Improvement in Tribological Properties by Modification of Grain Boundary and Microstructure of Ultrananocrystalline Diamond Films
學年 101
學期 2
出版（發表）日期 2013-05-01
作品名稱 Improvement in Tribological Properties by Modification of Grain Boundary and Microstructure of Ultrananocrystalline Diamond Films
作品名稱（其他語言）
著者 Kamatchi Jothiramalingam Sankaran; Joji Kurian; Niranjan Kumar; Chen, Huang-Chin; Ashok Kumar Tyagi; Sitaram Dash; Lee, Chi-Young; Tai Nyan-Hwa; Lin, I-Nan
單位 淡江大學物理學系
出版者 Washington: American Chemical Society
著錄名稱、卷期、頁數 ACS Applied Materials and Interfaces 5(9), pp.3614-3624
摘要 Grain boundaries and microstructures of ultrananocrystalline diamond (UNCD) films are engineered at nanoscale by controlling the substrate temperature (TS) and/or by introducing H2 in the commonly used Ar/CH4 deposition plasma in a microwave plasma enhanced chemical vapor deposition system. A model for the grain growth is proposed. The films deposited at low TS consist of random/spherical shaped UNCD grains with well-defined grain boundaries. On increasing TS, the adhering efficiency of CH radical onto diamond lattice drops and trans-polyacetylene (t-PA) encapsulating the nanosize diamond clusters break due to hydrogen abstraction activated, rendering the diamond phase less passivated. This leads to the C2 radical further attaching to the diamond lattice, resulting in the modification of grain boundaries and promoting larger sized clustered grains with a complicated defect structure. Introduction of H2 in the plasma at low TS gives rise to elongated clustered grains that is attributed to the presence of atomic hydrogen in the plasma, preferentially etching out the t-PA attached to nanosized diamond clusters. On the basis of this model a technologically important functional property, namely tribology of UNCD films, is studied. A low friction of 0.015 is measured for the film when ultranano grains are formed, which consist of large fractions of grain boundary components of sp2/a-C and t-PA phases. The grain boundary component consists of large amounts of hydroxylic and carboxylic functional groups which passivates the covalent carbon dangling bonds, hence low friction coefficient. The improved tribological properties of films can make it a promising candidate for various applications, mainly in micro/nanoelectro mechanical system (M/NEMS), where low friction is required for high efficiency operation of devices.
關鍵字 ultrananocrystalline diamond films;microstructure;grain boundary;clustered grains;trans-polyacetylene;high resolution transmission electron microscopy;tribological properties
語言 en_US
ISSN 1944-8244 1944-8252
期刊性質 國外
收錄於
產學合作
通訊作者 Lin, I-Nan
審稿制度 是
國別 USA
公開徵稿
出版型式 ,電子版,紙本
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