2024铝合金化学转化膜与磷化底漆耐蚀性的研究

通过盐雾实验、稳态阳极极化曲线和电化学阻抗谱3种测试方法，对磷化底漆和阿洛丁(1200)化学转化膜进行了测试，结果发现磷化底漆的耐蚀性明显优于阿洛丁化学转化膜．在中性盐雾实验10个周期中，阿洛丁化学转化膜腐蚀明显，而磷化底漆完好如初．在稳态和弱极化区，两者抗蚀性能相似，而在强极化区，磷化底漆明显优于阿洛丁化学转化膜、在电化学阻抗谱上，磷化底漆极化电阻(Rp)比阿洛丁转化膜高1个数量级．     

纳米金属Ti粉修饰电解磷化膜性能研究

利用电化学测试技术、扫描电子显微镜(SEM)和X射线衍射(XRD)仪对Ti粉修饰的电解磷化膜性能进行研究。结果表明,在电解磷化液中加入纳米金属Ti粉后,磷化晶粒由长条形结晶形貌且结晶颗粒尺寸不均转变为结晶颗粒大小均匀致密的片状结晶,制备得到的磷化膜交流阻抗明显增大,添加纳米金属Ti粉后,磷化膜腐蚀电流降低,耐CuSO4点滴腐蚀时间超过600s。     

冷轧家电板磷化后耐蚀性能的影响因素

利用ICP、金相显微镜、电化学测试系统和波纹度仪等设备,对影响A、B两种家电板磷化后耐蚀性能的原因进行了分析.结果表明:降低基体金属C、Si等元素含量以及基体组织中碳化物含量、增加金属的表面粗糙度等易于形成均匀致密磷化膜的条件,有利于增强家电板磷化后的耐蚀性能;锌系磷化膜的耐蚀性能优于铁系磷化膜的耐蚀性能;耐蚀性能优越的家电板,其磷化后的耐蚀性能也同样优越.对家电板进行电化学特性的测试,可以初步判断家电板磷化后耐蚀性能的优劣.     

脱脂对镀锌汽车板涂装性能影响

目的 研究脱脂影响镀锌钢板磷化反应的机理及电泳漆膜性能。方法 使用扫描电镜、电化学工作站、X射线光电子能谱分析仪、成形试验机和循环式腐蚀试验机等设备研究了磷化膜形貌、表面元素、电化学性能以及电泳漆膜性能。结果 脱脂不良时磷化膜在镀锌钢板表面生长异常,导致磷化膜呈现为明暗相间的花斑状;表面元素和材料在磷化液中的电化学性能说明磷化膜生长异常的原因是残存油膜阻碍磷化反应进行,同时异常磷化膜相对于正常磷化膜在3.5% NaCl溶液中开路电位负、阻抗小、自腐蚀电流大,说明异常磷化膜耐蚀性能差,易腐蚀;电泳漆膜性能表明,脱脂不良对漆膜的划格附着力影响小,评级为0级,但对电泳漆膜的杯突性能影响明显,杯突高度为6 mm时,漆膜发生破裂;电泳耐蚀性能下降明显,电泳漆膜扩蚀宽度从2.4 mm增加到3.9 mm。结论 脱脂不良会导致镀锌板表面磷化膜质量异常,进而影响电泳耐蚀性能,在实际生产过程中,需要对脱脂工序有效管控,结合车身材料用油种类及油量及时调控参数,避免脱脂不良问题出现。     

镁锂合金表面锌锰磷化膜的制备与性能表征

采用化学转化法在镁锂合金表面制备了外观深灰色、结构均匀致密、耐蚀性能良好的锌锰磷酸盐转化膜,并研究了磷化温度对磷化膜性能的影响。采用扫描电子显微镜(SEM)、能谱(EDS)仪、X射线光电子能谱(XPS)和X射线衍射(XRD)仪对膜层的表面形貌、化学组成及结构进行了表征。采用动电位极化曲线、电化学交流阻抗(EIS)和腐蚀失重实验对磷化膜的耐蚀性进行了研究。结果表明,锌锰磷化膜主要由Zn、Zn3(PO4)2、MnHPO4、Mn3(PO4)2组成。锌锰磷酸化膜起到了保护镁锂合金的作用,提高了镁锂合金的耐蚀性,当磷化温度为45℃时,磷化膜的腐蚀电流密度最低,腐蚀速率最小,耐蚀性能最好。     

脉冲频率对镁合金微弧氧化膜层在仿生液中耐蚀性的影响

研究了微弧氧化过程中不同电源脉冲频率下制备的膜层在仿生液中的电化学腐蚀行为。对膜层及腐蚀产物的微观组织,孔隙率,腐蚀形貌及相组成进行了分析。采用动电位极化曲线(Tafel)和电化学阻抗谱(EIS)法对膜层的耐腐蚀性能进行评价。结果表明,脉冲频率对AZ31镁合金微弧氧化膜层的耐蚀性有重要影响,随着频率的增加,腐蚀电流密度减小,而电化学阻抗增大。因此在本研究范围内,频率3000 Hz下制备的微弧氧化膜层具有最强的耐腐蚀性能。     

几种改进磷化膜耐蚀性对比和自修复性初探

研制了钼酸钠添加剂改进磷化膜及钼酸钠、硝酸铈、硅酸钠溶胶封闭后处理改进磷化复合膜,拟替代高毒性铬酸盐钝化膜。采用中性盐雾试验、Tafel极化和电化学阻抗测试对比分析了这4种改进磷化膜与几种传统无铬转化膜、铬酸盐钝化膜耐蚀性的差异;用SEM和EDS研究带划痕试样经盐雾腐蚀后划痕表面的组织形貌和化学成分,初步探讨了改进磷化复合膜的自修复性。结果表明:3种改进磷化复合膜的耐蚀性优于铬酸盐钝化膜,具有自修复作用,有望成为铬酸盐钝化膜的替代品;硅酸钠溶胶封闭后处理改进磷化复合膜的耐蚀性最优。     

酒石酸钾钠对镁合金表面磷化膜耐蚀性的影响

为进一步提高镁合金表面磷化膜的耐蚀性,在磷酸二氢铵和高锰酸钾组成的磷化液中加入酒石酸钾钠,通过扫描电镜和能谱分析分别对磷化膜的表面形貌和组成元素进行观察和测试,通过电化学阻抗谱和极化曲线对磷化膜的耐蚀性进行考察。结果表明,酒石酸钾钠加入到磷化液中以后,磷化膜表面的微裂纹数量明显减少,表面更加平整、致密,膜电阻和电荷转移阻力明显增大,减少了腐蚀介质渗入到基体的通道,增大了腐蚀性离子的迁移阻力。同时,磷化膜中Mn、O和P等元素含量的增加,磷化膜中含有更多镁的磷酸盐和锰的氧化物,使磷化膜的耐蚀性进一步提高。     

电化学法研究铝阳极氧化膜的抗腐蚀性

工业纯铝L2在硫酸溶液中进行阳极氧化制得阳极氧化膜,测试了此阳极氧化膜在NaCl溶液中的电化学性能。通过动态极化法和交流阻抗法对阳极氧化膜进行分析,发现阳极氧化膜的制备条件(电解液浓度、时间、电压等)不同时,膜的抗腐蚀性能也不同。电化学阻抗法测定表明,随浸泡时间的增加,膜阻抗值明显增大,可能是多孔膜在介质溶液中存在一个自然水合封闭的过程。     

偏钒酸铵对AZ91D镁合金表面磷酸盐转化膜的耐腐蚀性能影响的研究

为了提高镁合金磷化盐转化膜的耐腐蚀性能,向镁合金磷酸处理液中添加NH₄VO₃,采用中性盐雾实验、Tafel曲线和电化学阻抗测试、扫描电镜 (SEM) 测试和能量色散谱仪分析等方法检测膜层的性能,研究了NH₄VO₃对镁合金表面磷酸盐转化膜耐蚀性的影响。结果表明：加入NH₄VO₃后,镁合金化学转化膜表面的裂纹有细化和孔洞有减少的趋势;化学转化膜呈现明显的容抗特性,电化学阻抗可达273.6 Ω;自腐蚀电位正移了121.6 mV,自腐蚀电流密度明显减小,降低了接近一个数量级,耐腐蚀性能得到了很大的提升,表面化学转化膜的耐中性盐雾腐蚀时间大幅度增加,达到41 h。     

Stannate and permanganate conversion coatings on AZ31 magnesium alloy

The formation of stannate and permanganate–phosphate conversion coatings on AZ31 magnesium alloy was investigated in situ by EIS measurements and their protective performances were studied by different electrochemical techniques in diluted (0.05 M) sodium sulphate solution.The influence that short or long treatment times exert on the performances of such conversion coatings is discussed. While permanganate–phosphate baths always built layers characterized by penetrating cracks, long stannate baths produced layers without interconnected porosity, but were defective. This accounted for the initial greater protectiveness achieved with the stannate treatment; nevertheless, the easy penetration of the electrolytic solution through such a layer quickly decreased its corrosion resistance.     

The EIS investigation of powder polyester coatings on phosphated low carbon steel: The effect of NaNO2 in the phosphating bath

The effect of different type of iron-phosphate coatings on corrosion stability and adhesion characteristic of top powder polyester coating on steel was investigated. Iron-phosphate coatings were deposited on steel in the novel phosphating bath with or without NaNO₂ as an accelerator. The corrosion stability of the powder polyester coating was evaluated by electrochemical impedance spectroscopy (EIS), adhesion by pull-off and NMP test, while surface morphology of phosphate coatings were investigated by atomic force microscopy (AFM).The adhesion and corrosion stability of powder polyester coatings were improved with pretreatment based on iron-phosphate coating deposited from NaNO₂-free bath.     

Corrosion and protection characteristics of phosphate coatings: effect of yttrium oxide as additive

Abstract

The corrosion and protection characteristics of phosphate coatings formed in a phosphating solution containing mainly ZnO, H₃PO₄ and NaF, using Y₂O₃ as an additive, were investigated through SEM, polarisation curves and EIS diagrams. The results show that the corrosion protection of phosphate coatings has been improved when Y₂O₃ is added to the phosphating solution, making the free corrosion potential shift to the positive direction and causing the corrosion current to decrease. The protection ability of phosphate coatings depends mainly on their barrier performance. The phosphate coatings formed in the phosphating solution with 10 and 20 mg L^–1 Y₂O₃ have finer crystal structures and smaller porosity; therefore, they exhibit better corrosion resistance and adhesion properties than those without Y₂O₃ and with 40 mg L^–1 Y₂O₃.     

The mechanism of inhibition by zinc phosphate in an epoxy coating

Epoxy coatings containing different volume fractions of zinc phosphate have been successfully prepared and their inhibitive properties have been studied by electrochemical impedance spectroscopy (EIS) and immersion tests. The results show that zinc phosphate can improve the protection ability of epoxy coatings and its best volume fraction is 30%. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) results indicate that the presence of zinc phosphate can form an inhibiting film which is composed of the phosphating film of FePO₄, Fe₂O₃, and FeO, as well as the shielding film of zinc phosphate on the steel surface.     

碳钢超声磷化及在模拟干热岩地热水中的耐蚀性能

采用环境友好的硫酸羟胺为主要促进剂,避免使用强氧化性物质,并以超声处理来改进磷化工艺。通过动电位极化曲线方法研究了超声、促进剂、pH值和磷化时间对磷化膜耐蚀性能的影响。结果表明,超声处理能够细化磷化颗粒,提高其耐蚀性能。pH值和磷化时间显著影响磷化膜的耐蚀性,需保持在较优的范围。采用电化学阻抗谱研究了优化工艺得到的磷化膜在模拟干热岩地热水中的耐蚀性,发现其电荷转移电阻由碳钢的1.44×10³ Ωcm²增加到3.39×10⁶ Ωcm²。     

钼酸盐后处理提高热镀锌上磷化膜耐蚀性的探讨

将磷化后的热镀锌钢板用钼酸盐后处理,以提高磷化膜的耐蚀性。用SEM、EDS、电化学极化测量和盐雾试验研究了钼酸盐后处理对磷化膜组成和耐蚀性的影响。结果表明,经钼酸盐处理后,磷化膜上磷酸锌晶体间的孔隙被钼酸盐膜填补,从而在锌层表面形成了由磷化膜和钼酸盐膜构成的连续完整致密的复合膜;复合膜的极化电阻Rp显著增大,腐蚀电流密度显著减小,耐蚀性大大增强。磷化300s、后处理50s时复合膜的耐蚀性最优,Rp比单磷化膜的增加了一个数量级。     

The growth of zinc phosphate coatings on 6061-Al alloy

Zinc phosphate coating was formed on 6061-Al alloy through a phosphating bath containing mainly ZnO, H₃PO₄, NaF. Yttrium oxide (Y₂O₃) was used as an accelerator of phosphatization to replace nitrite. The morphology, composition and the growth process of the zinc phosphate coating were investigated by SEM, EDX, XRD, FTIR and electrochemical measurements. The phosphate coating formed is composed of hopeite and metallic zinc. The formation and morphology of the zinc phosphate coating were strongly influenced by the presence of yttrium oxide (Y₂O₃) in the phosphating bath. The formed zinc phosphate coatings exhibited high corrosion resistance in 3% NaCl solution as shown by polarization measurement.     

稀土硝酸盐促进的铝合金锌系磷化成膜过程

采用扫描电镜(SEM)、X射线衍射(XRD)及能谱(EDX)和电化学测试的方法,研究了稀土硝酸盐(REN)对6061铝合金锌系磷化成膜过程的影响,结果表明,少量的稀土硝酸盐添加到磷化液中可以提高磷化成膜速度和细化晶粒,改变磷化膜的组成,但稀土硝酸盐本身并不构成磷化膜的组成成分,它实质上是具有良好载氧能力的促进剂,具有良好的成核促进作用和阴极去极化作用.与在不含稀土硝酸盐的磷化液中所形成的磷化膜相比,铝合金在含有稀土硝酸盐的磷化液中所形成的磷化膜具有较低的化学活性,其耐蚀性得到提高,在所研究的工艺条件下,最佳硝酸盐含量为20～40 mg/L.     

两种低红外发射率涂层的防腐蚀效果研究

采用电化学阻抗谱(EIS)研究了分别以三元乙丙橡胶(EPDM)、马来酸酐改性三元乙丙橡胶(EPDM-g-MAH)为粘合剂,铜粉为填料的两种低红外发射率涂料在模拟海水环境中的电化学腐蚀行为.结果表明:浸泡初期腐蚀介质均能渗入两种涂层内部,涂层表现出较弱的防护性能,马来酸酐改性三元乙丙橡胶基涂料的防腐蚀性能优于三元乙丙橡胶...     

Study on Phosphating by Ultrasonic Wave at Room Temperature for Sintered NdFeB Magnet

The corrosion behavior of a NdFeB magnet obtained at room temperature,with and without ultrasonic were investigated.The corrosion resistance was investigated by corrosion immersion tests in 3 wt%neutral NaCl solutions,potentiodynamic polarization tests and electrochemical impedance spectroscopy(EIS).The morphology of the conversion coatings on NdFeB surface were analyzed by scanning electron microscopy(SEM).And the forming mechanism of coatings was studied by potential-time curves.The tests of corrosion resistances show that the combination of phosphating treatment with ultrasonic will further improve the corrosion resistance of the NdFeB.The SEM also confirms that phosphating coating under ultrasonic is more homogeneous and compact.