Significance and Use The thickness of a coating is often
critical to its performance. This magnetic method is suitable
for measuring nondestructively the thickness of some nickel
coatings and for specification acceptance. This method requires
that the magnetic properties of the coating and its substrate be
the same as those of the reference standards used for the
calibration adjustment of the instrument. 5.3 This method should
not be used to determine the thickness of autocatalytically
deposited nickel-phosphorus alloys containing more than 8 %
phosphorus on steel. Those coatings are sufficiently nonmagnetic
for Test Method B 499 to be suitable for that determination, as
long as the measurement is made prior to any heat treatment. 1.1
This test method covers the use of magnetic instruments for the
nondestructive measurement of the thickness of an
electrodeposited nickel coating on either a magnetic or
nonmagnetic substrate. It is intended to supplement
manufacturers’ instructions for the operation of the inst