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BAQ kaloMAX NT II
Do not keep the abrasive slurry near by heat sources (e.g. radiators, solar heat).
Most suitable would be a drawer near by the tester.
It is recommendable to use a reference sample (e.g. standard layer) to check the
„state" of the abrasive slurry in regular intervals. A change in viscosity of the
abrasive slurry causes mostly higher wear coefficients.
2
Test preparations
The wear coefficient is calculated from the volume of the wear crater, the bearing
strength (perpendicular to the surface of the specimen) and the grinding path.
2.1
Selection of the test parameter (grinding path / number of revolutions)
The appropriate grinding path (or the number of ball or shaft revolutions) and hence
the measurement duration, has to be determined experimentally according to the
requirements. The suitable value depends basically on the thickness and wear
resistance of the layer to test. It is important, that the depth of the resultant wear crater
is not greater than the thickness of the functional layer.
The experiences of the Fraunhofer Institute for Surface Engineering and Thin Films can
give a rough guide for the determination of the measurement duration. These values
are only valid for this special developed layer systems. For several layer systems, the
following wear crater depth have been determined (20°C, 50 % relative humidity
equivalent to 7,3 [g/kg dry air] at 1013mbar).
Layer system
Carbon films
(DLC)
Metal carbon films:
Ti-C:H
Metal carbon films:
W-C:H
Table 1: Layer systems/crater depth
The direct input of the grinding path has practical advantages over the input of the
number of ball or shaft revolutions. The calculation of number of ball revolutions
Revolutiuons
Measurement
of the ball
duration [min]
540
180
180
Wear crater
depth [µm]
9
0,7
3
1,1
3
0,8
Manual
Wear volume
[m
*m
*N
*10
]
3
-1
-1
-15
0,8
6,2
3,3
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