6
Why is surface profle measurement important?
Steel surfaces are frequently cleaned by abrasive impact prior to
the application of protective coatings. The resultant surface profile
must be accurately assessed to ensure compliance with job or
contract specifications. In the protective coatings industry, replica
tape is widely used for quantifying surface profile.
Peak height and peak density are important factors in the
performance of applied protective coatings. Low values may
reduce coating bond strength (adhesion). High values may cause
peaks to receive insufficient coverage and possibly rust
prematurely and for the surface to be insufficiently wetted.
The figure below is a simplified example of why BOTH peak height
AND peak density are important to the understanding of coating
performance. The two surfaces have different geometries yet their
height measurements are the same. Peak density measurements
give a clearer picture of the surface available for bonding.
Both surfaces have the same measured peak-to-valley height. A
second important measurable parameter, peak density, helps
explain why coatings bond differently to each surface.
For these reasons, surface profile should be measured prior to
coating application to ensure that it meets contract specifications.
