science24.com - On some peculiarities of electrochemical oxidation of Ti and Ti6Al6V alloy

Search for content and authors

On some peculiarities of electrochemical oxidation of Ti and Ti6Al6V alloy

Andrzej Sadkowski ¹, Janusz Kamiński ², Malgorzata Lewandowska ², Magdalena I. Walczak ¹

1. Polish Academy of Sciences, Institute of Physical Chemistry, Kasprzaka 44/52, Warszawa 01-224, Poland
2. Warsaw University of Technology, Faculty of Materials Science and Engineering (InMat), Wołoska 141, Warszawa 02-507, Poland

Abstract

Electrochemical oxidation is commonly used in industrial practice, e.g. as a method for coloring of the metal surface and modification of its properties. However, the process of oxide film formation is still not fully understood. Ti and Ti6Al4V electrodes were examined with various electrochemical methods in conditions of anodic film formation in 1M H₂SO₄. The influence of metal microstructure on the process of oxidation was found. Good conditions for anodizing were available only after etching electrodes surface in HNO₃/HF solutions revealing fresh, active metal surface ready to hydrogen intake. Etched microcrystalline Ti electrodes presented different interference colors at various crystallites seen under optical microscope while nanocrystalline anodized surfaces were colored uniformly. Rest potential of both etched and anodized electrodes drifted in long runs to reversible hydrogen electrode potential.

The process of anodic film formation in the voltage range of 10V – 95V examined with cyclic voltammetry (CV) was clearly stepwise with oxidation state attained at lower voltage preserved and only superadded in subsequent scan to higher voltage limit. CV tests in broad voltage range disclosed sharp current spikes possibly related to phase transition in interfacial region. There was not clear difference in electrochemical characteristics of anodized Ti and Ti6Al4V electrodes.

Electrochemical impedance (0.1 Hz – 100 kHz) showed that the electrodes with “native oxide” presented ohmic resistance component of several ohms typical for metal/electrolyte interface and oxide layer resistance of the order of 10⁷ Ohm while oxides formed electrochemically presented properties typical for semiconductor/electrolyte interface without clearly distinct ohmic resistance and at least three relaxation times. This character was preserved for many days for electrodes stored in laboratory atmosphere.

Legal notice

Legal notice:

Copyright (c) Pielaszek Research, all rights reserved.
The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/11544 must be provided.

On some peculiarities of electrochemical oxidation of Ti and Ti6Al6V alloy

Presentation: Oral at E-MRS Fall Meeting 2007, Symposium D, by Andrzej Sadkowski See On-line Journal of E-MRS Fall Meeting 2007 Submitted: 2007-05-14 13:44 Revised: 2009-06-07 00:44

Presentation: Oral at E-MRS Fall Meeting 2007, Symposium D, by Andrzej Sadkowski
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-05-14 13:44 Revised: 2009-06-07 00:44