TQC Sheen Buchholz indentation hardness tester

The TQC Buchholz hardness indentation test SP1900 provides a method for performing an indentation test of coatings that complies with the ISO 2815-2003 standard. The TQC Buchholz hardness indentation test consists of a calibrated mounting weight with a sharp-edged metal wheel, an illuminated microscope, a spirit level, a digital double timer and two markers with template.

Principle of the test

In the Buchholz indentation hardness test, a test specimen with a defined geometry is subjected to a defined test load for a specified time. After a certain recovery time, the length (L) of the resulting indentation is measured using a microscope. The hardness can be calculated on the basis of this indentation length (L) in mm:

• Buchholz indentation hardness = 100/L (1)
• Indentation depth (µm, approx.) = 8 x L² (2)

Both values are rounded up to whole numbers.

Area of application

The Buchholz indentation hardness test is applicable if the following boundary conditions are met:

• The coating to be tested must be even and smooth, have a clean surface and be applied to a level substrate that can withstand the test force.
• There must be a sufficient layer thickness (i.e. the remaining layer thickness under the indentation according to (1) must be at least 10 µm).
• For the comparative test, the samples should have the same coating thickness and the preparation and testing of the samples should be carried out under the same environmental conditions.

As the indentation test only damages the coating slightly, the test can also be carried out on finished products. The Buchholz hardness indentation test is a mandatory test in the laboratories accredited by Qualicoat, QIB and GSB.

This test is also included in the Qualicoat kit.