thinner and more equally distributed after sand blasting to the ring.The content of the graphite distributed the interfacial zone after the shot blasting treatment is little.With the increase of time by sand blasting,the hardness starts to slightly descend.The bonding strength of the sample by sand blasting is obviously higher than that by shot blasting and increases from 9.32 MPa to 19.53 MPa.
基金National Natural Science Foundation ofChina (No.5 98710 3 8)
文摘The process of laser cladding procedure has a closely relation with properties of composite cladding layers. When the input power of laser is certain, the low scanning velocity makes substrate with ahead of laser beam heat for a long time, which worsens interface bonding from surface oxidized; much higher scanning velocity makes the powder’s synthesis near substrate uncompleted fully, the remained powder in interface worsens interface bonding as well. Otherwise, the input specific energy of laser influences on in-situ synthesis courses. If the input energy is lower, the synthesis is not completed fully. In addition, the low temperature effects not only restrict the dispersion of particle leading uneven distribution of TiC, but also form some regions consisting of Al and Al 3Ti.
基金National Key Research and Development Program(2018YFA0707300)National Natural Science Foundation of China(52075472)Hebei Natural Science Foundation(E2023203129)。
文摘The effect of different surface treatments on the bonding strength of composite plates was investigated under the conditions of 400℃ and reduction ratio of 45%.Results show that the wire brush grinding treatment can only eliminate the oxide film on the plate surface,but it can hardly produce a hard layer on the plate surface.The bonding effect depends on the element diffusion promoted by the close contact between the metals on both sides of the interface.After anodic oxidation,there is a hard layer on the metal surface,and the hard layer broken during the rolling process forms a mechanical occlusion at the bonding interface.However,the hard layer cannot form an effective combination with the metal at the interface,and the bonding can only occur in the fresh metal bonding area at the crack of the hard layer.The acid-alkali washing treatment can completely remove the hard layer on the surface of both alloys without increasing the surface roughness of the plate,and the metal on both sides of the interface is more closely bonded during the rolling process.The optimal bonding strength can be obtained by surface treatment of acid-alkali washing for the aluminum-magnesium hot-rolled bonding.
