活性成分对金刚石膜沉积速率和质量的影响

采用微波等离子体化学气相法合成的金刚石膜质量好,但采用常规CH4-H2气体体系,金刚石膜的沉积速率低.为此,实验研究了C2 H5OH-H2、CH4-H2-Ar和CH4-H2-N2等含有活性成分的体系下,微波功率、碳源浓度、气体压力对金刚石膜沉积速率、表面形貌、电阻率的影响.结果表明:使用含氧、氩、氮等活性成分的体系,金...     

反应气体对纳米金刚石薄膜的显微力学特性影响

本文采用电子辅助增强热丝化学气相沉积(HFCVD)系统,CH4/H2、CH4/H2/Ar气体和不同比例的四种气氛制备了纳米金刚石薄膜,利用Raman光谱和原子力显微镜(AFM)表征了薄膜的结构和显微形貌,采用纳米压入测试技术测量了纳米金刚石薄膜的显微力学特性,获得了加载、卸载曲线,以及硬度和模量随压入深度的变化曲线。结果表明:薄膜具有明显的纳米结构特点,随着CH4、Ar浓度的增加,晶粒更加细化,表面粗糙度更低。无Ar气氛制备的纳米金刚石薄膜的弹性恢复较好,硬度和模量较高,CH4和Ar含量越低的制备气氛,其硬度和模量相对较高。     

超高分子量聚乙烯表面沉积类金刚石膜的摩擦磨损性能

利用射频等离子体增强化学气相沉积(RF-PECVD)技术在超高分子量聚乙烯(UHMWPE)表面制备类金刚石(DLC)膜,用激光拉曼(Raman)光谱仪和扫描电子显微镜(SEM)分析了DLC膜的形貌及结构特征,纳米硬度法测定DLC膜的纳米硬度。并在UMT-Ⅱ型摩擦磨损试验机上评价了DLC膜在牛血清溶液润滑条件下的摩擦磨损性能。结果表明,UHMWPE表面制备的DLC膜具有典型类金刚石薄膜的Raman光谱特征,属含氢a-C:H膜。表面沉积DLC膜可有效提高UHMWPE的表面硬度,改善表面润湿性能。25%牛血清润滑条件下,DLC膜UHMWPE的摩擦因数有所升高,但磨损率则有明显下降。UHMWPE磨损表面存在严重的犁削磨损和塑性变形,DLC膜磨损表面主要以剥层磨损为主。     

多晶氧化铍陶瓷上金刚石薄膜的生长

采用热丝化学气相沉积(HFCVD)系统,以CH4和H2为反应气体,在多晶氧化铍陶瓷基体上沉积了金刚石薄膜.采用场发射扫描电子显微镜(FESEM)、原子力显微镜(AFM)和激光热物性测试仪进行检测分析,研究工艺参数对金刚石薄膜生长及膜/基复合体热学性能的影响.结果表明:随着CH4浓度的增加(或CH4浓度一定,反应气体总流量增加),金刚石晶粒尺寸逐渐减小,膜/基复合体的热导率逐渐降低;当CH4浓度为2%(体积分数),流量为30 cm3/min,压强为1.33 kPa时,沉积的膜/基复合体的热导率最高,可达2.663 W/(cm·K).     

在CH4-H2微波等离子体中添加H2O对大面积金刚石膜生长的研究

用自制的微波功率为5千瓦的微波等离子体（MWCVD）装置，研究了在CH4-H2反应气体中添加安全廉价的H2O代替O2金刚石膜的沉积状况，以H2／CH4／H2O作为反应气体，成功制备了厚度达到1．1毫米，面积达20平方厘米的金刚石厚膜。在沉积温度为700-900℃范围内，研究了CH4／H2=3.0％，H2O／H2=0．0-2．4％范围内金刚石膜沉积的速率，均匀性，形貌以及质量的变化规律。研究结果表明，在反应气体CH4／H2中添加适量H2O能降低金刚石膜中非金刚石碳的含量，提高金刚石膜厚度的均匀性，并对反应气体中添加H2O对CVD金刚石膜生长影响机理进行了阐述。     

不同高浓度气体对金刚石薄膜制备的影响

采用微波等离子体化学气相沉积(MPCVD)法,分别制备了CH4/H2体系、CH4/H2/N2体系以及CH4/H2/Ar体系金刚石薄膜。主要采用了扫描电子显微镜(SEM)、激光拉曼光谱(Raman)和X射线衍射光谱(XRD)等方法对不同体系中制备的金刚石薄膜的晶粒尺寸及其品质进行了分析,研究了不同高浓度气体对金刚石薄膜的影响。结果显示:利用高浓度的甲烷可以在很大程度上细化晶粒,制备出纳米晶金刚石薄膜,但是薄膜的非晶相较多,品质下降;加入70%N2,薄膜中的金刚石晶粒生长速度较慢,但可制备出均匀的纳米晶金刚石薄膜;70%的Ar气氛中,金刚石晶粒生长较快,制得的薄膜中的金刚石晶粒是微米级别的。     

引入CO2提高金刚石薄膜的沉积速率

微波等离子体法合成的金刚石薄膜质量好,但常规小型微波等离子体沉积金刚石薄膜速率低,为此,本实验在H2-CH4系统中引入CO2来提高金刚石薄膜的沉积速率.研究了不同碳源体积分数、功率、压力对沉积速率、金刚石形貌、电阻率的影响.其规律是随着碳源体积分数的增加,金刚石膜的沉积速率增加;随着压力的增加,生长速率呈现一个先增后减的趋势;随着功率的增加,也存在一个先增后降的趋势.研究结果表明碳源体积分数对沉积速率影响最大.综合各种因素,得到在H2+CH4+CO2的条件下沉积金刚石薄膜的最佳工艺条件为:碳源体积分数为0.63%;C/O=1.086;功率为490 W;压力为5.33 kPa.引入CO2使沉积速率得到提高,为常规方法沉积速率的3倍左右,表明引入CO2.是一种提高沉积速率的有效方法.     

梯度基体温度法和反应溅射TiC过渡层对钛合金基体沉积金刚石薄膜的影响

以H2和CH4作为反应气体,采用热丝化学气相沉积法(HFCVD)在钛合金(Ti6Al4V)平板基体上制备金刚石薄膜,利用扫描电镜(SEM)、X射线衍射仪(XRD)、激光拉曼光谱(Raman)和洛氏硬度仪分析薄膜的表面形貌、结构、成分和附着性能,研究了高温形核-低温生长的梯度降温法对原始钛合金和反应磁控溅射TiC过渡层的钛合金表面沉积金刚石薄膜的影响。结果表明:原始基体区和TiC过渡层区沉积的金刚石薄膜平均尺寸分别为0.77μm和0.75μm,薄膜内应力分别为-5.85GPa和-4.14GPa,TiC层的引入可以有效提高金刚石的形核密度和晶粒尺寸的均匀性,并减少薄膜残余应力;高温形核-低温生长的梯度降温法可以有效提高金刚石的形核密度和质量,并提高原始基体上沉积金刚石薄膜的附着性能。     

真空中不同转速和对偶对a-C∶H膜摩擦学性能的影响

非晶碳氢(a-C∶H)薄膜作为空间润滑材料有很大的应用前景,它在真空中的摩擦磨损行为与掺杂元素、摩擦对偶、滑动速度等因素有关.采用中频非平衡磁控溅射法在AISI202不锈钢和p(111)单晶硅基体上沉积了厚度为1.3～1.6 μm的a-C∶H膜以及Cr、MoS2掺杂的a-C∶H复合膜.采用球盘摩擦试验机对3种膜的真空摩擦学行为进行了研究,摩擦性能较好的薄膜在真空中进行了GCr15、Si3N4和C不同对偶以及100、500、1000 r/min的不同转速摩擦实验.结果表明:在沉积气压为5.3×10-1 Pa,Ar和CH4的气体流量比为1∶1,单纯溅射石墨靶(溅射电流12 A)的条件下,制备的a-C∶H薄膜在真空中的摩擦因数最低(0.005),寿命相对最长;对偶对a-C∶H膜的摩擦因数影响不大,但薄膜的耐磨寿命随着对偶硬度的增加而降低;随着转速的增加,a-C∶H膜的摩擦因数和耐磨寿命均降低.     

H_2/CH_4流量比对含氢DLC薄膜结构及摩擦学性能的影响

利用等离子体增强化学气相沉积法在Si(100)基体上制备不同H2/CH4流量比下的类金刚石薄膜,采用拉曼光谱、红外光谱、扫描电子显微镜(SEM)、纳米力学性能综合测试仪以及摩擦磨损试验机对薄膜的组织结构、力学以及摩擦学性能进行了分析。结果表明:该条件下制备的薄膜具有典型的类金刚石结构且膜中氢含量较高,薄膜表面光滑,膜层致密且均匀,薄膜的硬度及与基底的附着力均随着H2/CH4流量比的增加而降低。薄膜在大气环境下具有优异的摩擦学性能,在相同的载荷及转速条件下,H2/CH4流量比对薄膜的摩擦因数影响不大。当载荷为5N时,随着转速的增加,摩擦因数降低;而载荷为10N时,摩擦因数约为0.05,转速对其影响较小。薄膜的磨损率在10-8~10-7 mm3/Nm之间变化,且随H2/CH4流量比的增加而增大。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.