Cross Hatch Adhesion Test
Testing Coating Adhesion on Metal Surfaces
The Cross Hatch Adhesion Test is a widely used method for evaluating how well a coating bonds to the metal substrate. In this test, cuts are made through the coating, adhesive tape is applied, and the surface is then inspected for any peeling or flaking.
This test is commonly used in the electroplating, coating, and surface finishing industries because it is simple to perform and easy to evaluate. It provides a practical and reliable way to verify coating adhesion and overall coating performance.
Under ASTM D3359, two common tape test methods are used. Method A uses an X cut pattern and is typically used for thicker coating systems. Method B uses a cross hatch grid pattern and is generally used for thinner coatings. Both methods help evaluate whether the coating remains firmly bonded to the substrate after testing.
How the Cross Hatch Adhesion Test Is Performed
The performance of a protective or decorative coating depends on strong adhesion to the metal substrate. To evaluate this, the Cross Hatch Adhesion Test is used to quickly assess how firmly the coating remains bonded after cutting and tape removal.
In this procedure, the tester is drawn across the coated surface using steady, even pressure to create a series of cuts through the coating layer to the substrate. The test area is then cleaned, adhesive tape is applied over the cut pattern, and the tape is removed to check for any peeling or flaking.
The inspected result helps determine the degree of coating adhesion and whether the coating system remains securely bonded to the substrate.
Step-by-Step Guide:
Use a multi-blade cutter to make a series of parallel cuts through the coating to the substrate.
Perform a series of perpendicular cuts at 90 degrees to create a precise cross-hatch grid.
Place a strip of standardized pressure-sensitive tape across the grid. Smooth it into place with your finger or a pencil eraser to ensure a uniform bond.
Wait approximately 90 seconds, then quickly remove the tape by pulling it back steadily at a 180-degree angle.
Inspect the grid area to determine if any of the coating has detached or flaked from the surface.
Use a magnifying glass to inspect the cross-hatch area. Evaluate the grid for any signs of coating detachment to determine the final adhesion rating.
Result:
Based on the inspection criteria, the PVD coating conforms to ASTM D3359 with an adhesion rating of 5B, indicating superior bond strength with zero detachment.
SGS test report:
