What is an indentation peel test?

If the needle-shaped indenter is pressed vertically into the coating surface, the coating is bonded to the almost indeformable substrate, and most of the deformation will occur inside the film, but there will also be some debonding at the interface.

From this, as shown in Figure 6.10, the peel torque can be calculated, which can be used as a measure of the ability of the film to withstand delamination near the indentation point. This is convenient, especially for thin coatings, to monitor the gradually increasing debonding Areas and optics can lead to evaluations based on, for example, Newton's rings, and clear coatings.

It is not necessary to limit the scope of the indentation test to the use of penetration against the coating. Other typical shapes of indenters have also been used with success. The results show that, considering the boundary conditions on the interface, as a basis for calculating the adhesion value, a good method is to use a cone with an angle of 60° as the indenter. An important advantage of this qualification test is that it can obtain the absolute value of the bond strength, As well as information on the durability of the connection between the coating and the substrate under specific loading conditions.

Principles of the indentation process for measuring adhesion at the polymer-substrate interface