Cr与B对镍基高温钎料在Cf/SiC陶瓷基复合材料上润湿性的影响

研究了Cr和B元素对镍基高温钎料在3D-Cf/SiC陶瓷基复合材料上的润湿性的影响.试验结果发现,在真空度小于10-3 Pa,工作温度1100 ℃,保温时间10 min条件下,当钎料中的Cr元素含量为15%,B元素含量为0.6%时,镍基钎料在Cf/SiC上的润湿角为10°,然而B元素含量增加到2.4%后,润湿角增大到62°,表明钎料中的元素B降低钎料在Cf/SiC上的润湿性.钎料中的活性元素Cr对润湿有重要影响.镍基钎料在Cf/SiC上的润湿过程属于反应润湿,润湿界面生成多种碳化物和硅化物.采用扫描电镜与能谱仪分析界面的微观结构与成分,通过X射线衍射仪检测界面产物.     

Fe-Cr合金在TiO陶瓷上的润湿及其机理

Fe Cr合金对一氧化钛的润湿性能较差 ,在熔点温度下各成分的Fe Cr合金在一氧化钛上的润湿角都在 90°左右。当铬含量≤ 5 0 %时 ,Fe与TiO间存在界面反应 ,生成Fe2 Ti和Ti3 O2 。但界面反应的产生 ,并不能有效改善其润湿性。随着润湿温度的升高 ,合金的润湿性略有改善。在Fe Cr合金中添加少量的表面活性物质Si,可改善Fe Cr合金在一氧化钛上的润湿性。因为在润湿过程中Si在界面的富集 ,不仅降低了界面能和液相表面张力 ,有效改善了合金的润湿性 ,而且阻止了Fe与TiO间的界面反应 ,使反应型润湿转变为非反应型润湿。添加合金元素Si1.5 %以上 ,可使润湿角降至 2 5°左右。     

Fe78B13Si9条带与液态Sn的润湿性

用座滴法研究了Fe78B13Si9原始非晶条带和其预退火条带与液态Sn的润湿性。结果表明，与普通晶态合金之间的润湿规律不同。原始非晶Fe78B13Si9基底与液体Sn的平衡接触角并不随温度升高而单调减小，与原始非晶Fe78B13Si9基底相比。当润湿温度低于预退火温度时，Fe78B13Si9非晶基底的预退火使其平衡接触角显著增大；当润湿温度高于预退火湿度时，Fe78B13Si9基底的预退火对其平衡接触角没有明显影响。     

激光钎焊AgCu基钎料润湿性理论模型构建

通过向Ag Cu_(28)共晶粉末中添加适量活性元素钛(Ti)、锆(Zr),制备了AgCu_(28)-4.5Ti和AgCu_(28)-4.5Ti-4Zr两种活性复合钎料,研究了脉冲激光作用下两种钎料的润湿性能。通过三维电控超景深显微镜实验及钎料润湿性理论模型两种方法进行了润湿角的测量计算。结果表明,活性元素Zr能够促进Ag Cu基钎料的润湿铺展性能,使钎料润湿角降低约10°,含Zr钎料的钎焊性能良好。当润湿角在40°左右时,该理论模型能够准确求得钎料焊后润湿角;当钎料润湿性能增强时,钎焊层润湿角测量值与计算值间的误差有所增大,钎料润湿角在30°左右时,其相对误差约为10%。     

两种Pd-Ni基高温钎料在Si3N4陶瓷上的润湿性

采用座滴法研究了两种钎料PdNi-(15～22)v和PdNi-(16～24)Cr在Si3N4陶瓷上的润湿性.结果表明,两种钎料的熔点及润湿性均有很大差别,PdNi-(16～24)Cr钎料对Si3N4陶瓷的润湿铺展良好.PdNi-(16～24)Cr钎料与Si3N4陶瓷形成的扩散反应层中,Cr元素主要分布在扩散反应层区域,根据各元素所占比例,Cr元素主要与母材扩散出的N元素形成Cr2N相.由于Cr原子向母材界面扩散,从而改善了钎料的润湿性.     

等离子喷涂含Al_2O_3-TiO_2颗粒的Fe基非晶合金涂层的性能(英文)

采用大气等离子喷涂技术成功在Fe普碳钢基材上制备了含有不同质量分数Al2O3-13%Ti O2颗粒的Fe基非晶复合涂层,其中Fe基非晶相成分为Fe71Cr5B4Si4Ni3Mo3W10(wt%),并对涂层的微观结构、显微硬度和耐蚀性能进行了研究。在Fe基非晶相与Al2O3-13%Ti O2陶瓷相界面观察到Fe、Ti、W、Al和O元素的互扩散现象,这种微区冶金结合减少了由于第二相的加入导致的涂层孔隙并增加了相间的结合强度。当加入的Al2O3-13%Ti O2质量分数≥16 wt%时,涂层的显微硬度升高≥20%;复合非晶涂层在10 wt%Na OH溶液中的耐腐蚀性能高于1Cr18Ni9Ti不锈钢。     

Fe基非晶纳米晶涂层在油润滑条件下的耐磨损性能

采用自动化高速电弧喷涂技术在AZ91镁合金基体上制备了厚度约为300μm的Fe基非晶纳米晶涂层。研究了Fe基非晶纳米晶涂层在油润滑条件下,不同速度(180r/min、300r/min、600r/min、900r/min、1200r/min)、载荷(2.5N、5N、10N、20N、30N)对涂层的摩擦磨损行为。采用扫描电镜、能谱分析仪、X射线衍射仪和透射电镜对涂层的组织结构进行了表征,利用纳米压痕仪对涂层的力学性能进行了分析。试验结果表明:Fe基非晶纳米晶涂层组织均匀、结构致密,氧化物含量和孔隙率低,主要由非晶相和纳米晶相组成;涂层具有较高的硬度(12.03GPa)和弹性模量(197.1GPa)。在载荷为30N、速度为300r/min、磨损时间为900s条件下,其相对耐磨性是3Cr13涂层的3倍。Fe基非晶纳米晶涂层的磨损失效机制为脆性疲劳剥落。     

HVOF喷涂Fe-Cr基涂层中非晶与纳米晶形成的研究

采用多元Fe基合金（含Cr、Si、Mn、B等）作为喷涂粉末,用超音速火焰（HVOF）喷涂法在不锈钢基体上制备厚度约200μm的Fe-Cr基涂层.用X射线衍射、扫描电镜、透射电镜、差示扫描量热仪（DSC）对涂层的组织结构特征进行了研究.涂层由于熔融和半熔化状态的液滴的连续堆积而成层状,由Fe基非晶、纳米晶及硼化物组成,纳米晶尺寸约为10-30nm.DSC分析表明非晶的晶化温度约为605℃.非晶的形成是由于喷涂液滴快的冷却速度及合适的粉末成分;非晶由于后续熔融液滴的堆积对前涂层产生退火效应,以非均匀形核的方式分别在非晶内部和非晶与硼化物的界面形成.     

镁对铝与粉煤灰润湿性的影响

用改进的座滴法测量了铝合金在粉煤灰上的润湿角.在铝中添加Mg能减小铝对粉煤灰的润湿角,由于Mg能在液滴表面挥发,破坏铝滴表面新产生的氧化铝,从而改善润湿性.粉煤灰中的SiO2、Fe2O3与铝发生反应,促进铝合金与基片的润湿,但铝滴表面Mg的挥发变慢,导致其破坏铝滴表面氧化铝的能力逐渐变弱,表层氧化铝的生长速度变快,同时SiO2、Fe2O3与铝反应减弱,反应性润湿影响变小,非反应性润湿在润湿过程中所起作用变大.     

镍基钎料对45#钢激光熔覆镍基WC合金熔覆层缺陷的影响

目的改善Ni60A+WC合金粉末激光熔覆中裂纹和气孔等缺陷性能。方法在Ni60A+WC合金粉末中添加膏状镍基钎料(BNi-1a)改善激光熔覆层的裂纹和气孔缺陷。使用Rofin FL020光纤激光器,在1 kW功率、扫描速度为4 mm/s、光斑直径约为2 mm的条件下,对经过烘干的预涂覆合金熔覆层进行激光加工处理。通过显微硬度测试评价熔覆层的硬度,通过扫描电子显微镜和X射线衍射仪对熔覆层形貌、相组织进行分析,并通过UMT和表面形貌仪对熔覆层的摩擦系数和耐磨性进行评估。结果在Ni60A+WC合金粉末中添加膏状镍基钎料(BNi-1a),优化了Cr和C合金相的组成,使熔覆层的裂纹和气孔等缺陷明显减低。添加膏状镍基钎料的熔覆层的摩擦系数约为0.45,熔覆层的摩擦系数大约降低了18%。同时熔覆层的耐磨性也有所提高,未添加膏状镍基钎料的熔覆层磨痕横截面积约为0.70×10~(-3) mm~2,而添加膏状镍基钎料的熔覆层横截面积约为0.50×10~(-3) mm。结论镍基钎料(BNi-1a)的加入可以有效减少熔覆层的裂纹和气孔等缺陷,同时提高熔覆层的耐磨性,但是使熔覆层的硬度有一定的降低。     

Network based requirement specification

Requirement specifications often resemble static design briefs. Whereas such unequivocal references are essential, the dynamics of product development require more insight, nuancing, flexibility and evolvement. This encompasses relative importance, context and provenance of the requirements related to the different stakeholders involved. In developing responsive requirement specifications, the so-called actor network is employed. Such a network maps the relevant stakeholders over the development life cycle, thus expressing the set of requirements as a whole, as well as the evolving coherence between them. This publication demonstrates the structure and purpose of network based requirements and the added value for product developers.     

Condition based factory planning

Consecutive planning approaches, common in the theory of factory design today, fail to support planning projects in practice. They neglect the interactions and dynamics in the planning task and project as well as the subjectivity introduced by the different stakeholders. Unconsidered interactions, conflicting motives and inflexible project structure lead to time-consuming, expensive and late adaptations. Local optimisation and deviations from the overall objectives are consequences of insufficient synchronisation and coordination. The approach proposed in this paper strives for a paradigm shift from consecutive processes to a modular, parallel approach, which can be reconfigured according to the specific conditions of the planning project and enterprise. This new approach integrates the modularisation and configuration of the planning process as well as aspects of management of instability and second order observation. It has been successfully employed in industry cases, which will be introduced in this paper.     

Development of Re‐based diffusion barrier coatings on nickel based superalloys

A diffusion barrier type coating with a duplex layer structure, an inner σ‐(Re, W, Cr, Ni) as a diffusion barrier and outer Ni‐aluminide as an Al reservoir, was formed on a Nickel based, single crystal, superalloy (TMS‐82 +) and on Hastelloy X. Oxidation properties of both the alloys with or without the diffusion barrier coating were investigated in air under thermal cycling between room temperature and 1423 K for up to 360 ks. The inner σ layer with a composition (at%) of (35–40) Re, (15–20) W, (15–25) Cr and (15–25) Ni was produced by electrodeposition of Ni‐70Re and Ni‐20W films from aqueous solutions followed by Cr‐pack cementation at temperatures between 1473 and 1573 K, and the outer Ni‐aluminides of β‐(Ni,Cr)Al + γ′‐(Ni,Cr)₃Al was formed by electrodeposition of a Ni film, followed by Al pack cementation. After the 360 ks oxidation it was found that the structure and composition of both σ layer and alloy substrate were retained with little change. Furthermore, there was little Al in the σ layer. It could be concluded that the Re‐based alloys such as σ (Re(W),Cr,Ni) are very promising candidates as a diffusion barrier between the outer Al‐reservoir layer and alloy substrate at temperature of 1423 K. It was found that the Re(W)‐Cr‐Ni acts as a diffusion barrier for both inward diffusion of Al and outward diffusion of alloying elements in the alloy substrate.     

Pentacene based photovoltaic devices

Photovoltaic diodes based on iodine- and bromine-doped pentacene single crystals as well as thin films (TFs) have been prepared. Two different device structures, a Schottky diode with a Mg/Al back contact and a heterojunction with a ZnO:Al window layer, are investigated. An immense increase of the photovoltaic conversion efficiency of these devices is observed upon doping with iodine as well as bromine, which is ascribed to a reduction of the series resistance, an increase in quantum efficiency, and a red shift of the absorption spectrum. AM1.5 efficiencies of 2.7 and 4.5% are obtained for single crystal Schottky diodes and heterojunctions, respectively. In addition, efficiencies exceeding 2% are realized in TF devices on flexible plastic substrates.     

Polyphosphate based electrochemical capacitors

Environmentally friendly electrochemical capacitors (ECs) were assembled using hybrid materials formed by a polyphosphate gel matrix in which carbon-based materials were inserted and polyaniline were formed in a single-step synthesis. The hybrid materials were deposited on FTO glasses and symmetric ECs were assembled using a cellulose membrane soaked with an aqueous NaH₂PO₄ solution as a separator. The capacitance values were calculated from impedance spectroscopy and galvanostatic charge/discharge measurements. The devices showed capacitances ranging from 4.0 to 27.0 F cm^?3, which are comparable to some commercial devices. Better results were achieved in samples with polyaniline, which were ascribed to the pseudocapacitance impaired to the samples by the conducting polymer.     

基于MAS和XML的网上产品报价系统的研究

文章分析了现行机械制造企业建立一个网上报价系统的必要性,利用目前流行的MAS理论构建了报价系统的框架,并利用XML语言进行网上数据的传输实现Agent间的通信,文章最后给出了系统的具体实现.     

戎于PROFIBUS—DP的计算机数控系统

在分析了传统计算机数控系统布线复杂和维护困难的基础上,提出基于PROFIBUS－DP现场总线的计算机数控系统。总结了该系统在应用时的特点。结合加工中心数控系统,给出了该系统的现场总线网络结构。     

基于PROFIBUS-DP总线的智能采集控制器

介绍了基于 PROFIBUS-DP总线的智能采集控制器研制 ,该控制器可应用到现场设备的数据采集及控制     

Misch metal based metallic glasses

In this paper, a glass-forming range of metallic glasses based on Ce-rich misch metal (Mm) was pinpointed in Mm-Al-Co composition map by melt spinning. The thermal analysis indicated that the wide supercooled liquid region (above 60 K) can be found out in a large composition range in Mm-Al-Co system. The investigation of the glass-forming ability (GFA) in this system indicated a glassy composition with a larger supercooled liquid region wouldn’t be the glassy former with higher GFA. The reduced glass transition temperature is a better indicator to explore metallic glasses with high GFA. Furthermore, the mechanical properties of Mm₆₅Al₁₀Co₂₅ bulk glassy samples were evaluated in a compressive measurement. The obvious advantages of the Mm-based BMGs with high GFA, good mechanical properties and low material cost make these BMGs hopeful to be applied in the future.     

Experimental and atomistic simulation based study of W based alloys synthesized by mechanical alloying

The present research work represents the synthesis of nanostructured W based alloys with the nominal compositions of W₉₀Mo₁₀ and W₈₀Ni₁₀Mo₁₀ (all in wt.%) by mechanical alloying and followed by conventional sintering at 1500 °C for 2 h in Ar atmosphere. The microstructure and evolution of phases during milling and consolidated products are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Energy dispersive spectroscopy (EDS). Crystallite size of 38.7 nm and 40 nm and lattice strain of 0.41% and 0.33% are achieved in W₉₀Mo₁₀ and W₈₀Ni₁₀Mo₁₀ alloy respectively at 20 h of milling. The lattice parameter of all the investigated alloys shows initial expansion at 10 h of milling and then contraction at 20 h of milling. W₈₀Ni₁₀Mo₁₀ shows maximum sintered density of 94.8% as compared to W₉₀Mo₁₀. The hardness as well as the compressive strength of W₈₀Ni₁₀Mo₁₀ alloy records maximum value of 8.57 GPa and 1.18 GPa, respectively. The minimum wear depth is attained in W₈₀Ni₁₀Mo₁₀ alloy to that of W₉₀Mo₁₀. Molecular dynamic simulation based study is also performed to reveal the mechanisms responsible for deformation. Atomistic simulation shows that addition of nickel lowers the flow stress and increases ductility of W-Mo alloy studied at nanoscale. Results of atomistic simulation based study correlates well with experimental analysis.