Corrosion Protection of Steel with Oxide Nanolaminates Grown by Atomic Layer Deposition

Abstract

Atomic layer deposited (ALD) aluminum and tantalum oxide (Al 2 O 3 and Ta 2 O 5 ) and their nanolaminates were applied as corrosion protection coatings on AISI 52100 steel. The aim was to combine the good sealing properties of Al 2 O 3 with the chemical stability of Ta 2 O 5 and to optimize the coating architecture in order to obtain the best possible long-term durability. Coating composition and morphology were studied with time-of-flight elastic recoil detection analysis (ToF-ERDA), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and field emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectrometry (EDS). Electrochemical properties were studied with voltammetry and electrochemical impedance spectroscopy (EIS), and corrosion durability with neutral salt spray (NSS) testing. The coatings were observed to be conformal and uniform over rough surfaces, and contained some carbon and hydrogen as impurities. The electrochemical results showed that the Al 2 O 3 coating had superior sealing properties compared to the Ta 2 O 5 coating, and nanolaminates had properties in between those of Al 2 O 3 and Ta 2 O 5 . However, in the NSS test the laminate-coated samples survived the best demonstrating long-term durability. Analysis of the laminate structure showed that for 40 and 80 nm laminates the best protection was achieved with 10 and 20 nm layers, respectively.

Electrochemical and Surface Analysis of the Corrosion Protection of Copper by Nanometer-Thick Alumina Coatings Prepared by Atomic Layer Deposition

“…This finding of a substrate oxide at the interface between ALD coating and substrate is in agreement with previous data for alumina and other oxides on stainless steel and low alloy steel substrates. 26,30,[37][38][39]41,42,45 On copper, interfacial copper oxide was not reported from AES depth profile and low resolution TEM cross-section measurements of 100 nm ALD alumina deposited at 100-200 • C. [34][35][36] However, AES poorly discriminates Cu(I) oxide from Cu metal and TEM may require high resolution if copper oxide forms a possibly discontinuous layer only a few nanometers thick. Our ToF-SIMS data show a much lower, by more than 2 orders of magnitude, intensity of the CuO 2 − peak compared to the AlO 2 − peak, which suggests that copper oxide, observed here for the first time at the ALD alumina/copper metal interface, must be present in quite low concentration (less than 1 equivalent monolayer) and likely forms a discontinuous layer.…”

Thin-Film Engineering of Mechanical Fragmentation Properties of Atomic-Layer-Deposited Metal Oxides

“…The pinhole-free nature of Al 2 O 3 , ZrO 2 , and TiO 2 ALD coatings-and especially their multilayer combinations-are interesting for these applications [1][2][3][4][5][6]. Thin films of Y 2 O 3 are considered to be a promising corrosion-resistant and protective coating for deposition chambers and other three-dimensional metal parts in the semiconductor industry [7]; high temperatures are often involved with semiconductor processing, and hence management of temperature-induced stresses is of high importance [8][9][10][11]. Earth-abundant semiconductors ZnO and Al/ZnO are interesting for flexible electronics, where materials have to be mechanically compatible with roll-to-roll processing and flexing in the end applications; flexible thin-film transistors have been demonstrated with ALD-fabricated layers as both the channel and the dielectric materials [12,13].…”

Fracture Mechanics and Oxygen Gas Barrier Properties of Al2O3/ZnO Nanolaminates on PET Deposited by Atomic Layer Deposition

“…Mechanical studies on ALD films mostly concentrated on elastic modulus, hardness measurement, or residual stress and can be classified into work on single compound film materials, mainly oxides and nitrides, prepared on stiff substrates, like Si or glass [15,16,17,18,19,20,21,22,23,24,25,26] and Al 2 O 3 [27]. The mechanical properties of nanolaminates films have also been investigated on stiff substrates [19,28,29,30,31,32,33,34]. Bull et al [21] pointed out that reliable modulus and hardness data on modulus mismatched ceramic films on polymers can be obtained only if a suitable modeling approach is adopted.…”