Table of Contents

Abstract

Specifies requirements for two methods of local thickness testing. The magnetic induction method is suitable for the measurement of thickness of gold, silver, tin, cadmium, lead and organic coatings on magnetic substrates. The eddy current method is suitable for measurement of thickness of anodic coatings and organic coatings on aluminium.
RECONFIRMATION NOTICE
Technical Committee MT-009 has reviewed the content of this publication and in accordance with Standards Australia procedures for reconfirmation, it has been determined that the publication is still valid and does not require change.
Certain documents referenced in the publication may have been amended since the original date of publication. Users are advised to ensure that they are using the latest versions of such documents as appropriate, unless advised otherwise in this Reconfirmation Notice.
Approved for reconfirmation in accordance with Standards Australia procedures for reconfirmation on 20 March 2017.
The following are represented on Technical Committee MT-009:
Australasian Institute of Surface Finishing
Australian Chamber of Commerce and Industry
Australian Industry Group
Australian Steel Institute
Bureau of Steel Manufacturers of Australia
Galvanizers Association of Australia
Galvanizing Association of New Zealand
New Zealand Metal Roofing Manufacturers

Scope

This Standard sets out the requirements for the following non-destructive methods for the measurement of the local thickness of metallic and non-metallic coatings:
(a) Magnetic induction (low frequency) method
The magnetic induction method is used for the thickness testing of non-magnetic and non-metallic coatings on magnetic substrates.
(b) Eddy current (high performance) method
The eddy current method is used for the thickness testing of —
(i) a non-conductive coating on a non-magnetic substrate; and
(ii) a metallic coating or a non-metallic coating on a substrate that has appreciably different conductivity.
These methods apply when the coating thickness is not less than 2 mm, and the surface contour permits calibration of the test instrument.
The magnetic induction (low frequency) method is suitable for the measurement of thickness of gold, silver, tin, cadmium, zinc, copper, chromium, lead and organic coatings, such as paints and plastics, on magnetic substrates.
The eddy current (high frequency) method is suitable for the measurement of thickness of oxide coatings on metals. Using selected frequencies, it is also possible to measure the thickness of various metallic coatings on either magnetic or non-magnetic substrates, e.g. tin-lead on copper, silver on nickel/silver, copper, zinc, cadmium or tin on steel, and copper or silver on a non-metallic base.
Under the best conditions of use, these methods are accurate to ±0.7 mm, or ±10%, whichever is the greater.
NOTES:
1 Factors affecting the accuracy of measurement are given in Appendix A.
2 The methods given in this Standard are not suitable for the measurement of chemical conversion coatings.

General Product Information

Published
Document Type	Standard
Status	Current
Publisher	Standards Australia
ProductNote	Reconfirmed 07/04/2017. This standard has been reconfirmed in Australia in 2017 and remains current in New Zealand. Reconfirmation Notice 07/04/2017
Pages
ISBN
Committee	MT-009
Supersedes	DR 99372 DR 99376 AS 2331.1.4-1982