纳米Ti-Si-N薄膜的高温热稳定性

用直流等离子体增强化学气相沉积(PCVD)方法在不锈钢基体上制备了Ti-Si-N硬质纳米复合薄膜,研究了Si含量对薄膜硬度的影响及高温退火对薄膜晶粒尺寸及其硬度的影响.结果表明:薄膜的硬度随着Si含量的增加有先增大后减小的趋势,最大硬度可达70 GPa以上.薄膜表现出了较高的热稳定性能,对于晶粒尺寸在4 nm以下的薄膜,Ti-Si-N薄膜的纳米结构和硬度可以维持在1000℃以上.沉积态薄膜的晶粒尺寸是影响薄膜再结晶温度的主要因素.薄膜的高热稳定性是由于沉积过程中发生的自发调幅分解形成了纳米复合结构,偏析使得纳米晶晶界具有强的热力学稳定性.     

沉积位置对脉冲激光沉积纳米Si晶薄膜微观结构的影响

在4.0×10-4Pa的真空条件下,采用脉冲激光烧蚀技术在单晶Si衬底和石英衬底上制备了非晶纳米Si薄膜.在N2气氛下,经过900℃热退火得到纳米Si晶薄膜.采用表面台阶测试仪、扫描电子显微镜、拉曼光谱仪等检测手段对样品不同位置的微观结构进行了表征.测量结果表明制备的纳米Si晶薄膜厚度及其晶粒尺寸分布不均匀,随着测量点与样品沉积中心距离的增加,薄膜的厚度逐渐减小,纳米Si晶粒的尺寸逐渐增大.从脉冲激光烧蚀动力学的角度对实验结果进行了定性的分析.     

基板偏压对Al_(0.3)CrFe_(1.5)MnNi_(0.5)高熵合金氮化物薄膜性能的影响

高熵合金氮化物薄膜性能优异,目前国内对Al0.3Cr Fe1.5Mn Ni0.5高熵合金的研究主要是对块体,对薄膜研究较少。采用直流磁控溅射技术在硅片上沉积了Al0.3Cr Fe1.5Mn Ni0.5高熵合金氮化物薄膜。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、纳米压痕仪等分析了基板偏压对薄膜的晶体结构、溅射效率、硬度和摩擦磨损性能的影响。结果表明:基板偏压为-50 V时,薄膜的晶体结构为面心立方结构(FCC),薄膜截面有明显的柱状结构;随着偏压幅值的增加,衍射峰的强度降低,晶粒尺寸减小,薄膜的溅射效率降低,硬度提高;基板偏压为-150 V时薄膜硬度最高,为13.74 GPa,此时薄膜的抗摩擦磨损性能最好。     

高压扭转制备的Mg-Sm-Ca合金组织演变及时效硬化行为

结合高压扭转(HPT)和热处理工艺研究了Mg-Sm-Ca合金的组织和力学性能的变化.光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、显微硬度计以及X射线衍射仪(XRD)测试的结果表明,高压扭转后成功制备了纳米晶,晶粒尺寸由209μm细化至108 nm,后续时效过程中在1.5 h时达到峰值硬度134HV,约为铸态样品的2倍,与一般冷变形合金不同,组织仍为纳米晶且具有一定的抗回复性和热稳定性,同时引入了大量纳米级析出物.HPT处理后的Mg-Sm-Ca合金具有较强的(0002)基面织构,时效处理对基面滑移有促进作用,时效时间延长会使合金织构变弱.     

脉冲激光烧蚀过程中阻尼系数的角度分布

采用脉冲激光烧蚀(PLA)技术,在半圆环衬底上制备了含有纳米晶粒的硅(Si)晶薄膜。分析了纳米Si晶粒尺寸和阻尼系数随角度和压强的变化关系。使用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和拉曼光谱仪(Raman)对其表面形貌和结构进行了表征。结果表明,在压强一定的情况下,纳米Si晶粒的尺寸和阻尼系数均相对于轴向呈对称分布,并随着偏离轴向角度的增加而减小;同时随着压强增大,晶粒尺寸和阻尼系数在各个角度处的值均增大。     

Si含量对(AlCrTiZrHf)-Six-N高熵薄膜微观结构和力学性能的影响

采用自制的复合靶材,通过直流磁控溅射技术,在单晶Si基片上沉积一系列不同Si含量的(AlCrTiZrHf)-Si_x-N高熵薄膜,并依次采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、高透射电子显微镜(HRTEM)和纳米压痕仪对薄膜进行表征和测试,研究Si含量对其微观结构和力学性能的影响。实验结果显示,(AlCrTiZrHf)N薄膜成柱状晶生长,并具有(111)晶面的择优取向。Si元素的掺入,使得原薄膜的(111)峰消失,(AlCrTiZrHf)-Si_x-N薄膜晶粒得到细化,同时生成网状非晶相,从而形成非晶包裹纳米晶的纳米复合结构。随着Si含量的增加,薄膜力学性能先上升后下降,这种趋势归因于所形成的纳米复合结构,并且当Si含量为8%(体积比)时,薄膜的硬度和弹性模量最高,分别为26.6和250.9 GPa。     

Cu/NbMoTaW纳米叠层材料具有尺寸效应的力学性能及变形机制（英文）

高熵合金(HEA)由于其在恶劣环境中优异的力学性能引起了研究者的广泛关注.我们将高熵合金NbMoTaW引入到纳米叠层材料中,制备出等层厚的Cu/HEA纳米多层膜,综合研究了其具有尺寸效应的力学性能及变形行为.实验表明,Cu/HEA纳米多层膜的硬度随着层厚h的减小而增加,随后在h≤50 nm的区域到达一个平台,而应变速率敏感性出现了一个最大值,这是由于Cu和HEA两相对应变速率敏感性的影响从协同转变为竞争.在层厚较大时,非共格界面导致Cu/HEA多层膜在变形后出现了剪切带,并且软相Cu层主导变形.     

不同厚度聚氯代对二甲苯膜的结晶与性能研究

在真空气相沉积条件下制备厚度分别为0.32μm、2.39μm、7.98μm和17.11μm的聚氯代对二甲苯膜(PC膜),采用X射线衍射仪(XRD)、原子力显微镜(AFM)和纳米压痕仪对不同厚度PC膜的结晶度、表面形貌以及力学性能进行了表征与测试。结果表明,随着成膜厚度的增加,聚氯代对二甲苯薄膜的结晶度提高,表面晶粒尺寸增大,结晶形态更加完整,其表面粗糙度、压入模量和压入硬度呈逐渐增大的趋势。而PC膜表面形貌、力学性能的差异又与结晶度密切相关。     

Fe_(78)B_(13)Si_9纳米晶合金中的 Hall-Petch 关系

采用晶化法由 Fe_(78)B_(13)Si_9非晶态合金条带制备纳米晶合金,测定了纳米晶合金的显微硬度。晶粒尺寸在纳米数量级时,Hall-Petch 关系仍然成立。FeBSi 纳米晶合金的硬度值约为相同成分的粗晶粒状态合金的2倍。位错作用机制仍为强度提高的主要因素。     

氮流量对采用独立钛靶制备的(Ti,Al)N薄膜结构与性能的影响

采用直流反应磁控溅射系统,选择独立Ti靶在3003AlMn合金表面在不同氮流量下制备(Ti,Al)N薄膜,采用扫描电镜、能谱分析、X射线衍射、极化曲线试验、磨损试验、薄膜厚度和显微硬度试验等手段表征了薄膜的沉积速率、化学成分、微结构和力学性能。结果表明,以独立Ti靶在铝衬底表面可以直接生成晶粒尺寸细小与基底结合良好的(Ti,Al)N薄膜,同时可以增加铝合金的表面硬度,提高表面耐蚀性能及表面光泽度。氮流量对(Ti,Al)N薄膜影响显著,氮流量为7cm3/min时制备的(Ti,Al)N薄膜晶粒最细小、致密,小尺寸纳米化的晶粒对提高3003AlMn合金耐磨损性和耐蚀性最佳,但沉积速率低,硬度增幅小。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.