期刊文献+
共找到3,615篇文章
< 1 2 181 >
每页显示 20 50 100
Challenges and opportunities in the production of magnesium parts by directed energy deposition processes
1
作者 Gürel Cam Ali Günen 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第5期1663-1686,共24页
Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aero... Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport industries.However,their widespread application is hindered by their low formability at room temperature due to limited slip systems.Cast Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high scrap.While casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain applications.Although metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast counterparts.Thus,MAM is a promising technique to produce Mg alloy parts.Directed energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive processes.However,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this technology.This review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and prospects.Furthermore,the predominant imperfections,notably inhomogeneous microstructure evolution and porosity,observed in Mg-alloy components manufactured through DED are discussed.Additionally,the preventive measures implemented to counteract the formation of these defects are explored. 展开更多
关键词 Additive manufacturing DED processes arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate
下载PDF
Controllable Modulation of Morphology and Property of CsPbCl_(3)Perovskite Microcrystals by Vapor Deposition Method
2
作者 Na Dong Fangfang You +2 位作者 Ting He Yi Yao Faqiang Xu 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2023年第5期613-619,I0002,共8页
As a direct wide bandgap semiconductor,CsPbCl_(3)has great potential applications in the eld of near-ultraviolet photodetectors,lasers and higher-order multiphoton uores-cent detectors.In this work,we synthesized CsPb... As a direct wide bandgap semiconductor,CsPbCl_(3)has great potential applications in the eld of near-ultraviolet photodetectors,lasers and higher-order multiphoton uores-cent detectors.In this work,we synthesized CsPbCl_(3)micro/nanocrystals by vapor depo-sition method with CsCl and PbCl_(2)powders as the source materials.It was con rmed that the formation of CsPbCl_(3)perovskite through the chemical reaction of CsCl with PbCl_(2)occurred in the quartz boat before the source evaporation,not in vapor or on sub-strate surface.The evaporated CsPbCl_(3)can form micro/nanocrystals on substrate surfaces under appropriate conditions.Various morphologies including irregular polyhedrons,rods and pyramids could be observed at lower temperature,while stable and uniform CsPbCl_(3)single crystal microplatelets were controllably synthesized at 450℃.Prolonging the growth time could modulate the size and density of the microcrystals,but could not change the morphology.Substrate types made little di erence to the morphology of CsPbCl_(3)crystals.The photoluminescence spectra indicated that the crystallinity and morphology of CsPbCl_(3)micro/nanocrystals have signi cant e ects on their optical properties.The work is expected to be helpful to the development of optoelectronic devices based on individual CsPbCl_(3)microcrystal. 展开更多
关键词 Vapor deposition method CsPbCl_(3)micro/nanocrystal Controlled synthesis PHOTOLUMINESCENCE
下载PDF
Effect of deposition rate on microstructure and mechanical properties of wire arc additive manufacturing of Ti-6Al-4V components 被引量:6
3
作者 ZHANG Pei-lei JIA Zhi-yuan +7 位作者 YAN Hua YU Zhi-shui WU Di SHI Hai-chuan WANG Fu-xin TIAN Ying-tao MA Song-yun LEI Wei-sheng 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第4期1100-1110,共11页
Wire arc additive manufacturing(WAAM)is a novel manufacturing technique by which high strength metal components can be fabricated layer by layer using an electric arc as the heat source and metal wire as feedstock,and... Wire arc additive manufacturing(WAAM)is a novel manufacturing technique by which high strength metal components can be fabricated layer by layer using an electric arc as the heat source and metal wire as feedstock,and offers the potential to produce large dimensional structures at much higher build rate and minimum waste of raw material.In the present work,a cold metal transfer(CMT)based additive manufacturing was carried out and the effect of deposition rate on the microstructure and mechanical properties of WAAM Ti-6Al-4V components was investigated.The microstructure of WAAM components showed similar microstructural morphology in all deposition conditions.When the deposition rate increased from 1.63 to 2.23 kg/h,the ultimate tensile strength(UTS)decreased from 984.6 MPa to 899.2 MPa and the micro-hardness showed a scattered but clear decline trend. 展开更多
关键词 wire and arc additive manufacturing titanium alloys cold metal transfer deposition rate
下载PDF
Micro arc oxidation and electrophoretic deposition effect on damping and sound transmission characteristics of AZ31B magnesium Alloy 被引量:1
4
作者 罗智 郝志勇 +2 位作者 蒋百灵 葛延峰 郑旭 《Journal of Central South University》 SCIE EI CAS 2014年第9期3419-3425,共7页
Micro arc oxidation(MAO) and electrophoretic deposition(EPD) process are employed to fabricate a dense coating on magnesium alloy to protect it from corrosion in engineering application. The EPD film changes the dampi... Micro arc oxidation(MAO) and electrophoretic deposition(EPD) process are employed to fabricate a dense coating on magnesium alloy to protect it from corrosion in engineering application. The EPD film changes the damping characteristic of magnesium alloy, and both the MAO and EPD process change the bending stiffness of samples being treated. Damping loss factor(DLF) test and sound transmission experiments were carried out for AZ31 B magnesium alloy with coating fabricated by MAO and EPD processes. The results indicate that DLF is improved in frequency range from 0-850 Hz. Bending stiffness of the samples is improved with MAO and EPD treatment. As a result, the sound transmission loss(LST) is improved in the stiffness control stage of the sound transmission verse frequency curve. To the samples by electrophoresis process, the LST is improved in frequency range from 2500-3200 Hz, because the damping loss factor is improved with EPD process. The results are useful for the surface treatment to enhance the damping loss factor, LST and widespread application of magnesium alloy while improving the corrosion resistance. 展开更多
关键词 magnesium alloy micro arc oxidation electrophoretic deposition damping loss factor sound transmission loss bending stiffness
下载PDF
Cathodic micro-arc electro-deposition of ZrO_2 coatings in an aqueous solution containing colloidal particles 被引量:2
5
作者 YANGXiaozhan GAOWei 《Rare Metals》 SCIE EI CAS CSCD 2002年第3期198-202,共5页
By a novel technique-cathodic micro-arc electro-deposition (CMED), ZrO_2coatings were deposited on an FeCrAl alloy. Experimental results show that the necessary conditionsfor obtaining ZrO_2 coatings are to apply a pu... By a novel technique-cathodic micro-arc electro-deposition (CMED), ZrO_2coatings were deposited on an FeCrAl alloy. Experimental results show that the necessary conditionsfor obtaining ZrO_2 coatings are to apply a pulse peak voltage over a critical value and addmoderate amounts of ZrO_2 colloidal particles and Zr(NO_3)_4 in the aqueous solution. Theas-deposited coatings are porous because hydrogen, water, and other vapors are generated andreleased from the coatings to the solution during the spark reaction. The coatings containmonoclinic and tetragonal crystalline ZrO_2 with certain degree of amorphous structure. Theprocessing parameters and mechanism of CMED were discussed. 展开更多
关键词 cathodic micro-arc ELECTRO-deposition ZrO_2 coating FeCrAl alloy
下载PDF
STUDY ON DIAMOND LIKE CARBON THIN FILM BY FILTERED VACUUM ARC DEPOSITION
6
作者 朱纪军 左敦稳 王珉 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1999年第1期102-106,共5页
Diamond like carbon thin film is successfully deposited on silicon, titanium and stainless steel substrate at low temperature in a filtered vacuum arc deposition system. Arc discharges are established on a graphite ... Diamond like carbon thin film is successfully deposited on silicon, titanium and stainless steel substrate at low temperature in a filtered vacuum arc deposition system. Arc discharges are established on a graphite cathode in the system with a toroidal macroparticle filter. A cathode activating magnetic field and a filtered magnetic field to collimate the plasma beam are applied. Ion current convected by the plasma beam is measured with a negatively biased probe. It is shown that the magnetic field of the coils located on the plasma duct has a strong influence on cathode spot behavior. Orthogonally the designed experiments are carried out to optimize the deposition parameters of arc stability. Finally, the diamond like carbon thin films are studied by scanning electron microscope (SEM) and Raman spectrum. 展开更多
关键词 diamond like carbon thin film filtered vacuum arc deposition
下载PDF
Micro Electrical Discharge Machining Deposition in Air for Fabrication of Micro Spiral Structures 被引量:4
7
作者 PENG Zilong CHI Guanxin WANG Zhenlong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2010年第2期154-160,共7页
Micro electrical discharge machining(EDM) deposition process is a new micro machining method for fabrication of metal micro structures. In this process, the high level of tool electrode wear is used to achieve the m... Micro electrical discharge machining(EDM) deposition process is a new micro machining method for fabrication of metal micro structures. In this process, the high level of tool electrode wear is used to achieve the metal material deposition. Up to now, the studies of micro EDM deposition process focused mainly on the researches of deposition process, namely the effects of discharge parameters in deposition process on the deposition rate or deposition quality. The research of the formation of micro structures with different discharge energy density still lacks. With proper conditions and only by the z-axis feeding in vertical direction, a novel shape of micro spiral structure can be deposited, with 0.11 mm in wire diameter, 0.20 mm in outside diameter, and 3.78 mm in height. Then some new deposition strategies including angular deposition and against the gravity deposition were also successful. In order to find the forming mechanism of the spiral structures, the numerical simulation of the transient temperature distribution on the discharge point was conducted by using the finite-element method(FEM). The results show that there are two major factors lead to the forming of the spiral structures. One is the different material removal form of tool electrode according with the discharge energy density, the other is the influenced degree of the movement of the removed material particles in the discharge gap. The more the energy density in single discharge is, the smaller the mass of the removed material particles is, and the easier the movements of which will be changed to form an order tendency. The fine texture characteristics of the deposited micro spiral structures were analyzed by the energy spectrum analysis and the metallographic analysis. It shows that the components of the deposited material are almost the same as those of the tool electrode. Moreover the deposited material has the brass metallic luster in the longitudinal profile and has compact bonding with the base material. This research is useful to understand the micro-process of micro EDM deposition better and helpful to increase the controllability of the new EDM method for fabrication of micro structures. 展开更多
关键词 micro electrical discharge machining deposition micro spiral structure forming mechanism fine texture analysis
下载PDF
Tribological properties of diamond-like carbon films deposited bv pulsed laser arc deposition 被引量:2
8
作者 张振宇 路新春 雒建斌 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第12期3790-3797,共8页
A novel method, pulsed laser arc deposition combining the advantages of pulsed laser deposition and cathode vacuum arc techniques, was used to deposit the diamond-like carbon (DLC) nanofilms with different thickness... A novel method, pulsed laser arc deposition combining the advantages of pulsed laser deposition and cathode vacuum arc techniques, was used to deposit the diamond-like carbon (DLC) nanofilms with different thicknesses. Spectroscopic ellipsometer, Auger electron spectroscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, atomic force microscopy, scanning electron microscopy and multi-functional friction and wear tester were employed to investigate the physical and tribological properties of the deposited films. The results show that the deposited films are amorphous and the sp2, sp3 and C-O bonds at the top surface of the films are identified. The Raman peak intensity and surface roughness increase with increasing film thickness. Friction coefficients are about 0.1, 0.15, 0.18, when the film thicknesses are in the range of 17-21 nm, 30-57 nm, 67-123 nm, respectively. This is attributed to the united effects of substrate and surface roughness. The wear mechanism of DLC films is mainly abrasive wear when film thickness is in the range of 17-41 nm, while it transforms to abrasive and adhesive wear, when the film thickness lies between 72 and 123 nm. 展开更多
关键词 pulsed laser arc deposition diamond-like carbon tribological property physical property
下载PDF
FUNDAMENTAL PROBLEMS IN PULSED-BIAS ARC DEPOSITION 被引量:1
9
作者 G.Q. Lin Z.F. Ding +6 位作者 D. Qi N.H. Wang M.D. Huang D.Z. Wang Y.N. Wang C. Dong L.S. Wen 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2002年第1期91-103,共13页
Arc deposition, a widely used surface coating technique, has disadvantages such as large droplet size and high deposition temperature. Recent trend in its renovation is the introduction of pulsed bias at the. substrat... Arc deposition, a widely used surface coating technique, has disadvantages such as large droplet size and high deposition temperature. Recent trend in its renovation is the introduction of pulsed bias at the. substrate. The present paper attempts to describe the deposition process of TiN films using this technique with emphasis laid on the understanding of the basic problems such as discharge plasma properties, temperature calculation, and droplet size reduction. We show that this technique improves the film micro structure and quality, lowers deposition temperature, and allows coatings on insulating substrates. After analyzing load current oscillation behaviors, we have determined that the plasma load is of capacitance nature due to plasma sheath and that it is equivalent to a circuit element consisting of parallel capacitance and resistance. At last, we point out the remaining problems and future development of the pulsed-bias arc deposition technique. 展开更多
关键词 arc deposition pulsed bias PLASMA
下载PDF
Improvement of thickness deposition uniformity in nickel electroforming for micro mold inserts 被引量:1
10
作者 蒋炳炎 翁灿 +2 位作者 周明勇 吕辉 DRUMMER Dietmar 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第10期2536-2541,共6页
Thickness deposition is a crucial issue on the application of electroformed micro mold inserts. Edge concentration effect is the main source of the non-uniformity. The techniques of adopting a non-conducting shield, a... Thickness deposition is a crucial issue on the application of electroformed micro mold inserts. Edge concentration effect is the main source of the non-uniformity. The techniques of adopting a non-conducting shield, a secondary electrode and a movable cathode were explored to improve the thickness deposition uniformity during the nickel electroforming process. Regarding these techniques, a micro electroforming system with a movable cathode was particularly developed. The thickness variation of a 16 mm×16 mm electroformed sample decreased respectively from 150% to 35%, 12% and 18% by these three techniques. Combining these validated methods, anickelmold insert for microlens array was electroformed with satisfactory mechanical properties and high replication precision. It could be applied to the following injection molding process. 展开更多
关键词 deposition uniformity nickel electroforming secondary electrode non-conducting shield movable cathode micro mold insert
下载PDF
Laser-assisted deposition of Cu bumps for microelectronic packaging 被引量:1
11
作者 Won-Seok CHOI Joohan KIM 《中国有色金属学会会刊:英文版》 CSCD 2012年第S3期683-687,共5页
Cu bump was transferred using a focused laser pulse for microelectronic packaging.An Nd:YAG laser pulse (maximum energy of 500 mJ;wavelength of 1064 nm;fluences of 0.4-2.1 kJ/cm2) was irradiated on a sacrificial absor... Cu bump was transferred using a focused laser pulse for microelectronic packaging.An Nd:YAG laser pulse (maximum energy of 500 mJ;wavelength of 1064 nm;fluences of 0.4-2.1 kJ/cm2) was irradiated on a sacrificial absorption layer with copper coating.The focused laser beam induced plasma between the semi-transparent donor slide and the sacrificial layer,causing a shock wave.The shock wave pressure pushed the Cu layer and transferred material to deposit a bump on substrate.A beam-shaper was used to produce uniform pressure at the interface to reduce fragmentation of the transferred material on the substrate.The calculated shock wave pressure with respect to laser fluence was 1-3 GPa.A Cu bump of diameter of 200 μm was successfully deposited at laser fluence of 0.6 kJ/cm 2.The pressure control at the sacrificial layer using a laser pulse was critical to produce a bump with less fragmentation.The technique can be applied to forming Cu bump for an interconnecting process in electronics. 展开更多
关键词 LASER induced FORWARD transfer BUMP deposition ND:YAG PULSED LASER micro system packaging beam SHAPING
下载PDF
Optical and electrical properties of BaSnO_(3) and In_2O_(3) mixed transparent conductive films deposited by filtered cathodic vacuum arc technique at room temperature
12
作者 姚建可 钟文森 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第1期559-562,共4页
For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular be... For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular beam epitaxy till now which limited there application in low temperature device process.In the article,the microstructure,optical and electrical of BTO and In_(2)O_(3) mixed transparent conductive BaInSnO_(x)(BITO)film deposited by filtered cathodic vacuum arc technique(FCVA)on glass substrate at room temperature were firstly reported.The BITO film with thickness of 300 nm had mainly In_(2)O_(3) polycrystalline phase,and minor polycrystalline BTO phase with(001),(011),(111),(002),(222)crystal faces which were first deposited at room temperature on amorphous glass.The transmittance was 70%–80%in the visible light region with linear refractive index of 1.94 and extinction coefficient of 0.004 at 550-nm wavelength.The basic optical properties included the real and imaginary parts,high frequency dielectric constants,the absorption coefficient,the Urbach energy,the indirect and direct band gaps,the oscillator and dispersion energies,the static refractive index and dielectric constant,the average oscillator wavelength,oscillator length strength,the linear and the third-order nonlinear optical susceptibilities,and the nonlinear refractive index were all calculated.The film was the n-type conductor with sheet resistance of 704.7Ω/□,resistivity of 0.02Ω⋅cm,mobility of 18.9 cm2/V⋅s,and carrier electron concentration of 1.6×10^(19) cm^(−3) at room temperature.The results suggested that the BITO film deposited by FCVA had potential application in transparent conductive films-based low temperature device process. 展开更多
关键词 BaSnO_(3)and In_2O_(3)mixed film filtered cathodic vacuum arc deposition transparent conductive films microstructure optical properties electrical properties
下载PDF
Ignition processes and characteristics of charring conductive polymers with a cavity geometry in precombustion chamber for applications in micro/nano satellite hybrid rocket motors
13
作者 Zhiyuan Zhang Hanyu Deng +2 位作者 Wenhe Liao Bin Yu Zai Yu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期55-66,共12页
The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of... The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually. 展开更多
关键词 micro/nano satellite hybrid propulsion arc ignition Charring conductive polymer Ignition mechanism Ignition characteristic Repeated ignition
下载PDF
Reduced magma generation and its implications for the Pulang giant porphyry Cu-polymetallic deposit in Northwest Yunnan,China
14
作者 Jingwei Guan Tao Ren +3 位作者 Lei Wang Shenjin Guan Lianrong Wu Baosheng Shi 《Acta Geochimica》 EI CAS CSCD 2024年第4期802-813,共12页
The Pulang giant porphyry Cu-Mo polymetallic deposit is located in the Zhongdian area in the center of the Sanjiang Tethys tectonic domain,which was formed by the westward subduction of the Garze-Litang oceanic slab b... The Pulang giant porphyry Cu-Mo polymetallic deposit is located in the Zhongdian area in the center of the Sanjiang Tethys tectonic domain,which was formed by the westward subduction of the Garze-Litang oceanic slab beneath the Zhongza massif.Chalcopyrite-pyrrhotite-pyritemolybdenite occurs as disseminations,veins,veinlets,and stockworks distributed in the K-silicate alteration zone in the monzonite porphyry,which is superimposed by propylitization.The chemical compositions of biotite and amphibole analyzed by electron probe microanalysis(EPMA)indicate that the ore-forming magma and exsolved fluids experienced a continuous decrease in the oxygen fugacity(fO_(2)).Primary amphibolite and biotite(type I)crystallized at relatively high temperatures(744-827°C)and low fO_(2)(log fO_(2)=−12.26 to−11.91)during the magmatic stage.Hydrothermal fluids exsolved from the magma have a relatively lower temperature(621-711°C)and fO_(2)(log fO_(2)=−14.36 to−13.32)than the original magma.In addition,the presence of a high abundance of pyrrhotite and an insufficiency of primary magnetite and sulfate in the ore(i.e.,anhydrite and gypsum)indicate that the deposit may be a reduced porphyry deposit.Magma and fluid fO_(2)results,combined with previous research on magmatic fO_(2)at the Pulang deposit,indicate that the magma associated with the reduced Pulang ore assemblages was initially generated as a highly oxidized magma that was subsequently reduced by sedimentary rocks of the Tumugou Formation. 展开更多
关键词 Porphyry deposit Oxygen fugacity(fO_(2)) Contamination of surrounding rock Pulang Zhongdian arc
下载PDF
Preparation and tribological properties of DLC/Ti film by pulsed laser arc deposition
15
作者 张振宇 路新春 +3 位作者 雒建斌 劭天敏 卿涛 张晨辉 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第11期2697-2705,共9页
This paper reports that DLC (diamond like carbon)/Ti and DLC films were prepared by using pulsed laser arc deposition. R-ray diffraction, Auger electron spectroscopy, Raman spectroscopy, atomic force microscopy, nan... This paper reports that DLC (diamond like carbon)/Ti and DLC films were prepared by using pulsed laser arc deposition. R-ray diffraction, Auger electron spectroscopy, Raman spectroscopy, atomic force microscopy, nanoindenter, spectroscopic ellipsometer, surface profiler and micro-tribometer were employed to study the structure and tribological properties of DLC/Ti and DLC films. The results show that DLC/Ti film, with I(D)/I(G) 0.28 and corresponding to 76% sp3 content calculated by Raman spectroscopy, uniform chemical composition along depth direction, 98 at% content of carbon, hardness 8.2 GPa and Young's modulus 110.5 GPa, compressive stress 6.579 GPa, thickness 46 nm, coefficient of friction 0.08, and critical load 95mN, exhibits excellent mechanical and tribological properties. 展开更多
关键词 diamond like carbon tribological property pulsed laser arc deposition Raman spectroscopy
下载PDF
Diagnosis of gas phase near the substrate surface in diamond film deposition by high-power DC arc plasma jet CVD
16
作者 Zuyuan Zhou Guangchao Chen +2 位作者 Bin Li Weizhong Tang Fanxiu Lv 《Journal of University of Science and Technology Beijing》 CSCD 2007年第4期365-368,共4页
Optical emission spectroscopy (OES) was used to study the gas phase composition near the substrate surface during diamond deposition by high-power DC arc plasma jet chemical vapor deposition (CVD). C2 radical was ... Optical emission spectroscopy (OES) was used to study the gas phase composition near the substrate surface during diamond deposition by high-power DC arc plasma jet chemical vapor deposition (CVD). C2 radical was determined as the main carbon radical in this plasma atmosphere. The deposition parameters, such as substrate temperature, anode-substrate distance, methane concentration, and gas flow rate, were inspected to find out the influence on the gas phase. A strong dependence of the concentrations and distribution of radicals on substrate temperature was confirmed by the design of experiments (DOE). An explanation for this dependence could be that radicals near the substrate surface may have additional ionization or dissociation and also have recombination, or are consumed on the substrate surface where chemical reactions occur. 展开更多
关键词 gas phase diamond film optical emission spectroscopy substrate surface high power DC arc plasma jet chemical vapor deposition
下载PDF
Numerical analysis on the effect of process parameters on deposition geometry in wire arc additive manufacturing
17
作者 Shilong FAN Fei YANG +3 位作者 Xiaonan ZHU Zhaowei DIAO Lin CHEN Mingzhe RONG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2022年第4期1-12,共12页
Here we develop a two-dimensional numerical model of wire and arc additive manufacturing(WAAM)to determine the relationship between process parameters and deposition geometry,and to reveal the influence mechanism of p... Here we develop a two-dimensional numerical model of wire and arc additive manufacturing(WAAM)to determine the relationship between process parameters and deposition geometry,and to reveal the influence mechanism of process parameters on deposition geometry.From the predictive results,a higher wire feed rate matched with a higher current could generate a larger and hotter droplet,and thus transfer more thermal and kinetic energy into melt pool,which results in a wider and lower deposited layer with deeper penetration.Moreover,a higher preheat temperature could enlarge melt pool volume and thus enhance heat and mass convection along both axial and radial directions,which gives rise to a wider and higher deposited layer with deeper penetration.These findings offer theoretical guidelines for the acquirement of acceptable deposition shape and optimal deposition quality through adjusting process parameters in fabricating WAAM components. 展开更多
关键词 additive manufacturing arc plasma process parameter deposition geometry numerical analysis
下载PDF
PROTOTYPE SURFACE MICRO- PRECISION IN FUSED DEPOSITION MODELING PROCESS 被引量:2
18
作者 WANG Tianming XI Juntong JIN Ye 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第1期100-106,共7页
To aim at prototype parts fabricated with fused deposition modeling (FDM) process, the problems how to improve and enhance their surface micro-precision are studied. The producing mechanism of surface roughness is e... To aim at prototype parts fabricated with fused deposition modeling (FDM) process, the problems how to improve and enhance their surface micro-precision are studied. The producing mechanism of surface roughness is explained with three aspects concretely including the principle error of rapid prototyping (RP) process, the inherent characteristics of FDM process, and some mi- cro-scratches on the surface of the extruded fiber. Based on the micro-characters of section shape of the FDM prototype, a physical model reflecting the outer shape characters is abstracted. With the physical simplified and deduced, the evaluating equations of surface roughness are acquired. According to the FDM sample parts with special design for experimental measurement, the real surface roughness values of different inclined planes are obtained. And the measuring values of surface roughness are compared with the calculation values. Furthermore, the causes of surface roughness deviation between measuring values and calculation values are respectively analyzed and studied. With the references of analytic conclusions, the measuring values of the experimental part surface are revised, and the revised values nearly accord with the calculation values. Based on the influencing principles of FDM process parameters and special post processing of FDM prototype parts, some concrete measures are proposed to reduce the surface roughness of FDM parts, and the applying effects are better. 展开更多
关键词 Rapid prototyping Fused deposition modeling micro-precision Surface roughness Post processing sequence
下载PDF
Fabrication of Tungsten Carbide Films by Filtered Pulse Arc Deposition with Cemented Tungsten Carbide Cathodes
19
作者 Ryo Isono Tsuyoshi Tanimoto +4 位作者 Yushi Iijima Toru Harigai Yoshiyuki Suda Hirofumi Takikawa Satoru Kaneko 《Materials Sciences and Applications》 2017年第13期966-978,共13页
Tungsten carbide films (W-C films) were fabricated on silicon substrates by using the filtered pulse arc deposition (FPAD) method. Two types of cemented tungsten carbide (WC) were used as cathode, one containing Co an... Tungsten carbide films (W-C films) were fabricated on silicon substrates by using the filtered pulse arc deposition (FPAD) method. Two types of cemented tungsten carbide (WC) were used as cathode, one containing Co and the other Ti, which were used as binders for forming the cathode shape. The films were fabricated by varying the pulse arc current and substrate bias voltage. The discharge, deposition and film properties were investigated under these deposition conditions. The cathode wear amount when using WC-Co (WC cathode containing Co) was found to be smaller than that measured when WC-Ti (WC cathode containing Ti) was used. The W-C film thickness was approximately 30 - 40 nm under all conditions, except when the pulse arc current was 50 A and the film thickness, was approximately 10 nm. Compared to the WC-Ti, the consumption of cathode material is suppressed in the WC-Co, indicating that the efficiency for film preparation of the latter is good. From the X-ray diffraction analysis, the crystalline phase of W-C films fabricated using WC-Co and WC-Ti were observed as W2C and WC1-x, respectively, indicating that different crystalline phases could be fabricated using different cathodes. From the X-ray photoelectron spectroscopy analysis, the oxidation layer formed by air exposure was observed to exclusively exist on the W-C film surface. Moreover, almost all oxygen in the oxidation layer bonded with tungsten. 展开更多
关键词 CEMENTED TUNGSTEN CARBIDE CATHODE THIN Film Filtered Pulse arc deposition
下载PDF
Deposition of TiN Films by Novel Filter Cathodic Arc Technique
20
作者 牛二武 范松华 +4 位作者 李立 吕国华 冯文然 张谷令 杨思泽 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第6期1533-1535,共3页
A straight magnetic filtering arc source is used to deposit thin films of titanium nitride. The properties of the films depend strongly on the deposition process. TiN films can be deposited directly onto heated substr... A straight magnetic filtering arc source is used to deposit thin films of titanium nitride. The properties of the films depend strongly on the deposition process. TiN films can be deposited directly onto heated substrates in a nitrogen atmosphere or onto unbiased substrates by condensing the Ti^+ ion beam in about 300 eV N2^+ nitrogen ion bombardment. In the latter case, the film stoichiometry is varied from an N:Ti ratio of 0.6-1.1 by controlling the arrival rates of Ti and nitrogen ions. Meanwhile, simple models are used to describe the evolution of compressive stress as function of the arrival ratio and the composition of the ion-assisted TiN films. 展开更多
关键词 VACUUM-arc ION-IMPLANTATION VAPOR-deposition TITANIUM
下载PDF
上一页 1 2 181 下一页 到第
使用帮助 返回顶部