Ni-P和Ni-Cu-P化学镀层对比研究

利用SEM、DSC、XRD、中性盐雾试验和显微硬度分析等手段,对Ni-10.54%P及Ni-9.25%Cu-10.23%P化学镀层的组织特征、相结构转变、热稳定性、耐蚀性和硬度进行了比较.结果表明:(1)两种镀层均匀致密,均为胞状结构和非晶态组织;(2)Ni-P镀层仅发生从非晶相向稳定的Ni3P相转变,而Ni-Cu-P镀层则先生成Ni-Cu固溶体和亚稳中间相Ni5P2,再向稳定相Ni3P转变;(3)Ni-Cu-P镀层的热稳定性高于Ni-P镀层;(4)镀态和低温热处理条件下两种镀层的硬度相差不大,Ni-P镀层经400 ℃、60 min热处理时硬度达到最高值981.1 HV,但Ni-Cu-P镀层经500 ℃、60 min热处理时硬度达到最高值1 144.8 HV;(5)镀态时Ni-Cu-P镀层的腐蚀速率只有Ni-P镀层腐蚀速率的2.85%;经过400 ℃、120 min相同条件的热处理,Ni-Cu-P镀层的腐蚀速率仅为Ni-P镀层腐蚀速率的0.351%.     

非晶态Ni-Cu-P合金镀层的结构及性能研究

研究了化学镀Ni-Cu-P非晶态合金镀层的成分，结构、硬度及形貌等性能．研究结果表明：镀层中铜含量随着镀液中硫酸铜浓度的增加而提高，镍、磷含量随着镀液中硫酸铜浓度的增加而降低。由于铜具有优先析出的特征，导致合金镀层中Cu／Ni质量比远高于镀液中Cu^2＋／Ni^2＋质量比．在镀态下，Ni-Cu-P合金镀层为含铜、磷原子的镍基饱合固溶体．X-ray衍射表明：在镀态下及300℃以下热处理时，Ni-7．929％Cu-8．227％P（质量分数）合金镀层为非晶态结构，经400℃热处理后，开始有热力学平衡相Ni3P和Cu3P析出，合金镀层已转为晶态结构．Ni-7．929％Cu-8．227％P合金镀层的硬度随热处理温度的升高而增加，在400℃时，硬度达到最大值（845HV），热处理温度继续升高，合金镀层的硬度反而下降．     

原位XRD研究热处理Ni-P化学镀合金的结构

通过改变镀液的CNi^2 ／CH2PO2-比例，在乙酸-柠檬酸体系中，获得组成分别为Ni-7．8P(质量比)和Ni-11．7P的镍磷化学镀层。用程序升温原位XPID分析了镀层在40～500℃之间的结构变化。镀态时Ni-7．8P为微晶结构而Ni-11．7P为非晶结构。在20℃／min升温速度下，Ni-7．8P在200℃后发生晶化，直接析出稳定的Ni3P和Ni相。Ni-11．7P在300℃后晶化，先析出介稳的Ni5P2相，375℃后转变为平衡的Ni3P和Ni相。     

热处理对非晶Ni-P电镀层结构与性能的影响

为进一步了解Ni-P合金电镀层的结构与性能的关系,利用X射线衍射(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)和显微硬度仪等,研究了P含量12.3%(质量分数)的Ni-P合金电镀层热处理前后结构的变化对性能的影响.结果表明:镀态镍磷镀层呈非晶态结构,270℃恒温10 min镀层开始晶化,析出亚稳相Ni12P5和Ni5P2,360℃亚稳相向Ni3P和Ni稳定相转变,且晶粒长大,420℃时只有Ni3P和Ni相;热处理后镀层的硬度大于非晶态镀层,300℃部分晶化析出的纳米晶弥散分布于非晶相中,镀层的硬度达到极大值,Ni3P硬质相的析出大大提高了镀层的耐磨性能.     

Ni—Cu—P合金化学镀层制备及组织结构的研究

研究了Ni-Cu-P化学镀液主要成分、pH值及时间等工艺参数对化学沉积Ni-Cu-P合金镀层分及镀速的影响。通过选择适当的镀液成分及工艺参数,得到了Cu含量从0到56．18wt%的Ni-Cu-P合金镀层。利用X射线能谱术（EDS）和X射线衍射术（XRD）研究了镀液中硫酸铜浓度对Ni-Cu-P合金镀层成分及组织结构的影响。在硫酸铜浓度低于3g/l时,Ni-Cu-P合金镀层中P含量高于7．05wt%,合金底层是非晶态结构。     

化学镀Ni-P合金镀层的微观结构

用X射线衍射仪和透射电镜研究了化学镀Ni-P合金镀层的微观结构,提出了镀层结构模型,分析了镀层生成的结晶机理,比较了低磷与高磷Ni-P合金的晶体结构区别;前者为致密的镍基相中弥散分布粒状Ni3P相的晶体结构,后者为几何形状不规则的非晶态结构。对非晶态组织在300℃和400℃进行热处理,合金镀层发生晶化转变,且生成的Ni3P微晶显示出调幅结构。     

化学镀Ni-P工艺对镀层结构和性能的影响

研究了化学镀Ni-P镀层时的施镀温度，pH等工艺参数对Ni-P合金镀层结构状态，P含量和耐盐雾腐蚀性能的影响，指出优选和控制工艺参数是保证镀层质量的关键。     

非晶态Ni-P电刷镀层晶化过程和动力学的研究

X 射线衍射分析和差热分析结果表明,Ni-P 电刷镀层自约300℃开始晶化,于约400℃晶化结束,最后转变为 Ni 与弥散分布的 Ni_3P 相的混合物组织。采用等温热分析法,利用 Johnsoa-Mehl-Avrami 方程,作出了 Ni-9.3%P 电刷镀层的晶化动力学曲线和 TTT 图;得到的晶化激活能为192kJ/mol,Johnson-Mehl-Avrami 方程转变方式指数 n为2.7。外推的瞬时晶化温度约为440—450℃。经不同温度热处理后,Ni-P 镀层的峰值硬度出现在400℃左右,对应于晶化后硬化相的最佳弥散分布状态。所以,热模具寿命的提高,是非晶态Ni-P 镀层在工作条件下发生晶化和沉淀硬化,使模具表面红硬性提高的结果。     

化学镀Ni-P-SiC镀层的微观组织结构特征

对化学镀Ni-P-SiC复合镀层的微观组织结构特征进行了研究，结果表明，SiC微粒弥散分布在复合镀层中，Ni-P合金主要作为粘结金属包络着SiC微粒，两之间存在电子转移，发生了界面反应，反应扩散层为10^-1nm级，界面结合紧密，无孔隙和裂纹等缺陷。元素存在形态主要表现为Ni和P以单质的形式存在，Si以共价健SiC的形式存在，Ni－Ni之间以金属键进行结合。     

粘结NdFeB永磁体化学镀Ni-Cu-P防护层及阻氢性能研究

对粘结NdFeB永磁体化学镀Ni-Cu-P合金防护层的工艺过程及镀层的阻氢性能进行了研究。磁体经碱性去油、缓蚀酸洗、镀前均匀隔离与活化处理后再进行化学镀Ni-Cu-P合金，可获得了质量良好的耐蚀性镀层，该镀层对磁体磁性能无不良影响，且有良好的阻氢性能，在25℃、10MPa高压H2环境中，阻氢时间为19min。     

Ni-Cu-P化学镀工艺及组织结构的研究

研究了Ni-Cu-P化学镀液主要成分、PH值、温度以及时间等工艺参数对化学沉积Ni-Cu-P合金镀层成分及镀速的影响。通过选择适当的镀液成分及工艺参数,得到了Cu含量从0到56．18wt%的Ni-Cu-P合金镀层。利用EDS和XRD研究了镀液中硫酸铜浓度对Ni-Cu-P合金镀层组织结构的影响。在硫酸铜浓度低于3g/L时,Ni-Cu-P合金镀层中P含量高于7．05wt%,合金镀层是非晶态结构。     

Microstructures and crystallization of electroless Ni-P deposits

A study has been made of microstructures and crystallization of the electroless Ni-P deposits containing 11.3 to 23.0 at% P obtained from acidic nickel sulphate baths with sodium hypophosphite as a reducing agent by means of differential scanning calorimetry, X-ray diffractometry and hot stage transmission electron microscopy. The deposits containing low phosphorus content of 11.3 at% could be represented as an fcc Ni-P solid solution of 5 to 10 nm microcrystallites, whereas the deposits containing high phosphorus content were amorphous. The crystallization process of amorphous Ni-P solution involved more than one intermediate phases; precrystallized nickel or off-stoichiometric Ni₃(P, Ni) or Ni₅(P, Ni)₂ phase in which some phosphorus sites are replaced by nickel atoms. The final equilibrium phases were bct Ni₃P and fcc nickel crystals regardless of phosphorus content. The amorphous phase containing 20 to 22 at% phosphorus was the most stable among the amorphous Ni-P alloys.     

Effect of annealing on magnetic properties and microstructure of electroless nickel-copper-phosphorus alloy deposits

The relationship between magnetic properties and microstructure of the as-deposited and heat-treated Ni-Cu-P alloy deposits has been studied by means of vibrating sample magnetometry, differential scanning calorimetry. X-ray diffractometry and hot-stage transmission electron microscopy. The Ni-Cu-P deposits consist of low-P Ni-Cu solid solution crystallites and high-P-low-Ni-Cu amorphous phase. When the deposits are annealed at elevated temperatures, the Ni-Cu crystallites grow rejecting P from themselves and absorbing Cu from the neighbouring amorphous phase, while the P-rich amorphous phase transforms into Ni₅P₂ phase or into Ni₅P₂ and Ni₃P phases. The metastable Ni₅P₂ phase finally transforms into the stable Ni₃P phase. The non-magnetism observed in Ni-Cu-P deposits having a copper content above 28% in both as-deposited and annealed states, is attributed to their Cu-rich Ni-Cu solid solution crystallites. Nickel phosphides which crystallize from the amorphous phase existing mixed with the Ni-Cu crystallites in the as-deposited state, do not affect the saturated magnetic moment of the deposits.     

The influence of microwave-assisted hydrogen plasma treatment on electroless Ni–P coatings

As-deposited electroless Ni–P coatings were heated in air and subsequently treated by microwave-assisted hydrogen plasma with various powers. The phase evolution and microstructure of the Ni–P coatings were studied in detail. The results indicate that the amorphous Ni–P coatings were first transformed into Ni, Ni₃P, and the residual amorphous phase after heating at 300 °C in air. The NiO, Ni₂P, and Ni₁₂P₅ phases with a half size of an island at the as-deposited state were formed after heating at 400 °C for 3 h. Furthermore, the 600 W or higher hydrogen plasma power was required to obtain the Ni and Ni₃P phases. A short hydrogen plasma treatment of 1 min at 600 W can reduce NiO into Ni and transform Ni₂P and Ni₁₂P₅ into larger N₃P grains. The NiO phase was first transformed into the Ni phase, which subsequently reacted with the Ni₂P into Ni₃P phases. In addition, no phosphorus loss was observed. For longer plasma treatment (10 min), the nickel phase dissolved into the lattice of the Ni₃P phase, and the surface morphology of the Ni–P coatings changed considerably because of the occurrence of phase transformation and partial melting.     

Electroless Ni‐P coating on Cu substrate with strike nickel activation and its corrosion resistance

Electroless Ni‐P coating was successfully deposited on Cu substrate by strike nickel activation process. The specific pretreatment steps were discussed. The surface and cross‐section morphologies, phosphorus content, adhesive force, and corrosion resistance were characterized for electroless Ni‐P coating. Scanning electron microscopy shows the compact surface. Energy dispersed X‐ray shows the 11.4% phosphorus content. Adhesive test shows the qualified adhesion of electroless Ni‐P coating to substrate. Porosity test shows pores free of the coating, and immersion test in 10% HCl solution indicates the better corrosion resistance of electroless Ni‐P coating in protecting Cu substrate from the corrosion of Cl ions. Thus, strike nickel activation pretreatment is suitable for electroless Ni‐P coating on Cu substrate.     

Solidification microstructures selection of Fe-Cr-Ni and Fe-Ni alloys

The transition of solidified phases in Fe–Cr–Ni and Fe–Ni alloys was investigated from low to high growth rate ranges using a Bridgman type furnace, laser resolidification and casting into a substrate from superheated or undercooled melt. The ferrite-austenite regular eutectic growth, which is difficult to find in typical production conditions of stainless steels, was confirmed under low growth rate conditions. The transition velocity between eutectic and ferrite cell growth had a good agreement predicted by the phase selection criterion. Which of either ferrite or austenite is easier to form in the high growth range was discussed from the point of nucleation and growth. Metastable austenite formation in stable primary ferrite composition was mainly a result of growth competition between ferrite and austenite. For a binary Fe–Ni system, a planar metastable austenite in the steady state, simultaneous growth such as eutectic and banded growth between ferrite and austenite in an initial transient region are confirmed.     

Crystallization and phase transformation behaviour of electroless nickel-phosphorus deposits with low and medium phosphorus contents under continuous heating

Electroless nickel-phosphorus deposits with 5–8 wt% P and 3–5 wt% P were analysed for the effects of continuous heating on the crystallization kinetics and phase transformation behaviour of the deposits. The as-deposited coatings consist of a mixture of amorphous and microcrystalline nickel phases, featuring in their X-ray diffraction patterns. Continuous heating processes to 300°C–800°C at 20°C/min were carried out on the deposits in a differential scanning calorimetric apparatus. The subsequent X-ray diffraction analyses show that the sequence of phase transformation process was: amorphous phase + microcrystalline nickel f.c.c. nickel + Ni₃P stable phases. Preferred orientation of nickel (200) plane developed in the deposits after the heating processes. Differential scanning calorimetry of the deposits indicates that the crystallization temperatures increased with decreasing phosphorus content, and increasing heating rate. Crystallization activation energies of the deposits (230 and 322 kJ/mol, respectively) were calculated using the peak temperatures of crystallization process, from the differential scanning calorimetric curves at the heating rates ranging from 5 to 50°C/min. It was found that the deposit with lower phosphorus content has higher activation energy.     

Intermetallic compound formation between lead-free solders (Sn) and Cu or Ni electrodes

A kinetic model based on the principle of maximum degradation rate of the total system free energy, MDR law using thermodynamic data, is proposed and successfully applied to the selection of the first intermetallic compound (IMC) phase in Cu/Sn and Ni/Sn diffusion couples. The first phases predicted with this model for Cu/Sn and Ni/Sn are Cu₆Sn₅ and Ni₃Sn₄, respectively, resulting in good agreement with experimental observations.     

Ni12P5微球的溶剂热合成与表征

以硫酸镍(NiSO4.7H2O)作为镍源,以乙二醇和水作为混合溶剂,利用溶剂热法成功地制备了磷化镍(Ni12P5)微球。X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电镜(TEM)和高分辨透射电镜(HRTEM)等分别对所制备样品进行了表征。结果表明,所得产物为纯的四方相磷化镍(Ni12P5)微球,粒径约为2～5μm;研究了不同实验参数对样品尺寸、形貌及微球形成过程等的影响。最后对磷化镍微球的发光性进行了研究。     

Effect of high magnetic field on the morphology of (Cu, Ni)6Sn5 at Sn0.3Ni/Cu interface

The effect of high magnetic field on the microstructure of (Cu, Ni)₆Sn₅ intermetallic compound layer in Sn0.3Ni/Cu couples at 250 °C was examined. The applied magnetic field changed the morphology of outer (Cu, Ni)₆Sn₅ crystals on the Sn side from faceted shape to stick shape. The high magnetic field affected the crystal orientations of (Cu, Ni)₆Sn₅ and reduced the Ni content in the outer layer. The morphology evolution of (Cu, Ni)₆Sn₅ is attributed to the content of Ni solute decreased by magnetic field. The effects of high magnetic field on the liquid convection and phase diagram are considered to be responsible for the Ni content.