A time-dependent direct current potential drop method to evaluate thickness of an oxide layer formed naturally and thermally on a large surface of carbon steel

Md Rostom Ali, Masumi Saka, Hironori Tohmyoh

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

This study describes the use of a time-dependent spring-loaded four-point-probe technique to measure the direct current potential drop (DCPD) on oxidized test surfaces for different spring force values, with the purpose of evaluating the thickness of the oxide layer. The force of the spring attached to the current probe was reduced by inserting spacers with different thicknesses under the supporting legs of the sensor block. The PD measurement was first performed on machined sample exposed to the atmosphere for approximately 6 months. The sample was made of carbon steel (SS400). Then, the thickness of the oxide layer formed on the surface of the sample was increased by heat treatment. The PD was also measured on the samples subjected to heat treatment. The measurements were performed at different locations on the test surface under the same experimental conditions. The experimental results establish a relationship between the spring force and the time required for the current probe to penetrate the oxide layer. This article also proposes a procedure for evaluating the thickness of the oxide layer. Finally, the proposed method was used to evaluate the thickness of the oxide layer formed on a large surface. The method was performed to evaluate thickness of single phase monolayer oxide in the range of 3.5-8.7 μm. To demonstrate the validity and accuracy of the proposed method, the obtained thickness was compared to the thickness measured directly using a field emission scanning electron microscopy.

Original languageEnglish
Pages (from-to)77-83
Number of pages7
JournalThin Solid Films
Volume525
DOIs
Publication statusPublished - 2012 Dec 15

Keywords

  • Direct current potential drop technique
  • Oxide layer
  • Spacer
  • Spring force
  • Thickness

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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