BAQ kaloMAX NT II
Manual
1 General information about measuring wear resistance on thin layers
1.1 Overview
In tribological orientated development of layers and in quality assurance of wear-
protective layers, the determination of wear resistance of layers is an essential
demand.
In a collaboration between the Fraunhofer Institute for Surface Engineering and thin
films (IST) and the company BAQ GmbH, the method of ball cratering tests according
to DIN EN 1071-2 has been adapted to tests of thin layers. A method for testing the
wear resistance of thin layers (µm range) has been developed.
The high-precision wear resistance tester kaloMAX NT is
useful for abrasive wear characterization of materials and
layers. By means of an automatic dosage apparatus, an
abrasive slurry is applied onto a 100Cr6 steel ball with a
diameter of 30mm. This ball is rotating against a specimen
(see Figure).
The wear crater should be ground into the layer without
breaking through to the base material. The width and
depth of the wear crater has to be measured by means
of a surface profiler or a microscope.
The wear coefficient specific to the abrasion slurry can
be calculated from the volume of the wear crater, the bearing load and the grinding
path. The volume of the wear crater can be calculated from the diameter of the
grinding ball and the depth or the diameter of the wear crater.
Bearing strength, grinding speed and grinding path must be constant to obtain
comparable wear resistance coefficients.
The minimum thickness of the layer which can be reliably measured is about 1 µm for
hard coatings. This is primarily determined by the shortness of measurement time.
Seite 4
Revolving Shaft
Sample Layer
K
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Abrasive
slurry
Test Set-Up
