1.What are the principles and key points of the grid method?
Principle: Use a special grid cutter to cut grid-like cuts on the coating surface and observe the coating shedding situation.
Key points: Use a hard blade to cut out squares with a spacing of 1-2mm (adjusted according to the thickness of the coating), and the depth must penetrate the coating to the substrate.
Use 3M tape (No. 600 or No. 800) to stick to the incision and quickly tear it off vertically.
Rating standard: 0 for no shedding, 5 for large-area shedding.
2.What are the principles and key points of operation of the bending test method?
Principle: Bend the sample to a specified angle and observe whether the coating cracks or peels off.
Key points of operation
The specimen is bent around a mandrel in a vise or bending device (the mandrel diameter is usually 2-10 times the specimen thickness).
The bending angle is generally 90° or 180°, and the bending speed is uniform.
Result judgment: No visible coating peeling or cracking is qualified.
3.What are the principles and key points of operation of the hammer method?
Principle: Use a hammer to hit the surface of the sample and evaluate the coating adhesion through the impact force.
Key points of operation:
The sample is fixed on a rigid substrate and struck vertically at a certain height with a hammer of a specified weight.
Observe whether the coating at the striking point is peeling or falling off.
4.What are the principles and key points of the peel test?
Principle: The bonding strength between the coating and the substrate is tested by peeling force.
Key points of operation:
Paste special peeling tape or metal test piece on the coating surface and peel it off at a constant speed using a tensile tester. Record the maximum tensile force during the peeling process and convert it into adhesion per unit area.
5.What are the principles and operating points of the friction test method?
Principle: Use a friction wheel or sandpaper to wear the coating surface and observe the coating shedding.
Key points of operation
Specify the number of frictions (e.g. 100 times) or the wear time, and use a standard friction medium (e.g. CS-10 rubber wheel).
Result judgment: The coating is qualified if the substrate is not exposed after wear.