硅酸铝短纤维增强ZL109复合材料的磨损机制

采用挤压铸造法制备了硅酸铝（Ａｌ２Ｏ３·ＳｉＯ２）短纤维增强ＺＬ１０９复合材料，并研究了该材料在干摩擦条件下的磨损行为．结果表明：Ａｌ２Ｏ３·ＳｉＯ２短纤维／ＺＬ１０９复合材料的耐磨机制为纤维断裂并在亚表层重新分布和排列形成高硬度的硬化层．这种硬化层的形成使复合材料具有比基体合金更优越的耐磨性．     

Ce—TZP结构陶瓷相变塑性区实验研究

用云纹干涉法对ＺｒＯ＿２相变多晶体三点弯曲梁切口周围应力诱导的相变塑性区进行了实验研究，得到了三点弯曲梁切口周围相变塑性区的形状及相变塑性分布。实验结果表明：Ｃｅ－ＴＺＰ结构陶瓷切口周围存在一个较长的扩展相变塑性区，相变塑性区内拉伸应力方向的塑性应变远大于垂直于拉伸应力方向的塑性应变。所得实验结果为进一步深入研究相变本构关系和相变增韧机理提供了重要的实验依据。     

一种陶瓷刀具材料的摩擦损性能研究

ＴｉＢ２具有熔点高、硬度高和导热性、导电性及抗氧化性能都好等优点，在切削刀具、耐磨零件和某些特殊工况下使用的材料等方面的应用前景广阔．目前，含ＴｉＢ２的Ａｌ２Ｏ３基陶瓷刀具材料已经开发出来并投入实际应用，但对其摩擦磨损特性研究却还不多．因此，采用热压烧结工艺制备了Ａｌ２Ｏ３／ＴｉＢ２陶瓷刀具材料，在ＭＭ－２００型摩擦磨损试验机上，对不同ＴｉＢ２含量的增加，Ａｌ２Ｏ３／ＴｉＢ２陶瓷材料与淬火４５＃钢配副的摩擦学性能作了试验研究．结果表明：ＴｉＢ２的含量增加，Ａｌ２Ｏ３／ＴｉＢ２陶瓷材料的耐磨性明显提高，而摩擦系数仅略有上升，在切削加工淬火４５＃钢的过程中，Ａｌ２Ｏ３／ＴｉＢ２陶瓷刀具的抗磨能力比目前广泛使用的Ａｌ２Ｏ３／ＴｉＣ陶瓷刀具的高１倍以上．Ａｌ２Ｏ３／ＴｉＢ２陶瓷刀具材料的磨损机理主要是粘着、耕犁和脆性微脱落     

Al2O3SiO2/ZL109 金属基复合材料的强度性能研究

介绍了硅酸铝短纤维增强ＺＬ１０９铸铝合金（Ａｌ２Ｏ３ＳｉＯ２／ＺＬ１０９ＭＭＣ）的静态实验和冲击实验结果。给出了这种复合材料的静态强度、动态屈服强度和层裂强度并对实验结果进行了分析讨论。     

有序态Fe3Al合金在水环境中的磨粒磨损行为

研究了不同载荷下含Ｃｒ的Ｂ２和ＤＯ３有序态Ｆｅ３Ａｌ合金在水中的磨粒磨损行为。采用扫描电镜分析了合金的磨损表面形貌和磨屑形貌。二次离子质谱分析结果表明：在水环境磨损条件下，随着载荷的增加，进入Ｆｅ３Ａｌ合金表层的氢浓度升高，合金表层的氢损伤加剧。在高载荷下由机械磨损所引起的材料流失仍占主导地位，相同载荷下Ｂ２有序态Ｆｅ３Ａｌ合金的磨损质量损失比ＤＯ３有序态Ｆｅ３Ａｌ合金低。     

三氧化二铝短纤维对ZA22合金干摩擦磨损性能的影响

针对无油润滑场合的实际需要，采用挤压铸造法制取了Ａｌ２Ｏ３短纤维强化ＺＡ２２合金复合材料，并对其在干摩擦条件下的摩擦磨损性能进行了试验研究，同时还用扫描电子显微镜对试样磨损表面形貌进行了观察，进而对材料的磨损机理作了分析与讨论。结果表明，随着Ａｌ２Ｏ３短纤维含量的增大，ＺＡ２２／Ａｌ２Ｏ３复合材料的耐磨性能提高，但摩擦性能降低；当纤维取向垂直于摩擦而时，复合材料的摩擦磨损性能比纤维平行于摩擦面取向     

THE CALCULATION OF EIGENVALUES FOR THE STATIONARY PERTURBATION OF COUETTE－POlSEUILLEFLOW

ＴＨＥＣＡＬＣＵＬＡＴＩＯＮＯＦＥＩＧＥＮＶＡＬＵＥＳＦＯＲＴＨＥＳＴＡＴＩＯＮＡＲＹＰＥＲＴＵＲＢＡＴＩＯＮＯＦＣＯＵＥＴＴＥ－ＰＯｌＳＥＵＩＬＬＥＦＬＯＷＳｏｎｇＪｉｎｂａｏ（宋金宝）ＣｈｅｎＪｉａｎｎｉｎｇ（陈建宁）（ＲｅｃｅｉｖｅｄＤｅｃ．３...     

四种陶瓷材料与SUS304不锈钢的高温摩擦学特性研究

为了探索陶瓷与金属组合作为高温润滑材料的可能性，利用端面摩擦磨损试验机测定了４种陶瓷ＳｉＣ、Ｓｉ３Ｎ４、Ａｌ２Ｏ３和ＺｒＯ２与ＳＵＳ３０４不锈钢在室温至５００℃下的摩擦学性能．摩擦试验结果表明，ＳｉＣ、Ｓｉ３Ｎ４和Ａｌ２Ｏ３在低于２００℃时的摩擦系数稳定且都低于０．２，但在２００℃以上时的摩擦性能却都不稳定，摩擦系数在０．２－０．４之间；ＺｒＯ２在２００℃以下时的摩擦性能不稳定，而在２００℃以上时的摩擦系数低于６．２且较稳定。磨损试验结果表明，在４种陶瓷中ＺｒＯ２的磨损率最低［－２．６０×１０－９ｍｍ３／（Ｎ·ｍ）］，ＳｉＣ和Ｓｉ３Ｎ４的磨损率居中［分别为１．８０×１０－６ｍｍ３／（Ｎ·ｍ）和４．４０×１０－６ｍｍ３／（Ｎ·ｍ）］，Ａｌ２Ｏ３的磨损率最高［３．６４×１０－５ｍｍ３／（Ｎ·ｍ）］；分别与这４种陶瓷对磨的不锈钢的磨损率都高［１．４０×１０－５－４．５２×１０－５ｍｍ３／（Ｎ·ｍ）］．     

含随机分布微裂纹的相变颗粒增韧陶瓷材料的强度和刚度预报

本文针对相变颗粒增韧陶瓷基复合材料中存在大量微裂的现象，分析了微裂纹产生的原因，利用作者改进的等效平杂理论，研究了相变陶瓷中微裂纹对材料强度与刚度的影响，通过与Ａｌ２Ｏ３／ＺｒＯ２陶瓷的三点弯曲实验结果的比较表明，理论与实验结果十分接近，说明本文理论模型是合理的，同时也证明了微裂纹对相变陶恣材料的重要影响。     

ZA22—Al2O3复合材料干摩擦磨损表面的微观分析

用扫描电子显微镜和Ｘ射线光电子能谱仪分析了ＺＡ２２合金和ＺＡ２２－Ａｌ２Ｏ３复合材料在干磨擦条件下的磨损表面。结果表明：在ＺＡ２２合金磨损表面形成了一层厚约１００μｍ的塑性变形层，而添加Ａｌ２Ｏ３短纤维能够有效地使这种变形层减薄；在垂直于磨损表面的纤维周围的基础体明显比其它部位的高，磨损后复合材料表面的元素Ｚｎ被氧化，并有偶件材料的转移物存在。     

TZP陶瓷在水润滑下的磨损机制转变图

在ＳＲＶ磨损试验机上对ＴＺＰ陶瓷在水润滑条件下的摩擦学行为进行了试验研究。用磨损机制转变图概括了ＴＺＰ陶瓷与５２１００钢在水润滑时于不同运行条件下的磨损机制。     

Effects of cerium incorporation on the catalytic oxidation of benzene over flame-made perovskite La1−xCexMnO3 catalysts

Perovskite-type La_1−xCe_xMnO₃ (x = 0–10%) catalysts were prepared by flame spray pyrolysis and their activities during the catalytic oxidation of benzene were examined over the temperature range of 100–450 °C. The structural properties and reducibility of these materials were also characterized by X-ray diffraction (XRD), N₂ adsorption/desorption, H₂ temperature-programmed reduction (H₂-TPR) and X-ray photoelectron spectroscopy (XPS). The incorporation of Ce was found to improve the benzene oxidation activity, and the perovskite in which x was 0.1 exhibited the highest activity. Phase composition and surface elemental analyses indicated that non-stoichiometric compounds were present. The incorporation of Ce had a negligible effect on the specific surface area of the perovskites and hence this factor has little impact on the catalytic activity. Introduction of Ce⁴⁺ resulted in modification of the chemical states of both B-site ions and oxygen species and facilitated the reducibility of the perovskite. The surface Mn⁴⁺/Mn³⁺ ratio was increased as a result of Ce⁴⁺ substitution, while a decrease in the surface-adsorbed O/lattice O (O_ads/O_latt) ratio was observed. The relationship between the surface elemental ratios and catalytic activity was established to allow a better understanding of the process by which benzene is oxidized over perovskites.     

Synthesis and characterization of PMMA/Al2O3 composite particles by in situ emulsion polymerization

In order to improve its dispersibility, superfine alumina (Al2O3) was encapsulated with poly (methyl methacrylate) (PMMA) by in situ emulsion polymerization. It was found that only when the concentration of sodium dodecyl sulfate (SDS) was much higher than its critical micelle concentration, could PMMA/Al2O3 composite particles with high percentage of grafting (PG) be prepared. The same results were obtained between the experimental and stoichiometric amounts of tris (dodecylbenzenesulfonate) isopropoxide (NDZ), indicating that single-molecule-layer adsorption had taken place between NDZ and Al2O3. Analysis using FTIR. TEM and XPS showed that PMMA/Al2O3 composite particles with core-shell structure had been successfully synthesized by in sire emulsion polymerization. Compared to Al2O3, thermal stability and dispersibility of the composite particles showed marked improvement.     

氧化铝纤维含量对Al2O3f＋Cf／ZL109混杂复合材料耐磨性能的影响

利用挤压铸造法制备了Al2O3f Cf/ZL09短纤维混杂金属基复合材料，并探讨了炭纤维体积分数为4％时，Al2O3纤维含量变化对该复合材料耐磨性能的影响。结果表明：随着Al2O3体积分数增加，复合材料的摩擦系数逐渐增大，复合材料从轻微磨损到急剧磨损的临界转变载荷大幅度提高，并随Al2O3含量的增加而逐渐增大；在临界载荷以下，影响复合材料磨损率的Al2O3含量临界值为12％，当Al2O3含量低于临界值时复合材料磨损表面无明显剥落，而当Al2O3含量超过临界值后，复合材料磨损表面存在大量的剥落坑，磨损率增大。     

Density functional theory study on the influence of cation ratio on the host layer structure of Zn/Al double hydroxides

A density functional theory (DFT) study has been carried out for [Znn-1Al(OH2)n+6(OH)2n-2]3+(n=3-6) and [Znn-1 Al(OH2)2n-2(OH)2n-2 ]3+ (n=7) clusters,which include the basic structural information of the brucite-like lattice structure of Zn/Al layered double hydroxides (LDHs) with Zn/Al molar ratio (R) in the range 2-6,in order to understand the effect of the Zn/Al ratio on the structure and stability of binary Zn/Al LDHs.Based on systematic calculations of the geometric parameters and formation energies of the cluster models,it was found that it is possible for Zn2+ and Al3+ cations to replace Mg2+ isomorphously in the brucite-like structure with different R values,resulting in differences in microstructure of the clusters and unit cell parameter a of the Zn/Al LDHs.Analysis of the geometry and bonding around the trivalent Al3+ or divalent Zn2+ cations reveals that Al3+ plays a more significant role than Zn2+ in determining the microstructure properties,formation and bonding stability of the corresponding ZnRAl clusters when R＜5,while the influence of Zn2+ becomes the dominant factor in the case of R≥5.These findings are in good agreement with experiments.This work provides a detailed electronic-level understanding of how the composition of cations affects the microstructure and stability of Zn-containing binary LDH layers.     

内氧化法制备Al2O3/Cu复合材料电滑动磨损性能的研究

采用内氧化法制备Al2O3/Cu复合材料,在自制电磨损试验机上评价Al2O3/Cu复合材料的磨损性能,采用扫描电子显微镜观察Al2O3/Cu复合材料的磨损表面形貌,用能谱仪对其磨损表面主要元素进行分析并探讨其磨损机制.结果表明:在相同试验条件下,Al2O3/Cu复合材料的磨损性能明显优于Cu-0.36Cr-0.06Zr合金,Cu-0.36Cr-0.06Zr合金的磨损率较0.40%Al2O3 /Cu复合材料的磨损率高1倍多;在无加载电流条件下,Al2O3/Cu复合材料的磨损机制为粘着磨损和磨粒磨损;在载流条件下其磨损机制主要以粘着磨损为主,并随着电流强度的增加,粘着磨损程度加重,Al2O3/Cu复合材料表面的粘着物主要来自于铜基粉末冶金滑块;Cu-Cr-Zr合金在无加载电流条件下的磨损机制主要为粘着磨损和磨粒磨损,在载流条件下主要为粘着磨损、磨粒磨损及电烧蚀磨损.     

Al_2O_3+PTFE(+PPS)复合材料滑动摩擦磨损的研究

作者采用冷压-烧结工艺研制了Al_2O_3+PTFE、PTFE+PPS和Al_2O_3+(PTFE+PPS)3类复合材料,并对这些材料的摩擦磨损行为及其磨损机理进行了研究。结果表明,适量Al_2O_3粒子的弥散可以明显提高复合材料的耐磨性,PTFE+PPS复合材料的耐磨性远比PTFE的好,摩擦系数几乎与PTFE的相同,是一种良好的减摩抗磨材料。复合材料的磨损过程主要受粘着、犁削和塑性流动机制的控制。     

电刷镀镍/镍包纳米Al_2O_3颗粒复合镀层微动磨损性能研究

应用电刷镀技术制备了含有镍包纳米 Al2 O3颗粒的镍基复合镀层 .与快速镍镀层对比考察了该复合镀层高温硬度的变化 ,同时还从微动磨损角度考察了该复合镀层耐磨性和摩擦系数的变化 .结果表明 :与快镍镀层相比 ,镍 /镍包纳米 Al2 O3复合镀层具有更高的高温硬度和更好的抗微动磨损性能 ;复合镀层在 40 0℃左右表现出较明显的强化趋势 ,具有较好的综合性能 ;纳米 Al2 O3颗粒使复合镀层的结构致密和细化 ,在磨损过程中起到了一定的减轻粘着和降低摩摩的作用 ;复合镀层的微动磨损机理主要为粘着磨损 .