基于电子理论Ni基体上电沉积Cu膜内应力研究

采用电沉积法在Ni基体上制备Cu膜。悬臂梁法在线测量沉积Cu膜后的Ni基片挠度,由测得的挠度值计算出Cu膜内的平均内应力和分布内应力。结果表明,Cu膜内的平均内应力和分布内应力均随膜厚的增加而急剧减小。膜内的界面应力很大,而生长应力很小。基于改进的Thomas-Feimi-Dirac-Cheng(TFDC)电子理论,对由于界面电子密度调整而引起的Cu膜内平均内应力作出了初步估算。结果表明,理论估算结果与实验结果较接近。这说明理论计算模型具有较高的准确性。     

基于电子理论Fe基体上电沉积Cu膜内的应力研究

采用电镀法在Fe基体上电沉积Cu膜.用悬臂梁法在线测量了沉积过程中的Cu膜内的平均应力,进而研究了Cu膜内的应力分布及应力来源.结果表明,Cu膜内的平均应力和分布应力均为拉应力,它们均随膜厚的增加而减小.Cu膜内的界面应力很大,而生长应力很小.再者,基于改进的Thomas-Feimi-Dirac(TFDC)电子理论,对Fe基体上Cu膜内由界面应力引起的平均应力做出了初步估算.结果表明,理论估算结果与实验结果的应力性质完全相同,其值也较接近.这说明理论计算模型具有一定的准确性.     

基于电子理论的电镀薄膜内应力分析（英文）

用电镀方法在Fe、Ni和Ag基体上沉积Cu膜,在Fe和Ag基体上沉积Ni膜,在Cu基体上沉积Ag膜,在Fe基体沉积Cr膜,以及在Ag基体上沉积Ag膜,在Ni基体上沉积Ni膜和在Cu基体上沉积Cu膜。采用悬臂梁法原位测量了除Cr膜外其他薄膜的平均内应力。结果表明,薄膜和基体为异种材料时薄膜内界面应力很大,而为同种材料时界面应力为零。由悬臂梁的弯曲方向得到的界面应力的性质与由改进的Thomas-Fermi-Dirac电子理论得到的结果一致。     

铬膜制备及其膜内残余应力研究

对六价镀铬的工艺进行研究,在45℃、电流密度为15 A·dm-2时电沉积出光亮平整、无缺陷的铬膜.在此基础上在纯铁基体上电沉积制备出一系列不同厚度的铬薄膜,并对其残余应力进行测量和研究.结果表明:Cr膜的平均残余应力和分布残余应力均为拉应力,由于Cr膜在较薄时残余应力的骤降,可判断出其残余应力主要来自于Cr膜的界面应力,与基于Thomas-Fermi-Dirac-Cheng(TFDC)电子理论的判断结果相一致.     

剥离法测量钛基体和不锈钢基体镍膜的界面结合能

依据能量平衡法则和Moidu等人塑性弯曲耗散功的算法，并考虑残余应力对界面结合能的影响，导出了包括残余应力因素在内的剥离实验界面结合能的表达式。对钛基体和不锈钢基体镍膜的膜基结合强度进行了剥离实验研究，求出了钛基体和不锈钢基体镍膜的界面结合能。结果表明，界面结合能与膜厚、剥离角和残余应力无关。不锈钢基体镍膜的界面结合能为5．47～6．08J／m^2，钛基体镍膜的界面结合能为5．33～6．72J／m^2。实验结果还表明，膜内残余应力的存在降低了剥离强度。     

悬臂梁法测量不锈钢基体上铜膜和银膜残余应力

用悬臂梁法研究了不锈钢4Cr13基体上的Cu膜和Ag膜的平均残余应力和残余应力分布。结果表明，Cu膜和Ag膜的平均残余应力和分布残余应力随膜厚的增加而急剧减小。2种膜生长过程中界面应力很大，而生长应力很小。Cu膜在厚度较小时，残余应力值很大，超过了铜块材的断裂强度。     

基于内聚力模型的纤维复合材料残余应力分析

采用界面弹性-软化内聚力模型,用解析法研究了单纤维/聚合物基体复合材料高温固化后的残余应力分布。结果表明:较高固化温度引起界面软化和脱粘;纤维中残余应力分布由应力增长区和应力平台区组成,残余应力平台值与固化温度及纤维和基体热膨胀系数差值成正比,界面参数只对残余应力增长区的分布有影响;在界面断裂韧性相同情况下,界面弹性模量增加缩短应力传递长度,界面软化模量增加减少软化长度,弹性和软化模量变化不影响界面脱粘的温度。     

ZrO2／NiFGM中微观残余热应力分析

陶瓷—金属FGM成分沿厚度方向变化，微观残余热应力分析对确定FGM材料体系极为重要。按球对称模型采用弹性理论进行分析，确定了微观残余热应力与陶瓷和金属相的弹性性能、在FGM中的位置的关系。结果表明，微观应力具有短程分布特点，并且在同一梯度层内最大微观应力处于相界面处。同时，通过对ZrO2／Ni FGM制备过程中的陶瓷—金属界面应力的分析表明，FGM制备过程中可能在基体中产生大量微裂纹。     

退火对NiTi合金材料表面氧离子注入所产生残余应力影响的试验研究

离子体与NiTi合金材料表面相互作用可以改变材料表面的特性,在工程技术、生物医学等方面有很高的应用价值.氧离子作为注入剂注入后,在NiTi合金材料表面形成Ti02膜,薄膜与基体材料之间的晶格错配,热力学等参数失配引起薄膜与基体间的界面上出现残余应力.文中用云纹干涉与钻孔法相结合测量了NiTi合金表面氧离子注入后所产生的残余应力,探讨了退火处理对残余应力的影响.     

热障涂层界面化合物与残余应力演变研究

用超音速氧燃料热喷涂在铁基合金上制备热障涂层粘结层,用大气等离子热喷涂技术制备陶瓷层。研究了高温氧化后其界面化合物和残余应力的演变。结果表明,随着高温氧化的进行,TGO和BC/基体界面均有氧化物生成,但生长形貌和趋势并不一致。TGO由Al2O3层与尖晶石层组成;BC/基体界面氧化物为单一Al2O3,且存在层状和块状两种形貌。合金的热化学动力学引起元素Co和Ni向基底扩散比较严重,Al元素扩散止于界面氧化物层,基本不向铸铁基底扩散,Fe元素会向粘结层方向扩散。TGO残余应力的演化分为0~15 h和15~100 h 2个阶段,且残余应力与TGO的凹凸生长形貌及其物相组成密切相关;而BC/基体界面单一氧化物的残余应力基本稳定,不受其生长形貌影响。     

Micromechanisms of damage nucleation during contact deformation of columnar multilayer nitride coatings

In order to resolve some missing micromechanistic details regarding contact deformation in nitride multilayer coatings we report here observations from cross-sectional transmission electron microscopy and focused ion beam studies of the Vickers indentations on TiN/TiAlN multilayer films of various total thicknesses as well as bilayer periods. The study of damage induced by contact deformation in a nitride multilayer coating is complemented by stress calculated using an analytical model. Kinked boundaries of sliding columns give rise to cracks which propagate at an angle to the indentation axis under a combination of compressive and shear stresses. It is seen that multilayers provide more distributed columnar sliding, thereby reducing the stress intensity factor for shear cracking, while interfacial dislocations provide a stress relief mechanism by enabling lateral movement of material.     

Re与Ru合金化对Ni/Ni3Al相界电子结构影响的第一原理研究

采用第一原理赝势平面波方法研究了Re与Ru合金化前γ-Ni/γ'-Ni3Al相界的电子与能态结构.断裂功计算结果显示:Re置换γ-Ni相区中的Ni或Ru置换γ'-Ni3Al相区中的Al,均可提高Ni/Ni3Al相界的断裂强度;Re与Ru在相界区复合合金化时,当Re与Ru分别占据共格(002)γ/γ'原子层邻近(001)γ原子层上的Ni原子位与(001)γ'原子层上的Al原子位时,γ-Ni/γ'-Ni3Al相界的断裂强度可进一步提高,若其中的Ru置换γ'-Ni3Al相区内层Al,刚复合合金化Ni/Ni3Al相界的断裂强度不仅没有提高,反而比Ru单独合金化时Ni/Ni3Al相界的断裂强度还低.电子态密度与电子密度分布图的分析表明:Re与Ru合金化对γ-Ni/γ'-Ni3Al相界断裂强度的影响可归因于Re和Ru与其最近邻Ni原子间强烈的电子相互作用引起的相界区域层间原子成键相互作用的改变.     

Mg—Ni THIN FILM—A POTENTIAL NEGATIVE ELECTRODE FOR NIKEL—METAL HYDRIDE BATTERY

Mg-Ni thin films for nickel-metal hydride (Ni-MH) battery negative electrode were prepared on three different substrates by using magnetron sputtering with compacted Ni and Mg mixture powder. The microstructure of Mg-Ni thin films deposited on the glass and the Ni foil substrate respectively was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the Mg-Ni thin films were in amorphous structure and the composition of the thin film was homogeneous. Electrochemical measurement show the discharge capacity of the thin film negative electrode deposited on the foam Ni substrate was 284.8mAh/g in 6M alkaline electrolyte and the internal resistance was much lower than that of the electrode prepared by the ball-milled powder during the charge-discharge cycle.     

Microstructure and interface fracture of LPPS Ni／Fe and Cu／Ni sprayed materials

The interfaces of two materials, Ni/Fe and Cu/Ni, deposited by low pressure plasma spraying method,were studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDS). The adhesion between coatings and substrates was measured with the aid of Knoop interfacial indentation testing method. The results show that the interfacial micrcstructures have strong influence on the mechanical properties. Cu/Ni interface is weak link with NiO amorphousphase. Ni/Fehave strong in-interracial layer consists primarily of Fe and Ni oxide crystalline phases, containing dispersive (Fe, Ni) spotlike intermetaUic compound phase in nanometer dimension, and the interracial interdiffusion was detected. The micro-mechanism of interracial fracture was discussed.     

Determination of interfacial fracture energies of Ni films on titanium and stainless steel substrates by peel test

The interracial fracture energy G, which includes the effect of residual stress, was deduced for Ni films on titanium and stainless steel substrates based on the energy-balance argument and the numerical method for the work expenditure Gdb of Moidu et al. The estimated interracial fracture energies G are independent of the film thickness, the peel angle and the residual stress. The value of G for Ni films on a stainless steel substrate is about 5.47-6.08N/m for various peel angles θ, while 5.33-6.72 N/m for Ni films on titanium substrate with various film thickness h. The effect of the residual stress on the peel strength P/b was also discussed.     

Ni-Al系金属间化合物价电子结构计算及界面反应预测

应用固体与分子经验电子理论,计算了Ni-Al系各相的价电子结构和理论结合能,并应用理论结合能值进一步计算了各相的反应生成焓,通过各相生成焓的比较对界面反应生成相进行了预测。Ni、Al、Ni3Al、Ni5Al3、NiAl、Ni2Al3和NiAl3的结合能计算值分别为427.44,324.58,441.11,440.10,435.51,432.66,395.05 kJ/mol,与实验值吻合良好。在Ni/Al界面,Ni2Al3相的生成焓最小,保温过程中,Ni2Al3相将最先析出。随后,NiAl相将在Ni2Al3/Ni的界面形成,而Ni3Al相将在NiAl/Ni的界面形成。在NiAl/Ni3Al界面,Ni5Al3生成焓绝对值较小,需要在较高温度下保温较长时间才可能形成。界面反应生成相预测结果与实验结果吻合。     

Evaluation of Ni film interfacial energy release rate on titanium and stainless steel substrates

An expression including the effect of residual stress on the interfacial energy release rate is proposed for peeling experiments according to the energy-balance argument. The influence of residual stress on the external work is also contained in the expression. Two numerical methods are employed to evaluate the values of the work expenditureG _db , which is the actual energy dissipated during bending of the peel arm near the peel front. The peeling method is employed to test the interfacial energy release rates,G, for Ni films on Titanium and stainless steel substrates. The results indicate that the value ofG for Ni films on stainless steel substrate is about 5.47–6.03 N/m, while 5.23–6.71 N/m for Ni films on titanium substrate; the interfacial energy release rates,G, do not depend on the residual stress in film, film thickness nor peel angle. The effect of residual stress in film on peel strengthP/h is also discussed.     

Effect of annealing on the interfacial adhesion energy between electroless-plated Ni and polyimide

The effect of annealing on the interfacial adhesion energy between electroless-plated Ni films and polyimide substrates was evaluated using a 180-degree peel test. The measured peel strength values decrease from 263.6 ± 7.8 J/m² to 109.3 ± 6.4 J/m² after annealing for 100 h at 200 °C in an ambient environment. XPS analysis on the peeled surfaces reveals that the peeling is due to cohesive failure inside the polyimide, which is related to the fact that wet treatment produces an activated bonding mechanism between electroless-plated Ni and polyimide. This implies a degradation of the polyimide structure due to oxygen diffusion through the interface between Ni and alkali wet-treated polyimide, which is also closely related to the decrease in the interfacial adhesion energy due to thermal treatment in ambient conditions.