The shear strength of the coating refers to the ultimate ability of the coating to withstand the shear stress in the tangential direction (along the coating surface). When the coating is applied in practice, there will be shear force, so it is necessary to measure the shear strength of the coating.
There are many test methods for measuring the shear strength of the coating. The usual method is to make the sample into a cylinder (as shown in Figure 11_5_11), prepare the coating on the center of the outer surface of the cylinder and grind it into the requested size. Place the sample in the female mold that is slippery with it, and slowly load it on the material testing machine (as shown in Figure 11_5_12), until the coating is sheared and peeled off, and record the load at the time of peeling. (Related instrument: impact Tester) The area of the sheared coating can be calculated from the diameter of the sample and the length of the coating, and the shear strength of the coating can be calculated from this. The shear strength was calculated according to the formula:
