金属—橡胶粘合促进剂硼酰化镍的制备及性能

研究了以碳酸镍、硼酸酯和混合羧酸合成新的金属－橡胶粘合促进剂硼酰化镍的新方法。系统地考察了各种因素对合成硼酰化镍的影响，以2－乙基己酸和硼三丁酯为有机原料合成的硼酰化镍，通过检测，与英国Manobond公司产品680℃比较，二工外光谱数据、300％定伸强度、拉伸强度、硬度和硫化曲线非常接近，而拉断伸长率、热空气老化的粘合性能则前者稍低、实验表明，制备的硼酰化镍可作用金属－橡胶粘合促进剂。     

废镍催化剂回收制备纤维状氢氧化镍

研究从废旧镍催化剂中回收镍以制备氢氧化镍。采用酸浸法,在90℃下用1mol／L硫酸浸没废镍催化剂,从中提取镍。向净化后的含镍溶液中加入NaOH,分别采用3种不同的方法,即尿素水解、传统方法和水热方法制得3种不同的氢氧化镍,分别命名为Ni（OH）2-U,Ni（OH）2-C和Ni（OH）2-H。与传统方法相比,采用水热方法制得的氢氧化镍具有更好的结晶度。Ni（OH）2-C和Ni（OH）2·H都含有β-Ni（OH）2与a-Ni（OH）2·0．75H20的混合相,而Ni（OH）2．U只含有a-Ni（OH）2．0．75H20相。TEM观察显示Ni（OH）2-U样品具有棒状结构。在这3种样品中,Ni（OH）2-U表现出最好的电化学活性。     

硼酸酯多功能添加剂合成及线切割工作液制备

以油酸、三乙醇胺、硼酸和聚乙二醇-400为原料合成一种具有较好水解稳定性、防锈性、润滑性和表面活性的硼酸酯多功能添加剂,通过正交试验确定添加剂合成的较优方案为:三乙醇胺5 g,硼酸2g,聚乙二醇-400 20 g,油酸10 g,采用一步法配制一种稳定透明的线切割工作液,并评定工作液的综合性能。结果表明:方法简单易行,成本低,配制的工作液具有良好的防锈性、消泡性、清洗性、润滑性与适当的电导率。     

Effect of borate coating on corrosion resistance of pure nickel in molten LiCl-Li2O

1　INTRODUCTIONAttheendofthetwentiethcentury ,alithiumreductiontechniquewasdevelopedtodisposeofnucle arfuel(UO2 )used[1] .Inthis process ,theoxide(UO2 )isreducedtothemetallicform(U)byreactionwithlithiumdissolvedinmoltenLiClat 75 0℃ .Thetechniquecaneffectivelyreducethevolumeandradia tionofspentnuclearfuel,whichisconvenienttostoreandmanage .Unfortunately ,thecontainmentmaterialsusedinthetechniqueundertakeseverecor rosionowingtothestrongbasicoxideLi2 OformedanddissolvedinmoltenLiCl.Sev…     

利用低冰镍制备铁酸镍前躯体

以低冰镍为原料,采用草酸盐共沉淀法合成颗粒细小的铁酸镍前躯体 NiFe2(C2O4)3·6H2O。NiCl2?FeCl2?(NH4)2C2O4?H2O体系的热力学研究表明：Ni2+和Fe2+的理论最佳共沉淀pH值为2,2?24C O 对Ni2+、Fe2+离子具有较强的络合作用。在理论研究的基础上,考察沉淀参数对沉淀率和前躯体粒度的影响。结果表明：最佳共沉淀条件为溶液pH=2,反应温度为45°C,(NH4)2C2O4加入量为理论值的1.2倍,PEG400加入量为3%。在此条件下,Ni2+和Fe2+的沉淀率达99.8%,所得前躯体的粒径为1~2 um。XRD和TG?DTA分析表明：所得前躯体为单相置换固溶体,反应过程中镍、铁原子相互取代。     

Breakdown of passive film on nickel in borate solutions containing halide anions

The effect of Cl⁻, Br⁻ and I⁻ anions as aggressive agents on the anodic behaviour of nickel electrode in deaerated Na₂B₄O₇ solutions have been investigated by galvanostatic polarization technique. Lower concentrations of the halide anions have no effect on the mechanism of nickel passivation. An increase in the halide anions concentration causes oscillation of the potential in the oxygen evolution region. This could be attributed to the destruction of the passivity by halide anions and repassivation of the film by anodic current and/or OH⁻ anions. Higher aggressive anion concentrations cause breakdown of the passive film and initiated pitting corrosion. As the temperature increases, the breakdown potential is shifted towards the more negative direction. On the other hand, as the pH of the solution increases, the breakdown potential is shifted toward more positive direction, indicating increased protection of the passive film. The activation energy, , of the oxide film formation in the presence of Cl⁻ anions was calculated and was found to be 21 kJ/mol.     

镍铁氧体/聚苯胺复合材料的制备及其性能

采用超声场下原位聚合法制备镍铁氧体/聚苯胺复合材料,并采用x射线衍射仪(XRD)和HP8510网络分析仪研究其结构和电磁性能.结果表明:十二烷基苯磺酸(DBSA)掺杂后的聚苯胺是部分结晶的,镍铁氧体与聚苯胺分子链之间存在某些相瓦作用;与聚苯胺相比,镍铁氧体/聚苯胺复合材料的介电损耗角正切值tanδ<,ε>与磁损耗角正切值tanδ<,m>都增大;镍铁氧体含量为5%和15%(质量分数)的复合材料分别具有最大的tanδ<,ε>暝值和最大tanδ<,m>值;镍铁氧体含量为15%的试样在8～18 GHz范围内综合吸波性能最好,具有最大衰减-23.4 dB,-8 dB带宽为5.73 GHz.     

疏水性硼酸镧纳米棒的制备及其在菜籽油中的摩擦磨损性能(英文)

采用水热法合成油酸修饰的硼酸镧纳米棒(OA/La BO3·H2O),利用X射线衍射和扫描电镜等测试技术对其微观结构进行表征,并在四球摩擦试验机上考察其在菜籽油中的摩擦磨损性能。结果表明,所制备的OA/La BO3·H2O为直径约50 nm、长达500 nm的疏水性纳米棒。OA/La BO3·H2O能显著提高菜籽油的抗磨减摩性能;当OA/La BO3·H2O的添加量为1%(质量分数)时,菜籽油的抗磨减摩性能最佳。     

Effect of substrate temperature on adhesion strength of plasma-sprayed nickel coatings

We plasma-sprayed nickel coatings on stainless steel and cobalt alloy coupons heated to temperatures ranging from room temperature to 650 °C. Temperatures, velocities, and sizes of spray particles were recorded while in-flight and held constant during experiments. We measured coating adhesion strength and porosity, photographed coating microstructure, and determined thickness and composition of surface oxide layers on heated substrates. Coating adhesion strength on stainless steel coupons increased from 10–74 MPa when substrate temperatures were raised from 25–650 °C. Coating porosity was lower on high-temperature surfaces. Surface oxide layers grew thicker when substrates were heated, but oxidation alone could not account for the increase in coating adhesion strength. When a coupon was heated to 650 °C and allowed to cool before plasma-spraying, its coating adhesion strength was much less than that of a coating deposited on a surface maintained at 650 °C. Cobalt alloy coupons, which oxidize much less than stainless steel when heated, also showed improved coating adhesion when heated. Heating the substrate removes surface moisture and other volatile contaminants, delays solidification of droplets so that they can better penetrate surface cavities, and promotes diffusion between the coating and substrate. All of these mechanisms enhance coating adhesion.     

Structural properties of Li–borate glasses doped with Sm and Eu ions

A Li–borate glass system doped with samarium and europium has been prepared by a conventional melt quenching technique. Europium content was kept constant at 0.01 mol%. The general formula was

xSm₂O₃ + (100 − x) [0.84B₂O₃ + 0.15Li₂O + 0.01Eu₂O₃]

where x = 0.1, 0.2, 0.5, 0.6 and 0.7 mol%. The density was measured and the corresponding molar volume was evaluated .The former was found to increase by increasing Sm while the later exhibits opposite trend. The average optical basicity, Λ_th, electron negativity χ_2av and electron polarizability α²⁻ were calculated for the prepared compositions. Infrared spectra were obtained at room temperature for the prepared glasses before and after γ irradiation. The results showed that the three main appeared bands are most likely due to the bending and/or stretching vibration of both tetrahedral BO₄ and triagonal BO₃ borate units. ESR spectra were recorded at room temperature before and after γ-irradiation. It was found that the oxygen atoms of BO₃ units are responsible for the formation of the hole paramagnetic centers after irradiation in the glass matrix.     

Preparation of basic nickel carbonate particles in solution system of Ni( Ⅱ )-NH3-CO2-3-H2O

Based on the principles of simultaneous equilibrium and mass balance, a series of thermodynamic equilibrium equations of Ni( Ⅱ )-NH3-CO2-3-H2O system at ambient temperature were deduced theoretically and the thermodynamic diagrams of lg[Ni]T versus pH at different solution compositions were drawn, which was quite effective to explain the formation mechanism of precipitation particles with different microscopic shapes. When pH of the solution is below 7.0, free nickel ions are dominant and when the precipitant is added, the fast coagulation will take place leading to the loose flocculation particles. While pH is above 7.0, because of the coordination of nickelion with ammonia, the precipitation proceeds slowly accompanying with the release of Ni2 from the multi-coordinated Ni(NH3)2 n (n= 1, 2, …, 6), which easily leads to the formation of the dense spherical particles.     

Synthesis of nickel aluminate nanoceramic compound from aluminum and nickel carbonate by mechanical alloying with subsequent annealing

The aim of present work was to produce pure nickel aluminate (NiAl₂O₄) nanoceramic compound by high energy milling of nickel carbonate (NiCO₃) and aluminum (Al) powders followed by annealing. Phase composition, thermal behavior, morphology and microstructure of powder samples were characterized by means of X-ray diffraction, differential scanning calorimeter, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The results showed that formation of NiAl₂O₄ spinel compound from NiCO₃ and Al powders took place in three steps: oxidation of Al to Al₂O₃, decomposition of NiCO₃ to NiO and CO₂, and finally the solid state reaction between Al₂O₃ and NiO. It was also demonstrated that single phase NiAl₂O₄ spinel compound can be produced by 5 h of mechanical milling with subsequent annealing of NiCO₃/Al mixture at 900 °C for 2 h, which is ∼500 °C lower than the temperatures used in the traditional solid state methods. The particle diameter of the produced NiAl₂O₄ spinel compound was found to be less than 100 nm as measured by transmission electron microscopy.     

Preparation and properties of the barium borate glassy matrix composite materials containing fused silica and monoclinic zirconia

In this work, the LTCC composite materials containing fused silica and monoclinic zirconia ceramic particles, respectively, which based on the composite matrix composed of the barium borate glassy matrix and α-alumina ceramic particles, were prepared by traditional solid-state preparation process at a sintering temperature of 900 °C. Sintering mechanism and physical properties, e.g. dielectric properties and coefficient of thermal expansion (CTE), of the LTCC composite ceramics are investigated and discussed in detail in terms of their mineral phase composition. The results indicate that a barium borate glassy phase can be easily formed from a barium borate compound, which is obtained by the chemical combination of barium hydroxide octahydrate and an aqueous solution of boric acid, at a sintering temperature of 900 °C. In turn, the barium borate glassy melts can supply a liquid phase sintering aid for the fabrication of the LTCC composite ceramics with the sintering temperature of 900 °C during sintering. The introduction of the α-alumina ceramic particles to the barium borate glassy matrix can improve the sintering behavior whereas the presence of fused silica or monoclinic zirconia particles in the composite ceramics is important to adjust the dielectric, thermal and mechanical properties of the LTCC composite materials. The work may be referenced for the fabrication of multi-layer LTCC structures with tailored physical properties.     

辅助磨擦对镍电铸层力学性能的影响

在磨擦辅助电铸镍过程中,通过改变游离微珠对电铸层表面的磨擦强弱,制备不同力学性能的镍电铸层。对所制备镍电铸层的表面形貌、织构等微观结构和显微硬度、抗拉强度及伸长率等性能进行测试和分析。结果表明:采用卧式放置的阴极能制得材料组织结构均匀的电铸层。且随着阴极表面线速度的提高,游离微珠对电铸层的整平作用和晶粒细化作用增强。在不同线速度下采用旋转阴极可以制备大范围力学性能的镍电铸层,其表面粗糙度为0.15~0.03μm、硬度为185~410HV、抗拉强度为525~1 020 MPa、伸长率为24%~4%。     

SnO2包覆硼酸铝晶须增强铝复合材料高温拉伸性能研究

利用挤压铸造方法制备了SnO2涂覆硼酸铝晶须增强纯铝复合材料(晶须体积分数为20%),研究了涂层和复合材料的微观组织结构、界面反应,并对复合材料的高温拉伸力学性能进行了测试和分析。结果表明,SnO2涂层的引入改善了晶须增强铝基复合材料的界面状态,使得复合材料的拉伸强度随着温度的升高和涂层含量的增加先增加然后降低,当SnO2包覆涂层与晶须的质量比为1∶20时,晶须增强纯铝基复合材料的拉伸温度在300℃得到了最好的拉伸塑性。     

Compressive properties and energy absorption characteristics of open-cell nickel foams

Open-cell nickel foams with different relative densities and pre-stretching degrees were subjected to room temperature quasi-static compressive tests to explore their compressive properties. The compressive properties of the nickel foams including yield strength, elastic modulus, energy absorption density and energy absorption efficiency were calculated accurately. The results show that the compressive properties of yield strength, elastic modulus and energy absorption density increase with the increase of relative density of nickel foams. The compressive properties are sensitive to the pre-stretching degree, and the values of yield strength, elastic modulus and energy absorption density decrease with the increase of pre-stretching degree. However, the energy absorption efficiency at the densification strain state exhibits the independence of relative density and pre-stretching degree. The value of energy absorption efficiency reaches its peak when the strain is at the end of the collapse plateau region.     

Regeneration and decontamination of a nickel citrate complex in spent electroless nickel plating solutions

The possibility of citrate precipitation by excess metal ions in alkaline solutions suggests the use of Ni(II) together with OH^? to precipitate a Ni(II)-citrate complex from spent electroless plating solutions. After treatment of the precipitate with acid, excess Ni(II) can be removed in the form of insoluble Ni(OH)₂. The solution of the Ni(II)-citrate complex can then be reused for electroless nickel plating. During this procedure the additive adipate is not regenerated. For decontamination of spent electroless nickel plating solutions Fe(III) can be used as Ni(II)-citrate complex precipitant.     

硼酸铝晶须增强铝基复合材料的显微组织、力学性能和磨损性能（英文）

通过传统的粉末冶金技术制备不同含量硼酸铝晶须(ABOw)(5%, 10%, 15%,质量分数)增强的商业纯铝基复合材料,并对其显微组织特征和力学性能进行研究。采用粉末冶金方法有效混合铝粉和ABOw,将混合粉冷压后在600℃下烧结。通过光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、透射电子显微镜(TEM)和X射线衍射(XRD)对烧结后的复合材料进行显微组织表征,测定复合材料的孔隙率随ABOw含量的变化,研究ABOw含量变化对复合材料的力学性能,包括硬度、抗弯强度和抗压强度的影响,及复合材料在恒定载荷下、不同滑动距离下的干滑动磨损行为。结果表明,当ABOw含量为10%(质量分数)时,复合材料具有最大的抗弯强度和抗压强度,分别为172 MPa和324 MPa,并且硬度得到改善,约为HV 40.2。但是,随着ABOw含量的进一步增加,性能降低。含10%ABOw复合材料的耐磨性能也得到显著提高。Al-10%ABOw复合材料优异的综合性能归因于其具有良好的界面结合性能、低的孔隙率和好的组织均匀性。     

Chromaluminizing of nickel and its alloys

Chromaluminide diffusion coatings on nickel and nickel-base superalloys, EI 867 and IN 100, have been formed by a two-step pack cementation technique. The effect of pack composition on coating formation and structure has been discussed. It has been stated that the appropriate choice of coating parameters enables the enrichment of aluminide coating in chromium either near its surface or near the coating/substrate interface.     

Temperature measurements and adhesion properties of plasma sprayed thermal barrier coatings

Metal-ceramic coatings have been widely used for industrial applications, mainly in the gas turbine and diesel engine industries as thermal barrier coatings (TBCs). Conventional thermal barrier coatings consist of a metallic bond coat and an insulating ceramic topcoat. Temperatures and temperature gradients in the coating during plasma spraying play an important role on the final coating quality, especially the temperature of the particles just hitting the substrate surface. In this work, metal-ceramic coatings were applied on nickel-superalloy substrates. The temperatures of both the coating surface and substrate were measured during spraying. The adhesion of the coatings was determined using ASTM C 633 and correlated with the measured temperatures. Optical pyrometry and thermocouples were used to measure the interfacial and substrate temperatures, respectively. Temperature was shown to have a significant influence where lower interfacial temperatures were found to result in lower adhesion values.