ǂThe ǂeffect of pore sealing in a multilayer Si–O–Zr/Al[sub]2O[sub]3 coating designed to protect aluminium from corrosion

Peter Rodič (Author), Barbara Kapun (Author), Ingrid Milošev (Author)

Abstract

This study deals with the combination of two corrosion protection strategies for aluminium: barrier protection (provided by a 3.8 μm thick hybrid sol–gel coating) and aluminium pore sealing via the use of a 100 nm thick layer of aluminium oxide. A Si–O–Zr hybrid sol–gel coating (TMZ) was synthesised by combining two separately prepared sols (i) tetraethyl orthosilicate and 3-methacryloxypropyl trimethoxysilane and (ii) zirconium(IV) n-propoxide chelated with methacrylic acid. The synthesis of the Si–O–Zr hybrid sol–gel was evaluated at various stages using real-time infrared spectroscopy. A 100 nm thick Al2O3 film was prepared via thermal atomic layer deposition at 160 °C using trimethyl aluminium and water as precursors. The coating and film properties were assessed via focused ion beam/scanning electron microscopy coupled with energy-dispersive X-ray spectrometry. Sealing with the Al2O3 film did not affect the microstructure and composition of the underlying sol–gel coating. The coating’s corrosion performance in 0.1 M NaCl solution was evaluated using electrochemical impedance spectroscopy. Compared to individual coatings, the multilayer TMZ/Al2O3 coating ensured prolonged (more than three weeks) durable corrosion protection for the aluminium. The impedance magnitude increased by two orders compared to the uncoated substrate (|Z|10 mHz from 16 kΩ cm2 to almost 830 MΩ cm2). Thus, the pore sealing of the sol–gel coating using an ALD alumina film produced a protective multilayer coating system, with |Z|10 mHz remaining above 5 MΩ cm2 after four weeks in NaCl solution.

Keywords

aluminum;corrosion;hybrid sol-gel;atomic layer deposition;pore sealing;

Data

Language:	English
Year of publishing:	2023
Typology:	1.01 - Original Scientific Article
Organization:	IJS - Jožef Stefan Institute
Publisher:	MDPI
UDC:	54
COBISS:	174730243
ISSN:	2075-4701
Views:	123
Downloads:	45
Average score:	0 (0 votes)
Metadata:

Other data

Secondary keywords:	Aluminij;Korozija;
Source comment:	Nasl. z nasl. zaslona; Opis vira z dne 4. 12. 2023;
Pages:	str. 1-23
Volume:	ǂVol. ǂ13
Issue:	ǂiss. ǂ12, [article no.] 1960
Chronology:	Dec. 2023
DOI:	10.3390/met13121960
ID:	26298430