Härkönen Emma, Kolev Ivan, Díaz Belén, Swiatowska Jolanta, Maurice Vincent, Seyeux Antoine, Marcus Philippe, Fenker Martin, Toth Lajos, Radnoczi György, Vehkamäki Marko, Ritala Mikko
Laboratory of Inorganic Chemistry, University of Helsinki , P.O. Box 55, FIN-00014 Helsinki, Finland.
ACS Appl Mater Interfaces. 2014 Feb 12;6(3):1893-901. doi: 10.1021/am404906x. Epub 2014 Jan 27.
Atomic layer deposition (ALD) is a thin film deposition technique that is based on alternating and saturating surface reactions of two or more gaseous precursors. The excellent conformality of ALD thin films can be exploited for sealing defects in coatings made by other techniques. Here the corrosion protection properties of hard CrN and diamond-like carbon (DLC) coatings on low alloy steel were improved by ALD sealing with 50 nm thick layers consisting of Al2O3 and Ta2O5 nanolaminates or mixtures. In cross sectional images the ALD layers were found to follow the surface morphology of the CrN coatings uniformly. Furthermore, ALD growth into the pinholes of the CrN coating was verified. In electrochemical measurements the ALD sealing was found to decrease the current density of the CrN coated steel by over 2 orders of magnitude. The neutral salt spray (NSS) durability was also improved: on the best samples the appearance of corrosion spots was delayed from 2 to 168 h. On DLC coatings the adhesion of the ALD sealing layers was weaker, but still clear improvement in NSS durability was achieved indicating sealing of the pinholes.
原子层沉积（ALD）是一种基于两种或更多气态前驱体交替且饱和的表面反应的薄膜沉积技术。ALD薄膜出色的保形性可用于密封其他技术制备的涂层中的缺陷。在此，通过用由Al2O3和Ta2O5纳米层或混合物组成的50nm厚的层进行ALD密封，改善了低合金钢上硬CrN和类金刚石碳（DLC）涂层的耐腐蚀性能。在横截面图像中，发现ALD层均匀地遵循CrN涂层的表面形态。此外，还证实了ALD生长进入CrN涂层的针孔。在电化学测量中，发现ALD密封使CrN涂层钢的电流密度降低了两个多数量级。中性盐雾（NSS）耐久性也得到了改善：在最佳样品上，腐蚀斑点的出现从2小时延迟到了168小时。在DLC涂层上，ALD密封层的附着力较弱，但NSS耐久性仍有明显改善，表明针孔被密封。
