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131.
E.M.K. Hillier 《Corrosion Science》2004,46(3):715-727
Slow strain rate tests were performed on quenched and tempered AISI 4340 steel to measure the extent of hydrogen embrittlement caused by electroplating with zinc-cobalt alloys. The effects of bath composition and pH were studied and compared with results for electrodeposited cadmium and zinc-10%nickel. It was found that zinc-1%cobalt alloy coatings caused serious hydrogen embrittlement (EI 0.63); almost as severe as that of cadmium (EI 0.78). Baking cadmium plated steel for 24 h at 200 °C gave full recovery of mechanical properties but specimens plated with zinc-1%cobalt and then baked still failed in 89% of the time of unplated controls. It was shown that hydrogen uptake and embrittlement could be controlled by depositing thin layers of cobalt or nickel at the steel/coating interface. For example, the least embrittlement was caused by zinc-10%nickel (EI 0.037) due to a nickel rich layer with very low hydrogen diffusion coefficient that formed during the initial stages of electroplating. Similarly, a 0.5 μm nickel layer was effective in lowering the embrittlement caused by zinc-1%cobalt to that of zinc-10%nickel. Furthermore, a 0.5 μm cobalt layer deposited before a zinc-1%cobalt coating gave virtually 100% recovery of mechanical properties after baking. 相似文献
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M.L. Zhang Y.D. Yan Z.Y. Hou L.A. Fan Z. Chen D.X. Tang 《Journal of Alloys and Compounds》2007,440(1-2):362-366
Mg–Li alloys have been prepared by electrolysis in a molten salt electrolyte of 50% LiCl–50% KCl (mass%) at low temperature of 420–510 °C. The effects of electrolytic temperature and cathodic current density on alloy formation rate and current efficiency were studied. For the deposition of metallic lithium on the cathode consisting of solid Mg and liquid Mg–Li, both electrolytic temperature and cathodic current density have no obvious influence on current efficiency; while for the deposition of metallic lithium on the solid magnesium cathode, both electrolytic temperature and cathodic current density greatly affect alloy formation rate and current efficiency. The optimum electrolysis condition is—molten salt mixture, LiCl:KCl = 1:1 (mass%), electrolytic temperature: 480 °C, cathode current density: 1.13 A cm−2. Mg–Li alloys with low lithium content (about 25 wt% Li) were prepared via electrolysis at low temperature following by thermal treatment at higher temperature. 相似文献
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The phase diagram of the Ti–In system was determined using DTA, XRD and EDX analyses. The existence of the phases Ti2In5 [Mn2Hg5 type structure, space group P4/mbm, a=0.99995(3), c=0.29960(2) nm] and Ti3In [Ni3Sn type structure, space group P63/mmc, a=0.5978(1), c=0.4812(1) nm] was confirmed. The phase previously labeled Ti3In2 was found to exist in a narrow homogeneity region near Ti56In44. Rietveld refinement of the XRD powder pattern yielded solutions compatible with a Cu3Au-type or a BiIn-type crystal structure, but not with a CuAu-type crystal structure. Furthermore, at 38.5 at.% In, a new phase was observed having a γ-brass related crystal structure [Ti8In5, space group
, a=0.99578(6) nm]. The intermetallic phases were formed by a cascade of peritectic reactions ending in a eutectic at >99 at.% indium between Ti2In5 and (In) at 0.4 K below the melting temperature of pure indium. 相似文献
139.
In this article, molybdenum particles were plasma sprayed on copper, zirconia, and glass substrates. The impact of the molten
particles was monitored using a fast two-color optical fiber pyrometer focused on a small spot on the substrate surface. The
apparent duration of the flattening process and the cooling speed, both determined from the pyrometer signals, were found
to depend on the substrate conditions and to vary with coating thickness. The substrate material and its roughness were also
found to influence the texture in the sprayed coatings. Furthermore, a transient thermal flow numerical model was used to
compute reliable thermal histories of the impinging particles and the underlying lamellae, the interfacial thermal resistance
being determined by comparison of experimental thermograms with computed ones. 相似文献
140.
用液态快淬法制备非晶合金条带时,通过加入15—30%的B与Si等类金属含量是形成非晶状态的必要条件。但是,由于Si与B等类金属元素的加入,使非晶态合金的磁性受到明显的影响。本文实验研究了Si与B含量间的相对变化对(Fe_(80)Ni_(20))_(78)Si_(22-x)B_x合金的饱和磁矩、平均原子磁矩与Curie温度的影响关系。利用电子转移模型与分子场近似理论定性的解释了(Fe_(80)Ni_(20))_(78)-Si_(22-x)B_x合金的磁矩(M_s)与Curie温度(T_c)随 相似文献