Properties of oxide-silane composite coating on AZ31 magnesium alloy

A. Da Forno, M. Bestetti, S. P. Trasatti, M. Trueba

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Various oxide films have been grown on AZ31 magnesium alloy by microarc oxidation in alkaline phosphate solution with addition of different compounds (Na2SiO3, NaAlO2). Because of the anodic oxide porosity, arising from the sparking treatment, organo-functional silane coatings have been applied to seal pores and cracks and achieve a more effective protective system. The surface and cross-section morphologies of the anodic films were analysed by scanning electron microscopy. The phase composition was determined by X-ray diffraction. Bare and anodised AZ31 specimens were post-treated with silanes, namely N-phenil-3-aminopropyltrimethoxysilane and Bis (trimethoxysilylethyl) benzene. The corrosion resistance of anodic oxides and oxide-silane composite coatings was evaluated in dilute Harrison solution by means of single-cycle anodic polarisation. The results showed that the addition of different salts to the alkaline phosphate solution affects the surface morphology and the phase composition of the coatings and, as a consequence, the corrosion resistance behaviour. Both silane post-treatments provide further corrosion protection to samples anodised in aluminate containing solution.

Original languageEnglish
Pages (from-to)275-280
Number of pages6
JournalTransactions of the Institute of Metal Finishing
Volume91
Issue number5
DOIs
Publication statusPublished - Sep 2013
Externally publishedYes

Keywords

  • Corrosion resistance
  • Magnesium alloys
  • Microarc oxidation
  • Silane based coatings

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Mechanics of Materials
  • Metals and Alloys
  • Surfaces, Coatings and Films

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