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Copper Substrate (copper + substrate)
Selected AbstractsSERS-active sites on various copper substratesJOURNAL OF RAMAN SPECTROSCOPY, Issue 4 2001C. Siemes The wavenumbers of the Raman bands of ethylene adsorbed on Cu in ultra-high vacuum depend on the surface structure of the copper substrate. Thus it is possible to differentiate between ethylene adsorbed at Cu(110) sites, Cu(111) sites and surface defect sites of unknown configuration. These latter are the ,SERS-active sites.' Only when these sites are annealed does the distance dependence of SERS follow the expectations from the electromagnetic model of SERS. In the presence of the SERS-active sites, also the signal of ethylene at (111) sites shows a ,first layer effect.' Ethylene adsorbed on cold-deposited copper films shows strong infrared absorption at the same wavenumber as the ethylene at SERS-active sites in Raman scattering, irrespective of the Raman,infrared exclusion rule for the free centrosymmetric ethylene molecule. This raises the possibility that SERS-active sites are also infrared-active sites. The SERS-active sites at stepped Cu surfaces decorated by 3 nm of cold-deposited copper anneal below 200 K, whereas they prevail beyond 400 K on Cu island films. Copyright © 2001 John Wiley & Sons, Ltd. [source] Structure of corrosion film formed on copper exposed to controlled corrosive environmentMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 4 2009M. Reid Abstract This paper describes a transmission electron microscopy (TEM) investigation of copper coupons exposed to a corrosive mixed flowing gas environment (MFG). A focused ion beam (FIB) lift-out technique was used to extract electron transparent specimens for TEM investigation. A duplex corrosion film comprising cuprite (Cu2O) and chalcocite (Cu2S) developed on the copper substrate. The oxide demonstrated a dense morphology with evidence of chlorine in the oxide layer showing that chlorine plays an important role in the corrosion of copper transforming the protective Cu2O layer to a non-protective layer. The outer layer of the Cu2S demonstrated a porous morphology allowing easy penetration of water and gases. [source] Wear and microstructural characteristics of spray atomized zircon sand reinforced LM13 alloy.MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 7 2010Verschleiß- und Gefügecharakteristik von sprühkompaktierter mit Zirkoniumsand verstärkter LM13 Legierung Verbundwerkstoff; Aluminiummatrix; Sprühkompaktieren; Verschleißverhalten Abstract The requirement of the high performance light weight materials demands the development of varieties of materials within the economical range to get it commercialized. Light weight aluminium alloys are used in several structural applications like automotive, aerospace, defense industry and other fields of engineering. The ceramic particle reinforced aluminium metal matrix composites (AMCs) have emerged as a suitable candidate for commercial applications. A variety of processing routes have been adopted to manufacture AMCs. In the present work LM13 alloy reinforced with zircon sand is formed via spray forming. During experimentation a self prepared convergent-divergent nozzle is used for inert gas atomization of the melt which is subsequently deposited on copper substrate placed vertically below the atomizer. The zircon sand particles are injected in the atomization zone by external injectors aligned perpendicular to the gas atomization axis. Zircon sand has been found to have new promising economical commercial candidate due to its easy availability and good mechanical properties like high hardness, high modulus of elasticity and good thermal stability. The microhardness of cast alloy and spray formed composite shows that the spray formed zircon sand reinforced composite has higher hardness. Also the lower wear rate has been observed in case of the zircon sand reinforced AMC as compared to LM13 alloy. This behaviour is further analyzed in light of microstructural features of the spray deposited composite using optical and scanning electron microscope (SEM). A comparative study of this material (LM13/Zircon sand) with the parent alloy (LM13) is presented in this work. [source] Asymmetry Induction by Cooperative Intermolecular Hydrogen Bonds in Surface-Anchored Layers of Achiral Molecules,CHEMPHYSCHEM, Issue 10 2006Alexandre Dmitriev Dr. Abstract The mesoscale induction of two-dimensional supramolecular chirality (formation of 2D organic domains with a single handedness) was achieved by self-assembly of 1,2,4-benzenetricarboxylic (trimellitic) acid on a Cu(100) surface at elevated temperatures. The combination of spectroscopic [X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS)], real-space-probe [scanning tunneling microscopy (STM)], and computational [density functional theory (DFT)] methods allows a comprehensive characterization of the obtained organic adlayers, where details of molecular adsorption geometry, intermolecular coupling, and surface chemical bonding are elucidated. The trimellitic acid species, comprising three functional carboxylic groups, form distinct stable mirror-symmetric hydrogen-bonded domains. The chiral ordering is associated with conformational restriction in the domains: molecules anchor to the substrate with an ortho carboxylate group, providing two para carboxylic acid moieties for collective lateral interweaving through H bonding, which induces a specific tilt of the molecular plane. The ease of molecular symmetry switching in domain formation makes homochiral-signature propagation solely limited by the terrace width. The molecular layer modifies the morphology of the underlying copper substrate and induces ,m-sized strictly homochiral terraces. [source] Single-Crystalline Scroll-Type Nanotube Arrays of Copper Hydroxide Synthesized at Room Temperature,ADVANCED MATERIALS, Issue 10 2003W. Zhang A novel nanolayer-rolled tubular structure of Cu(OH)2 has been grown in solution at ambient temperature and pressure. Significantly, the Cu(OH)2 nanotubes are phase-pure single crystallites and are arrayed uniformly on copper substrates (see Figure). The reaction conditions for the fabrication of the nanotube arrays are examined and possible growth mechanisms are discussed. [source] SERS-active sites on various copper substratesJOURNAL OF RAMAN SPECTROSCOPY, Issue 4 2001C. Siemes The wavenumbers of the Raman bands of ethylene adsorbed on Cu in ultra-high vacuum depend on the surface structure of the copper substrate. Thus it is possible to differentiate between ethylene adsorbed at Cu(110) sites, Cu(111) sites and surface defect sites of unknown configuration. These latter are the ,SERS-active sites.' Only when these sites are annealed does the distance dependence of SERS follow the expectations from the electromagnetic model of SERS. In the presence of the SERS-active sites, also the signal of ethylene at (111) sites shows a ,first layer effect.' Ethylene adsorbed on cold-deposited copper films shows strong infrared absorption at the same wavenumber as the ethylene at SERS-active sites in Raman scattering, irrespective of the Raman,infrared exclusion rule for the free centrosymmetric ethylene molecule. This raises the possibility that SERS-active sites are also infrared-active sites. The SERS-active sites at stepped Cu surfaces decorated by 3 nm of cold-deposited copper anneal below 200 K, whereas they prevail beyond 400 K on Cu island films. Copyright © 2001 John Wiley & Sons, Ltd. [source] | |||||||||||||