First principles calculation of stable structure and adhesive strength of plated Ni/Fe(100) or Cu/Fe(100) interfaces

A study the with first principles calculation of the interfaces of the Ni layer or Cu layer on the Fe(100) surface formed with metal plating was performed.Ni or Cu atoms were shown to adopt the corresponding position to the bcc structure of the Fe(100) substrate.Other calculations showed that the interfaces of Ni(5 atomic layers)/Fe(100)(5 layers) or Cu(5 atomic layers)/Fe(100)(5 layers) had square lattices.The orientation relationship of Ni/Fe(100) interface corresponds to fcc-Ni(100)//bcc-Fe(100),Ni[011]//Fe[010],and Ni[011]//Fe[001].Similar results were obtained for Cu/Fe(100) interfaces.This structure was supported by TEM analysis of plated Ni layer on Fe(100) surfaces.The adhesion strength of the Ni/Fe(100) interface evaluated by first principles calculation was higher than that of the Cu/Fe(100) interface.The experimental results of Hull cell iron plated with Ni or Cu supported the results of the calculation.These results indicate that the first principles calculation,which deals with the ideal interface at the atomic scale,has the potential to evaluate the adhesion strength of metallic material interfaces.

Push-out Bond Strength of Self-adhesive Methacrylate Resin-based Sealers to Root Dentin

This study examined the adhesive strength of two self-adhesive methacrylate resin-based sealers（MetaSEAL and RealSeal SE） to root dentin and compared them with RealSeal and AH Plus in properties. A total of 48 extracted human single-rooted teeth were used to prepare the 0.9-mm thick longitudinal tooth slice（each per tooth）. Standardized simulated canal spaces of uniform dimensions were prepared in the middle of radicular dentin. After treated with 5.25% sodium hypochlorite（NaOCl） and 17% EDTA, tooth slices were allocated randomly to four groups（n=12） in terms of different sealers used： MetaSEAL, RealSeal SE, RealSeal, and AH plus groups. The simulated canal spaces were obturated with different sealers in each group. There were 10 slabs with 20 simulated canal spaces（n=20） used in each group for push-out testing. The failure modes and the ultrastructures of fractured sealer-dentin interfaces were examined. The remaining 2 slabs in each group underwent partial demineralization for observation of the ultrastructure of resin tags. The results showed that the push-out bond strength was 12.01±4.66 MPa in MetaSEAL group, significantly higher than that in the other three groups（P0.05）. Moreover, no statistically significant differences were noted in the push-out bond strength between RealSeal SE（5.43±3.68 MPa） and AH Plus（7.34±2.83 MPa） groups and between RealSeal SE and RealSeal（2.93±1.76 MPa） groups（P0.05）. Mixed failures were predominant in the fractured sealer-dentin interfaces in MetaSEAL and AH Plus groups, while adhesive failures were frequently seen in RealSeal SE and RealSeal groups. In conclusion, after complete removal of the smear layer, MetaSEAL showed superior bond ability to root dentin. The RealSeal SE is applicable in clinical practice, with its adhesive strength similar to that of AH Plus. The self-adhesive methacrylate resin-based sealer holds promise for use in endodontic treatment.

Interface strengthening for thermal sprayed WC-10Co4Cr coating subjected to pulsed magnetic treatment

The reliability of the coated industry components demands ideal fatigue properties of the coating,and it is mainly determined by the performance of the interfaces.In this study,pulsed magnetic treatment(PMT)was applied to the thermal sprayed WC-10Co4Cr coating,and the fatigue lifetime of the coated bolt increased by 219.82%under an imitation of the operating mode condition.Scratch tests further proved that both the adhesion and cohesion strength were improved after PMT,and they benefit from the interface strengthening effects.The formation of coherent WC/Co interfaces was characterized by in-situ transmission electron microscopy(TEM),and the molecular dynamic simulations indicate that the work of separation of these interfaces is much higher than the original disordered ones.Residual stress was relaxed and distributed more homogeneously after PMT,and it mainly contributes to the coating/substrate strengthening.This work provides a new post-treatment method focusing on the interfaces in the WC-based coating and gives insight into its mechanism so that it is hopeful to be applied to other kinds of coatings.

诺丽对冠部牙本质粘接强度及纳米渗漏的影响

目的探讨诺丽(Morinda citrifolia juice,MCJ)联合乙二胺四乙酸盐(ethylene diaminete traacetic acid,EDTA)根管冲洗对冠部牙本质粘接强度及纳米渗漏的影响,并与临床上最常用的根管冲洗液次氯酸钠(sodi⁃um hypochlorite,NaClO)相比较,为临床应用提供参考。方法本研究已通过单位伦理审查委员会批准。选取63颗因正畸拔除的人前磨牙,去除表面釉质暴露牙本质平面后,根据冲洗液不同随机分为对照组(蒸馏水组)和6个实验组,即:A组2.5%NaClO、B组5.25%NaClO、C组6%MCJ、D组2.5%NaClO⁃17%EDTA、E组5.25%NaClO⁃17%EDTA和F组6%MCJ⁃17%EDTA(n=9),分别用相应冲洗液浸泡20 min后,在其表面分层堆积4 mm×4 mm×3 mm的Z350树脂块,每组选取6个样本,低速切割机将每个样本切割成1 mm×1 mm×8 mm的试件条,进行微拉伸粘接强度测试,随后在体视显微镜下观察断裂类型;每组剩余的3个样本经老化后切割成1 mm厚的薄片,进行界面纳米渗漏测试以及扫描电子显微镜下观察树脂⁃牙本质粘接界面。结果各组微拉伸粘接强度测试值均有显著性差异(P<0.05),对照组粘接强度最高。实验组中,B组粘接强度最低,以粘接界面破坏为主;F组粘接强度最高,以混合破坏为主。各组纳米渗漏值均有显著性差异(P<0.05),对照组纳米渗漏值最低。实验组中,B组纳米渗漏值最高、树脂突较细,F组纳米渗漏值最低、树脂突粗大且密集。结论NaClO浓度越高,冠部牙本质的粘接强度及边缘封闭性越差;MCJ联合EDTA根管冲洗对冠部牙本质的粘接强度和边缘封闭性的影响小于NaClO联合EDTA根管冲洗。

输电线路复合绝缘子伞裙与护套粘接界面强度预测

研究基于输电线路复荷绝缘子伞裙与护套粘接界面强度预测方法,明确复合绝缘子使用状态,使输电线路更好地进行电力传输。以FXBW-110/120-22型复合绝缘子为例,通过单边核磁共振传感器发射的CPMG脉冲序列,测量复合绝缘子伞裙与护套粘接界面横向弛豫时间,并经CPMG回波衰减数据双指数函数拟合,得到复合绝缘子伞裙与护套粘接界面强度衰减曲线,从而完成对伞裙与护套粘接界面强度的预测。实验结果表明,该方法利用横向弛豫时间进行复合绝缘子伞裙与护套粘接界面强度预测的灵敏度更高;在低温、高温环境、紫外线照射强度以及灰尘与泥土附着物含量增加的情况下,会导致复合绝缘子复合绝缘子等效横向弛豫时间降低,使伞裙与护套粘接界面强度衰减曲线衰减程度加大,降低伞裙护套粘接界面强度。

Enhanced adhesion of Cu-W thin films by ion beam assisting bombardment implanting

Cu-W thin film with high W content was deposited by dual-target DC-magnetron co-sputtering technology.Effects of the substrates surface treating technique on the adhesive strength of Cu-W thin films were studied.It is found that the technique of ion beam assisting bombardment implanting of W particles can remarkably improve the adhesive property of Cu-W thin films. Indentation and scratching test show that,the critical load is doubled over than the sample only sputter-cleaned by ion beam.The enhancing mechanism of ion beam assisting bombardment implanting of Cu-W thin films was analyzed.With the help of mid-energy Ar+ion beam,W atoms can diffuse into the Fe-substrate surface layer;Fe atoms in the substrate surface layer and W atoms interlace with one another;and microcosmic mechanical meshing and diffusing combination on atom-scale among the Fe and W atoms through the film/substrate interface can be formed.The wettability and thermal expansion properties of the W atoms diffusion zone containing plentiful W atoms are close to those of pure W or W-based Cu-W film.

An Improvement on Adhesion of Sputtered TiC Coating to Steel Substrate

Introducing N_2 during sputtering and pre-oxidation of substrate were investigated to improve the adhesion of sputtered TiC coating to steel substrate. The results show that yeactive gas N_2 increases the adhesion of TiC coating to steel because of a graded interface existing between coating and substrate. The interaction of discharge plasma with the surface of substrate was discussed. Pre-oxidation of substrate is effective for improving the adhesion due to the fomation of FeTi0_3 which appeared as an inteylayer between coating and pre-oxidized substrate.

基于正交设计的水泥基陶瓷砖胶粘剂拉伸粘结强度影响因素分析

对比分析了瓷砖背纹深度、晾置时间、界面处理等级对水泥基陶瓷砖胶粘剂拉伸粘结强度的影响规律。正交试验结果表明:3个影响因素主次顺序为:界面处理等级>瓷砖背纹深度>晾置时间;界面处理等级对拉伸粘结强度的影响最显著,有效的界面处理手段可以使陶瓷砖胶粘剂拉伸粘结强度测试值提高20%左右;瓷砖背纹深度和晾置时间对拉伸粘结强度的影响相对较小。

具有黏附性的吸能弹性体材料的合成与性能

首先,以羟基封端的聚二甲基硅氧烷(PDMS-OH)与三甲氧基硼氧六环(TMOB)反应制备冲击硬化聚合物(IHP);然后,采用乙烯基封端聚二甲基硅氧烷(vinyl-PDMS)与甲基含氢硅油(PDMS-H)反应生成交联聚二甲基硅氧烷(交联PDMS);再通过自由基聚合制备聚2-((((丁基氨基)羰基)氧代)甲基丙烯酸丁酯)(PBM);最后,以IHP、PBM和交联PDMS预聚液通过“一锅出”的方式,制备了具有黏附性的吸能弹性体材料(IHP-EA)。其中,IHP作为其动态交联网络提供吸能特性,交联PDMS作为其稳态交联网络提供机械强度,PBM与底物形成高密度氢键提供其黏附性能。采用多种结构表征方法及性能分析手段,探讨了IHP-EA中不同组分对性能的影响。结果表明:IHP-EA在玻璃基材上的黏附强度达198 kPa,且具备良好的转移黏附和多次黏附能力;同时IHP-EA在4.43 m/s的高速冲击下可实现78.44%的能量吸收率,表现出优异的吸能减震性能。

接缝砂浆对施工缝界面粘结及氯离子渗透性能的影响

施工缝是工程结构的薄弱部位,容易发生渗漏、钢筋锈蚀等破坏。设计了一种新型聚合物改性接缝砂浆,研究了新老混凝土不同浇筑时间间隔、不同界面状态下接缝砂浆对新老混凝土界面粘结劈拉强度、界面氯离子渗透性能的影响。结果表明,随着纯丙乳液掺量的增加,砂浆的抗压和抗折强度均逐渐降低,压折比逐渐减小,纯丙乳液的掺入可以提高砂浆的柔韧性。接缝界面粗糙度和新老混凝土浇筑时间间隔都对界面粘结劈拉强度和氯离子渗透系数有较大影响。相同条件下,采用接缝砂浆进行界面处理可以显著提高施工缝界面的粘结强度和抗氯离子渗透性能。

钢结构用界面处理砂浆的制备及影响因素研究

研究了水胶比、胶砂比、胶粉及憎水剂掺量对界面处理砂浆性能的影响,以拉伸粘结强度、压折比作为衡量指标,制备了与钢结构表面粘结性能优异的界面处理砂浆。试验结果表明:界面处理砂浆水胶比为0.5、胶砂比为1∶2.5、胶粉掺量为10%,憎水剂掺量为1.5%时,界面处理砂浆与钢构件的标准、耐水、耐热、热湿循环、耐冻融拉伸粘结强度分别为1.35、0.78、1.09、0.65、0.70 MPa,压折比为2.5。

单组分瓷砖背胶及粘结剂体系与玻化砖粘结强度试验研究

试验通过设计不同初粘性背胶、瓷砖胶粘剂厚度以及浸水时间,研究了瓷砖背胶与瓷砖胶粘剂的匹配机制和破坏机理。结果表明,使用初粘性较低或玻璃化温度较高的背胶,可有效提高胶粘剂与瓷砖的粘结强度;瓷砖胶粘剂厚度过大会导致内聚粘结强度降低,影响背胶对瓷砖胶粘结体系的增益效果,最佳施工厚度应该控制在8 mm左右;背胶膜吸水后内聚力降低,会导致粘结失效,玻璃化温度较高的背胶具有较好的耐水性,但浸水时间达到21 d时相差不大。理想施工环境下应尽量追求更高的界面破坏占比,减小瓷砖胶粘剂内聚破坏占比。

Understanding solid phase diffusion-bonding process of Ni(000)/-Al_(2)O_(3)(0001) interface

The dynamic processes and characteristics of solid phase diffusion-bonding of interfacial atoms at high tempera-tures and the effect of that on bonding strength of Ni(111)/)/-Al_(2)O_(3)(0001)interface were investigated through molecular dynamics.It is shown that atomic diffusion occurs at the Ni/Al_(2)O_(3) interface in the temperature range from 698 K to 1,098 K,and proceeds mainly from the Ni side to the ) Al_(2)O_(3) side.The interface was previously reconstructed by solid bonding below the melting temperature,leading to the amorphization of the interface.Be-sides,the intermetallic complexes such as Al_(m)Ni_(n)(e.g.,AlNi_(3)),metal oxide NiO and Ni-Al-O bonds were formed gradually during the diffusion process of atoms.The formation mechanisms of the Ni-Al,Ni-O,and Ni-Al-O bonds are revealed.Based on the reconstructed structure,the adhesion effort at the interface is compared.The higher the temperature,the larger the bond number and the higher the interfacial bonding strength.

固体火箭发动机粘接界面湿热老化与寿命评估

通过对固体火箭发动机衬层-推进剂粘接界面的湿热加速老化试验以及不同老化时间下粘接界面的扯离强度测量,分析了不同湿热老化条件下试验件扯离强度随老化时间的变化规律。综合运用Eyring模型与Arrhenius模型,建立了粘接界面湿热老化寿命模型,预测了正常贮存条件下发动机的贮存寿命。研究结果表明,粘接界面平均扯离强度随老化时间呈下降趋势,中间有一个强度趋于稳定的平台期;在温度为20℃,湿度为65%RH条件下,粘接界面的强度半衰期寿命为12.8 a。

复合绝缘子护套与芯棒界面粘接性及界面质量检测方法研究

为有效评价复合绝缘子护套与芯棒的界面质量,文中首先提出了一种护套—芯棒压剪试验方法,通过检测护套与芯棒的界面粘接强度对界面粘接性进行评判。对3支运行复合绝缘子不同位置的试样分别进行护套—芯棒压剪试验和解剖试验,结果表明护套—芯棒压剪试验可以有效检测护套与芯棒界面的粘接性。进一步研究护套与芯棒界面质量的检测方法,对水煮后的带护套芯棒试样先后进行改进的水扩散试验和护套—芯棒压剪试验,结果表明界面泄漏电流值和界面粘接强度,可以分别反映护套与芯棒界面的缺陷和粘接性。研究说明结合改进的水扩散试验方法与护套—芯棒压剪试验方法可以对护套与芯棒的界面质量进行有效检测。

机械镀锌层的结合强度分析

通过机械镀方法制备了镀层试样,采用冲击试验和拉伸试验研究了镀层的抗冲击性能及镀层-基体间的结合强度。研究结果表明,镀层的冲击载荷失效为镀层与基体间的剥离失效,随着镀层厚度的增加,镀层的抗冲击性能增强;镀层的拉伸破坏发生在镀层-基体界面,20μm、30μm、60μm镀层的结合强度分别为3.18 MPa、2.18 MPa、3.84 MPa;薄镀层时,拉伸失效主要发生于镀层-基体的界面;厚镀层时,拉伸失效发生于在镀层-基体界面和镀层内。

C60～C80高强抗冲磨混凝土配制技术研究

工程实践证明，强度越高的混凝土抗冲磨性也相对好，C60～C80高强抗冲磨混凝土属于“以硬碰硬”的抗冲磨材料。只要采用低水胶比，掺加高性能减水剂，优先使用硅灰与矿渣粉或粉煤灰的复合超细掺合料，骨料最大粒径不超过20mm，精心施工，充分养护，着力从微观上提高、改善骨料与水泥石界面结构黏结强度和水泥石强度，就能轻易配制出C60-C80高强抗冲磨混凝土。

新老混凝土粘结面的抗冻剪切性能试验研究

本文通过162块新老混凝土粘结Z形剪切试件的试验,研究了冻融循环对新老混凝土粘结面剪切性能的影响。试件在温度-18℃～8℃范围内经受了0、5、10、15、20和30次的冻融循环。分析了新老混凝土粘结面冻融损伤破坏的机理和冻融循环次数、界面处理方法、界面剂的类型以及新老混凝土的强度等对粘结面粘结剪切强度的影响。研究表明,在冻融循环作用下,新老混凝土粘结剪切强度随冻融循环次数的增加急剧下降,冻融30次时,所试验的试件几乎全部从粘结面冻融破坏。粘结剪切强度的下降是由于新老混凝土本身强度的下降和粘结剂强度的下降以及粘结面的损伤等共同作用的结果。

金钢石薄膜与基材之间过渡层技术的研究

通过TEM观察发现在金刚石膜与单晶硅片、金刚石膜与A1N陶瓷之间存在一层过渡层，过渡层的存在为金刚石的形核及生长提供了有利的条件，受此启发，为了改善金刚石与基材的结合强度，采用磁控溅射、空心离子镀、真空蒸镀等方法在MO片上沉积TiC、TiCN（C／N=1／2）、TiCN（C／N=1／10）等薄膜，研究了它们对金刚石膜与基材的结合强度的影响．

内氧化Cu/Al_2O_3界面热力学与杂质效应

基于第一性原理方法,研究温度、原子化学配比、Al活度、O活度和杂质偏聚对内氧化Cu/Al2O3界面的影响作用。计算得到的界面相图及相应能量学结果表明:界面平衡相结构随制备气氛的变化而变化;富O相界面的结合强度最高,富Al相界面的结合强度其次,它们均约3倍于理想化学配比相界面的结合强度;杂质S对界面的危害性明显,对富Al相和理想配比相界面具有强烈的偏聚能力,且严重削弱界面强度(约可达65%),并降低氧化铝颗粒尺寸的稳定性,但S不能向富O相界面偏聚;相较于S,另一种杂质P向富Al相和理想配比相界面的偏聚能力不强,偏聚后对界面的危害性也较S弱。但P能向富O相界面偏聚,使界面强度严重降低。