Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/2176-1523.1323
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

DEPOSIÇÃO ELETROASSISTIDA DE ORTOSSILICATO DE TETRAETILA (TEOS) COMO PRÉ-TRATAMENTO PARA A PINTURA DE ALUMÍNIO AA1100

TETRAETHYL ORTHOSILICATE (TEOS) ELECTRO-ASSISTED DEPOSITION AS A PRETREATMENT FOR PAINTING AA1100 ALUMINUM ALLOY

Moreira, Vitor Bonamigo; Cardoso, Henrique Ribeiro Piaggio; Ferreira, Jane Zoppas; Meneguzzi, Álvaro

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Resumo

A técnica convencional de produção de filmes de organossilanos por imersão pode promover a formação de pré-tratamentos pouco homogêneos, prejudicando a sua proteção por barreira contra a corrosão e a aderência de tintas. Sendo assim, a técnica de deposição eletroassistida, baseada na promoção da eletrólise da água e consequente favorecimento das reações de condensação do organossilano, é estudada com o objetivo de promover a formação de filmes com menos descontinuidades. Neste trabalho a deposição eletroassistida foi comparada com a técnica convencional de imersão, bem como com a cromatização hexavalente. O precursor utilizado neste trabalho foi o ortossilicato de tetraetila (TEOS), um silano não funcionalizado. A comparação entre os pré-tratamentos foi realizada através de ensaios de corrosão acelerada em névoa salina, medida de aderência de tinta, espectroscopia de impedância eletroquímica e espectroscopia de energia dispersiva. Os resultados indicam que a deposição eletroassistida em potenciais catódicos promoveu maior cobertura do substrato.

Palavras-chave

Silano, Deposição eletroassistida, Pré-tratamento, Alumínio

Abstract

The standard method for the production of organosilane films by dip-coating may lead to non-homogeneous pretreatment layers, weakening its barrier protection against corrosion and paint adhesion. Therefore, the electro-assisted deposition technique, based on promoting water electrolysis and the consequent favoring of condensation reactions of the organosilane, is studied with the aim of promoting the formation of less discontinuous coatings. In this work the electro-assisted deposition was compared to the standard dip-coating method and to hexavalent chromate conversion coating. The precursor used in this work was tetraethyl orthosilicate (TEOS), a non-functional silane. The comparison between the pretreatments was carried out by salt spray tests, paint adhesion measurement, electrochemical impedance spectroscopy and energy dispersive spectroscopy. The results indicate that the electro-assisted deposition in cathodic potentials promoted higher coverage of the substrate.

Keywords

Silane, Electro-assisted deposition, Pretreatment, Aluminum.

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