Defect growth in multilayer chromium nitride/niobium nitride coatings produced by combined high power impulse magnetron sputtering and unbalance magnetron sputtering technique
Defect growth in multilayer chromium nitride/niobium nitride coatings produced by combined high power impulse magnetron sputtering and unbalance magnetron sputtering technique
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DOI：
10.1016/j.tsf.2017.06.027
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发表时间：
2017-08-31
期刊：
影响因子：
2.1
通讯作者：
Hovsepian, Papken E.
中科院分区：
文献类型：
--
作者：
Biswas, Barnali;Purandare, Yashodhan;Hovsepian, Papken E.
近年来，高功率脉冲磁控溅射（HIPIMS）由于其能够产生致密的涂层而引起了用户的关注。然而，微观研究已经表明，HIPIMS沉积的涂层可能遭受一些表面缺陷，即使与例如类似厚度的电弧沉积涂层相比，缺陷的总数可能显著更低。缺陷会降低涂层性能，因此任何类型的缺陷都是不希望的。为了更好地理解这些缺陷的性质及其形成的科学性，使用HIPIMS技术结合非平衡磁控溅射（UBM）通过改变沉积时间（t = 15至120 min）来沉积一系列氮化铬/氮化铌（CrN/NbN）涂层。为了使存款这些涂层具有一致的沉积速率和化学计量比，所有其他沉积参数保持恒定。此外，使用纯UBM技术沉积涂层，以比较这两种不同的物理气相沉积方法产生的缺陷。高分辨率扫描电子显微镜图像显示，HIPIMS/UBM和纯UBM CrN/NbN涂层具有相似类型的缺陷，可归类为：结节，开放式空隙，锥状和针孔。缺陷密度计算表明，HIPIMS/UBM涂层的缺陷密度随着涂层厚度的增加而增加（从0.48%增加到3.18%）。在相对清洁的腔室中产生的涂层具有较低的缺陷密度。动电位极化实验表明，HIPIMS/UBM涂层中的腐蚀电流波动随涂层厚度的增加而减小。这表明，尽管在表面上可见，但这些缺陷中的大多数并没有穿透涂层的整个厚度。(C)2017爱思唯尔B. V.保留所有权利。
In recent years, high power impulse magnetron sputtering (HIPIMS) has caught the attention of users due to its ability to produce dense coatings. However, microscopic studies have shown that HIPIMS deposited coatings can suffer from some surface imperfections even though the overall number of defects can be significantly lower compared to, for example, arc deposited coatings of similar thicknesses. Defects can degrade the coating performance thus any kind of defect is undesirable. To better understand the nature of these imperfections and the science of their formation, a series of chromium nitride/niobium nitride (CrN/NbN) coatings were deposited using HIPIMS technique combined with unbalanced magnetron sputtering (UBM) by varying deposition times (t = 15 to 120min). All other deposition parameters were kept constant in order to deposit these coatings with a consistent deposition rate and stoichiometry.In addition, coatings were deposited using pure UBM technique to compare the defects generated by these two different physical vapour deposition approaches. High-resolution scanning electron microscopy images revealed that HIPIMS/UBM and pure UBM CrN/NbN coatings have similar types of defects which could be categorised as: nodular, open void, cone-like and pinhole. Interestingly, there was no evidence of droplet formation in HIPIMS/UBM deposited coatings.The defect density calculation indicated that the defect density of HIPIMS/UBM coatings increased (from 0.48 to 3.18%) with the coating thickness. A coating produced in a relatively clean chamber had a lower defect density. Potentiodynamic polarisation experiments showed that the fluctuation in corrosion currents in HIPIMS/UBM coatings reduced with the coating thickness. This indicated that though visible on the surface, most of these defects did not penetrate thorough the whole thickness of the coating. (C) 2017 Elsevier B.V. All rights reserved.