The effect of interfacial mixing on Ag/Al2O3 by N+ implantation

The Ag film/Al₂O₃ implanted with an N ion energy of 110 keV. The ion-induced interfacial mixing were examined using AES, STD and XPS. The frictional coefficient of implanted Ag/Al₂O₃ in air was determined by Drive friction precise measuring apparatus (DFPM). The influence of N⁺ implantation on the interfacial chemistry and adhesion of Ag films on Al₂O₃ substrates was examined, compounds formed by introducing a thin layer between the Ag and the Al₂O₃ at 1 × 10¹⁷ N·cm^–2. This investigation resulted in extensive interfacial grading, and new chemical bonding across the Ag/Al₂O₃ interfaces. The case for the Ag/Al₂O₃ reaction lead to the metal ceramic of 13Al₂O₃·AIN and -AgAlO₂ formation though non equilibrium processes of implantation, and friction decreased in initial cycle where ion implantation of lower vacuum lead to surface carbon film. The combination of these effects provided an adhesion increase that was approximately 3 times that obtained in unimplanted Ag/Al₂O₃ specimens.     

Effect of deposition pressure on the adhesion and tribological properties of a-CN<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>H films prepared by DC-RF-PECVD

Hydrogenated carbon nitride (a-CN _x H films) was deposited on n-type single-crystal Si (100) by direct current radio frequency plasma-enhanced chemical vapor deposition (DC-RF-PECVD), under the working pressure of 5.0–17.0 Pa, using the CH₄ and N₂ as feedstock. The composition and surface morphology of the a-CN _x H films were characterized by means of Raman spectroscopy and atomic force microscopy, while the Young’s modulus, elastic recovery, adhesion strength, and tribological properties were evaluated using nano-indentation, scratch test and friction test system. It was found that the surface roughness and Raman spectra peak intensity ratio I _D/I _G of the films increased with the increase of working pressure, while the Young’s modulus, elastic recovery and adhesion strength of the films significantly decreased. Moreover, the tribological properties of the films also varied with the working pressure. The wear life sharply increased with the increase of working pressure from 5.0 Pa to 7.5 Pa, further, an increase in the deposition pressure led to a gradual decrease in the wear life, consequently, the a-CN _x H film deposited at 7.5 Pa exhibited the longest wear life. The deposition pressure seemed to have slight effect on the average friction coefficients, whereas the surface roughness and adhesion strength have deteriorated with increasing deposition pressure.     

纤维素/ZnO复合膜的制备及其光催化性能

为克服纳米粉体光催化剂易团聚、难回收和容易引起二次污染等缺点,采用"一步"水热法在纤维素膜表面原位生长多孔球形微纳米ZnO颗粒。利用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)和热重分析仪(TG)分析了纤维素/ZnO复合膜的微观形貌、组成、晶体结构、热稳定性以及ZnO的负载量;采用紫外-可见分光光度计根据亚甲基蓝溶液的降解测试其光催化活性。结果表明:该方法可成功实现纤维素膜对ZnO颗粒的负载,且当加热时间为12h时,负载的ZnO颗粒数量多分布均匀,且为多孔球状并呈典型的纤锌矿结构。在紫外光照射下,纤维素/ZnO复合膜具有优越的光催化性能,可用于降解染料等有机物;当ZnO负载量为6 mg时,3h内亚甲基蓝的催化效率为90%。     

Facile preparation and electrochemical characterization of cobalt oxide/multi-walled carbon nanotube composites for supercapacitors

A series of cobalt oxide/multi-walled carbon nanotube (Co₃O₄/MWCNT) composites are successfully synthesized by a facile chemical co-precipitation method followed by a simple thermal treatment process. The morphology and structure of as-obtained composites are characterized by X-ray diffraction, scanning electron microscopy, and N₂-adsorption/desorption measurements, and the electrochemical properties are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS). For all Co₃O₄/MWCNT composites, MWCNTs are well dispersed in the loosely packed Co₃O₄ nanoparticles. Among them, the Co₃O₄-5%MWCNT composite exhibits the highest specific surface area of 137 m² g⁻¹ and a mesoporous structure with a narrow distribution of pore size from 2 to 10 nm. Because of the synergistic effects coming from Co₃O₄ nanoparticles and MWCNTs, the electrochemical performances of pure Co₃O₄ material are significantly improved after adding MWCNTs. The Co₃O₄-5%MWCNT composite shows the largest specific capacitance of 418 F g⁻¹ at a current density of 0.625 A g⁻¹ in 2 M KOH electrolyte. Furthermore, this composite exhibits good cycling stability and lifetime. Therefore, based on the above investigation, such Co₃O₄/MWCNT composite could be a potential candidate for supercapacitors.     

Ni3Al matrix high temperature self-lubricating composites

A Ni₃Al matrix high temperature self-lubricating composite Ni₃Al-BaF₂-CaF₂-Ag-Cr was fabricated by the powder metallurgy technique, and tribological behavior at a wide temperature range from room temperature to 800 °C was investigated. The results indicated that the composite exhibited low friction coefficients (0.30-0.36) and wear rates (0.65-2.45×10⁻⁴ mm³ N⁻¹ m⁻¹). It was found that the low friction coefficient was attributed to the synergistic effects of Ag, fluorides and chromates formed in the tribo-chemical reaction at high temperatures. The low wear rate of the composite was due to the high strength and the excellent lubricating properties.     

Achieving Low Tribological Moisture Sensitivity by a-C:Si:Al Carbon-based Coating

Owing to the requirements of the stable operation for mechanical components, the urgent challenges are to control tribological moisture sensitivity of protective coatings. In this letter, a-C:Si and a-C:Si:Al carbon-based coatings were successfully fabricated via magnetron sputtering Si, Al, and C. The microstructure, mechanical properties, and tribological moisture sensitivity of as-fabricated carbon-based coatings were comparatively investigated. Results showed that the as-fabricated a-C:Si and a-C:Si:Al coatings were dominated by typical amorphous structure. The co-introduction of Al could effectively relax internal stress and improve adhesive strength as well as maintain the moderately high hardness for the as-fabricated coating. The striking improvement in tribological moisture sensitivity of a-C:Si:Al carbon-based coating was mainly attributed to the superior mechanical properties and the formation of continuously compacted graphitized tribofilm under low relative humidity condition as well as low shear strength colloidal silica tribofilm under high relative humidity condition. The good balance between the hardness and toughness, low internal stress, and superior low tribological moisture sensitivity of a-C:Si:Al coating make it a good candidate for solid lubricating coating in engineering applications.     

掺杂磁性氧化物的介孔SiC材料的制备及磁性研究

采用纳米浸渍法,以有序介孔SiC为模板,铁和钴的硝酸盐为主要填充原料,制备了掺杂磁性氧化物的介孔SiC复合材料。研究了填充量和烧结温度对其介孔结构和磁学性能的影响。结果表明,相对较大的填充量和较高的烧结温度,有助于掺杂氧化物的结晶和复合材料磁学性能的增强。此外,800℃烧结制备的复合材料仍具有较大的比表面积(114m2/g)。     

环氧树脂研究与应用进展

综述了环氧树脂的研究应用工作，着重论述了环氧树脂的结构改性、聚合物复合改性、无机物复合改性及其改性机理，简要评述了今后的发展方向。     

含磷抗磨,极压添加剂在铝—钢摩擦副中摩擦学特性的研究

利用Ｏｐｔｉｍｏｌ ＳＲＶ试验机考察了边界润滑条件下四种含磷添加剂在铝－钢摩擦副中的摩擦，磨损特性，研究了添加剂的摩擦化学反应，结果表明：含磷添加剂在铝－钢摩擦融 中不仅没有起到抗磨作用，相反会增加基础油润滑对铝的磨损，尤以亚磷酸酯为甚。磷酸酯与亚磷酸酯之间抗磨作用的差别在于其与铝之间的反应活性不同，在试验条件下化学腐蚀磨损可能是主要的磨损形式。