Blister Test as Method of Measuring Adhesion of Solids on a Flat Surface

Abstract

The adhesion between coating and a flat metal surface has been investigated by measurements. The setup is based on the formation of a blister by injecting nitrogen gas under pressure between the coating and the substrate. The adhesion energy is determined by recording the pressure as a function of the recorded blister radius development. A laser is moved over the blister in 2D with two programmable step engines to measure the blister profile and thereby the radius of the blister between successive pressure increases. The design and operation of the instrument are described and an evaluation of its performance and limitations is given. The method could be useful for accurate measurement of adhesion of many types of surface coatings to metal and, possibly, to other substrates, as well as for studies of the various factors that influence adhesion. A better accuracy of the laser for measuring the blister profile would improve the setup. We treated aluminium surfaces in different manners (sand paper, polishing and blowing using glass particles) but found no significant impact on the adhesion energy between the x-linked coating layer and the metal. The adhesion energy measurements however have a large scatter. The coating layer that was not xlinked had a much lower adhesion energy.

Blister Test as Method of Measuring Adhesion of Solids on a Flat Surface