Pulsed laser deposition of carbon films: Dependence of film properties on laser wavelength

We have grown thin carbon films by pulsed laser deposition and have investigated the extent to which the properties of such films, as well as the processes responsible for these properties, are laser wavelength dependent. Films were grown by ablating material from a graphite target onto room temperature Si(100) substrates with 1064 and 248 nm laser radiation. The films were analyzed byin situ electron energy loss spectroscopy and byex situ Raman spectroscopy. The results indicated that films grown with 1064 nm ablation were graphitic, while those grown with 248 nm radiation were diamond-like. We have also examined the mass and kinetic energy distributions of the particles ejected from graphite by the two laser wavelengths. The results indicated that irradiation of graphite with 1064 nm laser radiation results in the ejection of a series of carbon cluster ions C _n ⁺ (1 ≤ n ≤ 30) with mean kinetic energies less than 5 eV. Ablation of graphite with 248 nm radiation results in the ejection of primarily C ₂ ⁺ and C ₃ ⁺ with mean kinetic energies of 60 and 18 eV, respectively. These results suggest that large, low energy clusters produce graphitic films, while small, high energy clusters produce films of diamond-like carbon.     

Synthesis of diamond crystals and films using an oxygen-acetylene flame under atmosheric pressure

Diamond growth with rates up to 100 to 140 μm/hr was achieved using an oxygen-acetylene combustion spraying technique in an atmospheric environment. Investigations on the processing indicated that the gas flow ratio, substrate position, substrate temperature, temperature distribution, and substrate pretreatment were the most important factors affecting the growth of diamond crystals. Evaluation by means of X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and electron probe microanalysis showed that the synthesized diamond was nearly perfect in morphology, structure, and purity.     

真空阴极弧离子镀类金刚石碳（DLC）膜的碳弧稳定性研究

选用氩气、氩气加氢气、氩气加乙炔等气体作为介质，石墨作为靶材进行真空阴极弧离子镀来制备类金刚石碳膜。石墨电弧有其独特的电弧特性曲线，不同气体介质对碳弧特性的影响不同，磁场的大小对电弧的稳定性有很大作用，碳弧下基片偏流随电弧电压的增加而减小，试验得到表面光滑的类金刚石碳（DLC）膜，对膜的表面进行了SEM分析。     

类金刚石膜的制备及其影响因素

概述了近年来制类金刚石膜的新技术如双射频辉光放电（RF－RF）法，射频－直流辉光放电（RF－DC）法和微波－射频（MW－RF）法等，并且对影响类金刚石膜制备及性能的因素如基体材料，制备类金刚石膜时在膜中添加元素，类金刚石膜与基材之间的中间层等进行了较全面的分析。     

星形微波等离子体化学气相沉积装置上类金刚石薄膜的制备

以甲烷、氢气和氧气为反应气体,分别在镜面抛光的单晶硅片和石英玻璃基片上制备了类金刚石薄膜,并用扫描电子显微镜、激光拉曼光谱和傅立叶红外透射光谱仪等测试方法对薄膜的表面形貌、质量和光学性能进行了表征;通过对类金刚石（DLC）薄膜制备过程中碳源浓度、基片温度等参数的研究,掌握了工艺参数对薄膜性能的影响规律,并在此基础上成功地对薄膜的沉积工艺进行了优化.结果表明,当反应气体中的流量配比为甲烷∶氢气∶氧气=10∶100∶1,腔体压力和基片温度分别为0.5 kPa和400℃,制备出的DLC薄膜表面光滑平整,薄膜中的纳米金刚石特征峰明显,在石英玻璃上沉积的DLC薄膜在3 000～4 000 cm-1波数区间透光率超过80％,达到了光学应用要求.     

端部霍尔等离子体源沉积类金刚石膜的研究

本文通过对端部霍尔离子源特性的研究 ,采用自行研制的用于离子束辅助沉积的端部霍尔离子源成功镀制了类金刚石膜 ,并对采用该离子源制备类金刚石膜的工艺进行了研究和分析。实验结果表明 ,采用端部霍尔离子源镀制类金刚石膜不仅操作简单、可实现大面积沉积 ,而且类金刚石膜的沉积速率较大 ,最大可达 0 .8nm s,其折射率依不同工艺在 1.8～ 2 .2之间可调。并对不同工艺条件下制备的类金刚石膜的硬度进行了测试和分析。     

常温生长类金刚石薄膜的实验研究

利用射频等离子体增强化学气相沉积(RFPECVD)工艺在常温下实现在不锈钢、硅片、玻璃等基底上大面积沉积类金刚石(DLC)膜.薄膜表面光滑致密,与衬底的结合力较高.用Raman,FTIR,SEM,EDX研究了薄膜的形貌、结构与组分.用栓-盘摩擦磨损试验机测试了薄膜的摩擦系数.通过优化沉积参数,所沉积的DLC膜在与100Cr6钢球对磨时摩擦系数低于0.01.在摩擦过程中DLC膜的磨损机制借助SEM进行了研究.     

类金刚石薄膜的折射率研究

利用脉冲真空电弧镀方法在硅基底上沉积类金刚石薄膜，研究薄膜折射率和工艺参数以及折射率与薄膜本征硬度的关系，结果表明：无氢类金刚石薄膜的折射率在2．5～2．7之间；不同的工艺参数可以得到不同折射率的薄膜；通过改变工艺条件来制备不同折射率的薄膜，和不同的基底材料的折射率匹配，使其有一定的机械强度。     

Effect of Magnetic Field on the Deposition of Transparent Diamond-Like Carbon ( DLC ) Films by RF-PCVD

In order to deposit transparent and hard DLC films, magnetic field was introduced to enhance the plasma density of radiofrequency plasma chemical vapor deposition (RF-PCVD). In this paper, the configuration and computation of external magnetic field B are introduced. The restriction effect of magnetic field B on the charged particles and the effect of magnetic field B on the primary parameters-nonindependent power Pf and self-bias Uz were also studied. The mechanism of how magnetic field B affects self-bias Uz was analyzed.     

镁合金表面铬掺杂类金刚石薄膜的制备与性能研究

本文利用阳极层离子束混合磁控溅射技术在AZ31镁合金表面制备了类金刚石涂层（DLC）和Cr掺杂DLC膜（Cr-DLC）,并利用Raman光谱、残余应力仪、划痕仪、摩擦磨损仪和电化学工作站等,对薄膜的碳结构、残余应力、结合力、摩擦学性能和耐腐蚀性进行了研究。结果表明：相比纯DLC膜,Cr-DLC膜具有较低的残余应力,较高的膜/基结合力。Cr-DLC膜能显著提高镁合金的抗摩擦磨损性能,但对改善镁合金耐腐蚀性能影响不大。