用含KBH4碱液处理改善M1Ni3.7Co0.6Mn0.4Al0.3贮氢合金电极的动力学 …

研究了用６ｍｏｌ／Ｌ ＫＯＨ＋ｙ ｍｏｌ／Ｌ ＫＢＨ４（ｙ＝０．０,０．００５,０．０１,０．０２,０．０３）表面改性处理对Ｍ１Ｎｉ３．７ｃＯ０．６Ｍｎ０．４Ａｌ０．３贮氢合金电极动力学性能的影响。结果表明：用含ＫＢＨ４碱液处理合金粉末可有效地提高氢化物电极的高倍率放电能力ＨＲＤ,交换电流密度Ｉ０,极限电流密度ＩＬ和α相中氢的扩散系数Ｄα等各项动力学性能,而且ＫＢＨ４的浓度越高（≤０．０３ｍｏｌ／     

贮氢电极合金Ml（NiMnTi）4.2Co0.8—XFex（x=0—0.8）的电化学性能

详细地研究了Ｍｌ（ＮｉＭｎＴｉ）４．２Ｃｏ０．８－ｘＦｅｘ（ｘ＝０－０．８）合金的电化学性能。试验发现,随着Ｆｅ含量ｘ从０增加至０．,合金的活化性能得到改善,但最大放电容量从３０２ｍＡｈ／ｇ逐渐降低到２８０ｍＡｈ／ｇ,高倍率放电性能从７８．５％缓慢降至７２．５％;当Ｆｅ含量ｘ≤０．４时,合金的自放电率与高Ｃｏ合金（ｘ＝０）相比有所降低,但当Ｆｅ含量ｘ超过０．４后,合金的自放电率较高Ｃｏ合金有所上升     

用含KBH_4碱液处理改善MINi_(3.7)Co_(0.6)Mn_(0.4)Al_(0.3)贮氢合金电极的动力学性能

研究了用表面改性处理对ＭＩＮｉ３．７Ｃｏ０．６Ｍｎ０．４Ａｌ０．３贮氢合金电极动力学性能的影响．结果表明：用含 ＫＢＨ４碱液处理合金粉末可有效地提高氢化物电极的高倍率放电能力 ＨＲＤ,交换电流密度Ｉ０,极限电流密度ＩＬ和α相中氢的扩散系数Ｄ等各项动力学性能,而且ＫＢＨ４的浓度越高（＜０．０３ ｍｏｌ／Ｌ）,动力学性能提高得也越大当碱液中所含 ＫＢＨ。浓度相同时氢在相中的扩散系数Ｄ的增加要小于交换电流密度Ｉ０的增加． ＫＢＨ４碱液处理对 ＭＩＮｉ３．７Ｃｏ０．６Ｍｎ０．４Ａｌ０．３贮氢合金电极动力学性能的改善导致合金电极的阴、阳极极化明显减小     

ZrMn0.9—xVxNi1.1（x=0.1—0.8）Laves相贮氢合金的电化学性能

研究了ＡＢ２型锆基Ｌａｖｅｓ相贮氢合金ＺｒＭｎ０．９－ｘＶｘＮｉ１．１（ｘ＝０．１～０．８）的晶体结构及其电化学性能。研究表明，ＺｒＭｎＶＮｉ合金为多相组织，当Ｍｎ含量较高时，合金的主相为Ｃ１５型Ｌａｖｅｓ相结构；随着Ｖ含量增加，合金中Ｃ１４型Ｌａｖｅｓ相的含量逐渐增加；合金的主相结构与电子浓度有关。Ｍｎ、Ｖ含量影响Ｌａｖｅｓ相合金中的不同类型四面体间隙数目及合金热力学和电化学性能。当合金中的Ｖ／（Ｍｎ＋Ｖ）比率在２／９～４／９范围内，合金表现出较好的综合电化学性能。ＺｒＭｎ０．５Ｖ０．４Ｎｉ１．１合金的最高容量为３４２ｍＡｈ／ｇ，高倍率放电能力为Ｃ２００／（Ｃ２００＋Ｃ５０）＝７５％，经１００次１００％ＤＯＤ充放电循环后，容量保持率为８５％左右。     

镁掺杂对贮氢电极合金Ml(NiCoMnTi)5电化学性能的影响

采用在Ｍｌ（ＮｉＣｏＭｎＴｉ）５合金中添加不同量镁的方法,系统地研究了镁掺杂量对贮氢电极合金Ｍｌ（ＮｉＣｏＭｎＴｉ）５电化学性能的影响。结果表明,当镁掺杂量从０．００３％增加至０．２６３％时,合金的最大放电容量逐渐升高,但当镁掺杂量进一步增加时,合金的最大放电容量又逐渐降低;增加镁掺杂量可以改善合金的活化性能,而且随着镁掺杂量的增加合金的高倍率放电性能也有不同程度的提高,但合金的２４ｈ荷电保持能力却大幅度下降;此外,增加镁掺杂量会明显恶化合金的充放电循环稳定性。     

Co对MlNi4.3-xCoxAl0.7贮氢电极动力学性能的影响

详细研究了Ｃｏ 对ＭｌＮｉ４ ．３ － ｘＣｏｘＡｌ０ ．７（ ｘ ＝ ０ , ０ ．３ , ０ ．５ ,０ ．７ ,０ ．９ ,１ ．１ ,１ ．３） 贮氢电极的动力学特性的影响; 研究的动力学参数包括高倍率放电特性ＨＲＤ、交换电流密度Ｊ０ 、极限电流密度ＪＬ、对称因子β以及氢在α相中的扩散系数Ｄα。实验结果表明： 随着ＭｌＮｉ４ ．３ － ｘＣｏｘＡｌ０ ．７ 贮氢电极中Ｃｏ 含量的增大, 合金的高倍率放电能力迅速减小, 交换电流密度Ｊ０ , 极限电流密度ＪＬ, 对称因子β以及氢在α相中扩散系数Ｄα显著降低     

Ti对Ml(NiCoMnTi)_5合金相结构和充放电循环性能的影响

研究了微量 Ｔｉ在 Ｍｌ（ＮｉＣｏＭｎＴｉ）５合金中的作用．结果表明,在铸态条件下,Ｔｉ几乎全部以 ＴｉＮｉ３第二相的形式在晶界析出,退火处理后 ＴｉＮｉ３相消失,但 ＳＥＭ和 ＥＤＳ表明 Ｔｉ取代了 ＡＢ５型化合物中 Ａ侧的稀土 Ｍｌ;而不是 Ｂ侧的 Ｎｉ．Ｔｉ在 Ａ侧的取代量以 ５％为宜．此时合金在铸态和退火态的放电容量都在 ３１０ ｍＡ·ｈ／ｇ以上．进一步提高取代量虽然会改善循环稳定性,但大大降低了放电容量．     

汽车和战车中用钛的动向

详细研究了通过机械合金化（ＭＡ）方法制备的Ｍｇ５０Ｎｉ５０－ｘ－ｙＭｘＮｙ（Ｍ，Ｎ＝Ａｌ，Ｃｏ和Ｓｉ）系列非晶态贮氢合金的电化学特性。结果表明，该系列ＭＡ非晶合金的电化学活化容易，电化学容量高，其中Ｍｇ５０Ｎｉ５０合金的最大容量达５００ｍＡ·ｈ／ｇ，约为晶态合金的１０倍；但是它们的化学稳定性较差，容量的循环衰减速率达（１０～６０）ｍＡ·ｈ／ｇ·ｃｙｃｌｅ。通过ＸＲＤ分析，证实Ｍｇ－Ｎｉ基合金的性能衰退是由于其中的Ｍｇ在碱性溶液中被氧化所引起。     

热处理对Ml(NiCoMnAl)_(4.76)合金的电化学性能的影响

研究了热处理对 Ml (Ni Co Mn Al) 4 .76合金电化学性能的影响。结果表明 :在 1 1 73K～ 1 373K下适当的热处理可以显著提高贮氢合金电极的放电容量和高倍率放电性能 ;铸态合金的放电容量为 31 0 Ah/kg,放电电流密度 id=30 0 A/kg时 ,高倍率放电率 H RD30 0 =91 % ,id =1 2 0 0 A/kg时 ,H RD12 0 0 =35% ;经 1 1 73K,1 0 h热处理的合金容量提高到 32 7Ah/kg,H RD30 0 提高到 97% ;经 1 1 73K,3h热处理的合金容量为 2 99Ah/kg,H RD30 0 提高到 98% ,H RD12 0 0 提高到 65% ;随热处理温度的升高和时间的延长 ,导致合金电极的放电容量和高倍率放电性能下降。     

(La_xCe_(1-x))_(0.9)(PrNd)_(0.1)(NiCoMnAl)_5贮氢合金结构和电化学性能的研究

研究了四元混合稀土（Ｌａ_ｘＣｅ_(１－ｘ)）０．９（ＰｒＮｄ）０．１（ＮｉＣｏＭｎＡｌ）_５（ｘ＝０．４～０．９）贮氢合金中Ｌａ, Ｃｅ的不同含量和比例对合金结构和电化学性能的影响。结果表明：合金晶胞的ａ轴和晶胞体积随Ｌａ含量ｘ的增加而增大,而 ｃ 轴则在小幅度内波动;合金电极的最大放电容量随 ｘ的增加而增大,并在 ｘ＝０． ９０时达到最大值（３２８． ９ ｍＡｈ／ｇ）,但平均每循环容量衰减率提高,充放电循环稳定性下降。     

Assessment of intergranular corrosion (IGC) in 316(N) stainless steel using electrochemical noise (EN) technique

In the present work, an attempt was made to demonstrate the use of electrochemical noise (EN) technique in assessment of intergranular corrosion (IGC) in 316(N) stainless steel (SS). Degree of sensitization (DOS) in the specimens aged at 923 K for 24, 40, 50 and 100 h was determined using double loop electrochemical potentiodynamic reactivation (DLEPR) technique. Immediately after applying a prior preconditioning treatment, current and potential noise measurements were made. The DOS was determined from standard deviation of current noise (σ_I) versus time plot and it was found to bear a good correlation with the values obtained by DLEPR. Shot noise analysis of the EN data confirmed the above results.     

Coprecipitation thermodynamics of iron(II-III) hydroxysulphate green rust from Fe(II) and Fe(III) salts

Iron(II-III) hydroxysulphate GR(SO₄²⁻) was prepared by precipitating a mixture of Fe(II) and Fe(III) sulphate solutions with NaOH, accompanied in most cases by iron(II) hydroxide, spinel iron oxide(s) or goethite. Its [Fe(II)]/[Fe(III)] ratio determined by transmission Mössbauer spectroscopy was 2±0.2, whatever the initial [Fe(II)]/[Fe(III)] ratio in solution. Proportion of Fe(OH)₂ increased when the initial [Fe(II)]/[Fe(III)] ratio increased, whereas proportion of α-FeOOH or spinel oxide(s) increased when this ratio decreased. GR(SO₄²⁻) is metastable vs. Fe₃O₄ except in a limited domain around neutral pH. Precipitation from solutions containing both Fe(II) and Fe(III) dissolved species seems to favour GRs formation with respect to stable systems involving iron (oxyhydr)oxides.     

The effect of glow discharge plasma on the surface properties of Poly (ethylene terephthalate) (PET) film

In the present work, Poly (ethylene terephthalate) films have been exposed to glow discharge air plasma to improve their surface properties for technical applications. Surface energy values have been estimated using contact angle value for different exposure times and different test liquids. Surface composition and morphology of the films were analyzed by XPS and AFM. Crystallinity of the plasma treated samples were studied by XRD analysis. The improvement in adhesive strength was studied by measuring T-peel strength and lap shear strength tests. It was found that the plasma treatment modified the surfaces both in chemical composition and morphology. Change of chemical composition made the polymer surfaces to be highly hydrophilic, which mainly depends on the increase in oxygen-containing groups. The AFM and XRD observation showed that the surface roughness and crystallinity of the PET film increased due to plasma treatment.     

Galvanic corrosion of polyacrylnitrile (PAN) and pitch based short carbon fibres in polyetheretherketone (PEEK) composites

When an electric current is conducted through a short fibre reinforced polyetheretherketone composite, being in contact with a stainless steel electrode, carbon fibre corrosion occurs. Surface analysis shows that structural defects range from debonding events and fibre cracking in the early stage of the corrosion process to the final disintegration of the fibre. The extent of fibre corrosion is quantified by atomic force microscopy, and the influence of fibre type, fibre volume content and the aqueous medium on the fibre corrosion is reported. Overall, polyacrylnitrile based fibres have a higher corrosion resistance than pitch based ones.     

Electrochemical etching of AA5083 aluminium alloy in trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ionic liquid

Trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ([P_6,6,6,14][NTf₂]) ionic liquid is shown to react with AA5083 aluminium alloy under a two-step anodic polarisation, leading to partial passivation of the surface. Surface characterisation established that an electrochemical etching process had occurred, comparable to acid etching of aluminium. Energy dispersive X-ray spectroscopy (EDXS) and X-ray photoelectron spectroscopy (XPS) results indicated that magnesium de-alloyed from Mg₂Si intermetallic particles and metal fluorides were deposited onto the remaining Mg₂Si sites, leading to a decrease in the anodic corrosion kinetics (to one third of that of the control) as well as a 100 mV vs. SCE increase in the corrosion and pitting potentials.     

Corrosion behavior of Cr electrodeposited from Cr(VI) and Cr(III)-baths using direct (DCD) and pulse electrodeposition (PED) techniques

A comparison was made between the electrochemical corrosion behaviors of chromium deposited from hexavalent [Cr(VI)] and trivalent [Cr(III)] chromium baths using direct current (DCD) and pulse electro deposited (PED) techniques. Chromium coatings were deposited on mild-steel (MS) substrate. The corrosion behavior of both DCD and PED chromium from Cr(VI) and Cr(III)-baths in 3.5%NaCl solution was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results indicated that PED chromium from Cr(VI) and Cr(III)-baths have higher charge-transfer resistance R_ct and very low I_corr than that of DCD chromium on mild-steel substrate.     

Solution chemistry of Mo(III) and Mo(IV): Thermodynamic foundation for modeling localized corrosion

To investigate the behavior of molybdenum dissolution products in systems that approximate localized corrosion environments, solubility of Mo(III) in equilibrium with solid MoO₂ has been determined at 80 °C as a function of solution acidity, chloride concentration and partial pressure of hydrogen. The measurements indicate a strong increase in solubility with acidity and chloride concentration and a weak effect of hydrogen partial pressure. The obtained results have been combined with literature data for systems containing Mo(III), Mo(IV), and Mo(VI) in solutions to develop a comprehensive thermodynamic model of aqueous molybdenum chemistry. The model is based on a previously developed framework for simulating the properties of electrolyte systems ranging from infinite dilution to solid saturation or fused salt limit. To reproduce the measurements, the model assumes the presence of a chloride complex of Mo(III) (i.e., MoCl²⁺) and hydrolyzed species (MoOH²⁺, Mo(OH)₂⁺, and Mo(OH)₃⁰) in addition to the Mo³⁺ ion. The model generally reproduces the experimental data within experimental scattering and provides a tool for predicting the phase behavior and speciation in complex, concentrated aqueous solutions. Thus, it provides a foundation for simulating the behavior of molybdenum species in localized corrosion environments.     

混合稀土贮氢合金(Ml)_x(Ni_(3.8)Co_(0.75)Mn_(0.4)Ti_(0.05))相结构与性能的研究

对 (Ml) x(Ni3.8Co0 .75Mn Ti0 .0 5)合金 (x =0 .90～ 1 .1 0 )的相结构 ,热力学性能及合金电极的充放电性能进行了研究。结果表明 :在 x <1 .0 0的成分范围内 ,合金保持单一的 La Ni5相 ;当 x≥ 1 .0 0时 ,合金中析出多种第二相 ,且总量随 x的增加而增多。随着 x的增加 ,合金的晶胞体积及氢化物生成焓 (-ΔH )增大 ,吸放氢平台压力降低 ,宽度增加。合金的最大放电容量在 x =1 .0 0 时达到最大值 (30 7.7m Ah/g)。x <1 .0 0 合金的循环稳定性优于 x≥ 1 .0 0 合金。     

Ion implantation studies of (SN)x and (CH)x

We report the results of the initial investigation of the application of ion implantation for the “doping” of the electroactive polymers, (SN)_x and (CH)_x. Increases in conductivity have been measured for some (CH)_x samples after being implanted. Evidence for the formation of a discrete chemical species has been observed in the case of (CH)_x implanted with Br⁺ ions. Advantages and drawbacks associated with this technique are discussed.     

Synthesis and properties of μ-cyano(phthalocyaninato)-rhodium(III)

This contribution reports on the synthesis of μ-cyano(phthalocyaninato)rhodium(III), [PcRhCN]_n (1), by splitting off potassium cyanide from potassium(dicyano)phthalocyaninatorhodium(III), K[PcRh(CN)₂] (2). Monomeric complexes, PcRh(L)CN (7), were formed when [PcRhCN]_n (1) was treated with base molecules L, such as n-butylamine and pyridine. All compounds were characterized by IR, far-IR spectroscopy, thermal and elemental analyses, and partly by UV, ¹H-NMR and FD (field desorption) mass spectroscopy. The undoped polymer [PcRhCN]_n (1) exhibits a d.c. dark conductivity of 4 × 10^?4 S/cm, which was diminished by eight orders of magnitude when the polymeric structure was decomposed by treatment with a competing ligand.