钢芯铝绞线钢芯表面植酸活化对化学镀Ni-P层耐蚀性的效用

为了提高钢芯铝绞线钢芯的耐蚀性,采用植酸对其活化再化学镀覆Ni-P合金,研究了植酸活化处理对钢芯钢表面Ni-P镀层耐蚀性的影响。采用SEM和EDS对Ni-P镀层腐蚀前后的形貌和成分进行了分析,在1mol/L H_2SO_4+3%NaCl混合溶液中测定了其极化曲线,比较了其腐蚀速率;利用超声波振荡法研究了植酸活化前后Ni-P镀层与基体的结合力。结果表明:钢芯表面经植酸活化后Ni-P镀层的胞状凸起细小,结构更加均匀、致密,与基体有较好的结合力;植酸活化后,Ni-P镀层的腐蚀电位变大,腐蚀电流减小,腐蚀9 h时Ni-P镀层表面几乎无变化。     

石英纤维热损伤机制

通过TG/DSC和高温XRD对石英纤维的高温相转变行为进行了研究,通过高分辨SEM对经不同温度处理过的石英纤维的表面形貌进行了研究,并用抗拉强度实验机测量了这些石英纤维的抗拉强度。研究结果表明,低于1000℃ 处理的石英纤维热损伤可分为两个阶段: (1) 在低于600℃的热处理温度范围内,由于石英纤维表面处理剂的挥发 , 石英纤维直径逐渐减小,原来表面的裂纹、条状和圆形凸起等缺陷逐渐显露出来,导致石英纤维抗拉强度缓慢降低;(2) 在600～1000℃ 的热处理温度范围内 , 石英纤维表面处理剂挥发完毕,在热处理的升降温过程中,由于热应力的作用,表面的条状和圆形凸起开始剥落,造成一定数量的新的表面裂口和裂纹缺陷。温度越高,石英纤维表面的条状和圆形凸起剥落现象越明显,这是造成这一温度条件下石英纤维强度显著降低的主要因素之一。此外,结合TG/DSC和XRD的研究结果,石英纤维低于1000℃热处理后,虽然没有明显的相变化,但是晶体结构有序化程度提高,表面开始析出α-方石英并导致纤维表面形成一定数量的凸起缺陷,这也是导致高温处理后石英纤维热损伤的原因之一。      

聚酰亚胺薄膜表面导电金属层化学沉积技术研究

为赋予聚酰亚胺(Polyimide, PI)薄膜材料表面良好的导电性,满足其在雷达天线等航空、航天领域的应用,采用化学碱蚀法对表面具有极高化学惰性的PI薄膜进行界面微纳改性处理,并结合化学镀铜沉积技术,实现了PI薄膜表面导电金属层的制备。利用SEM、XRD、AFM、FTIR等对聚酰亚胺薄膜表面改性前后的微观结构和表面金属层性能进行表征。常温化学碱蚀后的PI薄膜表面呈现出树枝状与铆钉状微观结构交错均匀分布的凸起结构形貌,60℃碱蚀后的PI薄膜表面呈现出微小凹坑特征,且碱蚀后PI薄膜表面亲水性明显增强。PI薄膜表面金属镀层均匀致密,导电性良好,且镀层与PI薄膜基材之间具有良好的结合力。碱蚀改性后PI薄膜表面呈现出相互交错的微观凸起亲水性结构,为PI薄膜表面金属层的成核、结晶提供良好的沉积与互嵌结合点,形成PI薄膜表面金属层与基材之间良好的界面互锁,从而有利于提高表面镀层结合强度。本工作实现了化学碱蚀作用下聚酰亚胺薄膜表面高导电、高结合强度金属层的制备,可为聚酰亚胺薄膜在雷达天线等航空、航天领域的应用提供技术支撑。     

仿生非光滑表面对对磨副的损伤机理研究

利用激光处理技术在灰铸铁表面加工了4种具有非光滑形态的试样,对比研究非光滑形态对对磨副的影响规律。结果表明:非光滑表面对对磨副的损伤机理与光滑试样不同,为非光滑表面凸起对对磨副的微观切削作用。非光滑表面对磨副的磨损质量均远大于未处理试样的对磨副,以对磨副磨损质量为评价指标,条状、环状、点状和网状对对磨副的损伤作用依次减小,损伤最小的网状对磨副其质量损失仅为等面积比下的条状对磨副的55.66%,在相同的单元体面积比和几乎相同的显微硬度条件下,通过调整单元体的形态可以有效地减轻对对磨副的损伤作用。这是由于不同形态的非光滑表面在磨损过程中的载荷分配机制不同。     

双脉冲电镀非晶态Ni-P工艺对镀层性能的影响

双脉冲电镀制备的镀层性能优异,而目前双脉冲电镀非晶态Ni-P镀层鲜见报道.利用双脉冲电镀制备非晶态Ni-P合金镀层,研究了平均电流密度、正向占空比、温度、亚磷酸及柠檬酸钠浓度对镀层性能的影响.结果表明:随着平均电流密度增大,Ni-P镀层的沉积速率增加,腐蚀电位越来越负,镀层表面由平整致密变得有气孔和凸起,甚至起皮;正向占空比从30%增大至70%时,镀层的组织结构从完全非晶态转变为晶态,腐蚀电位越来越负,正向占空比为30%时,腐蚀电位最正,最不易被腐蚀;温度影响镀层的光亮度和平整度,70℃时镀层外观形貌最优,腐蚀电位最正;随亚磷酸浓度的增加,镀层外观形貌由平整致密变得有大量黑色条纹和起皮,为了得到外观形貌较好且腐蚀电位较正的镀层,亚磷酸浓度在20～30 g/L之间为宜;随柠檬酸钠浓度的增加,镀层沉积速率降低,腐蚀电位变正,不易被腐蚀.     

表面活性剂对Ni-SiC复合镀层性能的影响

表面活性剂能改善复合镀层的性能,过去对离子型和非离子型表面活性剂影响复合镀层性能的研究报道不多.为此,利用电子探针分析仪、电化学分析方法以及摩擦磨损试验,系统地研究了表面活性剂对Ni-SiC复合镀层性能的影响.结果表明:非离子表面活性剂不易使微粒与基体金属发生共沉积,对沉积速度有一定的抑制作用;阳离子表面活性剂能够增加镀层中SiC粒子的含量,当浓度为0.12 g/L时SiC粒子含量最高,随着镀层中SiC离子含量的增加镀层的硬度增加,耐磨性能提高,其中XCG阳离子表面活性剂效果最好;非离子表面活性剂与阳离子表面活剂的协同作用,进一步促进了镀层中SiC微粒的共沉积,改善了复合镀层的性能.     

Al-Si镀层热成形零件表面颜色差异性研究

目的研究加热温度、加热时间等工艺参数对Al-Si镀层材料在热成形过程中存在的表面颜色差异、镀层厚度和扩散层厚度的影响规律,及影响零件表面颜色差异的主要原因。方法在不同加热时间及加热温度条件下,对厚度为1.0 mm的新日铁Al-Si镀层材料进行热冲压试验,测量热成形零件的镀层厚度和扩散层厚度,并对典型不同颜色零件表面进行SEM及EDS分析研究。结果 Al-Si镀层热成形零件表面颜色与加热温度和加热时间存在较好的对应关系,同时镀层厚度及扩散层厚度随着加热时间的增加及加热温度的提高而增大,Al-Si镀层热成形零件表面的颜色与镀层中不同铁氧化物的混合比例存在较好的对应一致性。结论Al-Si镀层热成形零件表面颜色的状态可以间接反应镀层厚度及扩散层厚度。     

基片偏压与氩分压对铀表面铝镀层结构与界面特性的影响

采用磁控溅射离子镀技术在贫铀表面以不同基片偏压与不同氩分压制备铝镀层,利用扫描电镜分析了镀层的表面和界面形貌,利用俄歇电子能谱仪分析了界面元素分布,利用透射电镜分析了镀层的微观结构.结果表明:钠表面脉冲偏压所得锚镀层较直流偏压所得镀层致密,脉冲偏压在-500～-1000V范围内镀层的致密性较好.铀表面脉冲偏压铝镀层与铀基体之间界面结合紧密,且存在"伪扩散层";随着脉冲偏压的提高,"伪扩散层"增宽.铝镀层为柱状结构,降低工作氩分压,可以细化铝镀层的晶粒,提高镀层的致密性.     

AZ91D镁合金表面Ni-P化学镀层的微观组织与性能

以直接化学镀的方法在AZ91D镁合金表面制备了光亮、均匀、致密、厚度达40μm的Ni-P合金镀层,用现代分析技术分析了镀层的微观形貌、组织成分、显微硬度、结合力以及耐蚀性能.结果表明:Ni-P镀层属于中磷镀层,微晶结构,表面形貌呈胞状;镀层与基体结合良好;镀层的显微硬度比基体提高了4倍;镀层与抛光基体的结合力比未抛光的高,基体表面保持机加工状态的镀层破坏临界载荷为80.6 N;镀层具有较好的耐蚀性能.     

石墨烯增强相对镍基复合镀层的强化作用及镀层制备

为促进石墨烯基复合材料的制备和应用,利用电沉积的方法在碳素钢基体表面分别制备了石墨烯/镍复合镀层及纯镍镀层,利用扫描电镜（SEM）对镀层的形貌进行了观察分析,利用X射线衍射仪（XRD）对镀层的物相进行了分析,利用硬度测试仪对镀层进行了力学性能的评价。研究表明：在相同的制备条件下,对于石墨烯/镍复合镀层,石墨烯的引入使镍基晶粒细化,且由于石墨烯导电性能比镍好,在电沉积过程中,镍离子优先在石墨烯片上沉积形成包状凸起;而未添加石墨烯的纯镍镀层在沉积过程形成的是较为光滑平整的纯镍镀层,晶粒较大。XRD检测结果显示,整个电沉积过程无相变发生,石墨烯的引入使得沉积镍的晶粒细小,组织更致密。Raman检测结果显示沉积电流越小,沉积的石墨烯的2D峰与G峰的强度比值越大,分散效果越好。添加石墨烯的镍镀层硬度明显高于未添加石墨烯的镀层,最高硬度可达约530 HV_{4.9 N}。以上结果表明：利用电沉积技术将石墨烯作为第二相引入到金属基体中,是一种有效制备高性能石墨烯/金属复合材料的方法。     

Funktionelle Schichten auf Metallen: Maßgeschneiderte Eigenschaften durch Sol‐Gel‐Technologie

Functional Layers on Metals: Tailored Properties by Sol‐Gel Technology The value of metal articles can be substantially enhanced by convenient surface coatings. Beside organic layers (e. g. paints) and inorganic layers (e. g. enamel) wellknown as coating materials, so‐called inorganic‐organic hybrid polymers set out to combine the advantages of both coating groups. For the manufacture of such hybrid materials functional particles with sizes of a few nanometers – so‐called nanoparticles – are synthesized in the sol‐gel process. The versatility of this procedure allows to cover an extreme variety of properties of the resulting layers. Thus, depending on their composition, sol gel coatings are suited as corrosion protection, as primer, as abrasion‐reducing coating or as easy‐to‐clean layer. A sufficient wetting and adhesion on vitually any substrate can be achieved by proper choice of functional groups and pretreatment steps.     

Laser Surface Strengthening Process of Al-Si Base Alloy

With a laser beam, the surface remelting/resolidifying treatment of ZL108 alloy was studied. Test results showed that a compact remelting layer was obtained with appropriate laser processing conditions and a suitable surface coating for laser energy absorption. The eutectic silicon phase in the laser-treating zone changed from the shape of thick-plate (stripe) into the very small grains, the structure was extremely fined, the hardness and wear resistance were improved greatly compared with that of the base alloy. A laser -treating layer, which is 3.5 mm thick and 5 mm wide, could be obtained.     

Modeling of the compression of coated papers in a soft rolling nip

An analytical model is developed for the compression of coated substrates in a soft rolling nip formed between a hard roll and a soft covered roll. The coating layer, substrate, and soft cover are modeled as a stack of three layers that are compressed jointly while passing through the nip. Material models have been adopted separately for each of the three layers and were combined together according to the thickness of individual layers. In this study, the substrate is considered to be a viscoelastic–plastic material and is represented by a modified solid element while the coating layer is assumed to be elastic and the soft cover material is approximated by a standard Maxwell model. A strain function is derived for the compression of substrate in the nip that appears to be a parabolic function of time. Substrate compression in the nip and its subsequent relaxation are calculated by solving a set of differential equations that describe the coating, substrate, and soft cover deformations. This model is used to study the soft-nip calendering of coated papers. Examples of numerical modeling that demonstrate the paper deformation and stress profiles in the nip are presented. In addition, the effects of paper and cover properties as well as calendering parameters on the dynamics of paper compression are discussed. Finally, a comparison of the modeling results is made with the experimental data.     

Scanning electron microscope studies of the grain surface of leather

The scanning electron microscope showed that the grain surface of leather (i.e. the surface exposed when the epidermis is removed in manufacture) was covered with a layer of non-fibrous material which was more resistant to rubbing in chrome-tanned ox hide than in chrome calf leather. Rubbing burnished the chrome-tanned ox coating which then, apart from occasional line cracks, appeared featureless, but in chrome calf the coating first broke into crenellated plates of fairly uniform size. The coating appeared to be a single layer but the plates could ride over each other during rubbing, to simulate a multi-layered structure. Although the under surface of the cover looked non-fibrous, some appearances suggest that it surrounded fine surface fibres and, when the coating was removed by rubbing, these fibres went with it. The cover was not extraneously produced during processing. It was resistant to the conditions of manufacture of the skin into leather, which included extremes of pH (pH 12.5 to 2.0), the use of a reducing agent (sodium sulphide) and brief treatment with a crude tryptic-type enzyme. It was also resistant to acetone and to dichloromethane. Experimental processing was, at best, only partially successful in producing a grain surface clear of the coating.     

Improvement of the lateral-mode discrimination of broad-area diode lasers with a profiled reflectivity output facet

The emission of a broad-area laser always contains several lateral modes (along the junction plane) even at low drive levels. To increase the discrimination against high-order lateral modes, we developed simple techniques for depositing a profiled thin layer of SiO on the output facet of a broad-area laser that has a 75-μm-wide injection current stripe. The profiled coating provided a nearly Gaussian reflectivity in the lateral direction (parallel to the junction plane). The resolved near-field spectra of the uncoated and coated lasers have been compared. The maximum output power in the single-lateral-mode regime was pushed to 25 mW with the profiled coating, compared with a corresponding power of less than 1 mW before deposition. Experimental results have confirmed the behavior predicted by our numerical simulations. This method is scalable to higher-power lasers.     

加热温度与保温时间对铝-硅镀层组织演变的影响

采用扫描电镜观察了钢板表面铝-硅镀层的微观组织,利用热模拟机研究了铝-硅镀层在不同加热温度和保温时间下镀层中合金层厚度的变化规律,利用辉光光谱仪测定了铁元素向合金层中的扩散规律.结果表明:热处理前镀层合金层组织由Fe2Al5二元金属间化合物和Fe2SiAl7三元金属间化合物组成,热处理后镀层合金层组织由Fe2SiAl2...     

钢铁镀Sn扩散处理中镀层组织的形成

根据钢铁试样镀Ｓｎ扩散处理后镀层的显微组织、物相组成及性能等分析，讨论了镀层组织在处理中的形成过程及其原理。试验表明，钢铁试样经镀Ｓｎ扩散处理时，镀层与基体形成一对扩散偶，其结合转变为扩散结合，镀层由ＦｅＳｎ白亮层、白色基底及其上的ＦｅＳｎ晶体与液相间包晶反应生成的ＦｅＳｎ２灰色和黑色暗点以及表面极薄富Ｓｎ合金层组成。     

Mechanical interactions between fiber and cracked coating layer and their influences on fiber strength

The mechanical interactions between the elastic fiber and cracked elastic coating layer and their influences on fiber strength for strong and weak interfaces were studied. In the case of a strong interface, the energy release rate for the propagation of the crack in the coating layer into fiber increases and, therefore, the fiber strength decreases with increasing elastic modulus and thickness of the coating layer. When multiple cracking occurs in the coating layer, the energy release rate becomes low because of the reduced crack-spacing, resulting in a higher strength of the fiber, the double and graded coatings reduce the energy release rate and, therefore, raise the fiber strength in comparison with that for a single coating with high elastic modulus if the material with low elastic modulus is used as the inner layer adjacent to the fiber. In the case of weak interface, when the critical energy release rate for the interfacial debonding is lower than 0.3 times the critical one for the crack propagation into fiber, the debonding occurs prior to the crack propagation, resulting in higher fiber strength than that for strong interface because of the blunting at crack-tip.     

一种碳－碳复合材料长寿命防氧化涂层的失效机制

用液相法联合ＣＶＤ法和硅化法制备了一种碳－碳复合材料复合梯度涂层，在此基础上对这种涂层在氧化过程中的失效机制进行了研究．结果表明：氧化层与液相层界面反应生成的气相产物是涂层失效的根本原因界面上气泡的不均匀形核、长大和破裂导致涂层表面出现孔洞．孔洞处气泡优先形核、长大和破裂并发展成为缺陷而使涂层失效     

聚钛硅氧烷与金属界面结合机理研究

用扫描电镜ＳＥＭ和Ｘ射线能量散布分析ＥＤＡＸ技术研究了聚钛硅氧烷（ＰＴＳ）涂层与铝基材界面,结果发现了ＰＴＳ涂层与铝界面有良好的结合,这一粘接机理可认为中铝氧化物与ＰＴＳ涂层产生化学反应,形成互渗层的结果。随热处理温度互渗层厚度增加。相反,ＰＴＳ涂层与铁基材界面无明显的化学结合随热处理温度提高,界面缺陷增加。