不锈钢表面氧化膜层对Zn与不锈钢交互作用的影响

对空气自钝化、HNO_3化学钝化、高温氧化的不锈钢与低熔点金属Zn之间的交互作用进行了研究,揭示了不锈钢表面氧化膜层对两者交互行为的作用机理。通过扫描电子显微镜(SEM)观察了交互作用后生成化合物的界面和表面形貌,采用能谱分析仪(EDX)和X射线衍射仪(XRD)检测了化合物的元素组成和相成分。结果表明:Zn与不锈钢通过形成细小颗粒状δ-(Fe,Cr)Zn_(10)相和块状ζ-(Fe,Cr)Zn_(13)化合物的方式直接接触。空气自钝化和化学钝化处理使不锈钢表面生长钝化膜,降低了Fe-Zn化合物层的厚度,钝化膜阻碍了两者之间的交互作用。原子通过钝化膜的缺陷进行扩散反应,使Zn与不锈钢直接接触形成界面化合物,而钝化膜也在一定程度上抑制了Zn与不锈钢的交互作用。     

Al-Fe液/固复合界面扩散溶解层研究

采用镶嵌式扩散偶技术制备了Al-Fe扩散偶,在Al熔点以上Fe熔点以下进行扩散热处理,研究了Al-Fe液/固界面扩散溶解层的组织结构演变、形成机理及生长规律。实验结果表明,Al-Fe扩散偶扩散热处理后的组织结构为Al+FeAl3/FeAl3/Fe2Al5/Fe;Fe2Al5层是保温过程中第一个出现的也是唯一出现的连续单相层,FeAl3层则是在冷却过程中形成;Al基中存在针状的和条状的FeAl3析出相,从界面附近到远离界面,析出相的密集程度和尺寸都逐渐小;在相同的保温时间下,热处理温度与扩散溶解层厚度之间存在指数关系;在相同的热处理温度下,保温时间与扩散溶解层厚度偏离抛物线关系。     

镁含量和硅对铁-锌铝镁合金固-液扩散偶中Fe-Al反应层的影响

在热浸镀锌中,铁基表面Fe-Al化合物层的形成会影响镀层的生长和质量。将Fe/(Zn-11%Al-3%Mg)和Fe/(Zn-11%Al-x%Mg-0.2%Si)扩散偶在600℃下进行25min的固-液扩散实验,利用扫描电子显微镜(SEM)和能谱仪(EDS)研究了镁含量和硅对铁-锌铝镁合金固-液界面Fe-Al合金层形成的影响。结果表明,Fe/(Zn-11%Al-3%Mg)固-液扩散偶反应层由FeAl3和Fe2Al5相层组成;随着Mg含量的增加,Fe/(Zn-11%Al-x%Mg-0.2%Si)扩散偶中反应层的厚度呈现先增加后减少再增加的变化趋势,当镁含量为3%时反应层厚度最薄;Fe/(Zn-11%Al-3%Mg)扩散偶中Fe-Al反应层的平均厚度比Fe/(Zn-11%Al-3%Mg-0.2%Si)扩散偶中反应层的厚度大60μm,证明Si元素起到抑制Fe-Al反应层形成的作用。研究结果为解释Super Dyma合金镀层中不形成明显的Fe-Al抑制层提供了实验依据。     

Cu/Zn扩散偶的实验研究

用铆钉法将块体铜和块体锌制成Cu／Zn扩散偶，经真空炉扩散处理后，在扩散偶Cu／Zn界面处形成一个既不同于铜也不同于锌的扩散层。实验表明，除扩散温度和时间对扩散层有影响外，扩散偶的几何尺寸对扩散层的形成也有影响。扩散偶中锌销子的直径越小，形成扩散溶解层的速度越快，扩散厚度越大。     

预镀镍对活性钢热镀锌的影响

研究了四种含硅钢板预镀镍后热浸锌时镀层的生长动力学,以及镀层中合金相的形成和生长规律,探讨了预镀镍对活性钢热浸锌镀层生长的抑制机理.实验结果表明:预镀镍法可以显著降低活性钢镀锌层的快速生长,获得厚度适宜、表面光亮,粘附性好的镀层.预镀镍钢板热浸锌时首先形成一系列的Ni-Zn合金γ',γ和δ2相,随着进一步的扩散和反应,γ',γ和δ2相逐渐消失,生成了Fe-Zn-Ni三元金属间化合物Г2和Fe-Zn金属间化合物Г和δ;随后Г2相消失,在δ相和液相Zn间生成块状的ζ晶粒,并逐渐变成稳定致密的连续ζ层.钢板预镀镍后热镀锌时完全改变了Fe-Zn相的生长顺序,明显延缓了ζ相的生长,显著抑制了活性钢热浸镀锌层的异常生长.     

Zn层添加AZ31/7075合金复合成形工艺及组织与性能研究EI北大核心CSCD

通过在异种材料界面添加厚度为100μm的Zn箔,采用预挤压与孔型轧制复合工艺成功制备出AZ31/7075复合材料,并利用光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)对复合界面进行表征及显微硬度测试,探究Zn过渡层在挤压复合孔型轧制过程中对产品的影响。结果表明:7075硬质铝合金芯部可细化AZ31镁合金,引入Zn过渡层可减少或者避免镁铝系金属间化合物生成;挤压及变形温升使Mg-Zn互扩散形成的低熔点共晶相熔化,同时加速元素自固相向液相扩散;然而降温冷却使Mg-Zn扩散层易出现不连续裂缝,但后续孔型轧制可显著改善;Mg-Zn扩散层经变形生成的MgZn_(2)金属间化合物具备较高的显微硬度(161HV),但Mg-Zn扩散层变形后厚度则较薄,结合层整体硬度变化不明显。     

退火工艺对Zn/AZ31/Zn复合板材界面微观结构及力学性能的影响EI北大核心CSCD

采用热轧工艺制备Zn/AZ31/Zn复合板材,研究退火温度与时间对板材界面微观组织及力学性能的影响。结果表明:退火温度对界面扩散层的形成影响较大,低温退火无法形成良好的界面扩散层,而在200℃退火,可获得由Mg4Zn7和MgZn2相组成的良好的冶金结合界面。较高的温度(300℃)导致界面脆性Mg2Zn11相的析出,而引发微裂纹。在同一温度下,退火时间的延长仅影响扩散层的厚度,对其相组成没有影响。退火处理使板材的强度降低,但是塑性有所提高,在200℃热处理1 h获得的复合板材综合力学性能较好。     

退火工艺对Zn/AZ31/Zn复合板材界面微观结构及力学性能的影响

采用热轧工艺制备Zn/AZ31/Zn复合板材,研究退火温度与时间对板材界面微观组织及力学性能的影响。结果表明:退火温度对界面扩散层的形成影响较大,低温退火无法形成良好的界面扩散层,而在200℃退火,可获得由Mg_4Zn_7和MgZn_2相组成的良好的冶金结合界面。较高的温度(300℃)导致界面脆性Mg_2Zn_(11)相的析出,而引发微裂纹。在同一温度下,退火时间的延长仅影响扩散层的厚度,对其相组成没有影响。退火处理使板材的强度降低,但是塑性有所提高,在200℃热处理1 h获得的复合板材综合力学性能较好。     

Sn8Zn3Bi-xCu/Cu焊接接头界面反应及力学性能研究

以Sn8Zn3Bi为研究对象,采用微合金化方法研究了不同含量的Cu元素对其显微组织、钎料合金与Cu基板钎焊后的界面金属间化合物(IMC)层尺寸及焊接接头剪切强度的影响。结果表明,Sn8Zn3Bi-xCu/Cu(x=0.3,0.5,0.8,1.0,1.5)焊接界面IMC主要为层状Cu5Zn8相。随着Cu含量的增加,界面IMC层的厚度逐渐减小,接头的剪切强度逐渐提高,Sn8Zn3Bi-1.5Cu/Cu接头剪切强度较Sn8Zn3Bi/Cu显著提高。经120℃时效处理后,Sn8Zn3BixCu/Cu(x=0,0.3,0.5,0.8,1.0,1.5)焊接接头剪切强度都明显下降,接头断裂方式由韧性断裂转为局部脆性断裂,但添加了Cu元素的钎料界面IMC生长速度较Sn8Zn3Bi钎料慢,因此Cu元素的添加抑制了界面IMC层的生长。     

Zn对钢/铝异种金属搅拌摩擦焊接头界面组织及性能的影响

采用离子喷涂方法在钢侧喷涂厚度为0.4 mm的Zn粉,对厚度同为3 mm的6005A-T6铝合金与S420MC钢板进行搭接搅拌摩擦焊实验。采用金相显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)和显微硬度等方法研究Zn对焊缝界面形貌、微观组织结构、力学性能及界面生长的影响。结果表明:无Zn层钢/铝接头和有Zn层钢/铝接头均在界面处形成了搅拌焊特有的"飞边",并延伸至铝基体中形成机械咬合接头,界面处均有AlFe,AlFe_3,Al_(13)Fe_4金属间化合物产生。有钢质颗粒弥散分布在无Zn层的钢/铝接头的铝基体中。Zn的添加降低了界面反应层厚度,钢/铝搅拌摩擦焊界面结合方式为"机械+冶金"。接头断裂位置均在界面处,无Zn层钢/铝断裂接头为典型的"韧-脆"混合型断裂,有Zn层钢/铝接头为韧性断裂。最高显微硬度值从无Zn层接头的388HV降低到有Zn层接头的210HV。     

Interfacial characteristics of Zn/AZ31/Zn clad sheets fabricated by hot roll-bonding and annealing

The Zn/AZ31/Zn tri-layer clad sheets are prepared by hot roll-bonding technology and post-roll annealing in this study and the interfacial microstructure, mechanical and corrosion properties are investigated. The annealing temperature can influence the interfacial bonding behaviour. Upon annealing at 200°C, a good metallurgical bonding interface composed of Mg₄Zn₇ and MgZn₂ phases is obtained. A higher temperature (300°C) can induce the precipitation of the brittle Mg₂Zn₁₁ phase at the interface. The clad sheets annealed at 200°C can attain the maximum bonding strength among all the clad sheets investigated. Importantly, the corrosion rate can be obviously reduced by cladding pure Zn layer on both sides of AZ31 alloys, which provides another effective method to improve the corrosion resistance of magnesium alloys.     

水解锌制备Zn/ZnO纳米结构及其光学性能研究

利用滚压振动磨在干法室温条件下将金属锌制备成尺度约为3~5nm的锌量子点,并使产物与水蒸气在250℃进行化学反应,得到纳米氧化锌或纳米氧化锌与锌的混合物。分别利用能量发射谱仪(EDS)、透射电镜(TEM)对样品成分和形貌进行了表征。结果表明,250℃反应温度下得到的产物具有良好的分散性,其特征是棒状和片状结构共存,而且纳米棒具有显著的沿[011 1]晶向生长的趋势。室温下光致发光(PL)谱显示,在360nm和388nm处有双紫外发射峰,属于激子态发光,双紫外发射峰可能与掺杂能级有关;同时,在496nm处有蓝光发射峰,在515nm处有绿光发射峰,这两种发射属于表面缺陷态发光。对各种发光峰的发光机制进行了讨论。UV-Vis吸收光谱表明,产物在紫外区有很强的紫外吸收,吸收峰出现了蓝移现象,验证了Zn纳米量子点的掺杂形成掺杂能级,也与测得的可见光发射一致。     

Spinodal decomposition in Al/Zn alloys

The effect of spinodal decomposition on the mechanical behaviour of Al/Zn alloys was studied over the range of 30 to 60 wt % zinc. Two solution treatment temperatures, 365 and 435° C, were used; extensive ageing studies were carried out at 22 and 100° C, and limited tests were made on samples aged at other temperatures, 0, 55, and 200° C. The yield and tensile strengths were significantly increased by spinodal transformation, but ductility was seriously impaired. The tensile fracture was intergranular, with one exception, and was related to grain-boundary precipitation and a narrow denuded zone.Calculated yield strengths based on Cahn's analysis did not agree with those derived from the correct dislocation model. The wrong model did give fortuitous agreement. Spinodal hardening appears to offer a promising new hardening mechanism in aluminium alloys if the particular composition and treatment can be found to eliminate the serious lack of ductility.     

纳米Zn/ZnO复合结构的光催化活性

采用干法室温振动研磨的方法制备纳米Zn粉,纳米Zn水解制备纳米Zn/ZnO复合结构。光催化实验证明在太阳光和紫外光照射时,纳米Zn/ZnO复合结构具有优良的光催化性能。TEM检测表明,经11h研磨的Zn粉粒度分布在10～20nm之间,纳米Zn水解反应生成的固相产品,纳米ZnO与未完全反应的纳米Zn构成棒状与片状共存的独特结构,XRD分析表明产物中仅含有Zn和ZnO两种物质;UV-Vis谱显示纳米Zn/ZnO复合体在可见光区的吸收强度明显高于纳米ZnO颗粒,颗粒尺寸减小引起激子吸收峰蓝移,与体相材料相比纳米颗粒有更高的光催化氧化-还原能力。     

Korrosionsuntersuchungen an mittels PVD mit Zn und Zn/Mn beschichteten Stählen

Corrosion Studies of Steels Coated by means of PVD with Zn and Zn/Mn Alternative methods for hot dip‐ or electrogalvanic deposition of zinc coatings on steel are gas phase depositions (PVD). They posess high flexibility with respect to alloy composition, and are environmentally harmless. However, a PVD‐coated steel must have at least the same corrosion resistance than steels with “classical” surface finishing. Therefore, the corrosion behaviour of Zn‐coatings and Zn/Mn/system‐coatings deposited by electron beam evaporation without and with ion beam assistance (IBAD) on low alloy steel, was determined by means of salt spray test and electrochemical potential/time measurements. At first the influence of chemical and irradiation pre‐treatment and ion bombardment during deposition on the corrosion resistance of the coatings was investigated. Than the effect of the Zn‐layer thickness was determined in comparison with an 8μm thick electrogalvanized reference coating. Finally Zn/Mn‐alloys, Zn/Mn‐multilayers and Zn‐coatings with Mn‐ or Zn/Mn‐surface layers (top layers) were investigated. By means of optimised pre‐treatment and ion bombardment conditions one obtains, considering the layer thickness, PVD‐Zn coatings with corrosion resistance comparable with the reference layer. The best Mn‐containing coatings are Zn‐coatings with Mn‐toplayer. They surpass the corrosion resistance of the reference layer considerably. Additionally it could be shown that in tendency the potential/time measurements agree very well with the results of the salt spray test.     

Fabrication of Cu2ZnSnS4 absorber layers with adjustable Zn/Sn and Cu/Zn+Sn ratios

In this work Cu₂ZnSnS₄ (CZTS) thin films were successfully prepared by sulfurization of spin coated CuO + ZnO precursor films under Sn and S ambience with different time. Precursor films were synthesized using air-stable inks consist of carboxylate-capped metal oxide nanoparticles. The composition, microstructure and properties of CZTS thin films prepared with different sulfurization time were investigated using inductively coupled plasma-mass spectrometry, X-ray diffraction, scanning electron microscopy, Raman spectroscopy and UV–vis–NIR spectroscopy. The inductively coupled plasma-mass spectrometry results show that mole ratios of Zn/Sn and Cu/(Zn + Sn) in the films can be adjusted by controlling sulfurization time. A composition of Cu/Zn + Sn = ~0.8, and Zn/Sn = ~1.2 can be reached after sulfurizating with proper time. The influence of element composition change was also studied in our work using X-ray diffraction and Raman scattering. Two laser sources of 325 and 514 nm were involved in the Raman scattering analyze in order to identify secondary phases such as ZnS and Cu_2?xS. The as-prepared CZTS films with a composition of Cu/Zn + Sn = ~0.8, and Zn/Sn = ~1.2 exhibit a direct optical band gap about 1.45 eV.     

开发Fe/Zn抗震复合材料的构想

系统阐述了地震动特性对结构破坏的影响、工程上增加阻尼的4种方式及研究材料滞回耗能的指导思想,首次提出开发Fe/Zn抗震复合材料的构想.研究了开发Fe/Zn抗震复合材料的实验基础,提出了Fe/Zn抗震复合材料的力学模型及其设计方案,并结合工程实践展望了Fe/Zn抗震复合材料的应用前景.     

SiC颗粒增强锌基复合材料的制备及其性能

采用曾顶处理的碳化硅颗粒,经半固态搅动铸造与热挤压相结合的综合工艺制备成的SiCp/ZA22复合材料,具有明显的强化效果。该方法成本较低,所得材料可重熔,易于成型加工,具有广阔的应用前景。