Synthesis of a-C coatings by HPPMS using Ar, Ne and He as process gases
Synthesis of a-C coatings by HPPMS using Ar, Ne and He as process gases
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DOI：
10.1016/j.surfcoat.2016.07.099
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发表时间：
2016-12
影响因子：
5.4
通讯作者：
K. Bobzin;T. Brögelmann;C. Kalscheuer;M. Engels
中科院分区：
文献类型：
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作者：
K. Bobzin;T. Brögelmann;C. Kalscheuer;M. Engels
类金刚石(DLC)涂层广泛应用于摩擦学领域，例如汽车动力总成的部件。这些涂层的普遍硬度HU与碳原子间的sp3/sp2键比有关。对这些涂层的合成研究主要采用物理气相沉积(PVD)工艺，特别是高功率脉冲/脉冲磁控溅射(HPPMS/HIPIMS)工艺。合成高SP3/Sp2比的DLC涂层需要高能碳离子，而高能碳离子的产生强烈依赖于HPPMS工艺参数。等离子体诊断表明，等离子体中碳离子的能量强烈依赖于过程气体混合物、过程气体压力和偏置电压。据报道，高能碳离子在HPPMS等离子体中的比例增加是因为工艺气体具有较高的电离能，以及较高的偏压和较低的工艺气体压力。因此，本工作的目的是研究等离子体参数与DLC涂层性能之间的关系。用Ar、Ne和He作为工艺气体。工艺气体压力和偏置电压分别在p=0.50-2.5pA和UB=−-300-0nV之间变化。涂层是在大容量半工业涂装设备中沉积的。观察到涂层性能与等离子体诊断结果有很强的相关性。发现了SP3/SP2比值和硬度与工艺气体的电离能、工艺气体压力和偏置电压的关系。硬度值已达到HU=445 GPA。综上所述，利用Ar、Ne和He混合气体的HPPMS工艺合成高硬度类金刚石涂层是可能的。
Diamond-like carbon (DLC) coatings are used in numerous tribological applications, for example components of the automotive powertrain. The universal hardness HU of these coatings correlates with the sp3/sp2bond ratio between the carbon atoms. Research on the synthesis of these coatings is upon physical vapor deposition (PVD) processes, especially the high power pulsed/impulse magnetron sputtering (HPPMS/HiPIMS). Synthesizing DLC coatings with a high sp3/sp2ratio requires high energetic carbon ions, whose generation strongly depends on the HPPMS process parameters. Plasma diagnostics have shown that the energy of the carbon ions in the plasma strongly depends on the process gas mixture, the process gas pressure and the bias voltage. An increased fraction of high energetic carbon ions in the HPPMS plasma has been reported for process gases with a higher ionization energy as well as for higher bias voltage and lower process gas pressure. Therefore, the aim of this work is to investigate the correlation of the plasma parameters with the properties of DLC coatings. Ar, Ne and He were used as process gases. Process gas pressure and bias voltage were varied betweenp= 0.5–2.5 Pa and UB= − 300–0 V, respectively. The coatings were deposited in a high volume semi-industrial coating unit. It was observed that the coating properties strongly correlate with the results from the plasma diagnostics. Dependencies of the sp3/sp2ratios and hardness on the ionization energy of the process gas, the process gas pressure and bias voltages could be found. Hardness values up to HU = 45 GPa have been achieved. In conclusion it can be claimed that synthesis of DLC coatings with high hardness is possible by HPPMS processes using process gas mixtures of Ar, Ne and He.