Teixeira V, Soares P, Martins A J, Carneiro J, Cerqueira F
Physics Department, University of Minho, Campus de Azurem, 4800-058 Guimaraes, Portugal.
J Nanosci Nanotechnol. 2009 Jul;9(7):4061-6. doi: 10.1166/jnn.2009.m11.
Carbon based films can combine the properties of solid lubricating graphite structure and hard diamond crystal structure, i.e., high hardness, chemical inertness, high thermal conductivity and optical transparency without the crystalline structure of diamond. Issues of fundamental importance associated with nanocarbon coatings are reducing stress, improving adhesion and compatibility with substrates. In this work new nanocomposite coatings with improved toughness based in nanocrystalline phases of metals and ceramics embedded in amorphous carbon matrix are being developed within the frame of a research project: nc-MeNxCy/a-C(Me) with Me = Mo, Si, Al, Ti, etc. Carbide forming metal/carbon (Me/C) composite films with Me = Mo, W or Ti possess appropriate properties to overcome the limitation of pure DLC films. These novel coating architectures will be adopted with the objective to decrease residual stress, improve adherence and fracture toughness, obtain low friction coefficient and high wear-resistance. Nanocomposite DLC's films were deposited by hybrid technique using a PVD-Physically Vapor Deposition (magnetron sputtering) and Plasma Enhanced Chemical Vapor Deposition (PECVD), by the use of CH4 gas. The parameters varied were: deposition time, substrate temperature (180 degrees C) and dopant (Si + Mo) of the amorphous carbon matrix. All the depositions were made on silicon wafers and steel substrates precoated with a silicon inter-layer. The characterisation of the film's physico-mechanical properties will be presented in order to understand the influence of the deposition parameters and metal content used within the a-C matrix in the thin film properties. Film microstructure and film hybridization state was characterized by Raman Spectroscopy. In order to characterize morphology SEM and AFM will be used. Film composition was measured by Energy-Dispersive X-ray analysis (EDS) and by X-ray photoelectron spectroscopy (XPS). The contact angle for the produced DLC's on silicon substrates were also measured. Thin film adherence was studied by micro-scratch test. Residual stresses in the produced coatings will be analysed by bending technique.
碳基薄膜可以兼具固体润滑石墨结构和坚硬金刚石晶体结构的特性，即具有高硬度、化学惰性、高导热性和光学透明性，且没有金刚石的晶体结构。与纳米碳涂层相关的一些至关重要的问题包括降低应力、提高附着力以及与基材的兼容性。在本研究项目的框架内，正在研发基于嵌入非晶碳基体中的金属和陶瓷纳米晶相的新型纳米复合涂层，以提高韧性：nc-MeNxCy/a-C(Me)，其中Me = Mo、Si、Al、Ti等。形成碳化物的金属/碳（Me/C）复合薄膜，Me = Mo、W或Ti，具有适当的性能以克服纯类金刚石碳（DLC）薄膜的局限性。采用这些新型涂层结构的目的是降低残余应力、提高附着力和断裂韧性、获得低摩擦系数和高耐磨性。纳米复合DLC薄膜通过使用PVD-物理气相沉积（磁控溅射）和等离子体增强化学气相沉积（PECVD）的混合技术，利用CH4气体进行沉积。变化的参数有：沉积时间、基材温度（180摄氏度）和非晶碳基体的掺杂剂（Si + Mo）。所有沉积均在预先涂有硅中间层的硅片和钢基材上进行。将展示薄膜物理力学性能的表征，以了解沉积参数和非晶碳基体中使用的金属含量对薄膜性能的影响。通过拉曼光谱对薄膜微观结构和薄膜混合状态进行表征。为了表征形态，将使用扫描电子显微镜（SEM）和原子力显微镜（AFM）。通过能量色散X射线分析（EDS）和X射线光电子能谱（XPS）测量薄膜成分。还测量了在硅基材上制备的DLC的接触角。通过微划痕试验研究薄膜附着力。通过弯曲技术分析所制备涂层中的残余应力。
