多弧离子镀Ti(C,N)/TiN多元多层膜研究

在LF6防锈铝的基体上采用多弧离子镀技术沉积了Ti(C，N)／TiN／Ti(C，N)/TiN／TiN(C，N)／TiN六层多元多层膜，并对其组织结构与性能进行了研究。结果表明：多元多层膜表面膜层均匀，未出现龟裂现象；膜与基体之间形成了纳米级厚度的Al3Ti新相层，说明膜与基体间的结合存在化学键合，结合强度良好，划痕临界载荷达79N。显微硬度达HV0．11911．0，与基体相比，其表面显微硬度提高了近20倍，耐磨性提高了10倍以上，但摩擦因数较高(μ＝0．66)，粘着对偶件磨损，使对偶件磨损较严重。     

类金刚石梯度膜的微观力学性能研究

采用非平衡磁控溅射及等离子体源离子混合注入方法在奥氏体不锈钢1Cr18Ni9Ti基体上制备N／TiNi/Ti(N,C)/DLC梯度涂层，采用原子力显微镜等手段观察分析梯度膜的显微组织与相组成，同时采用纳米压入技术评定膜层的力学性能。实验结果表明，采用此方法制备的金刚石膜组织致密，性能良好。     

纳米级类金刚石梯度膜机械特性研究

本文采用非平衡磁控溅射及等离子体源离子混合注入方法在奥氏体不锈钢1cr18N9Ti基体上制备N/TiN/Ti(N,C)/DLC梯度涂层。采用原子力显微镜（AFM）及喇曼光谱等手段观察分析梯度膜的显微组织与相组成，同时采用了纳米压入技术评定膜层的力学性能。实验结果表明，采用此方法制备的金刚石膜组织致密，性能良好。     

纳米级类金刚石梯度膜机械特性研究

本文采用非平衡磁控溅射及等离子体源离子混合注入方法在奥氏体不锈钢 1Cr18N9Ti基体上制备N TiN Ti(N ,C) DLC梯度涂层。采用原子力显微镜 (AFM)及喇曼光谱等手段观察分析梯度膜的显微组织与相组成 ,同时采用了纳米压入技术评定膜层的力学性能。实验结果表明 ,采用此方法制备的金刚石膜组织致密 ,性能良好     

用镍基薄带钎料真空熔结Cr3C2-NiCr涂层的组织和性能

提出了一种采用薄带钎料进行真空熔结的新方法，用BNi-2薄带钎料粘贴在Cr3C2-NiCr预置层表面进行了真空熔结处理，对涂层的组织和微动磨损性能进行了研究。结果表明，真空熔结涂层组织致密，涂层与基体、涂层内部硬质相与粘结相之间可形成良好的冶金结合。涂层主要由Cr3C2，Cr7C3，Cr23C6，Ni的硼化物、Cr的硼化物等硬质相和镍基固溶体韧性相组成。基于致密的组织、良好的结合和硬质相强化，真空熔结Cr3C2-NiCr涂层的抗微动磨损性能明显优于等离子喷涂Cr3C2-NiCr涂层和1Crl8Ni9Ti不锈钢。     

钛合金表面TiN/CrN纳米多层薄膜的制备及耐磨、耐腐蚀性能

纳米多层涂层在钛合金磨蚀防护领域具有重要应用。本实验采用电弧离子镀膜技术,在TC4钛合金表面制备TiN、CrN及TiN/CrN纳米多层涂层,分别对涂层的微观形貌、相结构、硬度、膜基结合力、摩擦磨损性能和电化学腐蚀性能进行了系统研究。结果表明,TiN/CrN纳米多层涂层沿(111)面择优取向生长,结构致密,调制周期为25 nm,硬度为24 GPa,多层结构打断柱状晶生长,有效阻断腐蚀介质扩散到基体的通道。相较于TiN、CrN涂层,TiN/CrN膜基结合力有显著提高。TiN/CrN涂层磨损率为3.44×10~(-7)mm~3·N~(-1)·m~(-1),自腐蚀电流密度(i_(corr))为3.16×10~(-8)A/cm~2,显著低于TC4及TiN、CrN涂层,说明TiN/CrN纳米多层涂层的耐磨/耐腐蚀性能优于TiN、CrN单层涂层,并能对TC4基体在摩擦腐蚀环境下提供更好的防护。     

真空阴极离子镀法制备Ti/TiN/Zr/ZrN多层膜

过去,在不锈钢上沉积10μm以上多元多层软硬交替Ti/TiN/Zr/ZrN厚膜用以提高材料耐腐蚀性能的报道不多.采用阴极电弧离子镀结合脉冲偏压的方法制备了厚度选15 μm的Ti/TiN/Zr/ZrN多层膜.运用扫描电镜(SEM)、X射线衍射(XRD)、显微硬度计、划痕仪等考察了多层膜的形貌、厚度、相组成、硬度以及膜/基结合力,并利用电化学方法评价了基体、单层TiN薄膜以及多层膜的电化学腐蚀性能.结果表明:制备的Ti/TiN/Zr/ZrN多层膜界面明晰、结构致密、晶粒细小;膜/基结合力大于70 N,显微硬度达28 GPa;多层膜比单层TiN膜在提高1Cr11Ni2W2MOV基体的抗腐蚀能力方面具有更显著的作用.     

Ti/TiN纳米多层薄膜改性层在Troyde s模拟体液中的抗腐蚀性能

用电弧离子镀设备，在医用不锈钢基体上沉积Ti／TiN纳米多层薄膜，考察薄膜在Troyde’s模拟体液中的抗腐蚀性能．结果表明，在中性与酸性模拟体液中316L Ti／TiN(45／45s)体系的击穿电位分别提高5倍和2倍，腐蚀电流密度为基体的1／8与1／3，明显降低发生局部腐蚀的敏感性，但滞后环的出现说明薄膜被击穿后自修复能力较差．分析说明薄膜的纳米多层结构与纯Ti层的存在可有效提高医用不锈钢在Troyde’s模拟体液中的抗点蚀能力．     

柱弧离子镀制备Ti/TiN/Ti(N,C)/TiC黑色硬质膜

利用自制的柱弧离子镀膜机，在不同硬度基体上制备了Ti／TiN／Ti（N，C）／TiC多层复合膜。膜呈深黑色，反射率小于14％，亮度值L^＊小于43，沉积速率约为0．78μm/h，表面分布较多液滴缺陷。膜的力学性能测试受基体硬度和膜层厚度影响较大，基体越硬、膜层越厚，膜的硬度以及与基体的结合力测试结果越大。YW2硬质合金基体上制备0．82μm的黑色硬质膜显微硬度Hv（25g）=3229，结合力为26．70N。该设备和工艺已成功应用于工业生产。     

TC4钛合金表面电弧离子镀TiN/CrN纳米多层薄膜研究

用电弧离子镀技术在TC4钛合金基体上通过改变偏压制备了4组TiN/CrN薄膜,对薄膜的表面形貌、厚度、相结构、硬度、膜基结合力和摩擦系数等组织、性能进行了测试表征。结果表明,薄膜是由TiN相和CrN交替叠加构成的纳米多层薄膜,薄膜的调制周期为60 nm,总的厚度约为480 nm。与基体钛合金相比,镀膜后样品的表面性能与偏压幅值密切相关并有显著提高:显微硬度从基体的3 GPa提高到16.5~24.7 GPa;摩擦系数从基体的0.35大幅度降低到0.14~0.17;薄膜与基体结合牢固,膜基临界载荷在60~80N之间。经电弧离子镀TiN/CrN纳米多层薄膜处理后,TC4钛合金可以满足沙粒和尘埃磨损条件下的耐磨性能要求。     

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.……     

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.     

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...     

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.……     

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.     

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.     

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 ...