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无 氧 条 件 下TiO2 薄 膜 界 面 光 催 化 反 应 的XPS 研 究  [PDF]
杨喜昆,胡显智,何 兵,楚国栋
分子催化 , 2009,
Abstract: 设 计 利 用 X 射 线 光 电 子 能 谱 仪 的 高 真 空 系 统 作 为 无 氧 条 件 下 光 催 化 反 应 和 分 析 的 场 所 , 研 究 真 空 无 氧 环 境 和 大 气 有 氧 环 境 中 紫 外 光 激 发 TiO2 薄 膜 表 面 的 光 催 化 反 应 , 并 对 无 氧 条 件 下 TiO2 薄 膜 降 解 亚 甲 基 蓝 进 行 初 步 探 索 . 结 果 表 明 , 在 大 气 有 氧 和 真 空 无 氧 条 件 下 TiO2 薄 膜 经 紫 外 光 照 后 , 表 面 的 化 学 组 成 和 化 学 状 态 均 发 生 了 变 化 ; 在 有 氧 环 境 中 TiO2 薄 膜 表 面 氧 含 量 增 加 , 而 在 无 氧 环 境 中 TiO2 薄 膜 表 面 氧 含 量 减 少 . TiO2 薄 膜 表 面 的 吸 附 氧 是 维 持 无 氧 条 件 下 光 催 化 反 应 的 重 要 原 因 , 增 加 薄 膜 表 面 吸 附 氧 的 含 量 能 提 高 TiO2 薄 膜 在 无 氧 环 境 中 的 催 化 活 性 . 此 外 , 无 氧 条 件 下 TiO2 薄 膜 降 解 亚 甲 基 蓝 光 催 化 反 应 过 程 中 , 亚 甲 基 蓝 分 子 只 是 脱 去 了 某 个 含 氮 的 基 团 , 生 成 了 中 间 产 物 , 而 并 没 有 完 全 降 解 .
peek-ha-cf复合材料的力学性能和体外生物活性  [PDF]
冯惺,隋国鑫,杨锐
材料研究学报 , 2008,
Abstract: ?制备peek-ha-cf复合材料,研究了引入cf对其力学性能和体外生物活性的影响.结果表明,cf的引入显著提高了peek-ha-cf的强度和模量,且其强度和模量在一定范围内具有更大的可设计性,能够在较宽的范围内满足与人体承力骨力学性能的良好匹配;peek-ha-cf复合材料具有良好的生物活性.
Multiple Regression Prediction Model for Cutting Forces in Turning Carbon-Reinforced PEEK CF30  [PDF]
Francisco Mata,Elena Beamud,Issam Hanafi,Abdellatif Khamlichi,Abdallah Jabbouri,Mohammed Bezzazi
Advances in Materials Science and Engineering , 2010, DOI: 10.1155/2010/824098
Abstract: Among the thermoplastic polymers available, the reinforced polyetheretherketone with 30% of carbon fibres (PEEK CF 30) demonstrates a particularly good combination of strength, rigidity, and hardness, which prove ideal for industrial applications. Considering these properties and potential areas of application, it is necessary to investigate the machining of PEEK CF30. In this study, response surface methodology was applied to predict the cutting forces in turning operations using TiN-coated cutting tools under dry conditions where the machining parameters are cutting speed ranges, feed rate, and depth of cut. For this study, the experiments have been conducted using full factorial design in the design of experiments (DOEs) on CNC turning machine. Based on statistical analysis, multiple quadratic regression model for cutting forces was derived with satisfactory -squared correlation. This model proved to be highly preferment for predicting cutting forces. 1. Introduction The machinability of composites in turning is studied in terms of tool wear, cutting forces, temperature, and surface quality. The addition of short fibres to thermoplastic composites enhances the properties such as stiffness, strength, and hardness and increases also the service temperature over unreinforced thermoplastics [1–5]. It has been reported that the addition of short fibers not only reduces the coefficient of friction and wear but also decreases the thermal expansion coefficient [6]. The carbon and glass fibres are the common reinforcements in thermoplastics because of low expansion rate and high flexural modulus. Park et al. developed heavy-duty hybrid carbon-phenolic hemispherical bearings. They used carbon-PEEK-phenolic hybrid composites with aluminum back up. They reported that the carbon fibre reinforcement provides maximum rigidity [7] the effects of PEEK powders and the bottom vent hole in the composite hemispherical bearing (CHB) on the strength were experimentally investigated. Based on the investigation, a new CHB was fabricated by molding rather than machining the hemispherical surface to eliminate crack and delamination and tested in an experimental set-up; the experimental results showed that the new CHB outperformed the existing carbon PEEK CHB both in the endurance life and load bearing capacity [8] whereas the glass fiber reinforcement provides high temperature service [9]. As a result of these properties and potential applications, there is a need to understand the machining of unreinforced and reinforced polyetheretherketone (PEEK) composite materials.
CF/PEEK复合材料界面层结构与性能关系研究  [PDF]
曾汉民,张志毅,章明秋,许家瑞,简念保,麦堪成
复合材料学报 , 1994,
Abstract: 本文根据聚醚醚酮(PEEK)在碳纤维表面形式的横晶层的结构特征分析,建立了CF/FEEK复合材料界面层微观力学性能的理论方程,计算了界面层的杨氏模量.通过超声浸渍法测量复合材料的力学性能验证了计算结果,证明所进行的分析合理.计算结果表明,PEEK界面横晶层在垂直于纤维方向的杨氏模量Er随PEEK结晶度的增大,或随横晶中PEEK晶片长度的增大而增大,并随晶片厚度的增大而减小.该界面层的上述模量值始终高于界面层附近球晶的模量值Es,两者之间的比值ET/Es;依赖于横晶及球晶中的晶片长度b、厚度c和宽度a.由于界面层的模量高于非界面层的模量,当复合材料中纤维表面形成横晶时,复合材料将有较高的刚性.
仿生多孔润滑耐磨CF/PTFE/PEEK复合材料的设计及其摩擦学性能  [PDF]
汪怀远,林珊,张帅,杨淑慧,朱艳吉
材料工程 , 2014, DOI: 10.11868/j.issn.1001-4381.2014.06.009
Abstract: 采用模压-滤取和高温真空熔渍工艺制备了自身发汗式润滑耐磨多孔CF/PTFE/PEEK复合材料。考察了造孔剂(NaCl)、PTFE的含量及炭纤维层间间距对多孔PEEK复合材料结构和摩擦学性能的影响。结果表明,当PTFE含量为20%(质量分数,下同)、NaCl为30%、炭纤维层间间距为0.4mm所得多孔CF/PTFE/PEEK复合材料摩擦因数和磨损率最低,200N下摩擦因数、磨损率分别为0.0192,3.47×10-16m3/Nm,较经典CF/PEEK复合材料摩擦因数降低了9倍,耐磨性提高了25倍。原因在于复合材料中PTFE能形成连续的转移膜,降低了材料摩擦因数;NaCl形成的多孔结构能储存住一定润滑油脂,摩擦过程中在载荷和温度的作用下能形成稳定润滑油膜,明显降低了材料磨损量;炭纤维布起到支撑骨架作用,并协同PTFE,NaCl提高多孔PEEK复合材料摩擦磨损性能。
PTFE微粉/CF改性PEEK复合材料的摩擦磨损性能  [PDF]
姚光督,王文东,沈景凤,杜鸣杰,司明明
- , 2018, DOI: 10.11951/j.issn.1005-0299.20170115
Abstract: 为解决核电水循环系统中鼓型旋转滤网驱动装置的耐腐蚀问题,本文研究了碳纤维和聚四氟乙烯微粉改性的聚醚醚酮复合材料在干摩擦、水润滑和油润滑条件下的摩擦磨损性能.通过机械共混、高温模压的方法,制备了不同质量分数的聚四氟乙烯(PTFE)微粉/碳纤维(CF)/二硫化钼(MoS2)/聚醚醚酮(PEEK)复合材料.采用拉伸试验机和塑料洛氏硬度计测试其力学性能,采用摩擦磨损试验机测试了复合材料在干摩擦、水润滑和油润滑条件下的摩擦磨损性能,采用扫描电子显微镜对其摩擦表面形貌进行分析.结果表明:复合材料在水润滑和油润滑时摩擦系数及磨痕宽度均较小,但水润滑时摩擦系数波动幅度较大且磨痕宽度略高;复合材料在干摩擦条件下的磨损机制以磨粒磨损为主,伴有疲劳磨损,油润滑时摩擦面可形成连续的润滑膜而保持光滑,水润滑时水流冲刷破坏了摩擦面上固体润滑膜的稳定性;CF质量分数增加时,复合材料的洛氏硬度和压缩强度递增,压缩强度达到164 MPa,PTFE微粉质量分数增加时,复合材料的洛氏硬度和压缩强度递减;CF质量分数增加时,复合材料的干摩擦系数及磨痕宽度下降,PTFE微粉质量分数增加时,复合材料的干摩擦系数下降,达到0.17.
In this paper, in order to solve the problem of corrosion resistance of drum type rotary filter drive in nuclear water circulation system, we studied the friction and wear properties of carbon fiber (CF) and polytetrafluoroethylene powders which modified polyether ether ketone composites under dry friction, water and oil lubrication. Through the mechanical blending and high temperature molding method, we prepared polyether ether ketone composite with different weight ratios of the PTFE powders, carbon fiber and molybdenum disulfide. The mechanical properties were examined by a tensile testing machine and a plastic Rockwell hardness tester. The friction and wear behaviors of the composites under dry friction, water and oil lubrication were tested by friction and wear tester. Finally, we analyzed the surface morphology of the friction surface by scanning electron microscopy (SEM). The results indicate that the friction coefficient and the wear width of the composites are small for the water and oil lubrication whereas the friction coefficient exhibits large fluctuation and the wear width is larger under water lubrication. The wear mechanism of composite materials is mainly abrasive wear accompanied by fatigue wear under dry friction condition. The friction surface can form continuous lubrication film and keep smooth under oil lubrication whereas the flow erosion destroys the stability of the solid lubrication film on the friction surface under water lubrication. As the mass fraction of CF increased, both the Rockwell hardness and compressive strength of the composites increased, and the compressive strength reached 164 MPa. As the mass fraction of PTFE powders increased, both the Rockwell hardness and compressive strength of composites decreased quickly. As the mass fraction of CF increased, the dry friction coefficient and the wear width of the composites decreased. Meanwhile when the mass fraction of PTFE powders increased, the dry friction coefficient of the composites decreased to 0.17.
Peek Arc Consistency  [PDF]
Manuel Bodirsky,Hubie Chen
Computer Science , 2008,
Abstract: This paper studies peek arc consistency, a reasoning technique that extends the well-known arc consistency technique for constraint satisfaction. In contrast to other more costly extensions of arc consistency that have been studied in the literature, peek arc consistency requires only linear space and quadratic time and can be parallelized in a straightforward way such that it runs in linear time with a linear number of processors. We demonstrate that for various constraint languages, peek arc consistency gives a polynomial-time decision procedure for the constraint satisfaction problem. We also present an algebraic characterization of those constraint languages that can be solved by peek arc consistency, and study the robustness of the algorithm.
Predictive Models for Different Roughness Parameters During Machining Process of Peek Composites Using Response Surface Methodology  [PDF]
Mata-Cabrera Francisco,Hanafi Issam,Khamlichi Abdellatif,Jabbouri Abdallah
Ingeniería, investigación y tecnología , 2013,
Abstract: Polyetheretherketone (PEEK) composite belongs to a group of high performance thermoplastic polymers and is widely used in structural components. To improve the mechanical and tribological properties, short fibers are added as reinforcement to the material. Due to its functional properties and potential applications, it’s impor- tant to investigate the machinability of non-reinforced PEEK (PEEK), PEEK rein- forced with 30% of carbon fibers (PEEK CF30), and reinforced PEEK with 30% glass fibers (PEEK GF30) to determine the optimal conditions for the manufacture of the parts. The present study establishes the relationship between the cutting con- ditions (cutting speed and feed rate) and the roughness (Ra , Rt , Rq , Rp ), by develop- ing second order mathematical models. The experiments were planned as per full factorial design of experiments and an analysis of variance has been performed to check the adequacy of the models. These state the adequacy of the derived models to obtain predictions for roughness parameters within ranges of parameters that have been investigated during the experiments. The experimental results show that the most influence of the cutting parameters is the feed rate, furthermore, proved that glass fiber reinforcements produce a worse machinability.
碱液中晶须增强PEEK复合材料的摩擦磨损性能  [PDF]
汪怀远,朱艳吉,冯新,陆小华
化工学报 , 2010,
Abstract: 研究了不同含量PTW增强PEEK复合材料在碱液中的摩擦磨损性能,并与经典的CF增强PEEK复合材料对比,借助于SEM分析了磨损面和对偶面微观形貌,探讨了相关机理。结果表明,干摩擦时15%(质量)PTW增强PTFE/PEEK复合材料耐磨性是相同含量CF增强时的10.5倍。在碱液中,CF增加了PTFE/PEEK复合材料的摩擦系数、降低了其耐磨性能,而PTW可以进一步降低PTFE/PEEK复合材料的摩擦系数、明显地提高其耐磨性能。含5%PTW可提高PTFE/PEEK复合材料碱液中耐磨性2.36倍。碱液阻止了对偶面转移膜的形成,犁削和磨粒磨损是CF增强PEEK复合材料碱液中的主要磨损机制,而隧道状晶体结构和细微尺寸的纤维态形貌使得PTW在碱液中仍具有显微增强耐磨作用。
Polyetheretherketone (PEEK) Composites Reinforced with Fly Ash and Mica  [PDF]
M. Rahail Parvaiz, Smita Mohanty, Sanjay K. Nayak, P. A. Mahanwar
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2010, DOI: 10.4236/jmmce.2010.91003
Abstract: Polyetheretherketone (PEEK) composites were developed using fly ash and mica as fillers. PEEK composites of 5-30 wt% loading were compounded using twin screw extruder. Tensile strength, tensile modulus and flexural modulus increased with the incorporation of both the fillers in PEEK matrix. Tensile modulus of PEEK fly ash composites was found to be higher than PEEK mica composites. Charpy impact strength of PEEK mica composites improved drastically up to 15 wt% of filler but in PEEK fly ash composites charpy impact strength was decreased. The effect of fly ash and mica on the percentage crystallinity of PEEK composites was studied by using modulated differential scanning calorimeter (MDSC). Limiting oxygen index (LOI) of PEEK fly ash and mica composites also improved by 11% and 24% respectively than pure PEEK at 30 wt% loading respectively. The dynamic modulus of PEEK composites shows over 133% increment at 100-250 °C, indicating improvement of elevated temperature mechanical properties. Effects of filler on the morphology of PEEK composites have also been discussed.
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