Effects of anodizing conditions and the addition of Al2O3/PTFE particles on the microstructure and the mechanical properties of porous anodic coatings on the AA1050 aluminium alloy

Michaela Remešová*, Serhii Tkachenko, Daniel Kvarda, Ivana Ročňáková, Bernhard Gollas, Melita Menelaou, Ladislav Čelko, Jozef Kaiser

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

In the present study, porous anodic aluminium oxide (AAO) coatings with and without particles of Al 2O 3 (aluminium oxide) and polytetrafluorethylene (PTFE) were produced on AA1050 aluminium alloy via galvanostatic anodizing in acidic electrolyte. The effects of anodizing conditions (i.e. temperature, current density and composition of electrolyte) on the morphology, thickness, and microhardness were studied via scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX) and Vickers hardness tester. The results showed that the decrease of electrolyte temperature from 24 to 10 °C and the addition of 20 g/L oxalic acid to 15% H 2SO 4 electrolyte led to the formation of thicker (34 µm) and harder porous AAO coating with hillocks. Furthermore, the decrease of applied current density from 3 to 1 A/dm 2 resulted in the formation of thinner coating (10 µm) without hillocks. The intermetallic phases based on Al-Fe and Al-Fe-Si compounds present in AA1050 alloy were not preferably dissoluted during the anodizing process at 10 °C of electrolyte. The tribological properties of the anodic coatings were investigated by the dry friction test. The results showed that the addition of Al 2O 3 and PTFE particles to sulfuric-oxalic acid electrolyte resulted in hard anodic composite coatings with enhanced wear resistance.

Original languageEnglish
Article number145780
Number of pages10
JournalApplied Surface Science
Volume513
DOIs
Publication statusPublished - 2020

Keywords

  • AA1050
  • Anodizing
  • Coating microstructure
  • Hillocks
  • Wear

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces, Coatings and Films
  • Chemistry(all)
  • Surfaces and Interfaces

Fields of Expertise

  • Advanced Materials Science

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