Adhesion Test As Per Standard MS 655-08

What is Adhesion Testing?

Adhesion testing measures the force required to detach a coating from its substrate. This test helps in assessing the quality and longevity of the coating. Poor adhesion can lead to premature failure of the coating, exposing the substrate to environmental factors and potential damage.

Equipment Used in Adhesion Testing

The BGD 503 Cross Cutting Rule is the primary tool used for adhesion testing as per MS 655-08. This instrument is designed to make precise cuts on the coating, allowing for an accurate evaluation of adhesion. Here are some key specifications of the BGD 503:

• Cutting Distance: 1mm, 1.5mm, 2mm, 3mm
• Cutting Length: 35mm
• Number of Cutting Teeth: 11
• Cutting Angle: 15° ~ 30°
• Blade Thickness: 0.43 ± 0.03mm

Adhesion Testing Procedure

1. Preparation:

   • Place the specimen on a horizontal surface.
   • Position the cutter guide on the specimen surface.

2. Cutting:

   • Use the cutter knife to make a cross-cut pattern (10×10) on the coating, ensuring each cut has a 2mm spacing. The knife should be held at an angle of around 30 degrees, cutting through the coating until it reaches the substrate.

3. Applying Adhesive Tape:

   • Within 5 minutes of making the cuts, attach cellophane tape to the cross-cut area. Ensure the tape conforms to JIS Z 1522 standards and is 24mm wide.

4. Peeling:

   • Pull the tape at an angle of 90 degrees within 0.5 seconds after application. This action will pull away any loose coating from the substrate.

5. Evaluation:

   • Examine the cross-cut area for flakes or delamination. The results are then classified based on the degree of adhesion loss.

Classification of Adhesion Test Results

The MS 655-08 standard provides a classification system to interpret the results of the adhesion test. This classification helps in understanding the extent of adhesion and identifying any potential issues with the coating process. Here are the grades as per MS 655-08:

• M-1.0 (ISO 2409 CLASS 0):

  • No flakes detected at the edges of cuts.
  • No exfoliation at intersections.
  • Less than 50% delamination per cross-cut area.

• M-2.0 (ISO 2409 CLASS 1):

  • Small flakes at the edges of cuts.
  • No exfoliation at intersections.
  • Less than 50% delamination.
  • Maximum 5% exfoliation at edges.

• M-3.0 (ISO 2409 CLASS 2):

  • Flakes at the edges of cuts.
  • Exfoliation at intersections.
  • Less than 50% delamination.
  • Total delamination greater than 5%, but not exceeding 15%.

• M-4.0 (ISO 2409 CLASS 3):

  • Considerable exfoliation at intersections.
  • Delamination area about 5%.
  • Total delamination greater than 15%, but not exceeding 35%.

• M-5.0 (ISO 2409 CLASS 4):

  • Significant exfoliation at edges.
  • Delamination area about 20%.
  • Total delamination greater than 35%, but not exceeding 65%.

• M-6.0 (ISO 2409 CLASS 5):

  • Complete delamination over the cross-cut area.