How to test the bonding strength of thermal spray coating

       The coating strength includes the cohesive strength between the coating particles (the bonding strength of the coating itself) and the bonding strength (adhesion) between the coating and the substrate material. Generally speaking, the bonding strength of the coating itself is greater than that between the coating and the substrate. Bond strength. Usually, only the bonding strength between the coating and the substrate is detected, which is referred to as bonding strength for short. Bonding strength refers to the force required to peel off the coating from the bonding surface of the base material per unit area between the coating and the substrate. It is a very important indicator to detect coating performance. If the bonding strength is too small, it will lead to a decrease in the life of the coating, resulting in early failure, and in severe cases, the coating will be partially peeled and peeled off and cannot be used.



The detection methods of coating bonding strength can be divided into two categories: one is qualitative detection, which is mostly used for production site inspection, such as grid test, bending test, impact test, cupping test, etc.; Tensile strength test, shear strength test and other destructive testing methods and ultrasonic non-destructive testing methods.



The characteristics of the qualitative detection test of coating bond strength are simple and easy to implement, and the basic condition of coating bond strength can be quickly known, but the accuracy is not enough. Although the quantitative test test is more complicated, the test data is accurate and can reflect the true bond of the coating. strength