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涂层 2

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超音速火焰喷涂WC涂层替代电镀硬铬：疲劳和摩擦磨损性能

周克崧,邓春明,刘敏

《中国工程科学》 2009年第11卷第10期页码 48-54

摘要：

以WC涂层在飞机起落架的应用作为研究背景，对300 M超高强钢基体上电镀硬铬和超音速火焰喷涂WC-17Co和WC-10Co4Cr涂层的疲劳及与结果表明，有WC涂层300 M钢的疲劳寿命与无涂层300 M钢的疲劳极限和过载下的疲劳寿命相当，WC涂层对300 M钢的疲劳寿命不会产生不良影响；而电镀硬铬使300 M钢的疲劳极限降低120 MPa，疲劳寿命则降低疲劳失效分析表明， WC涂层中的疲劳裂纹在界面上发生偏斜，转向沿界面扩展，因此对基体的疲劳寿命没有影响；而电镀硬铬中的的疲劳裂纹扩展到基体表面，显著降低基体的疲劳寿命。；而WC涂层仅略有失重，相应地Al—Ni—Bronze合金的失重仅为与电镀硬铬层磨损失重的1/50～1/100。WC涂层与Al—Ni—Bronze合金的磨损机理主要为磨粒磨损；电镀硬铬与Al—Ni—Bronze合金的磨损机理主要为黏着磨损。

关键词： 300 M钢超音速火焰喷涂 WC涂层电镀硬铬疲劳摩擦磨损

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Mechanism of methanol decomposition on the Pd/WC(0001) surface unveiled by first-principles calculations

Jinhua Zhang, Yuanbin She

《化学科学与工程前沿（英文）》 2020年第14卷第6期页码 1052-1064 doi: 10.1007/s11705-019-1908-y

摘要： In this study, the decomposition of methanol into the CO and H species on the Pd/tungsten carbide (WC)(0001) surface is systematically investigated using periodic density functional theory (DFT) calculations. The possible reaction pathways and intermediates are determined. The results reveal that saturated molecules, i.e., methanol and formaldehyde, adsorb weakly on the Pd/WC(0001) surface. Both CO and H prefer three-fold sites, with adsorption energies of ‒1.51 and ‒2.67 eV, respectively. On the other hand, CH O stably binds at three-fold and bridge sites, with an adsorption energy of ‒2.58 eV. However, most of the other intermediates tend to adsorb to the surface with the carbon and oxygen atoms in their sp and hydroxyl-like configurations, respectively. Hence, the C atom of CH OH preferentially attaches to the top sites, CHOH and CH O adsorb at the bridge sites, while COH and CHO occupy the three-fold sites. The DFT calculations indicate that the rupture of the initial C–H bond promotes the decomposition of CH OH and CH OH, whereas in the case of CHOH, O–H bond scission is favored over the C–H bond rupture. Thus, the most probable methanol decomposition pathway on the Pd/WC(0001) surface is CH OH → CH OH → -CHOH → CHO → CO. The present study demonstrates that the synergistic effect of WC (as carrier) and Pd (as catalyst) alters the CH OH decomposition pathway and reduces the noble metal utilization.

关键词： density functional theory methanol direct methanol fuel cells WC(0001)-supported Pd monolayer decomposition mechanism

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different dielectrics on environmentally conscious powder-mixed EDM of difficult-to-machine material (WC-Co

Jagdeep SINGH,Rajiv Kumar SHARMA

《机械工程前沿（英文）》 2016年第11卷第4期页码 374-387 doi: 10.1007/s11465-016-0388-8

摘要：

Electrical discharge machining (EDM) is a well-known nontraditional manufacturing process to machine the difficult-to-machine (DTM) materials which have unique hardness properties. Researchers have successfully performed hybridization to improve this process by incorporating powders into the EDM process known as powder-mixed EDM process. This process drastically improves process efficiency by increasing material removal rate, micro-hardness, as well as reducing the tool wear rate and surface roughness. EDM also has some input parameters, including pulse-on time, dielectric levels and its type, current setting, flushing pressure, and so on, which have a significant effect on EDM performance. However, despite their positive influence, investigating the effects of these parameters on environmental conditions is necessary. Most studies demonstrate the use of kerosene oil as dielectric fluid. Nevertheless, in this work, the authors highlight the findings with respect to three different dielectric fluids, including kerosene oil, EDM oil, and distilled water using one-variable-at-a-time approach for machining as well as environmental aspects. The hazard and operability analysis is employed to identify the inherent safety factors associated with powder-mixed EDM of WC-Co.

关键词： WC hazard and operability analysis (HAZOP) discharging aerosol concentration dielectrics powders

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Optimization of multi machining characteristics in WEDM of WC-5.3%Co composite using integrated approach

Kamal JANGRA, Sandeep GROVER, Aman AGGARWAL

《机械工程前沿（英文）》 2012年第7卷第3期页码 288-299 doi: 10.1007/s11465-012-0333-4

摘要：

Wire electrical discharge machining (WEDM) is a well known process for generating intricate and complex geometries in hard metal alloys and metal matrix composites with high precision. In present work, intricate machining of WC-5.3%Co composite on WEDM has been reported. Taguchi’s design of experiment has been utilised to investigate the process parameters for four machining characteristics namely material removal rate, surface roughness, angular error and radial overcut. In order to optimize the four machining characteristics simultaneously, grey relational analysis (GRA) coupled with entropy measurement method has been employed. Through GRA, grey relational grade has been computed as a performance index for predicting the optimal parameters setting for multi machining characteristics. Using Analysis of Variance (ANOVA) on grey relational grade, significant parameters affecting the multi-machining characteristics has been determined. Confirmatory results prove the potential of present approach.

关键词： tungsten carbide composite wire electrical discharge machining (WEDM) Taguchi method grey relational analysis (GRA) entropy measurement method

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基于同步波动原理的抗冲蚀弹性涂层设计

郭源君,肖华林,徐大清,李文斌

《中国工程科学》 2008年第10卷第9期页码 60-63

摘要：

基于过流面冲蚀波纹形貌特征与流体边界层扰动波参数的对应关系，提出了实现弹性涂层边壁与边界层扰动波的同步波动，从而变边壁被动承受粒子冲击为主动回避与粒子的碰撞的抗冲蚀设计思想；分析了实现弹性涂层边壁与边界层扰动波同步波动的条件，并由此确定出弹性涂层的材料常数。

关键词：冲蚀边界层弹性边壁弹性涂层同步波动

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钢桥梁电弧喷涂纳米封闭复合涂层体系设计

易春龙,沈旺,童育强,刘国彬,于旭东

《中国工程科学》 2010年第12卷第7期页码 53-56

摘要：

为了解决大型桥梁钢箱梁的长效防腐蚀问题，以浙江舟山连岛工程西堠门大桥防腐蚀工程为依托，结合电弧喷涂防腐蚀技术和纳米改性封闭涂层技术，提出了电弧喷涂纳米封闭复合涂层体系的设计思路，对比了电弧喷涂长效防腐传统方案与创新设计方案，对不同腐蚀环境下推荐设计采用不同的电弧喷涂金属涂层材料，对比分析了纳米封闭涂层与普通环氧底层的技术指标，简述了电弧喷涂纳米封闭复合涂层施工各工序的质量要求和检测方法

关键词：电弧喷涂复合涂层纳米材料钢桥梁防腐蚀

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蒸汽压力和超疏水纳米复合涂层对微电子器件可靠性的影响 Article

樊学军,陈良彪,汪正平,Hsing-Wei Chu,张国旗

《工程（英文）》 2015年第1卷第3期页码 384-390 doi: 10.15302/J-ENG-2015034

摘要：为了最大程度地减小湿度的影响，可以在器件外表面涂抹一层超疏水涂层，以防止水分渗入。但是，超疏水涂层提高微电子器件可靠性的具体机制目前仍没有完全被理解。笔者还根据实验结果论述了超疏水涂层在防止水蒸气进入器件方面的机制和有效性。本文重点讨论了两个理论模型：基于微观力学的全场蒸汽压力模型和对流扩散模型。这两种方法都已成功用于说明无涂层样本的实验结果。但是，当器件上涂有超疏水纳米复合涂层时，笔者仍发现器件质量增加，其原因很可能是水蒸气可以透过超疏水涂层渗入。这种现象导致人们对超疏水涂层的有效性产生怀疑。根据理论和实验结果，笔者认为需要提出一种新的理论来理解水蒸气如何渗透超疏水涂层。

关键词：蒸汽压力湿度半导体可靠性微机电系统(MEMS) 超疏水纳米复合涂层

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Al₂O₃-M_xO_y硬面陶瓷涂层的喷焊制备及性能研究

王飚,王宇栋,李慧玲,张自华

《中国工程科学》 2002年第4卷第9期页码 75-80

摘要：

在碳钢母材上，用氧乙炔焰喷焊镍包铝合金粉末制取预涂层，喷焊50% Al₂O₃+50% Ni的复合粉末制取过渡层，用等离子喷焊Al₂O₃ - M_xO_y复合粉末制取最终涂层。在质量分数为60%的硫酸与磷矿粉组成的混合介质（质量比为6∶4）中运转，所获得涂层的抗腐抗磨能力为18-8不锈钢的7.46倍，为德产316L不锈钢的4.06倍。

关键词： Al₂O₃-M_xO_y 涂层等离子抗腐蚀抗磨损

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Wide gap active brazing of ceramic-to-metal-joints for high temperature applications

K. Bobzin,L. Zhao,N. Kopp,S. Samadian Anavar

《机械工程前沿（英文）》 2014年第9卷第1期页码 71-74 doi: 10.1007/s11465-014-0291-0

摘要：

Applications like solid oxide fuel cells and sensors increasingly demand the possibility to braze ceramics to metals with a good resistance to high temperatures and oxidative atmospheres. Commonly used silver based active filler metals cannot fulfill these requirements, if application temperatures higher than 600°C occur. Au and Pd based active fillers are too expensive for many fields of use. As one possible solution nickel based active fillers were developed. Due to the high brazing temperatures and the low ductility of nickel based filler metals, the modification of standard nickel based filler metals were necessary to meet the requirements of above mentioned applications. To reduce thermally induced stresses wide brazing gaps and the addition of Al₂O₃ and WC particles to the filler metal were applied. In this study, the microstructure of the brazed joints and the thermo-chemical reactions between filler metal, active elements and WC particles were analyzed to understand the mechanism of the so called wide gap active brazing process. With regard to the behavior in typical application oxidation and thermal cycle tests were conducted as well as tensile tests.

关键词： wide gap active brazing nickel filler metals high temperature application WC Al₂O₃

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激光熔覆NiCrAl-陶瓷涂层的显微组织研究

陈庆华,魏仑,龙晋明,李俊昌

《中国工程科学》 2001年第3卷第10期页码 64-71

摘要：钢表面制备了(TiO₂+B₂O₃+Al₂O₃+TiB₂)/NiCrAl金属陶瓷涂层

关键词：激光熔覆金属陶瓷微观组织物相显微硬度

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通过 B 位Ta置换对 AB O₄型EuNbO₄的热学和力学性质进行优化 Article

陈琳, 冯晶

《工程（英文）》 2020年第6卷第2期页码 177-184 doi: 10.1016/j.eng.2019.12.006

摘要：

铁弹性的ABO₄型RETaO₄陶瓷和RENbO₄陶瓷（RE表示稀土）是具有潜在应用价值的热障涂层（TBC）材料，

关键词：热障涂层，稀土铌酸盐，置换，热导率，热膨胀系数，杨氏模量

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钠超离子导体型固体电解质的改性及其在钠离子电池中的应用 Article

张强强, 周权, 陆雅翔, 邵元骏, 戚钰若, 戚兴国, 钟贵明, 杨勇, 陈立泉, 胡勇胜

《工程（英文）》 2022年第8卷第1期页码 170-180 doi: 10.1016/j.eng.2021.04.028

摘要：

固体电解质的低离子电导率及固体电解质与固态电极之间较差的界面可靠性是阻碍固态钠电池（SSSB）应用的两大紧迫挑战。本文采用简单的两步固相法合成了名义成分为Na_3+2xZr_2‒xMg_xSi₂PO₁₂ 的钠（Na）超离子导体（NASICON）型固体电解质，其中在25 ℃时Na_3.3Zr_1.85Mg_0.15Si₂PO₁₂（x=0.15, NZSP-Mg_0.15)表现出了3.54 mS∙cm^‒1的最高离子电导率。通过深入研究，本文证实晶界成分在决定NASICON总离子电导率中起着至关重要的作用。此外，由于文献中缺乏关于NASICON是否能够提供足够的阳极电化学稳定性来实现高压固态钠电池的研究，我们首先使用了高压Na₃(VOPO₄)₂F (NVOPF)正极来验证其与优化后的NZSP-Mg_0.15固体电解质之间的兼容性。通过比较不同配置（低压阴极与高压阴极、液态电解质与固体电解质）电池的电化学性能，以及对循环后的NZSP-Mg_0.15进行X射线光电子能谱（XPS）评估，结果表明，NASICON固体电解质在高电压下不够稳定，这证明了研究NASICON固体电解质和高压阴极之间界面的重要性。此外，通过将NZSP-Mg_0.15 NASICON 粉末涂在聚乙烯（PE）隔膜（PE@NASICON）上，形成了2.42 A∙h 的碳|PE@NASICON|NaNi_2/9Cu_1/9Fe_1/3Mn_1/3O₂ 非水系钠离子电池，其具有出色的循环性能，在2000 周循环后容量保持率为88%，从而证明涂有NASICON型固体电解质的隔膜具有高可靠性。