Ni-Cr alloy electrodepositing technology on Fe substrate and coating performance

The Ni-Cr alloy electrodepositing technology on iron substrate in the chlorid-sulfate solution and the impacts of main processing parameters on coating composition were studied. The optimal Ni-Cr alloy electrodepositing conditions are that the cathode current density is 16 A/dm^2, the plating solution temperature is 30 ℃ and the pH value is 2.5. The bright, compact coating gained under the optimal conditions has good cohesion and 24.1% Cr content. The results show that the coating is composed of crystalline, the average grain size is 82 nm and the higher the Cr content of coating, the larger the rigidity, and the higher the corrosion resistance. The rigidity of coating reaches 78.6（HR30T） and the passivation area broadens to 1.4 V when the Cr content of coating is 24.1%.     

铝电解阴极过程的电化学研究

用电化学方法研究了在纯冰晶石、工业电解质和低熔点电解质中铝的电解沉积和溶解损失研究表明，铝的沉积为简单的3电子传递反应；铝的再溶解损失由金属／熔液界面层中的稳态传质控制，其速度分别为0．247，0102和0．0423A·cm－2结果证明在低熔点电解质熔液中，电解制取铝具有很高的电流效率．     

铁基/Ni-Cr合金制备工艺参数及结构性能表征的研究

采用电化学沉积法在45#钢上电镀Ni-Cr合金,利用XRD、SEM、EDS测试方法对所制备的样品进行分析。结果表明,通过X射线分析,镀层为镍铬合金的共溶体。当衍射角2θ为44.375度时出现了明显的衍射峰,且由谢乐公式（Scherrer）计算得晶粒尺寸为35.97nm。由扫描电镜测试分析可知阳极材料的选取对镍铬合金镀层的形貌结构有较大影响。通过能谱仪测试,可知随着电流密度的增加,合金中铬的含量也逐渐增加。     

用于冰晶石基熔体中铝电化学沉积和溶解研究的电极材料

用电化学方法研究了从冰晶石基熔体中电沉积在钽、铜、钨和石墨电极上的金属铝的行为，实验表明，沉积的铝与钨电极之间的合金化作用弱于其它金属电极，因此经适当处理，钨电极可用于研究铝的电解沉积和溶解损失，并测得铝原子在钨电极中的扩散系数，由子钠原子对碳结构的电渗作用，石墨不宜作为研究铝电解阴极过程的电极材料。     

Investigation on plasma-sprayed ZrO_2 thermal barrier coating on nickel alloy substrate

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Pb0.9Sn0.1合金电沉积物的微结构

在薄层电化学槽中制备了Pb0.9Sn0.1合金,并利用SEM、EPMA考察了合金的微结构.电沉积的Pb0.9Sn0.1合金具有固溶体-伪共晶-固溶体三层结构.研究表明,由于薄溶液层中离子输运受限,生长初期铅锡含量呈交替变化,导致铅基固溶体-伪共晶结构形成.随着生长的进行,屏蔽效应又使得端面电极电位降低,锡的沉积量减少,从而铅基固溶体层再次形成.     

Effects of Substrate Local Strain on Microstructure of Electrodeposited Aluminum Film

1 IntroductionElectrodeposition,has been widely usedin electron-ics, automobile and airliner industry, and has been anobject of intense research over the past years . Comparedwith other methods for preparing coatings ,the electro-deposition has several advantages , such as least cost ,controllability, avoidance of thermal stress and higherproduction, which can produce functional coatings withresistance to corrosion and wear and low coefficient offriction in engineering field[1 ,2]. Moreover ,t…     

电沉积基合金及其复合镀层在10%H2SO4中的腐蚀磨损特性研究

采用电刷镀技术制取了合金镀层和复合镀层,利用扫描电镜、能谱仪、射线衍射仪分别对镀层原始状态及其腐蚀磨损过程中的组织形貌、成分、和相组成进行了观察、分析.研究了在不同的载荷和速度条件下两种镀层的腐蚀磨损特性及腐蚀磨损的协同作用.结果表明本实验条件下,在较低的载荷和速度下,复合镀层的耐腐蚀磨损性能优于合金镀层,随着载荷和摩擦速度的增大,复合镀层的耐腐蚀磨损性能下降较合金镀层快.     

乙酰胺-尿素-NaBr熔体中电沉积Tb-Mg-Ni合金的研究

在353?K的乙酰胺-尿素 NaBr熔体中,Ni（Ⅱ）一步不可逆还原为金属Ni,测得在Pt电极上α为0.21和D0为1.15×10-8?cm2•s-1;Cu电极上α为0.18和D0为1.44×10-6?cm2•s-1.Tb（Ⅲ）和Mg（Ⅱ）不能单独还原为Tb和Mg,但是可以被Ni（Ⅱ）诱导共沉积.由恒电位电解法得到非晶态的Tb Mg Ni 合金膜.合金中Tb的含量随着阴极电势的负移先增大而后减小,随Tb（Ⅲ）/ Ni（Ⅱ）摩尔比增大而增大,Tb的最大含量可达87.88%;Mg的含量随着阴极电势的负移而增大,最大可达12.78%,在Tb（Ⅲ）/Ni（Ⅱ））摩尔比为3.4/1,Mg（Ⅱ）/Ni（Ⅱ）摩尔比为8/1时,Mg/Ni原子比为2/1,符合Mg2Ni储氢合金的组成.     

铝合金化学镀镍磷合金结构和性能

针对质子交换膜燃料电池双极板的需要,以铝合金为基体材料,采用碱性和酸性双溶液体系化学镀镍磷合金.采用电子探针方法测定了镀层中镍磷含量,X衍射方法研究了热处理对镀层结构的影响,伏安法研究了热处理对镀层耐蚀性的影响.试验结果表明,热处理明显影响镀层的结构和耐蚀性,对于P含量为12.1%（质量）的镍磷合金镀层,经过200～250℃热处理后,晶化不明显但耐蚀等性能明显改善,可以用作质子交换膜燃料电池双极板.     

镍铬合金高温抗氧化性与铬偏析

通过俄歇电子能谱,我们着重研究了低铬含量的镍铬合金(Cr<10％)高温抗氧化的微观机理,俄歇分析表明,高温下(300～500℃)铬向表面偏析相当明显,随着温度的升高,铬的偏析量明显增加,而且在同一温度下,铬的偏析量和退火时间成正比。     

锌电解沉积物的生长

采用电化学沉积方法，在薄层硫酸锌电解液中电解沉积锌，研究电解沉积物的生长情况发现，在适宜的条件下，电解沉积物可同时从阴极和电解液中预先放入的锌沉积物向阳极方向生长，并且电解沉积物的生长形态不受预先放入电解液中沉积物形态的影响，而在电解液厚度较大时没有发现类似现象，由此可知，电解沉积物的生长形态主要与外加电压、电解液浓度及其厚度有关。     

Mechanism of Nickel-Aluminium Alloy Electroplating

The effect of operating conditions on the aluminium content of Ni - Al allay deposit and the catalytic function of NaF on electrodeposition in the nonaqueous solution containing aluminium are investigated.The results indicate that the plated aluminuim content will be increased with the rise of current density in a given range. When the current density is 2.5A/dm^2, nickle-aluminium alloy conl, oJlurtg 13.1 wt% aluminium will be deposited. The plated aluminium content will be increased by 2wt% as 0. 1 mol/ L NaF is added to the bath.     

Laser cladding of Ni-based alloy on copper substrate

The laser cladding of Ni1015 alloy on Cu substrate was prepared by a high power continuous wave CO2 laser. Its microstructure was analyzed by optical microscope （OM）, scanning electron microscope （SEM）, and X-Ray diffraction （XRD）. The average microhardness of the cladding coating was Hv 280, which was almost three times of that of the Cu substrate （Hv 85）. OM and SEM observations showed that the obtained coating had a smooth and uniform surface, as well as a metallurgical combination with the Cu substrate without cracks and pores at the interface. With the addition of copper into the nickel-based alloy, the differences of thermal expansion coefficient and melting point between the interlayer and cladding were reduced, which resulted in low stresses during rapid cooling. Moreover, large amount of （Cu, Ni） solid solution formed a metallurgical bonding between the cladding coating and the substrate, which also relaxed the stresses, leading to the reduction of interfacial cracks and pores after laser cladding.     

Ni-Cr合金烤瓷材料界面组织结构和力学性能

应用扫描电镜、能谱、X射线衍射及电子拉伸试验机对Ni-Cr合金与烤瓷材料的界面组织结构与力学性能进行了分析。结果表明:Ni-Cr合金烤瓷制作过程中产生残余应力和缺陷将导致瓷崩、瓷裂、剥离或脱落。烤瓷温度T对金-瓷界面剪切结合强度影响较大,T=990℃、保温时间t=1.0 min时,金-瓷界面剪切结合强度可达到37.52 MPa。在金-瓷界面处由于Ni-Cr合金与熔融的玻璃相烤瓷材料相互作用,形成新的化合物型界面,对提高金-瓷界面结合强度将起到非常重要的作用。     

铝合金上电沉积Ni-P-CNTs复合镀层及其摩擦性能研究

采用复合电沉积法在铝合金表面上制备了镍 磷 碳纳米管（Ni-P-CNTs）复合镀层,并用X射线衍射（XRD）和扫描电镜（SEM）对其进行了表征,分析了电流密度和镀液中碳纳米管的质量浓度对复合镀层形貌及其摩擦磨损性能的影响.当电流密度为3.0 A/dm2时可以得到表面光亮、平整的复合镀层,复合镀层中碳纳米管体积分数随着镀液中碳纳米管质量浓度的增加而增加.Ni-P-CNTs复合镀层比Ni-P镀层具有更高的硬度、耐磨性能和更低的摩擦系数.随着复合镀层中碳纳米管体积分数的增加,复合镀层的磨损量和摩擦系数逐渐降低.复合镀层摩擦性能的改善是由于碳纳米管具有优异的力学性能和良好的自润滑性能.     

铝及铝合金化学着黄红色探讨

采用除油、碱蚀、化学着色和后处理四步法，将铝或铝合金着黄红色，丰富了多彩的装饰红色．通过实验得出了着色的最佳配方：硫酸镍45g／L，高锰酸钾20g／L，硫酸6g／L，西红素6g／L，着色促进剂A2g／L工艺过程中的处理液可循环利用．具有工艺简单、成本低和着色效率高等优点．生成的氧化膜既具有装饰性又具有耐蚀性．     

Investigation on plasma-sprayed ZrO2 thermal barrier coating on nickel alloy substrate

The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY-Y₂O₃ stabilized ZrO₂ transition layer and Y₂O₃ stabilized ZrO₂ ceramic layer are prepared on nickel alloy substrates using the plasma spray technique. The relationship among the composition, structure and property of the coatings are investigated by means of optical microscope, scanning electronic microscope and the experiments of thermal shock resistance cycling and high temperature oxidation resistance. The results show that the structure design of introducing a transition layer between Ni alloy substrate and ZrO₂ ceramic coating guarantees the high quality and properties of the coatings; ZrO₂ coatings doped with a little SiO₂ possesses better thermal shock resistance and more excellent hot corrosion resistance as compared with ZrO₂ coating materials without SiO₂; the improvement in performance of ZrO₂ coating doped with SiO₂ is due to forming more dense coating structure by self- closing effects of the flaws and pores in the ZrO₂ coatings. Biography of the first author: LU An-xian, Ph.D, professor, born in Jan. 1960, majoring in inorganic non-metal materials.     

酸性镀液铝合金表面沉积Ni-Mo-P三元合金非晶镀层

采用酸性化学镀液在铝合金表面沉积Ni-Mo-P三元合金非晶镀层。利用透射电镜（TEM）、场发射扫描电镜（FESEM）、X射线衍射分析（XRD）、能谱（EDS）等现代分析手段,对镀层显微结构进行了表征,探讨了钼酸钠浓度和热处理对镀层纳米压痕硬度的影响。结果表明,镀态下,化学镀Ni-Mo-P三元合金镀层为致密非晶态镀层,镀层中Mo元素分布均匀,镀层与基体结合良好。热处理可促使非晶镀层晶化,产生Ni和Ni3P晶相,获得了纳米压痕硬度为15.12 GPa的最大值。     

硬铝合金焊接性能的研究

为了有效地使用热处理强化变形铝合金制造各种结构材料和零部件。研究其焊接性能指标．以Al-Cu-Mn系铝合金(2A16)为对象，采用交流钨极氩弧焊焊接工艺及同质和异质焊丝，制备了2A16硬铝合金焊接试样．通过测试力学性能、金相组织和扫描电镜断口分析等方法，对其焊接性能进行了研究．结果表明：2A16硬铝合金有较好的抗结晶裂纹形成能力，影响其焊接性能的主要问题是过时效软化区的强度下降：当填充金属中Mg／Cu质量比比较大时，焊缝出现脆断倾向，欲进一步提高焊接接头强度，一方面可采用能量密度更高的热源，同时减小焊接线能量，以减少过时效软化区的不利影响；另一方面，限制填充金属中Mg／Cu的质量比，避免出现对焊接接头强化不利的β相和T相．