镀液中SiC的质量浓度对化学镀Ni-P-SiC复合镀层性能的影响

研究了镀液中SiC的质量浓度对化学镀Ni-P-SiC复合镀层中SiC的质量分数、表面形貌、镀速、耐蚀性、硬度、孔隙率及耐磨性的影响,并考察了稀土对镀层性能的影响。结果表明:随着镀液中SiC的质量浓度的增加,镀层中SiC的质量分数先增大后减小;当镀液中SiC的质量浓度过高时,镀层中会出现SiC微粒团聚的现象;化学镀Ni-P-SiC复合镀层的耐蚀性优于化学镀Ni-P合金镀层的耐蚀性;当镀液中SiC的质量浓度为8g/L时,镀层具有较高的硬度和较好的耐磨性;向镀液中添加适量的氧化铈可以细化镀层晶粒。     

镁合金化学复合镀Ni-P/纳米SiC工艺的研究

在AZ 91D镁合金表面制备Ni-P/纳米SiC化学复合镀层.探讨镀液中纳米SiC微粒的质量浓度对镀速、复合镀层性能等的影响.利用扫描电镜观察镀层表面形貌,采用能谱分析仪进行镀层表面成分的定性分析,采用显微硬度计测试镀层硬度,并对不同工艺下获得的镀层进行快速磨损实验.结果表明:镀液中添加适量的纳米SiC微粒,镀速和镀层硬度都有显著的提高.当镀液中纳米SiC的质量浓度为9 g/L时,镀速可达到25.6 μm/h;当镀液中纳米SiC的质量浓度为7 g/L时,镀层的维氏硬度可达到9 380 MPa;同时镀层的耐磨性能相比于Ni-P合金镀层的也有显著提高.     

化学复合镀Ni-P-金刚石的耐磨性研究

研究了金刚石和还原剂的质量浓度对镁合金Ni-P-金刚石复合镀层成分及耐磨性的影响.结果表明:镀层中金刚石的质量分数随镀液中金刚石的质量浓度的增加而增加,镀层中磷的质量分数随镀液中还原剂的质量浓度的增加而增加;随镀液中金刚石的质量浓度的增加,磨损量呈先降低后升高的趋势,当其质量浓度为8 g/L时,耐磨性最好;另外,随着镀...     

稀土离子对化学镀镍的影响

以镀液稳定性、镀速、镀层光泽度和镀层中磷的质量分数为评价指标,考察La3+、Nd3+和Y3+对柠檬酸体系化学镀镍的影响。结果表明:加入适量的稀土离子,可明显提高镀液的稳定性;当稀土离子的质量浓度为2~4mg/L时,可适当地提高镀速和镀层光泽度;当Y3+的质量浓度为4mg/L时,综合性能最佳。向镀液中添加稀土离子,可起到细化镀层晶粒和改善镀层性能的作用,但镀层中不含稀土元素。     

六价铬对三价铬镀铬的影响

六价铬杂质对三价铬镀液性能的影响较大,实验表明,对于硫酸盐型三价铬镀液,当六价铬的质量浓度超过10 m g/L时,镀层出现雾状,超过100 m g/L时,镀液的覆盖能力变差,当质量浓度更高时,镀件无镀层。在正常的工艺条件下,六价铬杂质产生的速度比较慢,能够控制在较低的浓度范围内,一般不影响镀层的质量。镀液的pH偏高和不搅拌镀液都会促使六价铬的升高。用双氧水还原法和小电流电解法处理六价铬,实验表明,双氧水还原法效果较好,其质量浓度为0.5 mL/L时较为适宜。     

La、Y、Yb对木材表面化学镀Ni-P的影响

在传统的化学镀镀液中分别添加稀土氧化物La203、Y203和Yb203在木材表面制备Ni-P镀层.重点考察了不同稀土氧化物浓度对化学镀镀速、镀液稳定性、Ni-P镀层质量和电磁屏蔽性能的影响.结果表明,Yb203对提高化学镀镀速、镀液稳定性、Ni-P镀层质量和电屏蔽性能具有较好的效果.与传统的化学镀方法相比,添加浓度为40mg·L-1的Yb203可提高化学镀镀速、镀液稳定性和屏蔽性能分别为13.8%、36.4%和8.6%,并使Nj-P镀层更加致密、平整和光亮.     

钙离子对化学镀镍溶液性能的影响

研究了钙离子对化学镀镍镀液的影响,测试了10、30和150mg/L的钙离子对镀液的寿命、稳定性及沉积速率的影响。结果表明,随着镀液中钙离子质量浓度的升高,镀液稳定性下降,使用寿命减短;同时还测试了钙离子对镀层结合力、耐蚀性、耐磨性及镀层显微形貌的影响。结果显示,随着钙离子质量浓度的升高,镀层耐蚀性及光亮性变差,结合力降低。钙离子对化学镀镍具有较大的影响,故在实际生产过程中应严格控制化学镀镍溶液中钙离子的质量浓度。     

Ni-AlN纳米复合镀层的制备及耐蚀性能研究

采用电沉积的方法在低碳钢表面成功制备了Ni-AlN纳米复合镀层,通过称量法计算出沉积速率,采用X-射线衍射、扫描电镜和电化学测量技术探究了镀液中不同AlN浓度对镀层的组织结构、微观形貌和耐蚀性能的影响。结果表明,在电沉积过程中,沉积速率随镀液中AlN浓度的增大呈先增大后减小的趋势;镀液中AlN的加入,使镀层表面产生了米粒状的多晶单元,提高了镀层的耐蚀性能,随着镀液中AlN浓度的增加耐蚀性能先提高后降低。当镀液中纳米AlN质量浓度为1 g/L时,复合镀层中的AlN质量分数约为4.5%,表面致密性最好,与纯Ni镀层相比,腐蚀电流密度降低了2个数量级,耐蚀性能最佳。     

甲基磺酸体系镀锡液中Fe2+含量对镀锡层性能的影响

通过扫描电子显微镜分析、贴滤纸法测试和塔菲尔曲线测量考察了甲基磺酸(MSA)体系镀锡液中Fe~(2+)质量浓度对镀锡层耐蚀性的影响。结果表明:当镀液中Fe~(2+)质量浓度大于5 g/L时,镀层中就会出现针孔,当镀液中Fe~(2+)质量浓度大于10 g/L时会严重影响镀层的耐蚀性。在实际生产中应将镀液的Fe~(2+)质量浓度控制在10 g/L以下。     

Ni-W-Fe-Co合金代铬电镀工艺的研究

研究了工艺条件对镍-钨-铁-钴合金镀层组分、显微硬度及阴极电流效率的影响.结果表明,镀液θ为60 ～ 70℃、pH为6.0 ～6.5、Jk为2～ 10 A/dm2、15 ～ 25 mL/L调色剂,在此条件下得到的合金镀层效果最接近硬铬镀层;提高镀液θ和pH,增加调色剂质量浓度,有利于阴极电流效率的提高;升高镀液θ,提高Jk和镀液中调色剂的质量浓度,降低镀液pH,镀层中的钨和显微硬度增加.还研究了热处理工艺对镀层显微硬度的影响,在350～400℃条件下热处理3h,镀层显微硬度可达1065 HV.     

The development of cerium oxide coatings from cryolite melts. A self-forming anode for aluminum electrowinning

The anodic deposition of cerium oxide from cryolite melts onto tin oxide substrates was investigated. Such a coated structure offers promise as an oxygen-evolving anode in Hall-Heroult cells. The development and dimensional stability of the coating is established by the equilibrium between the bath components and the cerium oxide. The coating thickness and morphology is shown to be dependent on the initial cerium oxide bath concentration and, to a lesser extent, on current density. The presence of the cerium oxide coating greatly diminishes dissolution of the anode substrate and increases the purity of the electrowon aluminum. The protection afforded by the coating is achieved by reducing the exposed substrate surface area.     

Effect of Processing Parameters on Cerium Oxide Coating Deposition in Solution Precursor Plasma Spray

Solution precursor plasma spray was used to deposit cerium oxide coating. This study is to understand the coating deposition mechanism in solution precursor plasma spray for cerium oxide using a cerium nitrate liquid precursor. This study includes the effect of various processing parameters on coating micro structure, such as plasma power, standoff distance, and solution concentration. Single scan experiments were performed to better understand the single splat formation and unpyrolyzed precursor deposition. X‐ray diffraction analysis was conducted to determine average crystallite size of the coating from different concentration and formation of single phase cerium oxide formation. Detailed microstructural characterizations of the coatings were carried out by scanning electron microscopy.     

铈对镀锡引线可焊性的影响

探讨了稀土元素铈对电子元器件引线镀锡层可焊性的影响。结果表明,在氟硼酸盐镀锡溶液中加入适量的铈能提高镀液的稳定性,镀层的抗氧化性和可焊性,并可获得更为光亮的镀层。     

铈对锌-铁合金电沉积的影响

研究了铈对电沉积锌-铁合金镀液及镀层性能的影响,通过分散能力、阴极极化曲线测定,得出在镀液中添加一定量的氯化亚铈能改善镀液性能。通过镀层耐蚀性、抗高温氧化性及镀层表面形貌测试表明,定量铈的参与,可获得更加致密的镀层,可有效提高镀层的耐蚀性及抗高温氧化性。     

装饰用铜合金镧-铈复合化学转化工艺及膜层耐蚀性

对装饰用H62铜合金进行稀土镧-铈复合化学转化.对转化液组成和工艺条件进行正交优化,得到最优参数为:硝酸镧4 g/L,硝酸铈4 g/L,苯并三氮唑15 g/L,钼酸钠2 g/L,柠檬酸13 g/L,磺基水杨酸9 g/L,十二烷基苯磺酸钠0.4 g/L,温度53°C,时间4 min.该条件下所得La-Ce复合转化膜的厚度...     

铈对化学镀Co-Ni-P合金工艺的影响

研究了稀土元素铈对化学镀Co-Ni-P合金工艺的影响，在正交试验的基础上分析了镀液组成对沉积速度的影响，综合考察了镀层表面质量及镀层与基体的结合力，结果表明化学镀Co-Ni-P合金的工艺中，当稀土元素铈加入时，镀液的稳定性，沉积速度和镀层质量能明显提高，并由此得出工艺的最佳佳镀液组成和操作条件。     

The effect of organosilane on corrosion resistance of epoxy coating containing cerium nitrate

Structure and corrosion resistance behavior of epoxy coating containing cerium nitrate in different amounts of γ-glycidoxypropyltrimethoxysilane (γ-GPS) were investigated. Corrosion resistance ability of coating systems was characterized by using electrochemical impedance spectroscopy and polarization techniques. Also atomic force microscopy was used to evaluate dispersion of cerium nitrate in the presence of γ-GPS. Furthermore, the effect of γ-GPS on flexibility of coatings was studied by using the cupping test. Increment of 10?wt.% of γ-GPS into the coating formulation led to the superior dispersion of cerium nitrate and also highest corrosion protection performance.     

Effect of cerium concentration on microstructure,morphology and corrosion resistance of cerium–silica hybrid coatings on magnesium alloy AZ91D

The aim of this work was to investigate the effect of cerium concentration on microstructure, morphology and anticorrosion performance of cerium–silica hybrid coatings on magnesium alloy AZ91D. Vinyltriethoxysilane (VETO) and γ-glycidoxypropyltrimethoxysilane (GPTMS) were employed as precursors to prepare sol–gel based silica coating. Cerium nitrate hexahydrate as dopant in five different concentrations was added into the silica coatings. Fourier transform infrared (FT-IR) spectrum analysis, viscosity measurements and scanning electron microscopy (SEM) were employed to characterize the microstructure and morphology of these coatings. It was found that with the increase of cerium concentration, the degree of decomposition of silane chains in the coating network increased. The corrosion resistance of the cerium–silica hybrid coatings was estimated by electrochemical impedance spectroscopy (EIS) measurements and potentiodynamic polarization tests. The results demonstrated that corrosion resistance of coatings initially increases and then decreases as cerium concentration goes up. When the cerium concentration is 0.01 M, corrosion resistance reaches its maximum.     

Self-healing and anticorrosive properties of Ce(III)/Ce(IV) in nanoclay–epoxy coatings

The self-healing and anticorrosion effects of cerium nitrate in epoxy–clay nanocomposite coatings systems were studied. Different amounts of cerium (III) were added to epoxy–montmorillonite clay composites and the nanocomposite coatings were prepared and applied on cold rolled steel panels. Ultrasonication was applied to disperse the nanoclay into the epoxy cerium nitrate composition. Electrochemical impedance spectroscopy (EIS) was used to study the self-healing and anticorrosion behaviors of the coatings. The structure of the dry coating and the protective mechanism of the pigments in the coating were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) analysis and field emission electron microscopy (FESEM). Transmission electron microscopy (TEM) illustrated the separation of clay layers which interacted with the epoxy resin. Electrochemical impedance data indicated that the epoxy cerium (III)–montmorillonite nanocomposite coatings were superior to the epoxy coatings in corrosion protection properties. The self-healing behavior of such coatings was due to the presence of cerium nitrate that could be released at the defects within the coating and hindered the corrosion reactions at the defective sites. It was shown that the best corrosion protection was achieved with nanocomposite coatings containing 4 wt% clay and 2 wt% cerium nitrate.     

电沉积Cu-Ni-Sn-Al_2O_3复合镀层及其性能的研究

采用电沉积方法在45~#钢表面制备出Cu-Ni-Sn-Al_2O_3复合镀层。研究了镀液中Al_2O_3的质量浓度对镀层的硬度、耐磨性及结合力的影响,并分别用SEM和XRD表征了镀层的表面形貌和结构。结果表明:当镀液中Al_2O_3的质量浓度为15g/L时,镀层具有较好的耐磨性。