乙炔气体流量对纳米TiC类金刚石复合膜的化学结构及力学性能影响

采用离子注入与反应磁控溅射相结合的方法在钛合金及硅片基体表面上制备了纳米TiC类金刚石(DLC)复合膜.通过纳米压痕技术检测了薄膜的纳米硬度，显微划痕试验评估了薄膜的结合力.通过X射线光电子能谱及X射线衍射表征了薄膜的化学结构.结果表明，通过改变C₂H₂气体流量，可以达到控制薄膜中钛原子含量的目的，合适的C₂H₂气体流量可以在DLC膜中形成较多的纳米TiC晶粒，形成DLC包覆TiC晶粒的复合结构，使DLC膜力学性能得到明显提高.另外，划痕试验表明掺钛、先注入后沉积工艺都使薄膜的结合力得到了较大提高. 关键词： 纳米TiC类金刚石复合膜 类金刚石膜 力学性能     

掺氮四面体非晶碳的第一性原理研究

采用基于第一性原理的分子动力学方法对掺氮四面体非晶碳进行结构建模,并对其显微结构和电子结构进行了研究. 氮在非晶碳网络中的配位形态与密度没有明显关系,主要是以三配位形态存在,其次是两配位,四配位氮的比例很小. 掺氮后碳网络结构sp²含量大大增加,随着氮含量的增加,费米能级附近态密度增加. 氮掺入后并未使费米能级发生明显移动. 关键词： 掺氮四面体非晶碳 第一性原理 密度泛函理论 电子结构     

微纳结构超疏水表面的浸润性分析及设计

微纳复合结构超疏水表面在防污、流动减阻、防冰等领域具有广阔的应用前景，超疏水表面主要通过设计表面化学性质和微观几何结构来获得.合理设计保持表面润湿态的稳定性是其性能发挥的关键.以"液滴-超疏水表面"系统为研究对象，基于最小能原理分析了四种稳定润湿形态，指出影响润湿状态的本征接触角和微观结构参数（相对柱距、相对柱高）.推导了本征接触角的计算公式并对常见材料的本征接触角进行了讨论.结合四种润湿态方程，绘制了随着相对柱距和相对柱高的润湿云图，并将润湿云图归纳为"一点三线六区四状态".分析了相对柱距和相对柱高对浸润状态的影响，结果表明较大的本征接触角、较小的相对柱距和较大的相对柱高能够减小浸润状态发生转变的临界参数，从而拓展超疏水表面的区域范围，有利于超疏水表面的稳定性.利用文献数据验证了上述润湿云图能够准确反映出润湿形态.在上述工作基础之上总结提炼了超疏水表面设计的一般思路.研究结果可为超疏水表面的设计提供理论依据和技术基础.     

Preparation and characterization of thick cubic boron nitride films

Cubic boron nitride （c-BN） films are prepared by the radio frequency magnetron sputtering technique. The stresses and crystallinities of the films are estimated by the Fourier transform infrared spectroscopy of c-BN samples, including the peak shifts and varieties of full widths at half maximum. The effects of the B-C-N interlayer and the two-stage deposition method on the c-BN films are investigated. Then the thick and stable c-BN films are prepared by a combination of the two methods. The properties of the interlayer and film are also characterized.     

Influences of nitrogen flow rate on the structures and properties of Ti and N co-doped diamond-like carbon films deposited by arc ion plating

In this paper, Ti-C-N nanocomposite films are deposited under different nitrogen flow rates by pulsed bias arc ion plating using Ti and graphite targets in the Ar/N2 mixture gas. The surface morphologies, compositions, microstructures, and mechanical properties of the Ti-C-N films are investigated systematically by field emission scanning electron mi- croscopy （FE-SEM）, x-ray photoelectron spectroscopy （XPS）, grazing incident x-ray diffraction （GIXRD）, Raman spectra, and nano-indentation. The results show that the nanocrystalline Ti（C,N） phase precipitates in the film from GIXRD and XPS analysis, and Raman spectra prove the presence of diamond-like carbon, indicating the formation of nanocomposite film with microstructures comprising nanocrystalline Ti（C,N） phase embedded into a diamond-like matrix. The nitrogen flow rate has a significant effect on the composition, structure, and properties of the film. The nano-hardness and elastic modulus first increase and then decrease as nitrogen flow rate increases, reaching a maximum of 34.3 GPa and 383.2 GPa, at a nitrogen flow rate of 90 sccm, respectively.     

Nanocomposite TiC/a-C：H film prepared on titanium aluminium alloy substrates by PSII assistant MW-ECRCVD

Thin films of titanium carbide and amorphous hydrogenated carbon have been synthesized on titanium aluminium alloy substrates by PSII assisted MW-ECRCVD with a mirror field. The microstructure, chemical composition and mechanical property were investigated. Using XPS and TEM, the films were identified to be a-C：H film containing TiC nanometre grains （namely, the so-called nanocomposite structure）. The size of TiC grains of nanocomposite TiC/DLC film is about 5 nm. The nanocomposite structure has obvious improvement in the mechanical properties of DLC film. The hardness of a-C：H film with Ti is enhanced to 34 G Pa~ while that of a-C：H film without Ti is about 12 G Pa, and the coherent strength is also obviously enhanced at the critical load of about 35N.