磷化液组分对铝合金磷化膜耐蚀性能的影响

采用电化学测试方法对LY12铝合金的锌系磷化膜的电化学性能进行研究.分别讨论了磷化液中磷酸二氢锌、硝酸锌、氯酸钠及氟化钠质量浓度的变化对磷化膜电化学性能的影响.结果表明,当溶液组成为10g/L磷酸二氢锌、35g/L硝酸锌、2g/L氯酸钠、3g/L氟化钠时,铝合金磷化膜的腐蚀电位最大,腐蚀电流最小,线性极化电阻最大,耐蚀性最好.     

锌钙系磷化液的研究

通过改变磷化液组成和工艺条件,考察其对磷化膜耐蚀性和膜厚的影响,研究了锌钙系磷化的主要控制因素,结果表明,影响磷化膜的成膜速率及质量的因素,主要有Zn2 /Ca2 、PO3-4/NO-3、Ca(NO3)2、Zn(H2PO4)2、促进剂B、磷化温度和时间,此外,Fe2 、Ni(NO3)2、促进剂A对锌钙系磷化也有一定的影响.根据磷化工艺中各项指标的影响,确定了锌钙系磷化液配方.     

磷化温度对铝合金磷化膜性能的影响

采用锌系磷化液对LY12硬铝合金进行磷化处理。通过测量膜质量、硫酸铜点滴试验、极化曲线测试等考查了磷化温度对磷化膜性能的影响,利用SEM、EDS等分析手段,对磷化膜的表面形貌、化学成分进行分析。结果表明,当磷化θ为50℃时,磷化膜外观颜色呈浅灰色,均匀光亮,膜面质量达5.18g/m2,硫酸铜试验耐蚀t为57s,铝合金磷化膜的腐蚀电位最大,腐蚀电流最小,线性极化电阻最大,耐蚀性最好。     

新型环保型磷化液的研制

开发了一种用于钢铁表面涂装前处理的常温清洁锌钙系磷化液.通过正交实验优选了常温锌钙系磷化液的配方,得到配制简单、能够快速成膜、磷化膜质量好的磷化液配方,且该磷化液不含亚硝酸盐和重金属.讨论了磷化的工艺条件对磷化膜质量的影响,并对磷化膜进行了检测.在5～35℃下浸渍磷化5～10 min,每平方米即可生成质量约为2 g的浅...     

成膜处理剂(Ⅲ)

<正>41二氧化铈对镁合金磷化的作用(1)提高成核率,加速成核过程,细化膜层。(2)减少沉渣。(3)大幅提高膜层的耐蚀性。42硝酸镧对低温锌系磷化的作用在低温锌系磷化液中加入硝酸镧,不仅可以促进磷化膜晶粒形核,还可以促进基底溶解出Fe2+。43硝酸铈对磷化的作用(1)优化铝合金磷化膜的性能硝酸铈在铝合金磷化过程中起到了形核与促进磷化的作用,同时形成的磷化膜具有较低的化学活性,耐蚀性得到提高。     

不锈钢表面电化学磷化及膜层性能

采用由4.0 g/L ZnO、4 g/L CaCl2、5%(体积分数)H3PO3、4 g/L酒石酸和3 g/L氯酸钠组成的锌钙系磷化液,在温度为70°C和电流密度为4 mA/cm2的条件下对1Cr18Ni9Ti不锈钢表面进行电化学磷化20 min。对比了所得磷化膜与采用相同磷化液化学磷化2 h所得膜层的表面形貌、相结构和耐蚀性。结果表明,与化学磷化相比,电化学磷化所需时间较短,所得膜层的结晶大小和分布均匀,耐腐蚀性更好。     

简析锌系磷化液和活化剂的组成

分析了锌系磷化液和活化剂的组成对磷化膜质量的影响,为获得最佳磷化膜提出了理想的组成和工艺条件,分析了磷化液各成分和活化剂组成的主要作用。     

铝合金磷化膜性能的研究

采用中温锌系磷化工艺对LY12硬铝合金进行磷化处理获得磷化膜.通过硫酸铜点滴试验,电化学测试等考查了磷化膜的耐蚀性;利用扫描电子显微镜、能谱仪等对磷化膜的表面形貌、化学成分进行分析.结果表明,该磷化膜外观颜色呈浅灰色,均匀光亮,耐蚀性好,硫酸铜试验耐蚀t为63 s,线性极化电阻为4.174 kΩ;表面形貌为片状晶体层层...     

常温清洁锌系磷化液的研制

开发了一种用于钢铁表面涂装前处理的常温清洁锌系磷化液.该磷化液不含亚硝酸盐和重金属,在10～35℃下浸渍磷化5～ 10 main,每m2即可生成质量约为2 9的浅灰色、均匀、致密的磷化膜,耐CuSo4溶液点滴时间达90～120 s,耐3％氯化钠溶液浸泡时间为3h.     

建筑结构钢表面锌系复合磷化膜的制备及耐蚀性研究

将纳米SiO2颗粒添加到磷化液中,在建筑结构钢表面制备出锌系复合磷化膜,并与纯锌系磷化膜进行了比对.结果表明:两种磷化膜都完全覆盖了基体,且都呈断层状形貌,锌系复合磷化膜的晶粒空隙被纳米SiO2颗粒填补,其含量约为7.54％.两种磷化膜的耐蚀性都好于建筑结构钢,且锌系复合磷化膜的耐蚀性最好.纳米SiO2颗粒在一定程度上填补了晶粒空隙,有效阻碍了腐蚀介质通过晶粒空隙渗透和扩散,从而保证锌系复合磷化膜具有较好的耐蚀性,使建筑钢构件能更好的满足防腐蚀要求.     

双镀锌铝合金镀层的组织结构和耐蚀性

采用“双镀法”在钢板表面热浸镀不同铝含量的锌铝镀层(Zn-5Al、Zn-11Al、Zn-17Al和Zn-23Al),利用扫描电镜和能谱仪考察浸镀液中铝含量对镀层组织结构的影响,采用电化学测试、中性盐雾试验等手段评价镀层耐蚀性的变化。随着浸镀液中铝含量升高,镀层表面由片层状交替排布的富铝、富锌共晶组织向富铝枝晶网络结构转变,耐蚀性逐渐提高。但铝含量过高(质量分数大于17%)会导致大量脆性Fe-Al-Zn金属间化合物生成,合金层厚度明显增大。     

Electromagnetic shielding and corrosion resistance of electroless Ni‐P and Ni‐P‐Cu coatings on polymer/carbon fiber composites

In order to study electrical properties, especially the electromagnetic interference (EMI) shielding property of ternary Ni‐P‐Cu plated polyether ether ketone/carbon fiber composites (CFs/PEEK) and their dependence on Cu content of the coating, electroless Ni‐P coating was first deposited on CFs/PEEK to obtain the optimum conditions for deposition rate, then a small quantity of CuSO₄•5H₂O (0.1∼0.4 g/L) was added in the electroless nickel‐based alloy plating (ENP) bath to investigate the influence of Cu content on the deposition rate and coating characterizations. The EMI shielding effectiveness (SE) was evaluated and corrosion resistance was characterized by electrochemical polarization measurement. It was found that coating phase change from amorphous to a mixture of amorphous and microcrystalline phases with the increase of Cu²⁺ concentration. Due to the neat morphology and uniform amorphous structure, the optimum coating Ni‐P‐2.2 wt% Cu obtained at the 0.2 g/L Cu²⁺ in the bath owns the best corrosion resistance, EMI SE and the lowest surface resistance. POLYM. COMPOS., 36:923–930, 2015. © 2014 Society of Plastics Engineers     

Nanocrystalline Ni–Co alloy coatings: electrodeposition using horizontal electrodes and corrosion resistance

Nanocrystalline Ni–Co alloy coatings containing 0–45 wt% Co were electrodeposited using horizontal electrodes in a modified Watts bath. Different techniques including scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, microindentation, and potentiodynamic polarization were used to characterize the alloy coatings. Properties of the alloy coatings were investigated as a function of the cobalt ion concentration (Co²⁺) in the bath. It was observed that the alloy codeposition exhibits anomalous behavior. Co content in the alloy coatings increases with increasing Co²⁺ in the bath and with electrolyte agitation. Morphology and grain size of alloy coatings are greatly affected by Co content. By increasing Co content, surface morphology of the alloy coatings changes from pyramidal to spherical. Microhardness of the alloy coatings increases with increasing Co content mainly due to decreasing grain size that follows the Hall–Petch relation. In addition, Ni–17 wt% Co alloy exhibits better corrosion resistance compared to pure Ni and other Ni–Co alloy coatings. The higher corrosion resistance of Ni–17 wt% Co coating is discussed based on its phase structure, grain size, and preferred orientation.     

镍镉合金扩散层内应力的研究

为了满足飞机发动机叶轮耐高温腐蚀性要求,研究了镍镉合金扩散层的结构,采取了两种方法来克服镍镉合金扩散层的弊病.选取合适的镀镍液或化学镀镍液制取低应力镍层;基体用液体喷丸方法提高零件表面强度及抗应力腐蚀能力.同时分析了电镀工艺参数对镍镉扩散层的影响.     

装饰性锡锌镍三元合金代镍工艺研究

研究了装饰性电镀锡锌镍三元合金代镍工艺。采用赫尔槽试验探讨了主盐、添加剂、溶液温度和pH对镀层镍含量、镀层外观及镀液稳定性的影响。结果表明:该工艺操作方便,镀液分散能力和覆盖能力好,所得锡锌镍合金镀层结晶细致,光亮,类似镍层,其耐蚀性明显优于锌镀层,适用于钢铁件高耐蚀装饰性电镀。     

溅射Ni11Co26Cr6Al0.5Y涂层对镍基合金在900℃腐蚀行为的影响

采用真空溅射技术在镍基合金表面沉积Ni11Co26Cr6Al0.5Y纳米晶涂层,研究有、无涂层合金在900℃的75%Na_2SO_4+25%K_2SO_4熔融混合硫酸盐膜中的热腐蚀行为。结果表明:无涂层合金发生腐蚀,生成内氧化物和内硫化物。而Ni11Co26Cr6Al0.5Y涂层在热腐蚀过程中,表面生成Al_2O_3、NiCr_2O_4、Cr_2O_3和NiO氧化膜,仅在近涂层与基体界面区域存在少量Al_2O_3内氧化物。     

氯离子对6063铝合金铈-锰转化膜耐蚀性的影响

在Ce-Mn稀土钝化液中添加Cl-作为促进剂,以6063铝合金为基体制备了Ce-Mn转化膜。分别采用扫描电镜(SEM)和能谱仪(EDS)研究了转化膜的表面形貌及元素组成,并采用硫酸铜点滴腐蚀实验、动电位极化曲线以及电化学阻抗谱(EIS)研究了Ce-Mn转化膜的耐蚀性。结果表明,Ce-Mn转化膜主要由Ce、Mn、O等元素组成,往稀土钝化液中添加Cl-可使膜层更平整、致密,转化膜的平均耐点滴时间从50s提高至100s,在NaCl质量分数为3.5%的腐蚀介质中的腐蚀电流密度明显降低,转化膜极化电阻增大,铝合金的耐蚀性显著提高。     

电流密度对电镀铜-镍合金微观结构和耐蚀性的影响

采用直流电沉积法在高锰铝青铜基体上制得Cu-Ni合金镀层,镀液组成和工艺条件为:CuSO4·5H2O 20 g/L,NiSO4·6H2O 84 g/L,C6H5O7Na3·2H2O 75 g/L,十二烷基硫酸钠0.5 g/L,H3BO320 g/L,电流密度15~30 mA/cm^2,pH 7,温度55℃,搅拌速率300 r/min,时间60 min。研究了电流密度对Cu-Ni合金镀层元素成分、微观形貌和耐蚀性的影响。结果表明,在电流密度30 mA/cm^2下所得到的Cu-Ni合金镀层最厚,为25μm,耐蚀性最好,经乙酸盐雾试验168 h后表面仅有几个微小的腐蚀坑。     

Corrosion behaviors of Zn/Al-Mn alloy composite coatings deposited on magnesium alloy AZ31B (Mg-Al-Zn)

After being pre-plated a zinc layer, an amorphous Al-Mn alloy coating was applied onto the surface of AZ31B magnesium alloy with a bath of molten salts. Then the corrosion performance of the coated magnesium alloy was examined in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the single Zn layer was active in the test solution with a high corrosion rate while the Al-Mn alloy coating could effectively protect AZ31B magnesium alloy from corrosion in the solution. The high corrosion resistance of Al-Mn alloy coating was ascribed to an intact and stable passive film formed on the coating. The performances of the passive film on Al-Mn alloy were further investigated by Mott-Schottky curve and X-ray photoelectron spectroscopy (XPS) analysis. It was confirmed that the passive film exhibited n-type semiconducting behavior in 3.5% NaCl solution with a carrier density two orders of magnitude less than that formed on pure aluminum electrode. The XPS analysis indicated that the passive film was mainly composed of AlO(OH) after immersion for long time and the content of Mn was negligible in the outer part of the passive film. Based on the EIS measurement, electronic structure and composition analysis of the passive film, a double-layer structure, with a compact inner oxide and a porous outer layer, of the film was proposed for understanding the corrosion process of passive film, with which the experimental observations might be satisfactorily interpreted.     

铁-钨-磷合金电沉积工艺及其性能研究

在含FeSO4·7H2O、Na2WO4·2H2O、NaH2PO2·H2O、Na3C6H5O7·2H2O、C6H8O7·H2O、NH3·H2O和苯亚磺酸钠的碱性镀液中,电沉积得到Fe–W–P三元合金,分析了不同镀液成分时所得镀层的化学组成,讨论了温度、pH、电流密度及NH3·H2O用量对镀层沉积速率和显微硬度的影响。结果表明:除NaH2PO2·H2O外,镀液中其他组分对镀层组成均有显著影响;工艺参数的改变对镀层沉积速率和显微硬度有一定影响,NH3·H2O体积分数对沉积速率的影响尤其显著。电沉积所得Fe–W–P合金镀层具有典型的非晶态结构,其耐蚀性略优于00Cr17Ni14Mo2不锈钢。