Low friction of graphene nanocrystallite embedded carbon nitride coatings prepared with MCECR plasma sputtering
Low friction of graphene nanocrystallite embedded carbon nitride coatings prepared with MCECR plasma sputtering
复制标题
MCECR等离子体溅射制备石墨烯纳米晶嵌入氮化碳涂层的低摩擦
DOI：
10.1016/j.surfcoat.2017.06.084
复制
发表时间：
2017-12-15
影响因子：
5.4
通讯作者：
Diao, Dongfeng
中科院分区：
文献类型：
--
作者：
Wang, Pengfei;Zhang, Weiqiang;Diao, Dongfeng
采用镜面约束电子回旋共振（MCECR）等离子溅射系统，在不同N-2/Ar比的低能电子辐照下制备了石墨烯纳米晶嵌入氮化碳（GNECN）涂层。N-2/Ar比是确定GNECN涂层组成和结构的有效沉积参数。结果表明，随着N-2/Ar比从1/11增加到1/3，制备的GNECN涂层的沉积速率、N/C原子比、内应力、表面粗糙度和划痕深度发生了较大变化。通过TEM、XPS和拉曼光谱分析，石墨烯纳米晶在非晶态氮化碳结构中得到了明确的鉴定。此外，在环境空气和N-2气流中，GNECN涂层与Si3N4球的摩擦行为对N-2/Ar比的依赖性较小。具体而言，在环境空气中获得了0.10至0.15的高摩擦系数，而在N-2气流中获得了< 0.05的稳定且低的摩擦系数。Si3N4球和GNECN涂层磨损表面的光学图像和拉曼光谱表明，在配合球表面形成均匀的摩擦膜以及GNECN涂层中纳米级石墨烯结构的生成和演化是GNECN涂层在N-2气流中获得稳定且摩擦系数< 0.05的关键。最后，本文认为在MCECR等离子溅射系统中结合低能电子辐照和氮原子掺入，可以使软石墨烯纳米晶嵌入到坚硬的氮化碳基体中，为在N-2气流中获得稳定和低摩擦系数的GNECN涂层提供了有利的体系结构。
Graphene nanocrystallite embedded carbon nitride (GNECN) coatings were fabricated with the mirror confinement electron cyclotron resonance (MCECR) plasma sputtering system under low energy electron irradiation at various N-2/Ar ratios. N-2/Ar ratio was clarified to be an effective deposition parameter for tailoring the composition and structure of the GNECN coatings. It was observed that the deposition rate, N/C atomic ratio, internal stress, surface roughness, and scratch depth of the prepared GNECN coatings change greatly with the increasing N-2/Ar ratio from 1/11 to 1/3. Graphene nanocrystallite was clearly identified in the amorphous carbon nitride structure from the analyses of TEM, XPS, and Raman spectroscopy. Moreover, the friction behavior of the GNECN coatings sliding against Si3N4 balls in both ambient air and N-2 gas stream showed less dependency on the N-2/Ar ratio. Specifically, high friction coefficients ranging from 0.10 to 0.15 were obtained in ambient air, whereas, stable and low friction coefficients of < 0.05 were achieved in N-2 gas stream. Optical images and Raman spectra of the worn surfaces on the Si3N4 balls and GNECN coatings suggested that a homogeneous tribofilm on the mating ball surface together with the generation and evolution of the nano-size graphene structure in the GNECN coating are the key points in achieving stable and low friction coefficients of < 0.05 of the GNECN coatings in N-2 gas stream. Finally, it was argued that the combination of low energy electron irradiation and nitrogen atom incorporation in the MCECR plasma sputtering system results in the embedding of soft graphene nanocrystallites into hard carbon nitride matrix, providing a beneficial architecture for achieving stable and low friction coefficients of GNECN coatings in N-2 gas stream.