用ECRCVD方法制备优质氮化硅钝化膜

利用电子回旋共振等离子体化学气相沉积(ECR—CVD)技术，以SiH4和N2为反应气体进行了氮化硅钝化薄膜的低温沉积技术的研究。采用原子力显微镜、傅立叶变换红外光谱和椭圆偏振光检测等技术对薄膜的表面形貌、结构、厚度和折射率等性质进行了测量。结果表明，采用ECR—CVD技术能够在较低的衬底温度条件下以较高的沉积速率制备厚度均匀的氮化硅薄膜，薄膜中H含量很低。薄膜沉积速率随微波功率和混合气体中硅烷比例的增加而增大。折射率随微波功率的增大而减小，随混合气体中硅炕比例的增大而增大。在相同气体混合比和微波功率条件下，较高衬底温度条件下制备的薄膜折射率较大。     

添加H2对SiH4/N2/Ar等离子体淀积的氮化硅电学和光学特性的影响

研究了加H2对SiH4/N2/Ar高密度、低离子能量的等离子体淀积的氮化硅薄膜(淀积的衬底温度为400℃)电学和光学性能的影响。实验结果表明,加入H2使氮化硅薄膜的光学带隙增加,其折射率以及在氢氟酸缓冲液中腐蚀速率减小,而XPS测试的N、Si原子比没有改变,均为1.3。FTIR测量表明,样品中Si-H键的密度低于仪器检测限,而添加H2的样品中N-H键密度稍增加。此外,由淀积的氮化硅膜构成的MIS结构的高频C-V测试(1 MHz)显示,当氢气流量从零增加到8sccm时,高频C-V的回滞幅度从(0.40±0.05)V降低到(0.10±0.01)V。基于这些实验结果和理论分析,表明了加适量H2能够促进弱的Si-Si键以及Si和N的悬挂键向Si-N键转化。     

添加H2对SiH4/N2/Ar等离子体淀积的氮化硅电学和光学特性的影响

研究了加H2对SiH4/N2/Ar高密度、低离子能量的等离子体淀积的氮化硅薄膜(淀积的衬底温度为400℃)电学和光学性能的影响。实验结果表明,加入H2使氮化硅薄膜的光学带隙增加,其折射率以及在氢氟酸缓冲液中腐蚀速率减小,而XPS测试的N、Si原子比没有改变,均为1.3。FTIR测量表明,样品中Si-H键的密度低于仪器检测限,而添加H2的样品中N-H键密度稍增加。此外,由淀积的氮化硅膜构成的MIS结构的高频C-V测试(1 MHz)显示,当氢气流量从零增加到8sccm时,高频C-V的回滞幅度从(0.40±0.05)V降低到(0.10±0.01)V。基于这些实验结果和理论分析,表明了加适量H2能够促进弱的Si-Si键以及Si和N的悬挂键向Si-N键转化。     

HfO2薄膜的制备与光学性能

采用射频磁控反应溅射法，以高纯热压HfO2陶瓷为靶材，在Si衬底上成功制备出HfO2薄膜。系统研究了工艺参数对薄膜沉积速率的影响规律，并对薄膜的光学性能进行了研究。结果表明，射频功率对薄膜沉积速率的影响最为明显，O2／Ar流量比和衬底温度对沉积速率的作用不明显，所制备薄膜的折射率较高在近红外波段趋于1．95，在500-1650nm波段范围内薄膜几乎无吸收，透过率较高。     

纳米Ta-Al-N薄膜的制备及其扩散阻挡特性的研究

采用直流反应磁控溅射方法在P型（100）Si衬底上制备了Ta-Al—N纳米薄膜与Cu／Ta-Al—N复合膜，并对薄膜样品进行了卤钨灯快速热退火（RTP）。用四探针电阻测试仪（VPP）、AFM、SEM—EDS、Alpha—stepIQ台阶仪和XPd）等分析测试方法对样品的形貌结构与特性进行了分析表征。实验结果表明，本实验条件下制得的Ta-Al—N纳米薄膜表面光滑；随着Al靶溅射功率的增加，Ta-Al—N薄膜中Al含量和方块电阻相应增大，均方根粗糙度降低，而沉积速率变化不大，且Ta-Al—N膜层对Cu扩散的阻挡能力增强。但在过高的温度下退火，导致Cu通过Ta-Al—N的晶界扩散到Ta-Al—N／Si界面并形成Cu3Si，从而引起阻挡层的失效。     

非晶硅薄膜的沉积速率研究

利用PECVD方法在硅片上制备了非晶硅薄膜,通过正交实验得出影响薄膜沉积速率和折射率的主要参数为气体流量和射频功率,分别研究了这两个参数对沉积速率和折射率的影响.结果表明当气体流量低于240sccm时,薄膜沉积速率随气体流量增加而增加,而折射率则随之减小;当流量大于240sccm时,沉积速率出现饱和,折射率的变化并不明显.当射频功率低于120W时,薄膜沉积速率随着功率的提高而增大,而折射率则随之减小;当功率大于120W并进一步提高时,沉积速率成下降趋势,折射率则随之增大.     

蓝宝石和硅衬底上氮化硅薄膜的制备和性能研究

采用射频磁控反应溅射法,以高纯Si为靶材,高纯N2气为反应气体,在蓝宝石和硅衬底上制备了氮化硅薄膜.并对Si3N4薄膜的沉积速率、成分、结构及红外光学性能等进行了研究.实验结果表明,沉积薄膜中Si和N的比接近3∶4,形成了Si3N4化合物,呈非晶态结构.制备的Si3N4薄膜的硬度明显高于蓝宝石衬底的硬度,且与蓝宝石衬底结合牢固,可提供良好的保护性能.     

气体流量比对反应溅射Si3N4薄膜的影响

利用射频磁控反应溅射法，以高纯Si为靶材，高纯N2气为反应气体，在Si衬底上制备出了Si3N4薄膜，研究了气体流量比对薄膜质量的影响。结果表明，薄膜的沉积速率主要与气体的流量比有关，随着气体流量比的增加，沉积速率下降，靶面的溅射由金属模式过渡到氮化物模式；薄膜中N／Si的原子比增加；红外吸收谱的Si—N键的振动峰向标准峰逼近。     

PECVD法沉积大尺寸氮化硅薄膜性能的研究

采用等离子体增强型化学气相沉积(PECVD)法在大尺寸玻璃基板上沉积氮化硅薄膜,对薄膜性能进行了研究,并从微观角度对所得结论进行了进一步分析与讨论。PECVD法在连续沉积氮化硅薄膜时,薄膜的厚度、沉积速率、均一性以及致密度会随镀膜基板数变化。结果表明,随镀膜基板数量的逐渐增加,氮化硅薄膜平均厚度呈上升趋势,均一性变好,薄膜致密度呈下降趋势。     

氮化硅薄膜材料的表面结构和热稳定性研究

研究了三种方法制备的氮化硅薄膜的组成、表面结构、热氧化稳定性以及抗离子束损伤等性能。研究发现APCVD法制备氮化硅薄膜的Si3N4含量最高，PRSD法制备的薄膜次之，而PECVD法制备的薄膜Si3N4含量最低。在PRSD薄膜中没有N－H键存在，仅有少量的Si－H键存在，薄膜的热氧化稳定性和抗离子束损伤性能最好。APCVD薄膜中含有少量的N－H和Si－H键，虽然膜层的热稳定性很好，但由于膜层具有较多的缺陷，因此其抗氧化性较差，抗离子束损伤性能也不好。对于PECVD薄膜，由于其形成温度较低，膜层中含有大量的N－H和Si－H键，因此膜层的热稳定性和抗离子束损伤性能最差。此外，还发现XPS获得的N／Si原子比和膜层的真实成分校一致，而RBS和AES由于离子束损伤效应，其结果偏低。氮化硅薄膜热稳定性差和离子束损伤的本质均因氯化硅的脱氮分解。热氧化的本质是膜层中自由硅和气氛中残余氧的氧化反应。     

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.