易碳化过渡层对碳基硬质薄膜结构和性能的影响

发布时间：2018-03-21 03:23

本文选题：碳基硬质薄膜　切入点：碳化　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：本文以制备高膜基结合性能、良好薄膜质量的碳基硬质薄膜为出发点,以复合和多层薄膜为主导,采用中频磁控溅射技术以及热丝化学气相沉积技术制备了不同厚度Ti过渡层的金刚石复合薄膜、不同调制周期Cr/DLC多层膜、不同碳源浓度Si C过渡层的Si C/DLC复合薄膜,探索了易碳化过渡层与类金刚石膜和金刚石膜结构性能间的作用关系,结果表明:(1)不同厚度Ti过渡层的碳化,能够通过影响Ti C晶面择优生长取向,进而对金刚石膜晶粒的生长和金刚石复合薄膜摩擦学性能造成影响。在金刚石膜制备过程中,金属Ti被完全碳化为Ti C。随着Ti间隔层厚度的增加,复合薄膜中Ti C间隔层晶面择优生长取向发生改变,从以Ti C(111)晶面择优生长最终转变为Ti C(111)、Ti C(220)和Ti C(200)三晶面竞争生长;同时,金刚石膜晶粒尺寸逐渐增大,导致金刚石复合薄膜摩擦系数不断变大。(2)Cr/DLC多层膜层间界面处Cr的碳化能够通过影响DLC层中碳价键结构及薄膜内应力进而影响多层膜力学性能。随多层膜调制周期减小,薄膜中硬质Cr3C2相的含量增加,导致类金刚石层中sp2-C的量增加,sp3-C的量减少;多层膜的硬度及弹性模量随调制周期的增大先增大后减小,当多层膜的调制周期为400 nm时,多层膜具有最大硬度为18 GPa以及最大弹性模量为175 GPa。此时,Cr/DLC多层膜还具有最大膜基结合力;三组Cr/DLC多层膜断裂韧性均很高且随着碳化的界面数量的增加而增大。(3)碳元素浓度不同的四组Si C间隔层能够通过影响Si C/DLC复合薄膜内sp3/sp2键的比例及薄膜内应力进而影响Si C/DLC复合薄膜力学性能。随着制备Si C过渡层的C2H2流量的增加,复合薄膜中sp3-C的量逐渐减小,sp2-C的量逐渐增加。Si C/DLC复合薄膜的硬度及弹性模量随C2H2流量的增加先增大后减小,当C2H2流量为70 Sccm时,复合薄膜有最大硬度值为15.3 GPa,最大弹性模量值为142 GPa。此时,Si C/DLC复合薄膜也拥有最大临界载荷80 N。随制备Si C过渡层碳源浓度的增加,四组复合薄膜断裂韧性基本呈增大趋势。
[Abstract]:In this paper, the preparation of carbon-based hard films with high binding properties and good film quality is taken as the starting point, and the composite and multilayer films are the dominant ones. Diamond composite films with different thickness Ti transition layers, Cr/DLC multilayer films with different modulation periods and sic / DLC composite films with different carbon source concentrations were prepared by intermediate frequency magnetron sputtering and hot filament chemical vapor deposition. The effect of easy carbonization transition layer on the structure and properties of diamond-like carbon film and diamond-like carbon film was investigated. The results show that the carbonization of Ti transition layer with different thickness can influence the preferred growth orientation of Ti C crystal plane. The grain growth of diamond film and the tribological properties of diamond composite film are affected. During the preparation of diamond film, the metal Ti is completely carbonized into TiC.The thickness of Ti interlayer increases with the increase of Ti interlayer thickness. The preferred growth orientation of the Ti C spacer in the composite film changed from the preferential growth of the Ti / C _ (111) crystal plane to the competitive growth of the Ti _ C _ (111) / Ti _ (C ~ (2 +) _ (220)) and Ti _ (C ~ (2 +)) _ (200) planes, and the grain size of the diamond film gradually increased. As a result of the increasing friction coefficient of diamond composite film, the carbonization of Cr at the interlayer interface of Cr / DLC can affect the mechanical properties of the multilayer film by affecting the structure of carbon valence bond in the DLC layer and the stress in the film, which decreases with the modulation period of the multilayer film. The increase of the content of hard Cr3C2 phase in the film leads to the increase of the amount of sp2-C in the diamond-like carbon layer, the decrease of the amount of sp3-C, the increase of the hardness and elastic modulus of the multilayer film with the increase of the modulation period, and the decrease of the modulus of elasticity with the increase of the modulation period of the multilayer film, when the modulation period of the multilayer film is 400nm, The maximum hardness of the multilayer film is 18 GPa and the maximum elastic modulus is 175 GPA. The fracture toughness of all three Cr/DLC multilayers is very high and increases with the increase of the number of carbonized interfaces.) four groups of sic spacers with different carbon concentration can influence the ratio of sp3/sp2 bond in sic / DLC composite film and the stress evolution in the film. But the mechanical properties of sic / DLC composite films were affected. With the increase of flow rate of C _ 2H _ 2 in Si / C transition layer, The amount of sp3-C in the composite films decreases gradually. The hardness and elastic modulus of Si / C / DLC composite films increase firstly and then decrease with the increase of C _ 2H _ 2 flux. When the flow rate of C _ 2H _ 2 is 70 Sccm, The maximum hardness and elastic modulus of the composite films are 15.3 GPA and 142 GPA respectively. At this time, the maximum critical load of Si / C / DLC composite films is 80 N. the fracture toughness of the four groups of composite films increases with the increase of carbon source concentration in the transition layer of sic.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2

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