COORDINATION POLYMERIZATION OF BENZOTRIAZOLE ON THE SURFACE OF METALLIC COPPER

The coordination polymerization of benzotriazole with metallic copper has been investigated by infrared and X-ray photoelectron spectroscopies. We found that benzotriazole could react with copper (0) under mild conditions to form bis (benzotriazolato) copper (Ⅱ) and benzotriazolato copper (Ⅰ)which covered the surface of copper metal in the shape of polymeric materials. Since benzotriazole is of great interest as a ligand in that its presence in many biological system with metal ions, and is considered as a corrosion inhibitor, this work will be in favour of the study of protective corrosion.

A NOVEL SYNTHETIC METHOD AND STRUCTURE OF TETRAKIS(BENZOATE)BIS(TRIPHENYLPHOSPHINE OXIDE)DICOPPER(II).OXIDATIVE ADDITION OF DIBENZOYL ON METALLIC COPPER

Dibenzoyl peroxide undergoes oxidative addition on metallic copper with triphenylphosphine in a mixed solvent(acetone,dichloromethane and trichloromethane),and affords the binuclear copper complex (Cu(C_6H_5COO)_2(OPPh_3))_2.Crystals are monoclinic,space group A_2/a,with cell parameters,a=24.337(3),b=10.566(1),c=21.579(2),β= 93.18(1)°, V=5540(1)~3,Z=4,R=0.042,and Rw=0.044 for 5872 observed reflections. Each copper ion is coordinated by four bridging benzoato ligands and one triphenylphosphine oxide group to form binuclear complexes.

SYNTHESIS AND STRUCTURE OF Cu(Ⅱ)COMPLEXES BY OXIDATIVE ADDITION OF DIBENZOYL PEROXIDE ON METALLIC COPPER

Dibenzoyl peroxide undergoes oxidative addition on metallic copper powder with 2,2′-bipyridine(or imidazole)in a mixed solvent(methanol and tetrahydrofuran),and affords the Cu(Ⅱ)complexes-[Cu(Ce(C_6H_5COO)_2(2,2'-bipy)]H_2O(1) and[Cu(C_6H_5COO)_2(C_3H_4N_2)_2](2).The structure was solved by direct methods and Fourier synthesis.C_(24)H_(20)N_2O_5Cu (1),Mr=479.78,space group P2(1)/c,a=6.986(7), b=18.833(I),c=17.021(3),α=γ=90°,Z=4,V=2218.1~3,Dc=1.443g/cm\+3,R=0.055 Rw=0.062.Complex(2),C_(20)H_(18)N_4O_4Cu(2),Mr=441.74,space group P2(1)/n,a=8.699(4), b=9.840(6),c=12.399(5),α=γ=90°,β=100.8°,Z=4,V=1010.9~3,Dc=1.654g/cm\+3,R=0.055, Rw=0.062.

Characteristics of alumina particles in dispersion-strengthened copper alloys

Two types of alumina dispersion-strengthened copper（ADSC） alloys were fabricated by a novel in-situ reactive synthesis（IRS） and a traditional internal oxidation（IO） process. The features of alumina dispersoids in these ADSC alloys were investigated by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. It is found that nano-sized γ-Al2O3 particles of approximately 10 nm in diameter are homogeneously distributed in the IRS-ADSC composites. Meanwhile, larger-sized, mixed crystal structure alumina with rod-shaped morphology is embedded in the IO-ADSC alloy. The IRS-ADSC composites can obtain better mechanical and physical properties than the IO-ADSC composites; the tensile strength of the IRS-ADSC alloy can reach 570 MPa at room temperature, its electrical conductivity is 85% IACS, and the Rockwell hardness can reach 86 HRB.

Microstructure and properties of pure iron/copper composite cladding layers on carbon steel

In the present study, pure iron/copper composite metal cladding was deposited onto carbon steel by tungsten inert gas welding. The study focused on interfacial morphological, microstructural, and mechanical analyses of the composite cladding layers. Iron liquid–solid-phase zones were formed at copper/steel and iron interfaces because of the melting of the steel substrate and iron. Iron concentrated in the copper cladding layer was observed to exhibit belt, globule, and dendrite morphologies. The appearance of iron-rich globules indicated the occurrence of liquid phase separation（LPS） prior to solidification, and iron-rich dendrites crystallized without the occurrence of LPS. The maximum microhardness of the iron/steel interface was lower than that of the copper/steel interface because of the diffusion of elemental carbon. All samples fractured in the cladding layers. Because of a relatively lower strength of the copper layer, a short plateau region appeared when shear movement was from copper to iron.

Kinetic Study of Cementation of Copper on Zinc Metal in Ethanol-Water Mixtures

The cementation reaction of copper on zinc metal in solutions of different concentrations ofcopper sulphate, at 25℃, has been studied and it is found to be a first order reaction. Moreover,the rates of this reaction at 0.15 mol'L-1 copper sulphate solution have been measured in a varietyof ethanol-water media at temperatures from 20℃ to 40℃. The correlation between the masstransfer coefficient and the dielectric constant has been investigated. Also, the thermodynamicparameters of activation have been calculated. The isokinetic relationship reveals the existenceof compensation effect, where the solute-solvent interactions play an important role.

ON-LINE ELECTROLYTIC DISSOLUTION OF SOLID METAL SAMPLE AND DETERMINATION OF COPPER IN ALLOY BY AAS

On-line dissolution of solid metal sample can be carried out by electrolysis under the control of flow injection analyzer(FIA),and the dissolved sample can be transferred to atomic spectrometer for the direct analysis.The hyphenated technique of FIA on-line electrolytic dissolution of alloy and atomic absorption spectrometer(AAS)detection is developed.The research is focused on the effects of electrolyte composition and electrolysis parameters on the sample dissolving,as well as the quantitative analysis of Cu in Al alloy samples.

Production of high-purity Mg metal from dolomite through novel molten salt electrolysis and vacuum distillation

In this study,a novel Mg production process for producing high-purity Mg metal from dolomite was developed.When the electrolysis of calcined dolomite was conducted using Cu cathode and C anode in MgF_(2)–LiF molten salt at 1083–1173 K by applying an average current of 1.42–1.46 A for 9.50–21.0 h,the current efficiency of 66.4–88.6%was obtained.The produced Mg alloys consisted of MgCu_(2)and Cu(Mg)or MgCu_(2)and CuMg_(2)phases,depending on the Mg concentration in the Mg alloy.When the electrolysis of calcined dolomite was conducted in MgF_(2)–LiF–CaF_(2)molten salt at 1083 K,the current efficiency was 40.9–71.4%,owing to undesired reactions such as electroreduction of Ca^(2+)or/and CO_(3)^(2−)ions.Meanwhile,the current efficiency increased from 40.9%to 63.2%by utilizing a Pt anode,because the occurrence of CO_(3)^(2−)ions in the molten salt was prevented.After vacuum distillation of the obtained Mg alloys at 1300 K for 10 h,Mg metal with a purity of 99.9996–99.9998%was produced.Therefore,the feasibility of this novel process for the production of high-purity Mg metal from dolomite was demonstrated.

Experimental Study of Parameters of a Plasma Antenna

A plasma column excited by a surface wave can act as a plasma antenna. Experiments are carried out to study the current and conductivity distributions, field, power patterns, directivity and efficiency of such a plasma antenna. In addition, an equivalent metallic copper antenna is built up and its antenna parameters are compared with that of the plasma antenna. Our findings indicate that the power content in the harmonics of the plasma antenna is more prominent as compared to the copper antenna （which only generates a fundamental frequency）. However, the power patterns for both antennae are quite similar. To provide a more qualitative understanding regarding the generation of harmonics in the field of the plasma antenna, a bi-spectral analysis is performed to study the nonlinear interactions in the current fluctuations. Some specific features of the plasma antenna are investigated in our study, which may enhance the application prospect of the plasma antenna with respect to the conventional metallic antenna.

Effect of sintering on the relative density of Cr-coated diamond/Cu composites prepared by spark plasma sintering

Cr-coated diamond/Cu composites were prepared by spark plasma sintering. The effects of sintering pressure, sintering temperature, sintering duration, and Cu powder particle size on the relative density and thermal conductivity of the composites were investigated in this paper. The influence of these parameters on the properties and microstructures of the composites was also discussed. The results show that the relative density of Cr-coated diamond/Cu reaches ~100% when the composite is gradually compressed to 30 MPa during the heating process. The densification temperature increases from 880 to 915℃ when the diamond content is increased from 45vol% to 60vol%. The densification temperature does not increase further when the content reaches 65vol%. Cu powder particles in larger size are beneficial for increasing the relative density of the composite.

Self-trapped exciton emission in inorganic copper(Ⅰ)metal halides

The broad emission and high photoluminescence quantum yield of self-trapped exciton(STE)radiative recombination emitters make them an ideal solution for single-substrate,white,solid-state lighting sources.Unlike impurities and defects in semiconductors,the formation of STEs requires a lattice distortion,along with strong electron–phonon coupling,in low electrondimensional materials.The photoluminescence of inorganic copper(Ⅰ)metal halides with low electron-dimensionality has been found to be the result of STEs.These materials were of significant interest because of their leadfree,all-inorganic structures,and high luminous efficiencies.In this paper,we summarize the luminescence characteristics of zero-and one-dimensional inorganic copper(I)metal halides with STEs to provide an overview of future research opportunities.

Metal confined in metal-organic framework-based mixed matrix membranes for efficient butadiene recognition separation

The efficient separation of butadiene(1,3-C_(4)H_(6))from C_(4)hydrocarbons is a critical step in petrochemical processes.However,the traditional cryogenic distillation suffers from energy-intensity and serious environmental stress,necessitating the development of alternative technologies for efficient 1,3-C_(4)H_(6)separation.Herein,a 1,3-C_(4)H_(6)recognition mixed matrix membrane is reported via incorporating metal copper encapsulated a metal-organic framework(CuBTC@Cu)into elastic poly(dimethylsiloxane)(PDMS).The resulting CuBTC@Cu/PDMS membrane can efficient separate 1,3-C_(4)H_(6)from various C_(4)hydrocarbons including 1,3-C_(4)H_(6)/n-C_(4)H_(8),1,3-C_(4)H_(6)/iso-C_(4)H_(8),1,3-C_(4)H_(6)/n-C_(4)H_(10)and 1,3-C_(4)H_(6)/iso-C_(4)H_(10),yielding superior selectivity of 5.11,6.35,4.78,and 10.30,respectively,with 1,3-C_(4)H_(6)permeability of 53240 Barrer.Notably,the appropriateπ-complexation interaction between butadiene molecules and CuBTC@Cu as well as suitable transmission channel size enable the membrane only permeable to 1,3-C_(4)H_(6)and block the permeation of other C_(4)hydrocarbons,showing a unique 1,3-C_(4)H_(6)recognition behavior in membrane separation.The concept of affinity-relying separation combining molecular sieving would open a new direction for designing gas membranes for efficient light hydrocarbon separations.

Surface modification of YS-20 with polydopamine for improving the tribological properties of polyimide composites

Recently,great effort has been devoted to prepare various reinforce fillers to improve polymer performances,but ignoring the importance of raw polymer powders which are indispensable parts of hot-pressed polymer composites.Herein,we engineer raw polyimide(PI)powders with the assistance of polydopamine(PDA)in aqueous solutions.After the modification,polymer powders change from hydrophobic to hydrophilic,which makes it is possible to further modification of polymer powders in liquid phase.During the curing process of modified polymer powders,the partial dehydration of the catechol groups and crosslinking of PDA via C–O–C bonds are confirmed.Based on the features of PDA,a non-destructive mixing method is utilized to realize homogeneous dispersion of multi-walled carbon nanotubes(MWCNTs)in polymer matrix.In comparison with ball milling method,this way can preserve the integrated innate structure of MWCNTs effectively.Besides,by taking full advantage of the reducing and metal-coordination capability of PDA,Cu2+is successfully loaded onto the surfaces of polymer powders.The related characterizations demonstrate that Cu2+in situ converts to metallic copper rather than copper oxide during the hot pressing process.The tribological properties of corresponding polymer composites are also studied.These results indicate that modifying polymer powders with PDA is multi-profit and presents practical application prospect.

A barrier to metal movement: Synchrotron study of iron plaque on roots of wetland plants

A wetland with attractive plants hosting birds and other wildlife is an esthetically pleasing prospect that is gaining popularity as a way of stabilizing or remediating metalcontaminated soils and sediment（Weber and Gagnon,2014;