Corrosion and Protection (Conversion Coating and Plasma Electrolytic Oxidation) of Ti6Al4V Processed by Powder Bed Fusion—Additive Manufacturing. EIS Study

J. Hazan, M. Bamberger

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

Green conversion coatings have been developed using oxyanion like permanganate additive (a conversion layer former) to an acidic medium (H2SO4). Reduction products of permanganate, mainly MnO2, occur due to the high standard reduction potential (Ered 0 = 1.695 V) for the electrochemical reaction in acid solution. An anodic oxide film by anodization (plasma electrolytic oxidation) has been also performed. The structure obtained for these two protective coatings consists of an outer (porous) layer, observed at high frequencies, and an inner (barrier) layer, at low frequencies in the impedance diagram. An electrical equivalent circuit describing the coated alloy is proposed. Electrochemical corrosion results in the corroding electrolyte (NaCl 3%) of Ti6Al4V will be presented and compared to that of a rolled (Ti–0.15% Pd) foil. Finally, semiconductive properties of the passive film formed on the additive manufactured titanium alloy have been investigated. TiO2−α is an n-type semiconductor having oxygen deficiency that provokes significant change in the electrical conductivity. Mott–Schottky plots (CSC −2 vs. E) have been drawn, and the donor concentration ND has been determined from the linear part.

Original languageEnglish
Title of host publicationTMS 2020 149th Annual Meeting and Exhibition Supplemental Proceedings
EditorsZhiwei Peng, Jiann-Yang Hwang, Jerome Downey, Dean Gregurek, Baojun Zhao, Onuralp Yucel, Ender Keskinkilic, Tao Jiang, Jesse White, Morsi Mahmoud
Pages1317-1327
Number of pages11
DOIs
StatePublished - 2020
Event149th Annual Meeting and Exhibition of the Minerals, Metals and Materials Society, TMS 2020 - San Diego, United States
Duration: 23 Feb 202027 Feb 2020

Publication series

NameMinerals, Metals and Materials Series
ISSN (Print)2367-1181
ISSN (Electronic)2367-1696

Conference

Conference149th Annual Meeting and Exhibition of the Minerals, Metals and Materials Society, TMS 2020
Country/TerritoryUnited States
CitySan Diego
Period23/02/2027/02/20

Keywords

  • Additive manufacturing
  • Corrosion
  • Impedance spectroscopy
  • Protective coatings
  • Titanium

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy Engineering and Power Technology
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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