镍/镍/铬多层电镀故障的处理

分析了镀镍层产生毛刺的原因 。

Characterization of fluidized reduction roasting of nickel laterite ore under CO/CO_(2)atmosphere

Fluidized reduction roasting is an efficient metallurgical technique.However,its application to nickel laterite ore has rarely been reported.In this paper,the effects of reduction temperature,reduction time,CO concentration,and material particle size on the roasting characteristics of ferronickel fluidization reduction were investigated.Combined with X-ray diffraction,scanning electron microscopy-energy dispersive spectrometry(SEM-EDS)characterization,the mineral phases and microscopic morphology of nickel laterite ore and its roasted ores were analyzed in depth.The results indicated that under the condition of a CO/CO_(2)ratio of 1:1,a reduction temperature of 800℃,and a reduction roasting time of 60 min,a nickel-iron concentrate with a nickel grade of 2.10%and an iron content of 45.96%was produced from a raw material with a nickel grade of 1.45%,achieving a remarkable nickel recovery rate of 46.26%.XRD and SEM-EDS analysis indicated that nickel in the concentrate mainly exists in the form of[Fe,Ni],while the unrecovered nickel in the tailings is primarily present in the form of[Fe,Ni]and Ni_(2)SiO_(4)in forsterite.This study established a theoretical foundation for further exploration of fluidized reduction roasting technology.

原位合成Ni/Ni-Al金属间化合物层板复合材料的组织转变

在原位合成的Ｎｉ／Ｎｉ－Ａｌ金属间化合物层板复合材料中，随着退火温度升高，层状化合物相逐渐由富Ａｌ相转变为富Ｎｉ相。在层状的化合物相生长过程中晶界扩散占主导地位。经１１５０℃Ｎｉ退火的层中，离Ｎｉ３Ａｌ层近的区域，均匀形核的析出相生长的比较粗大；在Ｎｉ层中间，细小的析出相是非均匀形核的。在连续冷却过程中，晶界析出相通过晶界扩散而长大的同时，也造成晶界两侧出现溶质的贫乏区，从而导致无析出带产生。

Dechromization and dealumination kinetics in process of Na_2CO_3-roasting pretreatment of laterite ores

A novel process was proposed for the activation pretreatment of limonitic laterite ores by Na2CO3 roasting. Dechromization and dealumination kinetics of the laterite ores and the effect of particle size, Na2CO3-ore mass ratio, and roasting temperature on Cr and Al extraction were studied. Experimental results indicate that the extraction rates of Cr and Al are up to 99%and 82%, respectively, under the optimal particle size of 44–74μm, Na2CO3-to-ore mass ratio of 0.6：1, and temperature of 1000 ℃. Dechromization within the range of 600–800 oC is controlled by the diffusion through the product layer with an apparent activation energy of 3.9 kJ/mol, and that it is controlled by the chemical reaction at the surface within the range of 900–1100 ℃ with an apparent activation energy of 54.3 kJ/mol. Besides, the Avrami diffusion controlled model with on apparent activation energy of 16.4 kJ/mol is most applicable for dealumination. Furthermore, 96.8%Ni and 95.6%Co could be extracted from the alkali-roasting residues in the subsequent pressure acid leaching process.

Thermodynamic analysis on synthesis of fibrous Ni-Co alloys precursor and Ni/Co ratio control

According to the principles of simultaneous equilibrium and mass equilibrium, a series of thermodynamic equilibrium equations in Ni（II）-Co（II）-C2O4^2--NH3-NH4^＋-H2O system at ambient temperature were deduced. The diagrams of logarithm ion concentrations versus pH values at different solution compositions were drawn. The results show that Ni^2＋ and Co^2＋ can completely precipitate at pH less than 5.0 and the predefined Ni/Co ratios can be well kept in the precursor. The precursor morphology is granular aggregation. However, rod aggregation precursor is obtained in the pH range of 5.0-8.0, and fibre-shape precursor is got at pH value higher than 8.0. The Ni/Co ratios in the above two precursors are not reproduced as that in the feed due to the formhtion of multi-coordinated Ni（NH3）n^2＋ and Co（NH3）n^2＋ （n=1-6）. Modification of precipitation medium is favorable for the precursors to keep the predefined Ni/Co ratios of the feed in the pH range of 2.0-8.6. Meanwhile, the precursors with fibrous morphology can be obtained.

Finite element simulation of ball spinning of NiTi shape memory alloy tube based on variable temperature field

As a new attempt,ball spinning was used to manufacture the nickel-titanium shape memory alloy（NiTi SMA） tube at elevated temperature.The NiTi bar with a nominal composition of Ni50.9Ti49.1（mole fraction,%） was solution treated and was used as the original tube blank for ball spinning.Based on the variable temperature field and the constitutive equation,rigid-viscoplastic finite element method（FEM） was applied in order to simulate the ball spinning of NiTi SMA tube.The temperature field,the stress field,the strain field and the load prediction were obtained by means of FEM.FEM results reveal that there is a temperature increase of about 160 ℃ in the principal deformation zone of the spun part.It can be found from the stress fields and the strain fields that the outer wall of NiTi SMA tube is easier to meet the plastic yield criterion than the inner wall,and the plastic deformation zone is caused to be in a three-dimensional compressive stress state.The radial strain and the tangential strain are characterized by the compressive strain,while the axial strain belongs to the tensile strain.The variation of spinning loads with the progression of the ball is of great importance in predicting the stable flow of the spun part.

Mineralogy and crystal chemistry of a low grade nickel laterite ore

To acquire understanding of Ni enrichment from laterite ore,the mineralogy and crystal chemistry of a low grade limonite type nickel laterite ore sample assaying 0.97% Ni from Indonesia were studied using optical microscopy,X-ray diffraction（XRD）,scanning electron microscopy（SEM） and electron probe microanalysis（EPMA）.According to EPMA results,the mineral includes 80% goethite（（Fe,Ni,Al）O（OH）） with 0.87% Ni,15% silicate minerals with lizardite（（Mg,Fe,Ni）3Si2O5（OH）） and olivine（（Mg,Fe,Ni）2SiO4）,and 1.19% Ni,and other minor phases,such as hematite,maghemite,chromite and quartz,and no Ni was detected.The mineralogy of the laterite ore indicates that due to the complicated association of the various phases and the variable distribution of Ni,this refractory laterite ore can not be upgraded by traditional physical beneficiation processes.

Extraction of molybdenum and nickel from Ni-Mo ore by pressure acid leaching

A direct hydrometallurgical route for nickel and molybdenum extraction from a nickel-molybdenum （Ni-Mo） ore using pressure acid leaching was studied. The nickel and molybdenum were extracted by acid leaching under oxygen pressure. Compared with traditional roasting methods, this hydrometallurgical method eliminates SO2 and As203 emission （the Ni-Mo ore containing 15%-25% S）. Compared with existing alkali leaching recovery of molybdenum process, almost all the nickel and considerable molybdenum were extracted in the acid leaching process. Under oxygen pressure conditions, almost all the nickel and a substantial part of the molybdenum were dissolved into the acid leaching liquor and the other part of the molybdenum was left in the acid leach residue. The acid leach residue was further leached under alkaline （NaOH） conditions. Under optimal experimental conditions, the extraction rates nickel and molybdenum reached 97% and 96%, respectively.

Effect of Nickel Contamination on Formation of Denuded Zone in Czochralski Silicon

The effect of nickel contamination under rapid thermal processing （RTP） on the magic denuded zone （MDZ） in Czochralski silicon is investigated. It is found that the bulk defects can effectively getter nickel atoms once the MDZ forms. However,if the silicon sample is initially contaminated with nickel, the MDZ cannot form during the subsequent RTP,and a high density of precipitates occurs near the surface. In conventional IG processes,the DZ can form regardless of the nickel contamination sequence. Based on the facts,we propose that the formation of nickel silicide （Ni3Si） at the surface keeps the concentration of vacancies in the near-surface zone still higher than the critical concentration for oxygen precipitation under the subsequent RTP, which prevents MDZ formation.

Extraction of molybdenum and nickel from roasted Ni-Mo ore by hydrochloric acid leaching, sulphation roasting and water leaching

To extract molybdenum and nickel from the roasted Ni-Mo ore, a process of hydrochloric acid leaching, sulphation roasting and water leaching was investigated. The results showed that this process could get a high leaching rate of Mo and Ni. Under the optimum conditions of hydrochloric acid leaching （roasted Ni-Mo ore leached with 0.219 mL/g hydrochloric acid addition at 65 ℃ for 30 min with a L/S ratio of 3 mL/g）, sulphation roasting （51.9% sulfiaric acid addition, roasting temperature 240 ℃ for 1 h）, followed by leaching with the first stage hydrochloric acid leaching solution at 95 ℃ for 2 h, the leaching rates of Mo and Ni reached 95.8% and 91.3%, respectively.

Effect of Pt Addition on the Stress of NiSi Film Formed on Si (100)

In order to clarify the effect of pt addition on the stress of NiSi film, in situ stress measurements were taken to evaluate the stress evolution during heating and cooling treatment of Ni1- x Ptx Si alloy films with different Pt concentrations. The room temperature stress, which is mainly thermal stress, was measured to be 775MPa and 1.31GPa for pure NiSi and pure PtSi films grown on Si （100） substrates,respectively. For Ni1-x Ptx Si alloy film, the room temperature stress was observed to increase steadily with Pt concentration. From the temperature dependent stress evolution curves,the stress relaxation temperature was found to increase from 440℃ （for pure NiSi film） to 620℃ （for pure PtSi film） with increasing Pt concentration, thus influencing the residual stress at room temperature.

Determination of trace elements in high purity nickel by high resolution inductively coupled plasma mass spectrometry

The contents ofMg, Al, Si, Ti, Cr, Mn, Fe, Co, Cu, Ga, As, Se, Cd, Sb, Pb and Bi in high purity nickel were determined by high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS）. The sample was dissolved in HNO3 and HCI by microwave digestion. Most of the spectral interferences could be avoided by measuring in the high resolution mode. The matrix effects because of the presence of excess HC1 and nickel were evaluated. Correction for matrix effects was made using Sc, Rh and T1 as internal standards. The optimum conditions for the determination were tested and discussed. The detection limits range from 0.012 to 1.76 ~tg/g depending on the type of elements. The applicability of the proposed method is also validated by the analysis of high purity nickel reference material （NIST SRM 671）. The relative standard deviation （RSD） is less than 3.3%. Results for determination of trace elements in high purity nickel were presented.

Distribution and Transformation of Native and Added Ni Fractions in Purple Soils from Sichuan Province

The distribution and transformation of added and native Ni in purple soils were investigated with both sequential extraction procedure and isotopic tracer technique.The distribution of added and native Ni was greatly dependent on soil properties.Low soil PH was favorable for soluble plus exchangeable (EX) Fraction,while Fe/Mn oxides and clay for Fe/Mn oxide bound (OX) and residual (RES) fractions. The added Ni,however,has not yet reached the distribution equilibrium up to the 150th day after incubation.This was reflected in the fact that the proportion of EX fraction from added Ni was 150%-600% as much as that of native Ni, while that of RES fraction was only about 80%.Once entering soil, the applied soluble Ni was rapidly transformed into Other fractions, but the organic complexed (OM) fraction of added Ni was relatively stable during incubation.The carbonate bound(CAB) fraction showed a progressive increase and attained a peak value after 0-14 d of incubation and thereafter decreased gradually. The occurrence time of this peak advanced as initial soil PH increased, but the peak would disappear when initial soil pH was higher than 7.5(or containing free CaCO3). The transformation processes of the EX,OX and RES fractions could be described by Elovich and two-constant rate equstions,and the rates were positively correlated with soil pH,CEC and clay.These findings could explain why there are differences in ecological and environmental effects of Ni in different soils and at various intervals.

Solvent extraction of zinc,manganese,cobalt and nickel from nickel laterite bacterial leach liquor using sodium salts of TOPS-99 and Cyanex 272

The extraction and separation of zinc, manganese, cobalt and nickel from nickel laterite bacteria leach liquor were carried out using sodium salts of TOPS-99 and Cyanex 272 in kerosene. The unwanted metal ions were removed by precipitation method and solvent extraction was used to extract/separate Zn, Mn, Co and Ni. The nickel laterite leach liquor which was obtained from bioleaching of chromite overburden samples contained 3.72 g/L Fe, 2.08 g/L Al, 0.44 g/L Ni, 0.02 g/L Co, 0.13 g/L Mn, 0.14 g/L Zn and 0.22 g/L Cr. From this leach liquor, 100% Fe, 96.98% Al and 70.42% Cr were removed by precipitation with Ca CO_3 at pH 4.4 followed by precipitation of remaining Al and Cr with 50% ammonia at p H 5.4. After precipitation, the extraction of Zn from the Fe, Al and Cr free leach liquor was carried out with 0.1 mol/L TOPS-99 followed by Mn extraction with 0.04 mol/L Na TOPS-99. The yields of Zn and Mn were 97.77% and 95.63%, respectively. After Mn extraction, cobalt was removed from the leach liquor using 0.0125 mol/L Na Cyanex 272 and finally nickel extraction was carried out using 0.12 mol/L Na TOPS-99 with 99.84% yield. The stripping of loaded organic（LO） phases were achieved with dilute H_2SO_4.

Efficient methane electrocatalytic conversion over a Ni-based hollow fiber electrode

Natural gas and shale gas,with methane as the main component,are important and clean fossil energy resources.Direct catalytic conversion of methane to valuable chemicals is considered a crown jewel topic in catalysis.Substantial studies on processes including methane reforming,oxidative coupling of methane,non-oxidative coupling of methane,etc.have been conducted for many years.However,owing to the intrinsic chemical inertness of CH4,harsh reaction conditions involving either extremely high temperatures or highly oxidative reactants are required to activate the C–H bonds of CH4 in such thermocatalytic processes,which may cause the target products,such as ethylene or methanol,to be further converted into coke or CO and CO2.It is desirable to adopt a new strategy for direct CH4 conversion under mild conditions.Herein,we report that efficient electrocatalytic oxidation of methane to alcohols at ambient temperature and pressure can be achieved using a NiO/Ni hollow fiber electrode.This work opens a new avenue for direct catalytic conversion of CH4.

Separation and recovery of Ni from copper electrolyte by crystallization of nickel ammonium sulfate double salt

The separation and recovery of Ni from the copper electrolyte by crystallization of nickel ammonium sulfate double salt were studied.It is found that the solubility of copper sulfate at the same temperature is less than that of nickel sulfate,while the solubility of copper ammonium sulfate is greater than that of nickel ammonium sulfate.So,by adding(NH_(4))_(2)SO_(4),the Ni can be selectively crystallized from the copper electrolyte.By adding(NH_(4))_(2)SO_(4)at the molar ratio of(NH_(4))_(2)SO_(4)/NiSO_(4)≤0.8,and crystallizing at−15℃for 10 h,the Ni in the copper electrolyte can be crystallized in the form of Ni(NH_(4))_(2)(SO_(4))_(2)×6H_(2)O.The qualified product of NiSO_(4)×6H_(2)O can be obtained by pyrolyzing the crystals,dissolving the pyrolysis product in water,and then concentrating the dissolved solution for crystallization.The method of double salt crystallization is a clean,environmentally-friendly,cost-effective and efficient method for separating and recovering nickel from copper electrolyte.

Efficient enrichment of nickel and iron in laterite nickel ore by deep reduction and magnetic separation

The process of deep reduction and magnetic separation was proposed to enrich nickel and iron from laterite nickel ores.Results show that nickel-iron concentrates with nickel grade of 6.96%,nickel recovery of 94.06%,iron grade of 34.74%,and iron recovery of 80.44% could be obtained after magnetic separation under the conditions of reduction temperature of 1275℃,reduction time of 50 min,slag basicity of 1.0,carbon-containing coefficient of 2.5,and magnetic field strength of 72 kA/m.Reduction temperature and time affected the possibility of deep reduction and reaction progress.Slag basicity affected the composition of slag in burden and the spilling and enriching rate of nickel-iron from a matrix to form nickel-iron particles.Nickel-iron particles were generated,aggregated,and grew gradually in the reduction process.Nickel-iron particles can be effectively separated from gangue minerals by magnetic separation.

Effect of CaO doping on mechanical properties and thermal shock resistance of 10NiO-NiFe_2O_4 composite ceramics

The CaO doped 10NiO-NiFe2O4 composite ceramics were prepared by the cold isostatic pressing-sintering process, and the effects of CaO content on the phase composition, mechanical property and thermal shock resistance of 10NiO-NiFe2O4 composite ceramics were studied. The results show that the samples mainly consist of NiO and NiFe2O4 when content of CaO is less than 4%(mass fraction), bending strength increases obviously by CaO doping. Bending strength of the samples doped with 2% CaO is above 185 MPa, but that of the samples without CaO is only 60 MPa. Fracture toughness is improved obviously by CaO doping, the samples doped with 2% CaO have the maximum fracture toughness of 2.12 MPa ·m1/2 , which is about two times of that of the undoped ceramics. CaO doping is bad to thermal shock resistance of 10NiO-NiFe2O4 composite ceramics.

Synthesis and characterization of fibrous nickel hydroxide obtained from spent nickel catalyst

The recovery of nickel from spent nickel catalyst for the preparation of nickel hydroxide was studied. Nickel was extracted from the spent catalyst by acid leaching with 1 mol/L sulfuric acid at 90 ℃. Purified nickel solution was used in the preparation of nickel hydroxide. Three different methods, namely urea hydrolysis, conventional, and hydrothermal methods, of precipitation using NaOH were employed to get various nickel hydroxides samples named as Ni（OH）E-U, Ni（OH）2-C, and Ni（OH）E-H, respectively. Hydrothermal treatment induced better crystallinity in the Ni（OH）2 compared with conventional method. Both Ni（OH）2-C and Ni（OH）E-H samples have mixed phases of fl-Ni（OH）2 and a＊-Ni（OH）E.0.75H20 phases, whereas Ni（OH）2-U has only a＊-Ni（OH）2.0.75H20. TEM image of Ni（OH）E-U sample shows rod-like Ni（OH）2 structures. Among all, Ni（OH）2-U shows the best electrochemical activity.

半导体晶圆ENIG/ENEPIG产品设计考量

通过化学自催化反应在半导体晶圆I/O铝或铜金属垫上沉积具有可焊接性的镍金/镍钯金层,此工艺已在MOSFET、IGBT、RFID、SAW Filter等产品上得到广泛应用。着重阐述了在新产品设计和工程评估阶段,对于晶圆产品本身应予以考量的因素,如钝化层种类及厚度,I/O金属垫的成分及结构,切割轨道上金属图形的大小及钝化层的覆盖,不同I/O pad的电势等。其中一些因素导致的问题会直接影响化学镍金/镍钯金后产品的性能应用。在化镀工艺过程中,要充分了解产品本身结构以及可能造成的相应缺陷及问题,并且应综合考虑这些因素的影响。