Lube-Tech
Susanne Beyer-Faiß Dr. Tillwich, GmbH Werner Stehr, Horb, Germany
PUBLISHED BY LUBE: THE EUROPEAN LUBRICANTS INDUSTRY MAGAZINE
No.117 page 1
Determination of adhesive properties of lubricants on surfaces
Summary There are various approaches to describe the physicochemical dependencies in the case of total wetting or nonwetting and the conditions in between, as well as measurements which directly or indirectly describe indications of the adhesive and dispersive energy of the liquids and surfaces. The interpretation of results achieved through laboratory tests in terms of function prediction of real components however is challenging and needs some experience. Within the scope of a development project a test method has been developed which allows one to dynamically measure the adhesive force of a lubricant drop directly on the respective materials and surfaces with the technology of a centrifuge. The detection of adhesion forces under dynamic conditions extends the range of laboratory test methods for the characterisation of surface wetting properties. In particular, the possibility of testing on real component surfaces and with small oil volumes opens up new aspects for the function prediction of lifetime lubricated systems in precision engineering.
30 LUBE MAGAZINE NO.146 AUGUST 2018
Introduction Choosing the correct lubricant for micromechanical parts is, amongst other things, hindered by the fact that the parts to be lubricated are very small and the life time of components sometimes is decades. The demands onto the lubricants, especially in terms of forlife lubrication, minimum quantity lubrication and single application lubrication therefore are very high. The evaluation of the adhesive properties of the lubricants is a critical aspect, since due to long-term wetting and spreading effects a lack of lubricant may occur, which results in a raise of friction and wear up to a failure of the component.
Modelling of Tests There are various approaches to describe the physicochemical dependencies in the case of total wetting or nonwetting and the conditions in between, as well as measurements which directly or indirectly describe indications of the adhesive and dispersive energy of the liquids and surfaces1
. These include e.g. the surface tension of the liquids or the surface
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64
