Jet formation and penetration performance of a double-layer charge liner with chemically-deposited tungsten as the inner liner

This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners.The microstructures of the tungsten layers were analyzed using a scanning electron microscope(SEM).The feasibility analysis was carried out by pulsed X-rays,slug-retrieval test and static penetration tests.The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method.The results showed that the double-layer liners could form well-shaped jets.The errors between the X-ray test results and the numerical results were within 11.07%.A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug.Compared with the traditional pure copper shaped charge jet,the penetration depth of the double-layer shaped charge liner increased by 11.4% and>10.8% respectively.In summary,the test results are good,and the numerical simulation is in good agreement with the test,which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner.

Edge effect during microwave plasma chemical vapor deposition diamond-film:Multiphysics simulation and experimental verification

This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor de-position.Substrate bulge height△h is a factor that affects the edge effect,and it was used to simulate plasma and guide the diamond-film deposition experiments.Finite-element software COMSOL Multiphysics was used to construct a multiphysics(electromagnetic,plasma,and fluid heat transfer fields)coupling model based on electron collision reaction.Raman spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the model.The simulation results reflected the experimental trends observed.Plasma discharge at the edge of the substrate accelerated due to the increase in△h(△h=0-3 mm),and the values of electron density(n_(c)),molar concentration of H(C_(H)),and molar concentration of CH_(3)(C_(CH_(3)))doubled at the edge(for the special concave sample with△h=−1 mm,the active chemical groups exhibited a decreased molar concentration at the edge of the substrate).At=0-3 mm,a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate,and their values increased with.The uniformity of film thickness decreased with.The Raman spectra of all samples revealed the first-order characteristic peak of dia-mond near 1332 cm^(−1).When△h=−1 mm,tensile stress occurred in all regions of the film.When△h=1-3 mm,all areas in the film ex-hibited compressive stress.

Fabrication of Graphene/Cu Composite by Chemical Vapor Deposition and Effects of Graphene Layers on Resultant Electrical Conductivity

Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the problem of how to control graphene to form desired Gr/Cu composite is not well solved. This paper aims at exploring the best parameters for preparing graphene with different layers on Cu foil by chemical vapor deposition(CVD)method and studying the effects of different layers graphene on Gr/Cu composite’s electrical conductivity. Graphene grown on single-sided and double-sided copper was prepared for Gr/Cu and Gr/Cu/Gr composites. The resultant electrical conductivity of Gr/Cu composites increased with decreasing graphene layers and increasing graphene volume fraction. The Gr/Cu/Gr composite with monolayer graphene owns volume fraction of less than 0.002%,producing the best electrical conductivity up to59.8 ×10^(6)S/m,equivalent to 104.5% IACS and 105.3% pure Cu foil.

Microstructure evolution and mechanical properties of Ti-B-N coatings deposited by plasma-enhanced chemical vapor deposition

Ternary Ti-B-N coatings were synthesized on AISI 304 and Si wafer by plasma-enhanced chemical vapor deposition (PECVD) technique using a gaseous mixture of TiCl4,BCl3,H2,N2,and Ar.By virtue of X-ray diffraction analysis,X-ray photoelectron spectroscopy,scanning electron microscope,and high-resolution transmission electron microscope,the influences of B content on the microstructure and properties of Ti B N coatings were investigated systematically.The results indicated that the microstructure and mechanical properties of Ti-B-N coatings largely depend on the transformation from FCC-TiN phase to HCP-TiB2 phase.With increasing B content and decreasing N content in the coatings,the coating microstructure evolves gradually from FCC-TiN/a-BN to HCP-TiB2 /a-BN via FCC-TiN+HCP-TiB2/a-BN.The highest microhardness of about 34 GPa is achieved,which corresponds to the nanocomposite Ti-63%B-N (mole fraction) coating consisting of the HCP-TiB2 nano-crystallites and amorphous BN phase.The lowest friction-coefficient was observed for the nanocomposite Ti-41%B-N (mole fraction) coating consisting of the FCC-TiN nanocrystallites and amorphous BN

Influence of In-doping on resistivity of chemical bath deposited SnS films

SnS and SnS：In films were deposited onto glass substrates by chemical bath technique. The structure and surface morphology of the SnS：In films were studied by X-ray diffraction （XRD） and scanning electron microscope （SEM） respectively. Energy dispersive spectroscopy （EDS） showed the existence of In in the films. The undoped SnS film exhibited a rather high resistivity and InCl3 could reduce the resistivity of these films by two orders approximately. The band gaps of the SnS and SnS：In films were evaluated from the optical transmission spectra.

Electron field emission characteristics of nano-catkin carbon films deposited by electron cyclotron resonance microwave plasma chemical vapour deposition

This paper reported that the nano-catkin carbon films were prepared on Si substrates by means of electron cyclotron resonance microwave plasma chemical vapour deposition in a hydrogen and methane mixture. The surface morphology and the structure of the fabricated films were characterized by using scanning electron microscopes and Raman spectroscopy, respectively. The stable field emission properties with a low threshold field of 5V/μm corresponding to a current density of about 1μA/cm^2 and a current density of 3.2mA/cm^2 at an electric field of 10V/μm were obtained from the carbon film deposited at CH4 concentration of 8%. The mechanism that the threshold field decreased with the increase of the CH4 concentration and the high emission current appeared at the high CH4 concentration was explained by using the Fowler-Nordheim theory.

Field emission characteristics of nano-sheet carbon films deposited by quartz-tube microwave plasma chemical vapour deposition

Nano-sheet carbon films are prepared on Si wafers by means of quartz-tube microwave plasma chemical vapour deposition （MPCVD） in a gas mixture of hydrogen and methane. The structure of the fabricated films is investigated by using field emission scanning electron microscope （FESEM） and Raman spectroscopy. These nano^carbon films are possessed of good field emission （FE） characteristics with a low threshold field of 2.6 V/μm and a high current density of 12.6 mA/cm^2 at an electric field of 9 V/μm. As the FE currents tend to be saturated in a high E region, no simple Fowler-Nordheim （F-N） model is applicable. A modified F N model considering statistic effects of FE tip structures and a space-charge-limited-current （SCLC） effect is applied successfully to explaining the FE data observed at low and high electric fields, respectively.

Optical and Structural Properties of Chemical Bath Deposited Cadmium Sulphur Selenide (CdS1–xSex (0 ≤ x ≤ 1)) Thin Films

The tuneable band gap property of Cadmium-sulphur-selenide (CdS1–xSex) thin film makes it an appropriate material for a wide range of optoelec-tronic applications and this has aroused a lot of interest. In this paper, we report the study of Cadmium-sulphur-selenide (CdS1–xSex) thin films, successfully grown on commercial glass slide substrate by the chemical bath deposition technique. The effect of selenium content (x value) on the structural, and some optical properties have been studied. The bath solution contained cadmium acetate dehydrate [Cd(CH3COO)2·2H2O], so-dium selenosulphate [Na2SeSO3] and thiourea [CS(NH2)2] were used as the sources of Cd2+, Se2﹣ and S2+, respectively. Tartaric acid (C4H6O6) was used as a complexing agent. The pH of the solution was adjusted to 12 by drop-wise addition of ammonia. The bath temperature was kept at 90°C for a deposition time of 1 hour. Post deposition annealing processes of the thin films were performed in a furnace at a temperature of 400°C for two hours. Both as-deposited and annealed films were characterised by Powder X-Ray Diffraction, Scanning Electron Microscopy, UV-Visible Optical Absorption Spectroscopy and Energy Dispersive X-Ray Analysis. Optical absorption data analysis indicates that direct allowed transitions occur in the films. The band gap of the as-deposited CdS1–xSex decreased linearly from 2.34 eV to 1.48 eV, with increasing selenium content, and in the annealed samples, decreased from 1.84 eV to 1.36 eV. X-ray diffrac-tion measurements revealed, that pure CdS, and CdSe had mixed hexago-nal and cubic phases. All the remaining ternary compounds were com-posed of cubic CdS and hexagonal CdSe phases. The annealed samples showed well defined and more intense peaks, suggesting an improvement in crystallinity. The average grain size increased slightly with increasing selenium content. SEM micrographs showed that the films were compact with a smooth texture and good coverage across the entire area of the substrate.

Electrochemically switched ion exchange performances of capillary deposited nickel hexacyanoferrate thin films

Thin films of capillary deposited nickel hexacyanoferrate(NiHCF) were investigated as electrochemically switched ion exchange(ESIX) materials. The films were generated on platinum and graphite substrates based on the ternary reagent diagram. In 1 mol/L KNO3 solution, cyclic voltammetry(CV) combined with energy-dispersive X-ray spectroscopy(EDS) was used to determine the influence of experimental conditions on the electroactivity of the NiHCF thin film on Pt substrates. The ion selectivity, ion-exchange capacity and the regenerability of NiHCF films on Pt and graphite substrates were investigated. The experiment results show that the NiHCF thin films from Ni2+-poor growth conditions have double peaks CV curves and contain relatively larger amount of potassium; while those from Ni2+-rich growth conditions are single peak CV curves and contain relatively smaller amount of potassium. It is demonstrated that the NiHCF thin films of capillary chemical deposition have good ESIX performances.

CHEMICALLY DEPOSITED SILVER FILM USED AS A SERS-ACTIVE OVER-COATING LAYER FOR POLYMER FILM

When colloidal silver particles were chemically deposited onto polymer film as an over-coating layer, surface-enhanced Raman scattering (SERS) spectra could be collected for the surface analysis. SERS measurements of liquid crystal film were successfully performed without disturbing the surface morphology.

Metal Organic Chemical Vapour Deposited Thin Films of Cobalt Oxide Prepared via Cobalt Acetylacetonate

The single solid source precursor, cobalt （Ⅱ） acetylacetonate was prepared and characterized by infrared spectroscopy. Thin films of cobalt oxide were deposited on soda lime glass substrates through the pyrolysis （metal organic chemical vapour deposition （MOCVD）） of single solid source precursor, cobalt acetylacetonate, Co[C5H7O2]2 at a temperature of 420℃. The compositional characterization carried out by rutherford backscattering spectroscopy and X-ray diffraction （XRD）, showed that the films have a stoichiometry of Co2O3 and an average thickness of 227±0.2 nm. A direct energy gap of 2,15±0.01 eV was calculated by the data obtained by optical absorption spectroscopy. The morphology of the films obtained by scanning electron microscopy, showed that the grains were continuous and uniformly distributed at various magnifications, while the average grain size was less than i micron for the deposited thin films of cobalt oxide.

High Quality SiGe Layer Deposited by a New Ultrahigh Vacuum Chemical Vapor Deposition System

An ultrahigh vacuum chemical vapor deposition (UHV/CVD) system is developed and the details of its construction and operation are reported. Using high purity SiH4 and GeH4 reactant gases, the Si0.82Ge0.18 layer is deposited at 550℃. With the measurements by double crystal X-ray diffraction (DCXRD), transmission electron microscopy (TEM) and Rutherford backscattering spectroscppy (RBS) techniques, it is shown that the crystalline quality of the SiGe layer is good, and the underlying SiGe/Si heterointerface is sharply defined.

Synthesis and Characterization of Metal Organic Chemical Vapour Deposited Copper Titanium Oxide (Cu-Ti-O) Thin Films from Single Solid Source Precursor

Thin films of copper titanium oxide were deposited by metal organic chemical vapour deposition technique from the synthesized single solid source precursor, copper titanium acetylacatonate Cu [Ti(C5H7O2)3] at the deposition temperature of 420°C. The deposited films were characterized using Rutherford Backscattering Spectroscopy, Scanning Electron Microscopy with Energy Dispersive X-Ray facility attached to it, X-Ray Diffractometry, UV-Visible Spectrometry and van-der Pauw Conductivity measurement. Results show that the thickness of the prepared film is determined as 101.236 nm and the film is amorphous in structure, having average grain size of approximately 1 μm. The optical behaviour showed that the absorption edge of the film was at 918 nm near infrared with corresponding direct energy band gap of 1.35 eV. The electrical characterization of the film gave the values of resistivity, sheet resistance and conductivity of the film as 3.43 × 10-1 Ω-cm, 3.39 × 106 Ω/square and 2.91 (Ω-cm)-1 respectively.

Synthesis and Characterization of Metal Organic Chemical Vapour Deposited Chromium Doped Zinc Oxide Thin Film for Gas Sensing Applications

Chromium (Cr) doped Zinc oxide ZnO thin films were deposited onto glass substrates by Metal Organic Chemical Vapour Deposition (MOCVD) technique with varying dopant concentration at a temperature of 420°C. The effect of the chromium concentration on morphological, structural, optical, electrical and gas sensing properties of the films were investigated. The scanning electron microscopy results revealed that the Cr concentration has great influence on the crystallinity, surface smoothness and grain size. X-ray diffraction (XRD) studies shows that films were polycrystalline in nature and grown as a hexagonal wurtzite structure. A direct optical band energy gap of 3.32 to 3.10 eV was obtained from the optical measurements. The transmission was found to decrease with increasing Cr doping concentration. Rutherford Backscattering Spectroscopy (RBS) analysis also demonstrates that Cr ions are substitutionally incorporated into ZnO. I-V characteristic of the film shows a resistivity ranges from 1.134 × 10-2 · cm to 1.24 × 10-2 · cm at room temperature. The gas sensing response of the films were enhanced with incorporation of Cr as a dopant with optimum operating temperature around 200°C.

Optical and Morphological Studies of Chemical Bath Deposited Nanocrystalline Cd_1-xZn_xS Thin Films

Cadmium Zinc Sulfide, Cd1-xZnxS thin films were deposited by chemical bath deposition technique at bath temperature of 75°C. The morphology of the films was analyzed by scanning electron microscope, the optical constants of the films were estimated from the transmission and reflection spectra of the films in the wavelength range of 300 - 900 nm. The films had a transmittance between 75% and 85% and optical band gap in the range 2.8 - 3.4 eV. The dependence of the refractive index of the films on the wavelength was investigated using the single oscillator model, from which the dispersion parameters were determined. The high frequency dielectric constant εL and the ratio of the carrier concentration to the effective mass N/m* were estimated based on the Spitzer and Fan model. Both εL and N/m* show a decrease in value with increase in Zinc content.

Modification of ACFs by chemical vapor deposition and its application for removal of methyl orange from aqueous solution

Viscose activated carbon fibers （ACFs） were characterized using specific surface area, scanning electron modified with chemical vapor deposition （CVD）. The samples were microscopy （SEM）, pore size distribution and Fourier transform infrared spectroscopy （FTIR）. Batch adsorption experiments were carried out to investigate the adsorption behavior of modified ACFs for methyl orange（MO） from its aqueous solutions. The results show that the adsorption isotherms of MO onto modified ACFs well follows the Langmuir isotherm equation. The adsorption kinetics of MO can be well described by the pseudo second-order kinetic model. The adsorption process involves the intra-particle diffusion, but is not the only rate-controlling step. Thermodynamic parameters including AG, AH and AS were calculated, suggesting that the adsorption of MO onto modified ACFs is a spontaneous, exothermic and physisorption process. FTIR result indicates that the major adsorption mechanism of modified ACFs for MO is hydrogen bond.

THE STUDY OF ADSORPTION MODEL FOR 4,4'-BIPYRIDINE ADSORBED AT THE CHEMICALLY DEPOSITED SILVER FILM BY SERS

This paper presents the SERS spectru spectrum of 4,4′-bipyridine adsorbed at the chemically deposited silver filem.Comparing with the normal Raman spectra of 4,4′-bipyridine in the solid state and in 0.5 mol/L methanol solution ,we have studied the SERS spectrum and further discussed the adsorption model for 4,4′-bipyridine adsorbed at the chemically deposited silver film,and also explained the experimental results with image field mode,Experimental results show that 4,4′-bipyridine adsorbed at the chemically deposiled silver ilm via N-atom of pyridinering (Upright).

Si-doped diamond films prepared by chemical vapour deposition

The effects of Si doping on morphology, components and structure characteristics of CVD diamond films were studied. Si-doped CVD diamond films were deposited on Si substrate by adding tetraethoxysilane （TEOS） into acetone as source of reactant gas. The morphology and microstructure of diamond films were characterized by scanning electron microcopy （SEM）. The crystalline quality of diamond films was studied by Raman spectroscopy and X-ray diffractometry （XRD）. The surface roughness of the films was evaluated with surface profilometer. The results suggest that Si doping tends to reduce the crystallite size, enhance grain refinement and inhibit the appearance of （11 I） facets. Raman spectra indicate that Si doping can enhance the formation of sp2 phase in diamond films. Moreover, Raman signal of SiC was detected, which suggests the existence of Si in the diamond films. Smooth fine-grained diamond （SFGD） film was synthesized at Si to C ratio of 1%.

GROWTH MECHANISM OF TiC WHISKERS PREMRED BY A MODIFIED CHEMICAL VAPOR DEPOSITION METHOD

High quality TiC whiskers have been prepared by a modified chemical vapor deposition (CVD) method using TiCl4 and CH4 as reactant gases and Ni as substrate. The deposition temperature and gas flow mies have ampreciable effect on the whisker growth.The whisker orientations and morphology are determined by X-my diffraction (XRD),scanning electron micmpmph (SEM) and transmission electron microgmph (TEM).In addition to the spherical tips, spiral growth microsteps and obvious terraces are observed at the tips and side faces of whiskers in the present eoperiment. The whiskers grow mostly along (100) direction. The whisker growth mechanism is discussed in detail.

Ore Genesis of the Kalatongke Cu-Ni Sulfide Deposits, Western China: Constraints from Volatile Chemical and Carbon Isotopic Compositions

The Kalatongke Cu-Ni sulfide deposits located in the East Junggar terrane, northern Xinjiang, western China are the largest magmatic sulfide deposits in the Central Asian Orogenic Belt （CAOB）. The chemical and carbon isotopic compositions of the volatiles trapped in olivine, pyroxene and sulfide mineral separates were analyzed by vacuum stepwise-heating mass spectrometry. The results show that the released volatiles are concentrated at three temperature intervals of 200-400°C, 400-900°C and 900-1200°C. The released volatiles from silicate mineral separates at 400-900°C and 900-1200°C have similar chemical and carbon isotopic compositions, which are mainly composed of H2O （av. ~92 mol%） with minor H2, CO2, H2S and SO2, and they are likely associated with the ore-forming magmatic volatiles. Light δ13CCO2 values （from -20.86‰ to -12.85‰） of pyroxene indicate crustal contamination occurred prior to or synchronous with pyroxene crystallization of mantlederived ore-forming magma. The elevated contents of H2 and H2O in the olivine and pyroxene suggest a deep mantle-originated ore-forming volatile mixed with aqueous volatiles from recycled subducted slab. High contents of CO2 in the ore-forming magma volatiles led to an increase in oxygen fugacity, and thereby reduced the solubility of sulfur in the magma, then triggered sulfur saturation followed by sulfide melt segregation; CO2 contents correlated with Cu contents in the whole rocks suggest that a supercritical state of CO2 in the ore-forming magma system under high temperature and pressure conditions might play a key role in the assemblage of huge Cu and Ni elements. The volatiles released from constituent minerals of intrusion 1# have more CO2 and SO2 oxidized gases, higher CO2/CH4 and SO2/H2S ratios and lighter δ13CCO2 than those of intrusions 2# and 3#. This combination suggests that the higher oxidation state of the volatiles in intrusion 1# than intrusions 2# and 3#, which could be one of key ore-forming factors for large amounts of ores and high contents of Cu and Ni in intrusion 1#. The volatiles released at 200-400°C are dominated by H2O with minor CO2, N2＋CO and SO2, with δ13CCO2 values （-25.66‰ to -22.98‰） within the crustal ranges, and are considered to be related to secondary tectonic-hydrothermal activities.