Plasma can be used to effectively remove coke from a metal surface. The plasma etching conditions of coke and emission spectrum characteristics on the metal surface in a complex structure can be determined in real-time using the flexible optical fiber of an emission spectrometer. In this study, the glow discharge hydrogen plasma etching characteristics of a graphite sheet covering Cu and Fe electrodes were investigated. Methane plasma and a bare Cu electrode without graphite were used to conduct experiments for comparison. The cathode was heavily etched owing to the chemical and physical reactions of abundant H and other active species. Many hydrocarbon particle shells with fuzzy boundaries of multilayer graphite were observed on the ground electrode as black dots with diameters less than 1 micron. The cracking reaction of etching process in the case of hydrogen plasma with graphite electrodes plays a leading role, but polymerization reaction is dominant for the methane plasma with bare Cu electrodes. Significant excitation peaks of the emission spectrum are observed in regions centered at 388 and 776 nm for the etching of carbon-rich electrodes in hydrogen-rich plasma. Different hydrocarbon and metal substrate bonds can exist even under strong etching conditions.

中文翻译：

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封闭腔内碳氢等离子体对石墨和金属基体的刻蚀特性

等离子体可用于有效去除金属表面的焦炭。使用发射光谱仪的柔性光纤可以实时确定焦炭的等离子体蚀刻条件和复杂结构金属表面的发射光谱特性。在这项研究中，研究了覆盖 Cu 和 Fe 电极的石墨片的辉光放电氢等离子体蚀刻特性。甲烷等离子体和没有石墨的裸铜电极用于进行实验以进行比较。由于大量 H 和其他活性物质的化学和物理反应，阴极被严重蚀刻。在接地电极上观察到许多具有多层石墨边界模糊的碳氢化合物颗粒壳，为直径小于1微米的黑点。在氢等离子体与石墨电极的情况下，蚀刻过程的裂解反应起主导作用，而在裸铜电极的甲烷等离子体中，聚合反应占主导地位。在富氢等离子体中蚀刻富碳电极时，在以 388 和 776 nm 为中心的区域中观察到发射光谱的显着激发峰。即使在强蚀刻条件下，也可能存在不同的碳氢化合物和金属基材键。