电镀光亮镍-钛合金工艺的研究

介绍了一种在含有主、辅配位剂的水溶液中电镀光亮Ni-Ti合金工艺。运用赫尔槽、小槽电镀、电化学测试、扫描电子显微镜和X-射线衍射等方法,研究了Ni2+、Ti2+在溶液中的电沉积行为和合金沉积层的结构。结果表明,在含有配位剂的水溶液中,Ti借助于Ni的"诱导"作用,可以以合金的形式在阴极上电沉积,所得的Ni-Ti合金层光亮、均匀,Ti质量分数在10%~35%之间,为层状的均匀的晶态结构。合金层中的Ti质量分数与溶液中Ti盐的质量浓度成正比,与阴极电流密度成反比。在5%Na Cl溶液中,Ni-Ti合金比Ni层耐蚀能力高40%。可作为Ni、Cr或Ni+Cr的替代镀层。     

铝青铜表面粉末火焰喷涂Ni60合金涂层的耐蚀性研究

采用氧-乙炔火焰喷涂-重熔技术在QAL9-4铝青铜表面制备Ni60合金涂层,通过静态浸泡试验﹑电化学实验及表面分析技术等方法对铝青铜基体和Ni60合金涂层在3.5%NaCl溶液中的腐蚀行为进行了研究。结果表明,Ni60合金涂层可以明显提高铝青铜基体的耐蚀性能;基体主要发生脱铝腐蚀,而涂层的腐蚀过程则是铬元素的优先溶解。     

机械合金化制备的纳米晶Ag-25Ni合金在H_2SO_4溶液中腐蚀电化学行为研究

通过机械合金化法通过控制球磨机球磨时间分别制备出纳米晶(Nanocystalline,简化NC)和常规尺寸(Coarse grained,简化CG)Ag-25Ni合金粉末,利用真空热压法将粉末压成块体,通过电化学工作站研究两种不同尺寸Ag-25Ni块体合金在0.02mol/L H_2SO_4溶液中的腐蚀电化学行为。由动电位极化曲线可以看出,两种Ag-25Ni合金均发生活性溶解,且纳米晶NC Ag-25Ni合金的腐蚀电流密度明显小于常规尺寸CG Ag-25Ni合金;从交流阻抗谱可以看出,纳米晶NCAg-25Ni合金的曲率半径明显大于常规尺寸CGAg-25Ni合金,NCAg-25Ni合金电子传递电荷电阻大于CGAg-25Ni。可见,纳米化后,Ag-25Ni合金耐蚀性能提高。     

代铬镀层--Ni-W、Ni-W-B非晶态合金镀层性能研究

通过在浓硝酸、ω=5％NaCl溶液c=1mol/L H2SO4溶液中的浸渍试验,研究了不同基体上的Ni-W非晶态合金镀层的耐蚀性;通过测定在ω=5％ NaCl溶液及c=1mol／1．的HNO3溶液、H2SO4溶液、HCl溶液中的阳极极化曲线,研究了Ni-W非晶态合金镀层薄膜本身的耐蚀性;采用线性极化方法对Ni—W—B非晶态合金镀层在u=5％ Na—Cl溶液、c=1mol／L H2SO4溶液及HNO3溶液中的腐蚀速度进行了测定,并测定了以上2种非晶态合金镀层的硬度与耐磨性.结果表明．非晶态的Ni—W、Ni-W-B镀层比晶态镀层的耐腐蚀性能要好．而Ni—W—B非晶态合金镀层比Ni—W非晶态合金镀层的耐蚀性能又明显提高;经热处理后,Ni—W—B非晶态镀层的硬度值明显高于Ni—W非晶态镀层,耐磨性能都提高了1倍以上Ni—W、Ni—W—B非晶态镀层极有望成为一种比较好的代铬镀层。     

安棚天然碱矿石溶解速度的研究

测定了不同温度下,天然碱矿石在清水和烧碱溶液中的溶解速度,并整理成方程式,在清水中的溶解速度是动力学控制的,其活化能为45.87kJ/mol;在烧碱溶液中的溶解速度在60℃以上是扩散控制的,与浓度无关,活化能为22.152kJ/mol,在40℃则与浓度有关。     

高频脉冲镀Ni-Co合金的形貌、微观结构及耐蚀性研究

研究了紫铜基体上采用高频(20~140kHz)脉冲电流获得的Ni–Co合金镀层在w=10%的NaOH溶液中的耐蚀性。采用扫描电镜观察了碱蚀前后Ni–Co合金镀层的表面形貌,并测定了镀层在w=10%的NaOH溶液中的阳极极化曲线。结果表明,脉冲条件下所得的镀层致密,均匀,呈胞状生长,对w=10%的NaOH溶液有较强的耐蚀性。采用X射线衍射,分析了Ni–Co合金镀层的微观结构。当镀层中钴含量较低时,合金由面心立方结构的固溶体组成。随着脉冲频率的升高,Ni–Co合金镀层中的Co含量不断增加,其耐蚀性则不断降低。     

晶粒细化对Cu-20Co-20Ni块体合金在H2SO4溶液中腐蚀电化学行为的影响

利用电化学测试技术测试了纳米晶块体Cu-20Co-20Ni合金材料在H₂SO₄溶液中的自腐蚀电位、交流阻抗以及极化曲线,并将粉末冶金法（PM）制备的常规尺寸Cu-20Co-20Ni合金与机械合金化法（MA）制备的纳米晶Cu-20Co-20Ni合金进行对比,探究了纳米晶块体Cu-20Co-20Ni合金材料在H₂SO₄溶液中的腐蚀电化学行为及晶粒细化对其腐蚀行为的影响。结果表明,随着H₂SO₄溶液浓度增加,常规尺寸和纳米晶Cu-20Co-20Ni合金的腐蚀速度均变快,在相同酸度下,纳米化后的合金腐蚀速度增加。电化学阻抗谱表明,2种合金都是由电化学反应控制着腐蚀过程。H₂SO₄溶液浓度增加,电荷传递电阻变小,在相同酸度下,纳米晶（MA）Cu-20Co-20Ni合金的传递电阻小于常规尺寸（PM）Cu-20Co-20Ni合金,表明纳米化后Cu-20Co-20Ni合金的耐蚀性能下降。     

电刷镀Monel合金

蒙乃尔(Monel)合金是一种机械性能和加工性能好、耐腐蚀性强的Ni—Cu合金。Ni—Cu晶态合金镀层有良好的耐腐蚀性、耐磨性和较高的硬度，并具有良好的导电性和可焊性，其综合性能较Ni—P合金优越得多。采用电刷镀技术，利用X光衍射仪等测试手段，对Ni—Cu合金刷镀溶液的配方组成、施镀工艺、镀层组织结构及成份进行了分析研究，从而确定了Ni—Cu镀液的组成及刷镀工艺。     

焦磷酸盐-柠檬酸盐体系电镀光亮Zn-Ni合金的研究

介绍了一种电镀光亮Zn-Ni合金的新工艺.应用赫尔槽试验、小槽电镀、扫描电子显微镜等方法,研究了溶液中ρ(Ni2+)/ρ(Zn2+)、温度、pH、阴极电流密度等对合金镀层中含Ni量的影响.其溶液组成是:100～120g/L焦磷酸钾,45～55g/l柠檬酸钠,25～35g/L ZnSO4.7H2O,35～45g/L Ni...     

Raney Ni催化碱性硼氢化钠溶液水解制氢

以Ni Al合金粉末为原料,经浓碱溶液处理后制得Raney Ni催化剂,并用于催化碱性硼氢化钠溶液水解制氢。通过场发射扫描电子显微镜和氮气吸附/脱附法对催化剂微观物理结构进行表征,考察了硼氢化钠溶液组成、反应温度、催化剂用量和循环使用对体系产氢速率的影响。研究结果表明,当硼氢化钠和氢氧化钠质量分数分别为15%和10%时,产氢速率达到1085m L/(min·g)(25℃);相应表观活化能为38.6k J/mol;催化剂用量与单位时间内氢产量成线性关系。循环测试结果表明,经过4次重复使用后,产氢速率降低78%,其原因主要在于硼化物的累积和镍的氧化。     

电沉积Ni-Fe-P非晶态合金镀层变温晶化的研究

用差热分析的方法研究了电沉积Ｎｉ－Ｆｅ－Ｐ非晶态合金镀层的变温晶化过程。通过实验得出不同铁含量的Ｎｉ－Ｆｅ－Ｐ合金在不同加热速度下的开始晶化温度、结束晶化温度,并计算出其晶化激活能。对不同Ｆｅ含量镀层的晶化激活能进行比较发现,Ｆｅ元素在Ｎｉ－Ｆｅ－Ｐ合金镀层中具有稳定非晶态组织的作用。     

THERMODYNAMIC AND KINETIC STUDY OF ADSORPTION OF Ni(II) IONS ON CARBON ANODE DUST

In this study the use of carbon anode dust (CAD), which is the solid residue from aluminum production, as a low-cost adsorbent for the removal of Ni(II) ions from wastewater was investigated. A mechanism of adsorption kinetics and thermodynamics was proposed. In order to investigate the adsorption process of nickel ions on CAD three kinetic models were used: Lagergren's pseudo-first-order model, pseudo-second-order model, and the intra-particle diffusion model. Various thermodynamic parameters, such as the energy of activation (E_a), activation enthalpy (ΔH*), activation entropy (ΔS*), and free energy of activation (ΔG*), were evaluated. Observation of the value of the energy of activation suggests that the process uptake of Ni(II) ions can be described as activated chemisorption. The positive values of enthalpy of activation and free energy of activation, as well as negative values of entropy of activation, mean that the process of removal of Ni(II) ions is endothermic, non-spontaneous, and without structural changes in the solid carbon anode dust particles.     

Methane activation on clean and oxidized Ni(100)

The activation of methane was investigated on a clean and oxidized Ni(100) surface in the pressure range of 0.05–1.0 Torr. The results are most consistent with a precursor mediated mechanism being primarily responsible for the reactive sticking of methane on the clean Ni(100) surface. This contrasts with the Ni(111) surface where dissociative adsorption has been determined to occur predominantly through the direct mechanism. The reaction probability of methane on the NiO films was significantly lower than that observed for the clean Ni(100) surface and exhibited an apparent activation energy of 8.8±1.1 kcal/mol. The results suggest that methane activation on NiO occurs on defect metallic nickel sites.     

Electrochemical behavior of Ni(II)/Ni in a hydrophobic amide-type room-temperature ionic liquid

Electrochemical reaction of Ni(II)/Ni was investigated in a hydrophobic room-temperature ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing Ni(TFSA)₂ as a Ni source. The UV–vis spectra showed that Ni(II) in BMPTFSA is octahedrally coordinated with TFSA⁻ anions. The average activation energy for the diffusion coefficients of this Ni(II) complex was 26 kJ mol⁻¹, which was close to that for the viscosity. The diffusion coefficient of Ni(II) was estimated to be 9.3 × 10⁻⁸ cm² s⁻¹. Chronoamperometric measurements showed that the electrodeposition of Ni on a platinum substrate involved three-dimensional instantaneous nucleation under diffusion control at room-temperature. The electrodeposits obtained by galvanostatic electrolysis with the current density of −0.046 mA cm⁻² at 70 and 100 °C were identified as metallic Ni by XRD.     

Characteristics of Ni 8 wt%-doped titanium dioxide photocatalyst synthesized by mechanical alloying

Nanocrystalline Ni 8 wt% doped TiO₂ powder was synthesized by mechanical alloying. Microstructural and photo-spectrometiric analysis showed that the Ni added up to 8 wt% was dissolved into the rutile TiO₂ matrix. The absorption threshold of the Ni doped powder shifted from 380 to 500 into the visible light region. (480–500 nm)     

High-Temperature Plastic Behavior of TZP–Ni Cermets

The creep behavior of tetragonal zirconia TZP–Ni cermets with metal contents below, close to, and above the percolation limit has been studied. Compressive creep tests were performed on as-received materials and samples in which the metal phase was chemically removed (ceramic skeletons). The stress exponent and the activation energy for plastic flow are independent of the nickel content and decrease continuously on increasing the stress and/or the temperature; skeleton structures display the same trend, suggesting that creep is controlled by the zirconia matrix. The steady-state constitutive equation for high-purity monolithic zirconia applies to the cermets when the stress is corrected with the porosity and volume fraction of percolated nickel.     

碳羟磷灰石的制备及其吸附镍离子的动力学研究

研究了碳羟磷灰石(CHAP)对Ni2+的吸附性能。从pH值、吸附时间及初始Ni2+浓度三方面对吸附能力的影响进行吸附试验。试验结果表明,在常温常压,CHAP吸附Ni2+的最佳pH值为6,最佳吸附时间为60 min,吸附量达到35.48 mg/g。CHAP对Ni2+的吸附过程符合准二级反应动力学模型。CHAP吸附Ni2+的能力随着废水中Ni2+浓度增加而增加,最大吸附量为38.8 mg/g,CHAP对Ni2+的吸附符合Langmuir吸附等温式。     

On the reaction kinetics of Ni with amorphous carbon

The kinetics of the graphitisation of thin films of amorphous carbon (a-C) by supported Ni particles was investigated by in situ transmission electron microscopy. Ni particles were deposited on a-C films at temperatures from 350 to 500 °C, and reactions with the support were recorded at 600 up to 720 °C. The activity was found to strongly depend on temperature. Reactions generally started with encapsulation of Ni particles with a graphite shell, out of which the metal was eventually expelled and spread on the substrate, which was then graphitised. The propagation speed of the reaction front, and the increase with time of its length and of the graphitised area were measured as function of temperature. Through this, an activation energy of 1.8 ± 0.2 eV was determined; such result is significantly comparable to the theoretical estimate of 1.6 eV, reported by other authors.     

凹凸棒石对废水中Ni~(2+)吸附性能的研究

采用靖远凹凸棒石对废水中Ni2+离子的吸附性能进行了研究。确定了Ni2+离子的吸附平衡时间、最大吸附量对应的pH、最大吸附率对应的吸附剂用量,最大吸附量对应的Ni2+的初始浓度及吸附速率方程。实验结果显示,Ni2+离子浓度在100 mg/L下,吸附平衡时间为90 min,pH值在5~6时,凹凸棒石用量为0.8 g时吸附率达到最大值16.54 mg/g,速率方程为V=0.200 1C。     

链式燃烧反应中Ni基与Cu基金属载氧体的动力学研究

化学链燃烧是一种新型的清洁燃烧技术。其中载氧体的反应性能对其发展具有重要意义。对2种金属（Cu、Ni）添加惰性载体（Al2O3）通过机械混合法制备的氧载体进行了化学动力学和持续循环性能做了比较研究。结果发现通过添加惰性载体之后可以改变其化学反应的表观活化能从而增强载氧体的反应性能,借助SEM表征技术,并且发现可以大幅度改善载氧体的循环能力。