Ternary rare earth germanium systems with Cu and Ag—A review and a contribution to their assessment

Constitutional data of the R-(Ag, Cu)-Ge systems, with R=rare earth, are summarized and discussed. Crystal structures of the phases formed in the binary boundary systems and in the ternary systems are assessed, and the phase equilibria observed in the reported ternary systems are reviewed with special attention to the isothermal sections (generally at 400 or 600 °C) of the phase diagrams. Some regularities observed in the trends of the constitutional properties of the ternary R-(Ag, Cu)-Ge alloys are briefly described.     

Ternary rare earth germanium systems with Cu and Ag—A review and a contribution to their assessment

Constitutional data of the R-(Ag, Cu)-Ge systems, with R=rare earth, are summarized and discussed. Crystal structures of the phases formed in the binary boundary systems and in the ternary systems are assessed, and the phase equilibria observed in the reported ternary systems are reviewed with special attention to the isothermal sections (generally at 400 or 600 °C) of the phase diagrams. Some regularities observed in the trends of the constitutional properties of the ternary R-(Ag, Cu)-Ge alloys are briefly described.     

Oxide coatings modified with transition and rare-earth metals on aluminum and their activity in CO oxidation

Oxide catalysts, which, in addition to Al₂O₃ + SiO₂, contain from one (Ni) to four oxides or compounds of transition metals (Ni, Cu, Mn, and Co) and oxides or compounds of rare-earth elements (Ce, La), are produced on D16 aluminum alloy by plasma electrolytic oxidation combined with impregnation and subsequent annealing. The composites formed begin to catalyze the CO oxidation in a temperature range of from 100 to 300°C. The catalysts used can be arranged in the following series of decreasing catalytic activity: Ni-Cu-Mn-Co-Ce > Ni-Cu-Mn-Co-Ce-La ≈ Ni-Cu-Mn-Co > Ni-Cu-Mn > Ni-Cu > Ni. Oxygen compounds of Cu⁺, Cu²⁺, Mn⁴⁺, Co³⁺, Ce³⁺, and Ce⁴⁺, which seem to determine the catalytic properties of the oxide systems studied, are found on the surface and in the subsurface layer with a total thickness of ～6 nm of the most active Ni-Cu-Mn-Co-Ce catalyst.     

Organic acid vapours and their effect on corrosion of copper: a review

Abstract

Carboxylic acids of low molecular weight, such as formic, acetic, propionic and butyric acids, as well as other acids (n-pentanoic, hexanoic, heptanoic, etc.), are present in rain, snow, clouds and particulate matter. They contribute about 16–36% of rain acidity. It is estimated that ～64% of formic acid and ～88% of acetic acid are in the vapour phase. Carboxylic acids are produced by the combustion of biomass, and analyses of the smoke from fire events reveal concentrations of about 300–500 ppb for formic acid and 3000–5000 ppb for acetic acid. Industrial emissions of carboxylic acid are produced by plants processing biological materials, such as food, paper, wood, etc. Acetic acid vapours are found in several industrial atmospheres. Vinegar is one important source of acetic acid vapours in food processing plants. The present review shows that for copper specimens exposed to organic vapours for 21 days at 100% relative humidity (RH) and a contaminant level in the range of 10–300 ppm, the relative aggressiveness of these acids is (from high to low): acetic>formic>butyric>propionic.     

Addendum: Ternary and higher order aluminum phase diagram updates

Phase Diagram Evaluations

Addendum: Ternary and higher order aluminum phase diagram updates     

High-temperature strength of silicon carbide ceramics sintered with rare-earth oxide and aluminum nitride

The effect sintering additives comprising AlN and Re₂O₃ (Re = Sc, Lu, Yb, Er and Y) in a 2:3 molar ratio on the high-temperature strength of liquid phase-sintered and subsequently annealed SiC ceramics was investigated. Clean SiC–SiC boundaries and clean SiC-junction phase boundaries without the amorphous inter-granular phase (IGP) were observed in Sc₂O₃-, Lu₂O₃- and Yb₂O₃-doped SiC ceramics. Clean SiC–SiC boundaries and SiC-junction phase boundaries with the amorphous IGP were also observed in Er₂O₃-doped SiC ceramics. The amorphous IGP was present in both SiC–SiC and SiC-junction phase boundaries in Y₂O₃-doped SiC ceramics. The high-temperature strength was not dependent on the crystalline nature of the IGP and junction phases, but was dependent on the chemistry of these phases. Lu₂O₃-, Er₂O₃-, Sc₂O₃- and Y₂O₃-doped SiC maintained their room-temperature strengths up to 1600, 1500, 1400 and 1400 °C, respectively. However, Yb₂O₃-doped SiC manifested a drastic degradation in strength at 1400 °C. Thus, clean boundaries and/or crystallization of junction phases did not always lead to the hoped-for increase in strength at temperatures above 1400 °C.     

BAO光度法测定铝及铝合金中微量铜

研究了在弱碱性介质中,双乙醛草酰二腙(BAO)与铜形成稳定的紫色络合物的反应条件,通过对测定波长、发色酸度、试剂用量、络合物稳定性、共存离子干扰等试验,建立了BAO光度法测定铝及铝合金中微量铜的新方法.方法检出限为0.0003%,线性范围为0～20μg/50mL,增量回收在96%～101%,具有操作简单,选择性好,精度高的特点,测量结果满意.     

Solutions of aluminum in liquid lithium: contribution to the Li-Al phase diagram

The Li-rich (up to 15.8 at.% Al) region of the Li-Al phase diagram has been determined by resistivity-temperature and thermal analytical methods. The eutectic lies at 180.5 ± 0.4 °C (453 ± 0.4 K) and 0.57 ± 0.04 at.% Al. The hypereutectic liquidus rises smoothly from the eutectic in two sections corresponding to the crystallization of Li₉Al₄ and Li₃Al₂, respectively. The peritectic decomposition of Li₉Al₄ into Li₃Al₂ and a liquid of composition of 9.2 ± 0.3 at. % Al occurs at 347 ± 4 °C. The hypoeutectic liquidus could not be differentiated from the eutectic horizontal. The depression of the freezing point of Li on adding Al is extremely small, suggesting significant positive deviations from ideality. The calculated γ_Li value at the eutectic composition is 1.0051.     

A contribution to collision-free trajectory planning for handling systems in varying environments

In highly flexible and complex handling systems the risk of collision of moving machine components is continuously increasing. When, for example, several robots share the same workspace and the environment in the workspace is changing due to the operation, the robot trajectories can no longer be planned in advance without the risk of collision. The objective of this paper is the collision-free motion planning of handling system manipulators from the start to the end position within a changing environment. For this purpose, the trajectories on the control system have to be planned during the operating time most efficiently depending on the current state of a varying environment. This paper describes a new approach for trajectory planning based on curve shortening flows combined with potential fields. The functional capability of the method will be demonstrated initially on a simple robot kinematics with two degrees of freedom.     

Inhibition of copper corrosion by 1,2,3-benzotriazole: A review

Benzotriazole (BTAH) has been known for more than sixty years to be a very effective inhibitor of corrosion for copper and its alloys. In spite of numerous studies devoted to the investigation of BTAH action, the mechanism of its action is still not completely understood. The aim of this review is to summarize important work in the field of BTAH as a copper corrosion inhibitor, from the early discoveries to the present time. Special attention is given to the BTAH surface structure. The disagreement between findings and mechanisms is discussed.     

A comparison of the mesomechanism of dynamic deformation between copper and aluminum

In this paper, a comparison of the mesomechanism of dynamic deformation between Cu alloy and Al alloy is made. It is shown that, during dynamic deformation, two effects occur, one being a hardening effect by the increasing of dislocations, the other being a softening effect by the nucleation, growth and coalescence of microvoids. Fracture is due to the coalescence of a large amount of voids. It is shown also that the nucleation of microvoids is due to fault energy and second-phase particles. The nucleations of Al alloy rely on the second-phase particles and the nucleations of Cu alloy rely on the second slipping of dislocation by lower fault energy.     

Fujihokka: A high-emissivity approach to aluminum anodizing

Aluminum treated with the new process offers obvious benefits in energy efficiency and exceptionally uniform temperature distribution for applications in heating, cooling, and drying. In addition, it shares the light weight, excellent corrosion, and abrasion resistance of conventional anodizing. Depending on the final application, the surface can be further enhanced with impregnation or further coating with Teflon and lacquers.     

Material flow and core/multi-shell structures in a friction stir welded aluminum alloy with embedded copper markers

The objective of this study was to reveal the material flow and temperature distribution in a thick aluminum plate during friction stir welding and examine the subsequent microstructural change with particular attention to the reaction between copper marker and aluminum matrix. It is shown that the material adjacent to the threaded pin was transported from the top to bottom non-symmetrically, and then was forced to move upwards at a small distance from the pin due to the constraint of an extrusion-die-like configuration. The interaction between the copper marker and aluminum matrix led to the formation of (i) a unique core/multi-shell microstructure consisting of copper core, inner shell of AlCu and outer shell of Al₂Cu, and (ii) a composite band containing uniformly-distributed Al₂Cu particles with refined grains due to the lower stacking fault energy of copper and the pinning role of Al₂Cu particles.     

Physical simulation of alloying between copper and aluminum on electrode tip for resistance spot welding of 5A02 aluminum alloy

The application of aluminum alloy in the automotive and aviation fields is impeded by the wear and life of electrode for resistance spot welding (RSW). The alloying interaction between the copper elect...     

Al-Si-Cu合金粉末扩散钎焊Al/Cu接头组织及性能

采用Al-Si-Cu合金粉末扩散钎焊铝铜异种金属,采用SEM,EDS和XRD分析接头微观组织结构,结合三元相图分析了接头形成机理,最后检测了接头力学性能.结果表明,在连接温度530℃,保温时间60 min,压力为1MPa时可形成均匀致密的接头,接头中存在大量条状和鱼骨状的Al-Si-Cu共晶组织,中间层与两母材结合界面处的组织结构不同,在靠近铜侧界面存在三种层状金属间化合物,其成分依次为Cu₃Al₂,CuAl和CuAl₂,在靠近铝侧界面存在一个扩散区,没有形成层状金属间化合物.接头的抗剪强度随保温时间的变化而变化,在保温60 min时达到35 MPa.     

Al-Si-Cu合金粉末扩散钎焊Al/Cu接头组织及性能

采用Al-Si-Cu合金粉末扩散钎焊铝铜异种金属,采用SEM,EDS和XRD分析接头微观组织结构,结合三元相图分析了接头形成机理,最后检测了接头力学性能.结果表明,在连接温度530℃,保温时间60 min,压力为1MPa时可形成均匀致密的接头,接头中存在大量条状和鱼骨状的Al-Si-Cu共晶组织,中间层与两母材结合界面处的组织结构不同,在靠近铜侧界面存在三种层状金属间化合物,其成分依次为Cu₃Al₂,CuAl和CuAl₂,在靠近铝侧界面存在一个扩散区,没有形成层状金属间化合物.接头的抗剪强度随保温时间的变化而变化,在保温60 min时达到35 MPa.     

Atoms to autos: A multi-scale approach to modeling aluminum deformation

A multi-scale, computational design approach for aluminum sheet alloys, which includes key inputs from the electronic, atomistic, microstructural, and continuum length scales, is reviewed within the context of room and elevated temperature forming. Specific examples, which are aimed at improving aluminum sheet materials for automobile components, include prediction of flow curves from tensile testing, forming limit diagrams, and component forming.     

2012年氟化铝市场回顾及2013年展望

2012年中国氟化铝产能继续增长,增幅15.27%。产能利用率48.56%,与2011年基本持平,产能过剩严重。全年产量与需求量基本平衡。2012年氟化铝价格宽幅波动,高点到低点跌幅达38%。行业内大多数企业亏损。预计2013年全球经济缓慢回升,氟化铝供应和需求均保持增长趋势。在成本支持下,预计2013年氟化铝价格会继续上涨,但受产能过剩制约,上涨幅度不会太大。