The wear behaviour of composite coatings is related to the nature of embedded particles.The effects of particle size on the wear behaviour of composite coatings are analyzed.Electroless nickel composite coatings conta...The wear behaviour of composite coatings is related to the nature of embedded particles.The effects of particle size on the wear behaviour of composite coatings are analyzed.Electroless nickel composite coatings containing diamond particles with the sizes in the range of 0—0.5,0.5—1,1—2μm are prepared.The surface morphology of diamond particles and composite coatings are observed by scanning electron microscopy(SEM).The wear tests of composite coatings are comparatively evaluated by sliding against a cemented tungsten carbide ball.The 3D morphology of worn scar is evaluated by using a 3Dprofiler.The results show that the hardness and wear resistance of composite coatings can increase with the increase of particle sizes.The mixture mechanism of adhesive wear and abrasive wear turn into single abrasive wear with the increase of particle sizes as well.The transformation of wear behaviour is mainly attributed to particle roles during wear process.展开更多
Si-based materials have been extensively studied because of their high theoretical capacity,low working potential,and abundant reserves,but serious initial irreversible capacity loss and poor cyclic performance result...Si-based materials have been extensively studied because of their high theoretical capacity,low working potential,and abundant reserves,but serious initial irreversible capacity loss and poor cyclic performance resulting from large volume change of Si during lithiation and delithiation processes restrict their widespread application.Herein,we report the preparation of multi-shell coated Si(DS-Si)nanocomposites by in-situ electroless deposition method using Si granules as the active materials and copper sulfate as Cu sources.The ratio of Si and Cu was readily tuned by varying the concentration of copper sulfate.The multi-shell(Cu@CuxSi/SiO2)coating on Si surface promotes the formation of robust and dense SEI films and the transportation of electron.Thus,the obtained DS-Si composites exhibit an initial coulombic efficiency of 86.2%,a capacity of 1636 mAh g^-1 after 100 discharge-charge cycles at 840 mA g^-1,and an average charge capacity of 1493 mAh g^-1 at 4200 mA g^-1.This study provides a low-cost and large-scale approach to the preparation of nanostructured Si-metal composites anodes with good electrochemical performance for lithium ion batteries.展开更多
The weak interface bonding of metal matrix reinforced by carbon fibers is the central problem of fabricating such composites. Depositing copper coating on carbon fibers is regarded as a feasible method to solve the pr...The weak interface bonding of metal matrix reinforced by carbon fibers is the central problem of fabricating such composites. Depositing copper coating on carbon fibers is regarded as a feasible method to solve the problem. In this paper, copper coating has been deposited on the fibers through both electroless deposition and electroplating methods. Two kinds of complexing agents and two stabilizing agents are taken during the electroless plating process. The solution is stable, and little extraneous component is absorbed on the surface. After adding additive agents and increasing the concentration of H2SO4 to the acid cupric sulfate electrolyte, the "black core" during usual electroplating process is avoided. The quality of copper coating is analyzed using SEM and XRD, etc.展开更多
基金Supported by the National Natural Science Foundation of China(51175260)the Fundamental Research Funds for the Central Universities(NP2012506)the Open Fund of Jiangsu Province Key Laboratory for Materials Tribology(kjsmcx0901)
文摘The wear behaviour of composite coatings is related to the nature of embedded particles.The effects of particle size on the wear behaviour of composite coatings are analyzed.Electroless nickel composite coatings containing diamond particles with the sizes in the range of 0—0.5,0.5—1,1—2μm are prepared.The surface morphology of diamond particles and composite coatings are observed by scanning electron microscopy(SEM).The wear tests of composite coatings are comparatively evaluated by sliding against a cemented tungsten carbide ball.The 3D morphology of worn scar is evaluated by using a 3Dprofiler.The results show that the hardness and wear resistance of composite coatings can increase with the increase of particle sizes.The mixture mechanism of adhesive wear and abrasive wear turn into single abrasive wear with the increase of particle sizes as well.The transformation of wear behaviour is mainly attributed to particle roles during wear process.
基金supported by the China Postdoctoral Science Foundation(2018M632575)the National Natural Science Foundation of China(21875197 and 21621091)the National Key Research and Development of China(2016YFB0100202)。
文摘Si-based materials have been extensively studied because of their high theoretical capacity,low working potential,and abundant reserves,but serious initial irreversible capacity loss and poor cyclic performance resulting from large volume change of Si during lithiation and delithiation processes restrict their widespread application.Herein,we report the preparation of multi-shell coated Si(DS-Si)nanocomposites by in-situ electroless deposition method using Si granules as the active materials and copper sulfate as Cu sources.The ratio of Si and Cu was readily tuned by varying the concentration of copper sulfate.The multi-shell(Cu@CuxSi/SiO2)coating on Si surface promotes the formation of robust and dense SEI films and the transportation of electron.Thus,the obtained DS-Si composites exhibit an initial coulombic efficiency of 86.2%,a capacity of 1636 mAh g^-1 after 100 discharge-charge cycles at 840 mA g^-1,and an average charge capacity of 1493 mAh g^-1 at 4200 mA g^-1.This study provides a low-cost and large-scale approach to the preparation of nanostructured Si-metal composites anodes with good electrochemical performance for lithium ion batteries.
文摘The weak interface bonding of metal matrix reinforced by carbon fibers is the central problem of fabricating such composites. Depositing copper coating on carbon fibers is regarded as a feasible method to solve the problem. In this paper, copper coating has been deposited on the fibers through both electroless deposition and electroplating methods. Two kinds of complexing agents and two stabilizing agents are taken during the electroless plating process. The solution is stable, and little extraneous component is absorbed on the surface. After adding additive agents and increasing the concentration of H2SO4 to the acid cupric sulfate electrolyte, the "black core" during usual electroplating process is avoided. The quality of copper coating is analyzed using SEM and XRD, etc.
