工作气压对制备立方氮化硼薄膜的影响

本文报道了工作气压对射频溅射法制备立方氮化硼(c-BN)薄膜影响的实验结果.c-BN薄膜沉积在p型Si(100)衬底上,溅射靶为六角氮化硼(h-BN),工作气体为Ar气和N2气混合而成,薄膜的成分由傅里叶变换红外吸收谱标识.结果表明,与射频功率、衬底温度和衬底负偏压一样,工作气压也是影响c-BN薄膜生长的重要参数.要得到一定立方相含量的氮化硼薄膜,必须要有合适的工作气压,否则,薄膜中不能形成立方相.在工作气压为5×10-3乇时,得到了立方相含量在90%以上的立方氮化硼薄膜.     

高速钢基体离子注氮对c-BN薄膜制备的影响研究

采用射频磁控溅射法在离子注氮的高速钢基体上沉积制备c-BN薄膜,主要研究离子注氮层对c-BN薄膜相结构和内应力的影响;采用各种现代分析方法对沉积的薄膜进行了表征分析,包括傅立叶红外光谱(FTIR)、X射线光电子能谱(XPS)和原子力显微镜(AFM)等分析方法;试验结果表明:高速钢基体上离子注氮有利于立方氮化硼含量的提高和薄膜内应力的降低,同时注氮处理的高速钢基体上沉积的薄膜表面形貌平整,结晶性较好.并采用X射线衍射分析(XRD)对高速钢基体的离子注氮层进行了相结构分析,探索研究了离子注氮层对c-BN薄膜生长的影响.     

HFPECVD法沉积BN薄膜及其生长机理的研究

本文介绍了用HFPECVD(hot filament plasma enhanced chemical vapor deposition)法制备BN薄膜.通过红外吸收谱和x射线衍射图谱分析确定,射频功率和反应气体(N2)气流量显著影响薄膜中立方相BN(c-BN)的相对含量.当射频功率小于200W时,薄膜中立方相的相对含量随它的增加而增大;而当射频功率大于200W时,则随它增加而减小.当N2气流量增加时,薄膜生长速率增加,但立方相的相对含量却减少.最后通过对不同沉积时间样品的红外吸收谱的分析对BN薄膜的生长机理进行了探讨.     

c-BN薄膜的生长过程和可重复性的研究

用常规射频(RF)溅射系统,采用三步法在p型Si(111)上高重复率地制备出高品质的立方氮化硼(c-BN)薄膜.通过对c-BN薄膜生长过程的分析,找出了传统两步法制备高品质的c-BN薄膜重复率不高的原因.在两步法之前增加了使湍流层结构氮化硼(t-BN)转化为斜方六面体结构的氮化硼(r-BN)的步骤,即将形核过程分也为两步,使重复率显著提高.傅立叶变换红外吸收光谱的结果表明当第一步偏压为180 V,时间为5 min时,得到了立方相含量为85%的c-BN薄膜.     

沉积参量对硼碳氮薄膜光透过性质的影响

采用射频磁控溅射技术,用六角氮化硼和石墨为溅射靶,以氩气(Ar)和氮气(N2)为工作气体,在玻璃衬底上制备出硼碳氮(BCN)薄膜.通过改变氮气分压比、衬底温度及沉积时间,研究了沉积参量对薄膜光透过性质的影响.利用X射线光电子能谱(XPS)、原子力显微镜(AFM)及可见-近红外透过光谱对薄膜进行了表征.实验结果表明,所制备薄膜在400～1000nm波段具有较高透过率.并且沉积参量对BCN薄膜的透过性能有很大影响,适当改变沉积参量能获得透过率高于90%的BCN薄膜.在固定其它条件只改变一个沉积参量的情况下,得到制备具有较高透过率的BCN薄膜的最佳沉积条件:氮气分压比为1/3、沉积温度为300℃、沉积时间为1h.     

射频磁控溅射制备硼碳氮薄膜

采用射频磁控溅射技术,用六角氮化硼和石墨为溅射靶,以氩气(Ar)和氮气(N2)为工作气体,在Si (100)衬底上制备出硼碳氮薄膜.通过X射线衍射(XRD)、傅里叶红外吸收光谱(FTIR)和X射线光电子能谱(XPS)等分析手段对样品结构、组分进行了分析.结果表明,样品的组成原子之间实现了原子级化合,且薄膜为乱层石墨结构.样品中B、C、N的原子比近似为1:1:1.     

反应磁控溅射法沉积的氟化类金刚石薄膜的结构分析

以高纯石墨作靶、Ar／CHF3作源气体采用射频反应磁控溅射法室温下制备了氟化类金刚石薄膜(F-DLC)。发现随着射频功率的增加,F-DLC薄膜拉曼光谱的D峰与G峰强度之比ID／IG加大,薄膜中芳香环式结构比例上升。红外吸收光谱则显示射频功率增加导致薄膜中的氟含量上升．氟原子与碳原子以及芳香环的耦合加强。控制射频功率可以有效调制薄膜中的氟含量以及芳香环结构的比例,F—DLC可能成为热稳定性较好的碳氟薄膜。     

射频功率对微晶硅薄膜微结构和光电性能的影响

采用射频等离子体增强化学气相沉积(rf-PECVD)技术,在玻璃和硅衬底上沉积微晶硅(μc-Si:H)薄膜。利用拉曼光谱、AFM和电导率测试对不同射频功率下沉积的薄膜的结构特性及光电性能进行分析。研究表明:随着射频功率的增加,薄膜的晶化率和沉积速率也随之增加,而当射频功率增加到一定的程度,晶化率和沉积速率反而减小。薄膜的暗电导率与晶化率的变化情况相对应。     

射频与直流磁控溅射制备DLC薄膜的工艺研究及特性对比

采用直流与射频磁控溅射技术,用高纯石墨在单晶硅(100)表面制备了类金刚石薄膜(DLC).采用拉曼光谱、扫描电镜分析了薄膜的结构、表面和截面形貌,以及与溅射工艺的关系,并且对溅射过程中粒子输运机理进行了解释.结果表明,2种溅射方法制备的薄膜均含有相当的sp3杂化碳原子.射频磁控溅射沉积的DLC薄膜所含sp3杂化碳原子的量要高于直流磁控溅射沉积的DLC薄膜,且薄膜质量优于直流磁控溅射沉积的DLC薄膜.     

类金刚石薄膜的制备及其电阻率、光谱特性研究

采用射频磁控溅射法在单晶硅表面制备了类金刚石薄膜;对薄膜的电阻率进行了测量,研究了薄膜的溅射工艺参数,采用拉曼光谱、原子力显微镜、扫描电镜分析了薄膜的结构、表面形貌以及薄膜的截面形貌.结果表明,薄膜中含有sp2、sp3杂化碳原子,拉曼谱高斯拟合峰的ID/IG为3.67;薄膜的电阻率达6×103 Ωcm.最佳溅射气压在0.4 Pa左右,最佳溅射功率在140 W左右;薄膜的表面平整光滑,平均粗糙度低达0.17 nm;SEM形貌表明薄膜由大量大小均匀的碳颗粒组成,薄膜内部十分致密,与基底结合很好.     

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.