Defect growth in multilayer chromium nitride/niobium nitride coatings produced by combined high power impulse magnetron sputtering and unbalance magnetron sputtering technique
| Autor: | S. Creasey, Arutiun P. Ehiasarian, Yashodhan Purandare, Barnali Biswas, Daniel A.L. Loch, Papken Eh. Hovsepian, Imran Khan, Arunprabhu Arunachalam Sugumaran |
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| Rok vydání: | 2017 |
| Předmět: |
Niobium nitride
Materials science Scanning electron microscope 02 engineering and technology engineering.material 01 natural sciences Corrosion chemistry.chemical_compound Coating 0103 physical sciences Materials Chemistry Composite material Chromium nitride 010302 applied physics Metallurgy Metals and Alloys Surfaces and Interfaces Sputter deposition 021001 nanoscience & nanotechnology Microstructure Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry engineering High-power impulse magnetron sputtering 0210 nano-technology |
| Zdroj: | Thin Solid Films. 636:558-566 |
| ISSN: | 0040-6090 |
| DOI: | 10.1016/j.tsf.2017.06.027 |
| Popis: | 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 120 min). 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. |
| Databáze: | OpenAIRE |
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