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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Dual Role of Lithium on the Structure and Self-Healing Ability of PMMA-Silica Coatings on AA7075 Alloy

Texto completo
Autor(es):
Trentin, Andressa [1] ; Harb, Samarah V. [1] ; Uvida, Mayara C. [1] ; Pulcinelli, Sandra H. [1] ; Santilli, Celso V. [1] ; Marcoen, Kristof [2] ; Pletincx, Sven [2] ; Terryn, Herman [2] ; Hauffman, Tom [2] ; Hammer, Peter [1]
Número total de Autores: 10
Afiliação do(s) autor(es):
[1] Sao Paulo State Univ UNESP, Inst Chem, BR-14800060 Araraquara, SP - Brazil
[2] Vrije Univ Brussel, Dept Mat & Chem, Res Grp Electrochem & Surface Engn, Pl Laan 2, B-1050 Brussels - Belgium
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: ACS APPLIED MATERIALS & INTERFACES; v. 11, n. 43, p. 40629-40641, OCT 30 2019.
Citações Web of Science: 0
Resumo

In this work, structural and active corrosion inhibition effects induced by lithium ion addition in organic inorganic coatings based on poly(methyl methacrylate) (PMMA)-silica sol gel coatings have been investigated. The addition of increasing amounts of lithium carbonate (0, 500, 1000, and 2000 ppm), yielded homogeneous hybrid coatings with increased connectivity of nanometric silica cross-link nodes, covalently linked to the PMMA matrix, and improved adhesion to the aluminum substrate (AA7075). Electrochemical impedance spectroscopy (EIS), performed in 3.5% NaCl aqueous solution, showed that the improved structural properties of coatings with higher lithium loadings result in an increased corrosion resistance, with an impedance modulus up to 50 G Omega cm(2), and revealed that the lithium induced self-healing ability significantly improves their durability. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) suggest that the regeneration process occurs by means of lithium ions leaching from the adjacent coating toward the corrosion spot, which is restored by a protective layer of precipitated Li rich aluminum hydroxide species. An analogue mechanism has been proposed for artificially scratched coatings presenting an increase of the impedance modulus after salt spray test compared to the lithium free coating. These results evidence the active role of lithium ions in improving the passive barrier of the PMMA-silica coating and in providing through the self-restoring ability a significantly extended service life of AA7075 alloy exposed to saline environment. (AU)

Processo FAPESP: 15/11907-2 - Estrutura e propriedades eletroquímicas de revestimentos híbridos PMMA-silica modificados com ions cério e lítio.
Beneficiário:Andressa Trentin
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 17/14061-2 - Influência de íons Ce3+ e Ce4+ nas características estruturais e eletroquímicas de revestimentos híbridos PMMA-sílica
Beneficiário:Andressa Trentin
Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
Processo FAPESP: 15/09342-7 - Desenvolvimento de híbridos PMMA-(TiO2, ZrO2 e CeO2) multifuncionais
Beneficiário:Samarah Vargas Harb
Linha de fomento: Bolsas no Brasil - Doutorado