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.     

弱酸性无铵锌镍合金电镀工艺的研究

研究了一种无铵弱酸性锌镍合金电镀工艺,并深入探讨了镀液的成分及工艺条件对镀层含镍量的影响,得到了镀层为γ相Ni5Zn21与δ相Ni3Zn22、且含镍量为13%的全光亮锌镍合金镀层,确定了电镀工艺规范.该镀层具有极好的耐高温性能及优良的耐腐蚀性.     

锌浴温度对0.49%Si活性钢热浸镀锌层组织的影响

研究了高硅钢(0.49%Si,质量分数)在不同浸镀温度(440,480,520,560,600℃)和不同浸镀时间(1,3,5,10min)下的热镀锌试样镀层组织,探讨了浸镀温度和浸锌时间对镀层组织的影响。SEM/EDS结果表明:440℃和480℃热镀锌,镀层由薄而连续δ层和破碎的块状ζ相组成,无Γ相。ζ相生长过快,镀层过厚、灰暗、黏附性差,镀层生长主要由界面反应机制控制;520℃热镀锌时,镀层由极薄的Γ层、致密δk层和疏松的δp层组成,镀层生长主要受扩散机制控制;560℃和600℃镀锌时,镀层为Γ层和致密的δ相层,部分δ粒子弥散分布在η层中,镀层生长为扩散机制控制并伴随有显著的δ溶解过程。最佳高温镀锌温度应在520~560℃。     

电沉积Zn-Ni合金纳米多层膜的耐蚀性能

为了研究Zn-Ni合金纳米多层膜的耐蚀性能,制备了纯锌、锌镍合金及镍含量不同的锌镍合金纳米多层膜3种镀层.采用中性盐雾试验、浸泡试验和电化学试验法对锌镍合金多层膜的耐蚀性进行了研究.采用EDAX、锌镍合金相图、扫描电镜,对多层膜的成分、相结构和镀层的表面形貌进行了研究.结果表明:合金多层膜是由含镍量为14%左右的低镍层和含镍量为77%左右的高镍层叠加而成,其低镍层的相结构主要为γ相,高镍层的相结构为γ+α2种相组织的混合相;多层膜表面较为致密,无明显的缺陷组织,其调制波长为366 nm左右,其耐蚀性能优于纯锌镀层和锌镍合金镀层.     

工业纯铁和Fe-0.1Si合金热浸镀锌层的生长规律及其组织特征

以铁损来判断热浸镀锌的温度对镀锌层的影响,结果欠准;硅元素对镀锌存在sandelin效应.这2种因素对锌镀层的生长、质量及性能都有重大的影响,且都难以控制.为此,以工业纯铁和Fe-0.1Si(0.1%,质量分数)合金薄片为热镀锌基材,探讨锌液温度和钢中硅元素对镀层生长和镀层组织的影响.利用扫描电镜对2种基材在450～530℃内的热镀锌层厚度及其组织进行了测量与分析.结果表明:工业纯铁在480 ℃下热镀锌时镀层生长最快,Fe-0.1 Si合金在470℃热镀锌时镀层生长最快;在镀层生长最快的温度下,2种基材的镀层特征具有相似性;当镀锌温度超过500℃时,工业纯铁和Fe-0.1Si合金镀层中的ζ相消失,镀层由δ相组成.     

低碳钢热浸Zn-0.15%Ni合金镀层组织及第二相粒子

采用热浸Zn-Ni合金镀锌方法，在含0.03%-0.36%Si的低碳钢上获得Zn-Ni合金镀层，研究了镀浴中Ni含量和钢中Si含量对镀层中δ相和ζ相生长速率的影响，以及Zn-Ni合金镀层η相中的第二相粒子即Zn-Fe-Ni三元化合物Γ2相粒子的形成和长大过程，结果表明，在Zn-0.15%Ni镀浴中，含硅0.03%-0.215%钢镀层的ζ相明显受到抑制，δ相厚度略有增加，Γ2相粒子的形成和长大过程包括ζ相的溶解，Γ2相的形核和成比例吸收铁，镍而长大。     

热镀锌和锌铝合金镀层的微观组织及盐雾腐蚀行为

采用间歇式中性盐雾加速试验方法研究了Q235钢热镀锌及55Al-Zn合金镀层的腐蚀行为，利用扫描电镜（SEM）和能谱仪（EDS）分析了镀层的微观组织和腐蚀产物的成分。镀层的微观组织分析结果表明热镀锌层由表及里是η相（纯锌），ζ相（FeZn13),δ1相（FeZn7）和α固溶体组成；热镀锌铝合金镀层由两层组成，外层由富锌和富铝两相固溶体组成，内层由单一的η相（Fe2Al5)组成。盐雾试验和腐蚀产物分析结果表明，热镀锌铝合金层的耐腐蚀性能优于热镀锌层。     

锌浴中加锡对0.37%Si钢热浸镀锌的影响

为避免热镀锌时含硅活性钢形成表面灰暗、超厚而粘附性差的镀层,研究了0.37%Si钢在含锡量分别为0,3%,5%,7%和12%(质量分数)的锌浴中浸镀不同时间时镀锌层的生长及组织变化.结果表明,在锌浴中加入一定量的锡以后,镀层的超厚生长得到了抑制.当锡含量小于5%时,抑制效果随锡量增加而增加,当锡含量大于5%时,抑制效果随锡量增加不再明显增加.在锌浴中加5%锡以后,高硅钢的镀层中的δ层变厚而非常致密,ζ层显著变薄并由疏松的块状变为排列整齐的柱状晶.基于镀层中微区成分分析结果,锌浴加锡抑镀层快速生长的原因是由于在ζ层的前沿形成了一个阻碍铁锌互扩散的富锡区.     

锌镍合金镀液中锌镍离子浓度对镀层镍含量的影响

为了得到成分较稳定的锌镍合金镀层,考察了镀液中锌、镍离子浓度对镀层镍含量影响情况,发现镀液中锌镍离子摩尔浓度比对镀层镍含量影响最大;控制镀液中c(Ni2 )/[c(Ni2 ) c(Zn2 )]为0.15～0.17、c(Ni2 ) c(Zn2 )在0.17～0.40 mol/L范围内,能得到镍含量质量分数在13%左右的高耐蚀性锌镍合金镀层.循环伏安曲线分析表明,在合金电镀过程中,Zn2 的存在和析出会在阴极表面形成中间产物吸附膜,使镍的还原受阻,导致合金镀层的镍含量低于镀液中的c(Ni2 )/[c(Ni2 ) c(Zn2 )],锌镍合金共沉积表现为异常共沉积.     

二元配合物中电镀锌镍合金的结构与抗腐蚀性

为深入了解碱性锌酸盐体系的工艺参数对锌镍合金镀层结构和耐蚀性的影响,在以四乙烯五胺(TEPA)为镍离子主络合剂、三乙醇胺(TEA)为辅助络合剂的碱性镀液中电沉积制备了锌镍合金镀层,利用电子能谱、X射线衍射、极化曲线和电化学阻抗谱等方法表征镀层的组成结构和在氯化钠溶液中的耐腐蚀性.结果表明:镀层含镍原子数分数11.54%~20.12%,为γ-Ni2Zn11+纯Zn两相结构(低含镍原子数分数时)或单一γ相结构(较高含镍原子数分数时),γ相晶粒在(600)方向上具有不同程度的择优取向性;随着镀液中镍原子数分数的提高,镀层的腐蚀电位正移,阻抗增加,耐蚀性提高;当电流密度为2 A/dm2时,镀层的腐蚀电位和电荷传递电阻最高,耐蚀性最好.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Instructions & Forms for Authors

Journal of Materials Sciences ＆ Technology is a monthly journal for the rapid dissemination of new, impor- rant results in material and related fields. Submission Electronic files of MS Word and PDF are acceptable. Please visit http：//www.jmst.org and submit online.