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- Tribologie (7)
- Friction (3)
- Humidity (3)
- Relative humidity (3)
- Gleitbewegung (2)
- Reciprocating sliding (2)
- Salzwasser (2)
- Silicon carbide (2)
- Stainless steel (2)
- Wear quantities (2)
Verformung und Gefügetransformation bei Schwingungsverschleiß von austenitischen FeCrNi-Legierungen
(2004)
Tribological Characterisation of a Sl3N4-TiN Composite Ceramic in Fretting Tests at Room Temperature
(2004)
Tribological Characterisation of Hard Coatings with and without DLC Top Layer in Fretting Tests
(2004)
Tribological Characterisation of a-C:H Coatings at Room Temperature - Effect of Counterbody Material
(2004)
This paper discusses the results and the consequences of the results obtained in a finished project on fretting
testing at very small amplitudes. In this project a crossed cylinders model contact (radius 2.5 mm) was tested
mainly in tangential oscillatory modes with strokes 2-100 µm, with forces between 0.5 and 5 N and frequencies
of 1 and 10 Hz, financed by the European Commission.
For non-noble contact platings it has been shown that very small amplitudes (< 10 µm) result in surface damage
and contact failure. For noble platings it results in surface damage, only followed by contact failure after wear
causes exposure of the non-noble underlayer.
The most important conclusion from the project work was that the contact resistance remains low and stable in
partial slip, while gross slip causes electrical failure(>0.5 .).
In this paper the following items are discussed: i) The application of the Mindlin theory to predict the transition
from partial to gross slip ii) Aspects of tribo simulation testing of electrical contacts iii) The methods of extending
the allowable external displacement amplitude by additional springs that absorb part of the motion, and iv)
The options if large vibrations at the contact interface can not be avoided.
COMPOSITE MATERIALS OF A 99.7 % ALPHA-ALUMINA MATRIX WITH PLATELETS OF SILICON CARBIDE (SICP) HAVE BEEN PREPARED BY GELCASTING. DENSIFICATION WAS CARRIED OUT BY GAS-PRESSURE SINTERING WITHOUT FURTHER SINTERING AIDS. FIVE DIFFERENT COMPOSITIONS WITH 0, 5, 10, 15, AND 20 VOL.% SICP RESP. HAVE BEEN INVESTIGATED AND TRIBOLOGICAL PROPERTIES WERE CHARACTERIZED. INCREASING AMOUNT OF SICP AS RIGID PARTICLES IN THE FINE GRAINED MATRIX COMPLICATE THE DENSIFICATION PROCESS. WITH THE APPLICATION OF 50 BAR AR PRESSURE DURING THE FINAL SINTERING STEP AT A TEMPERATURE OF 1700 DEGREE C THE DENSITY OF THE SAMPLES COULD BE INCREASED BY 3-5%. INVESTIGATION OF THE TRIBOLOGICAL PROPERTIES AGAINST STEEL AS A COUNTERBODY UNDER UNLUBRICATED OSCILLATING SLIDING CONDITIONS SHOWED A HIGH COEFFICIENT OF FRICTION AND AN INCREASING WEAR RATE UP TO A SICP CONTENT OF 10 VOL. % . AT 15 AND 20 VOL. % SICP RESP. BOTH THE COEFFICIENT OF FRICTION AND THE COEFFICIENT OF WEAR DROP DOWN.
Possibilities of fretting corrosion model testing for contact surfaces of automotive connectors
(2001)
The number of electrical contacts in automotive applications increases steadily. The trends of miniaturisation in all fields of technique and the increasing demands concerning functionality, mechanical and thermal load require the permanent development of connectors. An improvement of electrical connectors can be achieved by coating of the connector elements. Additionally, the price of improved connectors has to remain as low as possible. One of the most important degradation processes that limits electrical functionality is fretting corrosion, caused by vibrations. The development of better coatings requires a check of functionality at a very early state of development. For this purpose different test facilities are available, that be used in order to qualify the improvement. In model tests with simple specimens made of original connector materials the electrical degradation mechanisms caused by friction and wear processes can be studied. It is shown for tin- and gold-coatings that in tribometer tests under certain parameters wear appearances and mechanisms can be similar to that in product testing. Thus, model testing methods can help to reduce time-to-market.
Einfluss elektrischer Spannungen auf Reibung und Verschleiß in wassergeschmierten Tribokontakten
(2001)
Influence of electrical voltages on friction and wear in water lubricated sliding of SiC/SiC-TiC
(2001)
Influence of normal force and humidity on friction and wear of unlubricated steel / steel couples
(2001)
Tribologische Prüfungen als begleitende Maßnahme zur Entwicklung von keramischen Tribowerkstoffen
(1999)