The method is applicable to qualitatively inspecting the adhesion strength between the metal deposit coating and the basis metal or the basis plastic.
This standard is formulated by reference to the international standard ISO 2819-1980 Metallic coatings on metallic substrates - Electrodeposited and chemically deposited coatings - Review of methods available for testing adhesion.
1 Method principle
The following methods are used to observe whether the coating peels off under the external force action using the differences in physical and mechanical properties between the coating and the basis. Different methods are selected depending on the basis material, shape, purpose and coating type of the test piece.
2 Inspection methods
2.1 Bending method
2.1.1 Bend the test piece 180° along a shaft having a diameter equal to the thickness of the test piece, and then check whether the coating of the bent portion peels off or not.
2.1.2 Clamp the test piece in the vise and repeatedly bend the test piece until the basis breaks. Check whether the coating at the break peels off or not.
2.1.3 Wind wires with a diameter less than 1mm around a shaft with a diameter of 1mm; wind wires with a diameter greater than 1mm around a shaft (having a diameter same as the wire diameter) into 10~15 closed coils, and observe whether the coating peels off or not.
2.1.4 Bend the wire or sheet test piece 180° on shafts having a diameter of 10, 8, 6 and 4mm respectively, and then observe whether the coating peels off or not.
2.2 File method
2.2.1 Clamp the test piece in the vise, file the edge of coating in the direction from the basis metal to the coating at an angle of approximately 45° to the coating surface, and observe whether the coating near the file opening is lifted or peels off.
2.2.2 The specification of the file selected are determined according to the requirements of test piece, coating type and product.
