黄铜腐蚀速度与Cl-浓度的关系

为了定量确定黄铜腐蚀与Cl浓度的关系,对HSn70-1A、HAl77-2A两种黄铜进行静态挂片浸泡试验,并根据试验数据拟合了关系曲线.试验结果表明,在含Cl-的水溶液中HSn70-1A较HAl77-2A腐蚀严重;HSn70-1A、HAl77-2A的腐蚀速度随Cl-浓度的变化均呈三次方关系,区别在于HAl77-2A的腐蚀速度随Cl-浓度的变化较为平缓,而HSn70-1A的腐蚀速度随Cl-浓度的变化较为显著,HSn70-1A的腐蚀对Cl-较HAl77-2A更为敏感.     

表面膜对含硼HA177-2黄铜腐蚀的影响

测定了成膜前后加硼HA177－2铝黄铜的静态腐蚀速率、脱锌系数和电化学行为.用离子探针（SIMS）分析了铝黄铜表面膜的组成和深度分布．结果表明：表面膜中富集Zn、AI、B；退火形成的表面膜提高了铝黄铜在中性介质中的耐蚀性，但不能提高它在酸性介质中的耐蚀性能．     

实海暴露双相黄铜脱锌的扩散机制

研究了不同相结构双相黄铜的扩散机制,计算出黄铜在实海暴露过程中锌在β相的体扩散系数和α相晶界的扩散系数.证实了合金元素Sn对黄铜脱锌的抑制作用,揭示出脱锌深度与腐蚀速度之间的相关性.     

黄铜脱锌腐蚀机理的研究进展

从黄铜脱锌的现象,特征及其影响因素出发,对黄铜脱锌的优先溶解机制、溶解－再沉积机制,双空位机制和渗流机制等进行了描述,结合作者在微量元素对铜合金组织和性能影响方面的实验研究工作,讨论了了加硼及加砷加硼在黄铜脱锌腐蚀过程中的作用和机制,进而提出了黄铜脱锌的渗流学晶体模型,并对双空位的来源及砷硼的最佳含量及协同作用过程和机理作用了分析论证,在最佳硼砷含量条件下硼和砷以Ａｓ－Ｂ对作用凶制了黄铜脱锌腐蚀的     

BTA与KI对天然海水中黄铜复配缓蚀机理的XPS和EDS谱分析

将海水用于冷却对管道和换热设备有腐蚀。在天然海水中以不同方式添加缓蚀剂苯并三氮唑(BTA)及KI,将黄铜浸泡其中,采用X射线光电子能谱仪(XPS)、扫描电镜(SEM)及其能谱仪(EDS)分析了黄铜腐蚀前后的结构、形貌及成分。结果表明:在同时添加BTA和KI的海水中浸泡后,黄铜表面的Cu2p XPS谱峰向高束缚能区的位置偏移,形成Cu(Ⅰ),黄铜表面膜主要由Cu2O,CuCl,CuI,Cu(Ⅰ)-BTA和ZnO组成;空白海水中的黄铜发生了严重的脱锌腐蚀,Cu富集在金属表面,添加缓蚀剂后,黄铜的脱锌腐蚀得到抑制,且先添加BTA后添加KI的海水中的黄铜显示了更好的抗Cl-侵蚀的能力,I-起到了补膜的作用;在只添加了BTA的海水中的黄铜表面有明显的点蚀坑,在同时加入BTA,KI的海水中的黄铜表面无明显腐蚀,在先后加入BTA,KI的海水中的黄铜表面光亮,腐蚀抑制的效果更明显。     

表面膜对含硼HAl77—2黄铜腐蚀的影响

测定了成膜前后加硼ＨＡｌ７７－２铝黄铜的静态腐蚀速率、脱锌系数和电化学行为，用离子探针分析了铝黄铜表面膜的深度分布。结果表明，表面膜中富集Ｚｎ、Ａｌ、Ｂ；退火形成的表面膜提高了铝黄铜在中性介质中的耐蚀性，但不能提高它在酸性介质性的耐蚀性能。     

双稀土处理液对H62黄铜成膜耐蚀性能的影响

为了提高H62黄铜合金的表面性能,通过正交试验获得了最佳锅、钵双稀土处理液配方。利用硝酸点滴、中性盐雾试验评价了H62黄铜合金钝化膜的耐蚀性能,通过电子探针(EPMA)观测了其表面形态结构及元素分布,利用电化学方法表征了 H62黄铜表面钝化膜在3.5%NaCl溶液中的缓蚀行为,采用XRD对H62黄铜表面钝化膜的成分进行了检测。结果表明:H62黄铜合金由镉、钵双稀土处理液钝化成膜的主要成分为Cu2O,CeO2,La(OH)3,Ce(OH)4;致密的钝化膜耐硝酸点滴时间达到21.98s,在3.5%NaCl溶液自腐蚀电位增加,腐蚀电流降低,腐蚀速度明显降低,耐蚀性能增加,耐中性盐雾性能明显优于鋪单一稀土处理液。     

HMn58—2实海暴露4年的脱锌腐蚀及其机理

对HMn58-2锰黄铜板实海暴露遭受严重脱锌腐蚀,且机械性能遭到破坏的情况。用扫描电镜、金相分析和化学分析的方法进行了研究。得知HMn58-2板在海水中的脱锌是以选择性脱锌为主;而且脱锌是从β相开始,然后蔓延至α相。     

高硼铸钢的研究进展

高硼铸钢是以B为主要合金元素的新型耐磨材料。围绕高硼铸钢组织中的Fe_2B,简单介绍了合金元素对高硼铸钢组织及力学性能的影响。然而,除耐磨以外,高硼铸钢在耐高温熔体(Zn、Al)腐蚀方面也展现出优异的性能。结合笔者已有的研究成果,重点介绍了新型高硼铸钢的耐铝液腐蚀及耐铝液腐蚀-磨损性能,硼化物对改善高硼铸钢的耐铝液腐蚀及耐铝液腐蚀-磨损性能起到了非常重要的作用。富Cr和富Mo的Fe_2B在铝液腐蚀过程中表现出不同的行为:富Cr的Fe_2B与铝液反应生成周期性层片结构,而富Mo的Fe_2B则是发生断裂、剥落;在铝液腐蚀-磨损过程中,初生富Cr的Fe_2B发生Fe元素的优先溶解,之后在磨损的作用下开裂、剥落,但相关机理还需深入研究。最后,对高硼铸钢的研究进行了展望。     

金属喷涂层在海洋环境中的防护性能

对铝、锌、锌-铝、铝-镁-稀土等4种金属喷涂层在东海厦门试验站和南海榆林试验站进行了海水全浸、潮差、飞溅条件下暴露4年的海水腐蚀试验,并对其防护性能进行了讨论。试验结果表明,4种涂层的腐蚀面积比(％)从大到小的顺序为:喷锌>喷铝-镁-稀土>喷铝>喷锌-铝,可见,喷锌-铝/油漆保护涂层体系的抗海水腐蚀性能最优良。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...