稀土对Ni-P-SiC复合镀层的工艺及性能的研究

研究了稀土化合物对化学复合镀Ni-P-SiC镀液稳定性、镀速、镀层中SiC含量及镀层性能的影响;并对镀层的表面形貌进行了测定.结果表明:复合稀土的适量加入有利于延长镀液的使用周期,加快施镀速度,所得镀层表面光亮均匀,耐腐蚀性能较强.     

稀土元素对电沉积Ni-W镀层组织结构的影响

研究镀液中添加的稀土元素La对电沉积Ni-W的影响,采用XRD和SEM分别对镀层的晶体结构和表面形貌进行分析,通过电化学综合测试系统测量添加稀土元素La后,Ni-W合金镀层在3.5%Na Cl溶液中的电化学腐蚀行为。结果表明,添加适量的稀土元素La使Ni-W合金镀层结构细化,表面更平整,提高了镀层的耐腐蚀性能。     

镀液中稀土掺杂对镍基化学镀的影响

在酸性镍基化学镀液中掺杂稀土离子Y3+,Nd3+或La3+,研究了稀土对镀液稳定性、沉积速度及镀层性质(组织结构、显微硬度和耐蚀性能)的影响。结果表明:添加微量稀土即能提高镀液稳定性和沉积速度,其中Y3+的效果最明显,而La3+的效果最差;稀土应用于化学镀中可有效细化镀层晶粒,提高镀层硬度和耐蚀性。     

稀土La对电沉积Ni-P电磁屏蔽镀层组织结构的影响

借助等离子发射光谱仪、电子能谱仪、X-射线衍射仪、透射电子显微镜和扫描电子显微镜等分析了稀土La对电沉积Ni—P合金镀层的化学成分、晶体结构和表面形貌的影响。结果表明：在电沉积镀液中添加少量稀土La,改变了电极界面双电层结构,使镀层表面更为平整;稀土元素La进入镀层后,微晶态结构的Ni—P合金转变成了非晶态结构的Ni-P-La合金。     

稀土对亮镍镀液及镀层性能的影响

以普通亮镍镀液为基础，测定加入稀土元素前后镀液的极化能力；分别制备亮镍和镍镧镀层表面及截面试样，用显微硬度计观察表面、断面组织并测定硬度。研究结果表明，在镀液中添加稀土可以提高亮镍镀液的极化能力和镀层的硬度。     

丁二酸及钨酸钠对化学镀Ni-W-P镀层沉积速度的影响

采用配方不同的化学镀液,在低碳钢基材上制备出不同的Ni-W-P三元合金镀层,对镀层沉积速度和表面形貌进行了表征。结果表明:镀液中成分的含量对镀速及镀层表面形貌都具有很大的影响,丁二酸具有十分明显的加速作用,而镀速随着钨酸钠含量的增大而减小,改变丁二酸和钨酸钠的含量可以改变镀层的表面形貌。     

稀土对碳钢表面纳米TiO_2化学复合镀性能的影响北大核心CSCD

采用化学镀的方法,将含轻稀土Pr的硫酸镨和含重稀土Y的硫酸钇加入Ni-P合金掺杂纳米TiO_2酸性复合化学镀中以提高碳钢表面的整体性能。通过计算、化学及仪器分析法,借助紫外分光光度仪、显微硬度仪、扫描电镜、X射线荧光衍射、能量弥散X射线谱、电化学工作站进行分析,研究了稀土对沉积速率、纳米TiO_2在镀液中的分散性和复合镀层性能的影响。结果表明:添加一定质量浓度的稀土元素,能够提高沉积速率及纳米TiO_2在复合镀液及镀层的分散性,增加复合镀层的显微硬度和耐蚀性,并且使得复合镀层中P和Ti含量略有增加且仍为非晶态结构,细化了晶粒。添加重稀土Y比添加轻稀土Pr性能更优,最优添加稀土Y的质量浓度为10 mg/L。     

稀土对碳钢表面纳米TiO_2化学复合镀性能的影响

采用化学镀的方法,将含轻稀土Pr的硫酸镨和含重稀土Y的硫酸钇加入Ni-P合金掺杂纳米TiO_2酸性复合化学镀中以提高碳钢表面的整体性能。通过计算、化学及仪器分析法,借助紫外分光光度仪、显微硬度仪、扫描电镜、X射线荧光衍射、能量弥散X射线谱、电化学工作站进行分析,研究了稀土对沉积速率、纳米TiO_2在镀液中的分散性和复合镀层性能的影响。结果表明:添加一定质量浓度的稀土元素,能够提高沉积速率及纳米TiO_2在复合镀液及镀层的分散性,增加复合镀层的显微硬度和耐蚀性,并且使得复合镀层中P和Ti含量略有增加且仍为非晶态结构,细化了晶粒。添加重稀土Y比添加轻稀土Pr性能更优,最优添加稀土Y的质量浓度为10 mg/L。     

稀土元素Pr,Nd对无铅钎料组织和性能的影响北大核心

综合了国内外含稀土元素Pr,Nd的无铅钎料最新研究成果,归纳并总结了添加稀土元素Pr,Nd对无铅钎料(Sn-Ag-Cu,Sn-Cu(-Ni)以及Sn-Zn钎料等)的组织和性能的影响规律,分析了稀土元素Pr和Nd对无铅钎料焊点可靠性的影响以及稀土相表面Sn须的形貌与生长机制,并展望了稀土元素改性无铅钎料研究的发展趋势,为进一步开发性能更优良的新型无铅钎料提供了参考依据。     

机械镀Zn-RE复合镀层的结构

以机械镀方法制备了Zn-RE复合镀层,采用SEM观察了镀层的结构,采用XRF、XPS分析了镀层表面的化学组成和镀层的表面化学状态,采用XRD分析了镀层的物相组成。结果表明,Zn-RE复合机械镀层主要由锌粉颗粒组成,稀土有利于镀层中的锌粉颗粒发生变形。镀层中主要含有Zn、Sn、Fe、La、Ce元素,其中La、Ce含量很低;Zn、Sn、Fe以单质态存在,La以La2O3存在。镀层表面主要由Zn、Sn、La、O组成,Zn以单质态存在,Sn以单质态和氧化态共存,La以La2O3存在。Zn-RE复合镀层形层过程中所添加混合稀土中的La未发生化学位态的变化。     

氧化镱对碳钢表面化学镀 Ni-Zn-P 合金的影响

目的改善Ni-Zn-P合金镀层的制备工艺和镀层的物理性能。方法鉴于稀土镧系元素因特殊电子结构表现出优异的物理和化学性能,向基础镀液中添加Yb2O3,在低碳钢钢管表面化学镀沉积NiZn-P合金镀层。通过称量法算得沉积速率,通过盐水浸泡实验测试镀层耐蚀性,采用扫描电镜观察镀层的表面形貌,用X-射线衍射仪检测镀层的晶体结构,考察镀液中Yb2O3浓度对镀层的沉积速率、表面形貌、耐蚀时间、晶体结构等的影响。结果随着Yb2O3浓度的增大,镀层的沉积速率呈先升高、后下降的趋势,镀层的表面形貌、耐蚀时间和晶体结构均是先得到改善,而后被削弱。向基础镀液中添加15 mg/L Yb2O3后,镀速提高了21.6%,耐蚀时间延长了16.7%,镀层由粗糙、灰暗、不均匀和有缺陷,变为平整、光亮、均匀和致密,镀层的非晶相程度得到一定强化,耐蚀性能有所提高。结论基础镀液中添加Yb2O3的适宜质量浓度为15 mg/L,该条件下可提高Ni-Zn-P合金的镀速,并改善镀层的质量。     

Effect of rare earth (Ce, La) compounds in the electroless bath on the plating rate, bath stability and microstructure of the nickel-phosphorus deposits

Effects of added rare earth elements (RE) in the acidic hypophosphite plating bath on the plating rate, bath stability and microstructure of the electroless nickel-phosphorus (EN) deposits were studied. The surface appearance and microstructure were examined under a reflection optical microscope and a scanning electron microscope equipped with an in-situ energy dispersive X-ray spectroscopy, which can evaluate the elemental analysis of deposits. It was demonstrated that the rare earth elements can decrease grain size and refine microstructure.The deposition rate of the Ni-P deposits was estimated by gravimetric, polarization and quartz crystal microbalance (QCM) methods. Results revealed that up to an optimum concentration of rare earth elements, the deposition rate increases. The stability test method was used to determine the stabilization effect of RE on the stability of the bath. It was found that the addition of RE significantly improved the Pd stability of the EN bath.     

Effect of rare earth metals and the stability of sulfide inclusions on Localized corrosion of low alloy steels

Effect of alloying with rare earth elements RE (La, Pd + Nd, or so called “Mischmetall” containing Ce, Pr, Nd, La and traces of the other RE) on the ability to passivate and susceptibility to chloride breakdown of low alloys steels was investigated. Electron microprobe analysis revealed that the effect of RE depends upon the element and is connected with a modification of the composition and morphology of MnS inclusions present within the steels without RE addition. La seems to be most detrimental. The nonstability of La sulfide inclusions in air results in their spontaneous oxidation and growth into fantastic “flower-like” forms which facilitates the formation of corrosion pits.     

添加稀土元素对Ni-P/PVDF化学复合镀层耐蚀性的影响

在化学镀Ni-P/PVDF合金镀液中添加稀土元素Y³⁺和La³⁺制备Ni-P/PVDF(RE)复合镀层,用电化学腐蚀测试系统测试复合镀层的耐蚀性,研究了稀土元素的添加量对镀层耐蚀性能的影响。结果表明,在基础镀液中加入适量稀土元素后,所获得的Ni-P/PVDF(RE)复合镀层的晶粒较Ni-P/PVDF镀层更为细小,表面更加均匀和致密;镀层的耐蚀性随着稀土元素加入量的增加呈现先增强后减弱的趋势;在稀土元素的添加量为0.1g/L时,复合镀层的耐蚀性最好。在PVDF微粒和稀土元素的共同影响下,进一步提高Ni-P/PVDF(RE)镀层的耐蚀性。     

NdFeB磁体表面化学镀Ni-P合金防腐研究

采用正交试验法对NdFeB磁体表面化学镀镍磷合金的工艺进行了优化，测量了镀层和基体在3．5％（ω）NaCl溶液、10％（φ）盐酸和20％（ω）NaOH溶液中的腐蚀速度，以及在3．5％NaCl溶液中的极化曲线和电化学阻抗谱，对比分析了在酸性和碱性条件下所得Ni-P镀层的结构和表面形貌。结果表明，采用EIS谱图及等效电路模型可对镀层和磁体在介质中的电化学参数进行拟合分析，化学镀Ni-P合金能够显著改善NdFeB磁体的耐腐蚀性能，且酸性条件下所获得的镀层为非晶态结构，表面胞状组织呈密集连续分布，耐腐蚀性能更佳。     

Effects of rare earth cerium addition on the synthesis and corrosion resistance of electroless Ni–PTFE–P coating

Electroless Ni–PTFE–P coatings have been successfully deposited on the surface of mild steel shaft from plating baths containing various concentrations of rare earth metal cerium (RE Ce). Surface morphology, Ce fraction, and thickness of the coatings were characterized by scanning electron microscope, inductively coupled plasma optical emission spectrometry, and reflection optical microscope, respectively. Salt spray test was used to determine the corrosion resistance of the coating. Results revealed that structure, compactness, and deposition rate of the Ni–PTFE–P coatings were increased significantly by addition of a small amount of RE Ce (10–20 ppm) to the plating bath. Electroless Ni–PTFE–P coating deposited from plating baths with 20 ppm Ce shows the highest corrosion resistance, owing to its high compactness and thickness. Deposition rate and corrosion resistance of the Ni–PTFE–P coating were deteriorated greatly as concentration of RE Ce in the plating baths exceeds 100 ppm.     

稀土铈对锌-铁合金镀层耐蚀性的影响

研究了铈盐对电沉积锌-铁合金镀层耐蚀性的影响,通过失重法、浸泡实验、电化学腐蚀参数的测量,得出在镀液中添加一定量的铈盐能显著改善镀层的耐蚀性能.扫描电镜测定镀层表面形貌的结果表明,定量铈盐参与下,可获得更加致密的镀层,这正是提高镀层耐蚀性的原因.     

Effect of rare earth on inclusion evolution and corrosion resistance of HRB400E steel

The effect of rare earth elements Ce and La on the evolution behavior of inclusions in HRB400E steel was studied through experimental observations and thermodynamic calculations. Neutral salt spray corrosion experiments were also conducted to investigate the effect of Ce–La on the corrosion resistance of steel. The results showed that the typical inclusions in steel without rare earth were MnS and MnO–SiO₂. A small amount of Mn–Si–O–S inclusions was also observed. After adding rare earth, the typical inclusions were transformed into isolated (Ce,La)₂O₂S, (Ce,La)₂O₃ + MnS, and (Ce,La)₂O₂S + MnS complex inclusions. The thermodynamic calculations indicated that the rare earth elements in molten steel preferentially reacted with MnO–SiO₂ inclusions and dissolved oxygen and sulfur to form (Ce,La)₂O₃ and (Ce,La)₂O₂S. Small amounts of [S] and [Mn] adhered to the surface of the nucleated rare earth inclusions to form complex inclusions. After Ce–La treatment, the corrosion rate of the steel decreased from 3.491 to 1.992 mm year⁻¹, and the corrosion resistance was improved. The change in corrosion behavior is due to the modification of the inclusions into rare earth inclusions with good compatibility with the steel matrix.