7A04铝合金表面DLC薄膜制备及性能研究

为提高7A04铝合金的表面性能,利用射频辅助等离子体浸没离子注入与沉积设备,在其表面制备类金刚石(DLC)薄膜。由于DLC薄膜与铝合金基体力学性能差别较大,导致膜基结合力差。本研究采用非平衡磁控溅射技术预先沉积一层Si膜,作为过渡层改善膜基结合力;利用激光拉曼光谱仪、维式显微硬度计、纳米划痕仪、摩擦磨损试验机等设备,系统分析了薄膜结构、显微硬度、膜基结合力及耐磨损性能。结果表明,Si过渡层的制备提高了基体的承载能力和膜基结合力,进而使耐磨损性能得到大幅度提高。     

过渡层对TC4钛合金基类金刚石多层薄膜磨损特性的影响

在钛合金(TC4)表面制备类金刚石(DLC)薄膜是提高其耐磨损性能和使用寿命的一种有效方法。本文采用磁过滤阴极弧源技术在钛合金表面上制备软硬相间的类金刚石多层薄膜、Ti和Ti/TiC过渡层组成的类金刚石多层薄膜。利用光学显微镜和扫描电镜分析多层膜表面外观形态,并使用台阶仪、纳米压痕仪、摩擦实验机等分析多层膜的残余应力、纳米硬度、膜基结合力和摩擦磨损特性。研究结果表明：DLC多层薄膜的残余应力均低于单层DLC薄膜,残余应力从12.63 GPa降低到6.21 GPa,增加Ti/TiC过渡层的DLC多层薄膜的残余应力最小。压痕结合力研究结果表明,加入Ti/TiC过渡层的DLC多层薄膜的结合状况得到了显著提高。Ti/TiC过渡层构成的类金刚石多层薄膜,有较大的硬度和良好减摩耐磨性能。试验结果将为TC4钛合金基体上制备硬质耐磨损DLC多层薄膜提供技术方案和理论依据。     

脉冲真空电弧离子镀在不锈钢上沉积类金刚石薄膜的研究

利用脉冲真空电弧离子镀技术在3Cr13不锈钢上制备了类金刚石(DLC)薄膜,通过Raman光谱分析了膜的结构特征,采用摩擦磨损试验机测试了薄膜在不同载荷下的摩擦系数,运用划痕仪研究了膜基的结合强度.结果表明:所镀制的薄膜具有典型类金刚石结构特征,膜中ID/IG为1.33;摩擦系数随着载荷的增大而减小,载荷为5 N,转速120 r/min时的摩擦系数为0.12;Ti过渡层的引入显著地提高了膜基结合力.     

缝纫机针杆表面沉积含过渡层DLC薄膜及性能的研究

本文以C2H2为碳源,Ar气为辅助气体,采用新型离子束源和磁控溅射源的混合技术在缝纫机针杆上成功制备了具有不同过渡层的类金刚石薄膜,并表征了薄膜的表面形貌,测量了其硬度、结合力、摩擦系数,划痕法的结果表明,增加过渡层后薄膜的结合状况得到明显改善.DLC膜的硬度也得到了提高,摩擦磨损实验结果可以看出样品的摩擦系数均在0.1以下,可以极大地改善不锈钢针杆的摩擦性能.     

类金刚石薄膜对纯钛的磨损保护及安全性评价

评价了以TiN为过渡层的类金刚石（DLC）复合梯度膜对齿科纯钛（TA2）的磨损防护效果以及生物安全性。采用脉冲真空多弧等离子体镀膜机,在齿科纯钛表面镀制TiN梯度膜和DLC表面膜。在体外对比检测镀膜的耐磨损能力和与纯钛的结合力,同时观察检测磨损后的表面形貌和元素分布。应用MTT法评价其生物相容性。结果表明,DLC薄膜的耐磨损能力以及与纯钛的结合力明显高于其余表面处理方法,表面形貌改变小。细胞毒性实验表明,DLC膜表面的L-929细胞增值良好。复合梯度膜的应用,可以明显提高DLC镀膜与纯钛基体的结合力。耐磨试验表明,DLC复合梯度膜可以承受日常口腔刷牙的磨耗,安全可靠,可以应用于人体。     

空间对接锁系表面强化及润滑处理技术

为了改善空间对接锁系在空间环境中的抗磨损和防冷焊性能,采用等离子体浸没离子注入与沉积技术在钛合金零部件表面制备类金刚石碳膜(DLC)。通过摩擦磨损试验、划痕试验、压痕试验来表征DLC膜的摩擦性能、膜-基结合力及显微硬度。结果表明,经复合强化制备的DLC膜摩擦系数低于0.15、磨损率为1.7×10-7mm3/N·m、膜-基结合力达256 mN、显微硬度为21 GPa,能够有效地提高航天用钛合金零件的使用性能。采用DLC膜和Braycote 601EF真空润滑脂的固体-油脂复合润滑方式来进一步改善DLC膜在空间应用性能,试验证实该项技术可满足空间对接锁系零部件的抗磨损、防冷焊需求。     

铜合金垫片表面类金刚石薄膜的制备及其摩擦学性能研究

采用物理气相沉积工艺在黄铜H62垫片上制备了DLC薄膜,对DLC薄膜进行了拉曼光谱分析和截面形貌观察,测试了薄膜厚度、纳米硬度和结合力,进行了磨擦磨损试验,分析了薄膜的减摩耐磨性能.结果 表明,在H62铜合金垫片制备碳膜为DLC薄膜,薄膜总厚约2.31 μm,底层厚约0.49 μm.薄膜纳米硬度22.1GPa,薄膜与基...     

多弧离子镀制备TiN/TiAlN多层薄膜性能研究

采用多弧离子镀技术选取钛靶电流分别为60A、70A、80A和基体偏压分别为-240V、-300V、-360V在高速钢基体上制备Ti N/Ti Al N多层薄膜。使用划痕仪、显微硬度计、摩擦磨损试验机和马弗炉对膜层的膜基结合力、显微硬度、摩擦磨损性能和热震性能进行检测。结果表明:在钛靶电流为70A和基体偏压为-240V时膜基结合力最高,同时显微硬度也较高;在基体偏压为-300V的条件下,钛靶电流为70A时的摩擦系数最小,其耐磨性能良好;基体偏压为-240V时的抗热震性能良好。     

钴合金表面多层碳薄膜的制备及其性能研究

为了改善人工关节的生物摩擦学性能,采用磁过滤直流阴极真空弧源沉积技术在Co-Cr-Mo合金基体表面制备了多层C/C膜。采用拉曼光谱对薄膜的结构进行了表征;利用原子力显微镜观察了多层C/C膜的表面形貌;采用CSEM纳米硬度计测试了多层膜的纳米硬度;在销盘式摩擦磨损试验机上考察了多层膜的生物摩擦学性能。结果表明:多层C/C膜为典型的类金刚石结构,其表面光滑致密,硬度高达52 GPa,它与SiC球在磷酸盐缓冲溶液中的稳定摩擦系数仅为0.012,明显提高了人工关节用材料钴合金的生物摩擦学性能。     

脉冲真空弧源沉积类金刚石薄膜耐磨特性研究

本文利用脉冲真空弧源沉积技术在Cr17Ni14Cu4不锈钢和Si(100)基体上制备了类金刚石(DLC)薄膜,研究在不同基体偏压下,DLC薄膜的结构与性能.采用拉曼光谱和X射线光电子能谱(XPS)研究DLC薄膜的原子结合状态,利用CSEM销盘摩擦磨损试验机研究其耐磨性,利用HXD1000B显微硬度仪测试其显微硬度,并采用压痕法评价其结合力.研究结果表明:DLC薄膜与基体结合牢固.随着基体偏压的提高,DLC薄膜内sp3键含量增大,薄膜硬度提高.Cr17Ni14Cu4不锈钢表面沉积DLC薄膜后,耐磨性大幅度提高,本文探讨了DLC薄膜的耐磨机理.     

热交换器的分类及优缺点分析

热交换器是将不同温度介质之间的热量通过热传导的形式,由高温介质传递给低温介质,使介质达到生产所需温度的工艺设备,也可作为一种节能设备使用.通过对不同热交换器的结构分析,总结不同热交换器的优缺点、适用环境,为生产工艺设计人员及设备制造单位在选择可降低能耗、提高效率的设备上提供参考.     

聚苯胺及其复合物的制备和结构及形貌分析

通过化学氧化法分别制备盐酸,盐酸和十二烷基苯磺酸,碳纳米管(MWNTs-COOH)掺杂的聚苯胺,利用红外光谱,紫外光谱,扫描电子显微镜和透射电子显微镜对所制备聚苯胺的结构和形貌进行分析。分析不同掺杂物对聚苯胺的结构和形貌的影响;同时研究了超声波作用对聚苯胺形貌以及聚苯胺包裹MWNTs-COOH情况的影响。     

Modelling and computation of curing and damage of thermosets

The curing of thermosets is a complex process involving the transition from a fluid into a (visco-) elastic solid. This phase transition comes along with an increase in stiffness and a volume shrinkage of the polymer. The latter may lead to severe residual strains and stresses, which in turn can cause damage in the final, usually quasi-brittle material. In this contribution a constitutive model is developed which takes into account the curing of a thermosetting material together with the process-induced damage as resulting from curing shrinkage. The curing of the material is governed by a phenomenological hypoelastic constitutive equation which includes temporal evolutions for stiffness and volume shrinkage. Thermal and viscous effects are neglected in the present study. An isotropic gradient-enhanced damage model is adapted to describe the damage evolution. The curing-damage model is implemented into a finite element code and numerical examples for thermosetting materials demonstrate that the proposed model is capable to predict cure-induced damage in thermosets.     

Thermodynamic similarity and prediction of the properties and characteristics of substances and processes

Principles of the theory of thermodynamic similarity are considered in application to all aggregate states of a substance, including phase transitions, and to the change in dissipative structures in open systems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 5, pp. 709–716, November, 1987.     

Mechanisms of Corosion and Oxidation of Metals and Alloys

Selected topics in field of the study of the mechanisms of corrosion and of oxidation of metals or alloys are presented. The first part reports a new model for the mechanism of the breakaway oxidation of ferritic stainless steels in water vapour. The second part is devoted to the physico‐chemical aspects of oxidation and presents experimental methods useful in the kinetic modelling applied to two alloys, the zircalloy‐4 and an AlMg5 % in the liquid state. In the third part the physical and numerical modelling of the stress corrosion cracking behaviour in face‐centered cubic (fcc) alloys is detailed, which enables the study of the influence of macroscopic parameters (such as the temperature or hydrogen activity) on the fracture process.     

碳化硼陶瓷增韧补强和致密化研究现状及其展望

碳化硼陶瓷具有极高的硬度,然而其低韧性、低抗弯强度、难以致密化限制了它的广泛应用.已有一些研究集中于碳化硼陶瓷增韧补强和致密化,对这一方面国内外研究进展进行了归纳与评述,阐明各种增韧补强和致密化方法的优缺点,提出碳化硼陶瓷增韧补强和致密化研究值得发展的一些方向.     

Measurement and analysis of elastic and anelastic properties of alumina and silicon carbide

Measurements of dynamic Young's modulus, E, and damping as a function of temperature, T, were made for alumina and silicon carbide. The Young's modulus data were compared with some from the literature, and analysed in terms of a theoretical framework relating the Debye temperature, θD, with the elastic constants. For both materials this analysis yielded a ratio T₀/θ_D which was near 0.4, where T₀ is an empirical fitting constant for the plot of (E(0)−E)/T versus 1/T (E(0) is the value of E at 0 K). The analysis of the damping data in terms of an Arrhenius type dependence led to effective activation energies near kT, where k is Boltzmann's constant. This revised version was published online in November 2006 with corrections to the Cover Date.     

Preparation and characterization of phosphate and arsenate apatites of strontium and their solid solutions

Samples of phosphate and arsenate apatites of strontium and six of their solid solutions, spread over the entire compositional range, were prepared by a wet method. They were characterized by chemical, X-ray, electron microscopic and infrared analyses. The validity of Vegard's law established the homogeneity of the solid solutions.     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。