Filtern
Dokumenttyp
- Zeitschriftenartikel (8) (entfernen)
Sprache
- Englisch (8)
Schlagworte
- Friction (8) (entfernen)
Organisationseinheit der BAM
Zero wear (Null Verschleiß)
(2013)
Self-mated magnesia stabilized zirconia (Mg-PSZ) ceramic sliding couples have been investigated at 100 N load (P0max= 1324 MPa) in oscillating sliding conditions in different humidity conditions in air and in hot steam. Temperatures have been varied up to 400 °C and pressures up to 6 bars. The results show that the wear behavior of MgO-ZrO2 under high Hertzian contact pressures is strongly dependent on temperature and is similar for both dry oscillating and oscillating in hot steam. However, although the evolution in wear rates on temperature is similar and the wear rates of MgO-ZrO2 plunged above 300 °C in hot steam and air by nearly three orders of magnitude, SEM micrographs revealed in hot steam at 400 °C smooth wear tracks. In contrast, hot steam enhanced the tribochemistry of self-mated alumina couples and reduced wear rates. Hot steam decreased the coefficients of friction of MgO-ZrO2 with increasing temperature, but not the wear rates.
The friction and wear behaviour of a new developed, pressureless sintered TiB2 ceramic was studied in comparison to SiC against SiC and Al2O3 balls under unlubricated conditions at room temperature. Special attention was paid to the influence of relative humidity on friction and wear results. For both ceramics the coefficient of friction against both ball materials decreases with increasing humidity and is higher in tests against alumina than against SiC. The wear rate is affected significantly by humidity and decreases by one order of magnitude for Al2O3/SiC system and by 2 orders of magnitude for SiC/SiC system. For TiB2 wear rates are nearly not affected by humidity against both ball materials and are much smaller than for SiC.
Tribological characterisation of siliconcarbonitride ceramics derived from preceramic polymers
(2006)
Amorphous SiCN ceramics were prepared in a laboratory scale as disk shaped specimens with 10 mm diameter and 0.3 mm thickness. The friction and wear behaviour was characterised in gross slip fretting tests under unlubricated conditions at room temperature against steel (100Cr6) and ceramic (Al2O3). Tests with a ball-on-disk contact were performed in laboratory air with different content of water vapour. The results show clearly that the relative humidity has a significant effect on friction and wear behaviour. All tests in dry air lead to higher friction and higher wear rate than in normal air. Improved friction and wear behaviour was observed with increasing pyrolysis temperature up to 1100 °C of the SiCN specimens. This is attributed to increasingly better mechanical properties and higher stiffness of the amorphous network due to the evaporation of gaseous organic species and the formation of free graphite like carbon.
Ceramic particulate composites in the system SiC-TiC-TiB2 sliding against SiC and Al2O3 under water
(1999)
The tribological behaviour of SiC, SiC-TiC and SiC-TiC-TiB2 was determined in oscillating sliding against SiC and -Al2O3 in water at room temperature. The tribo-systems with the composite materials containing TiC and TiB2 differ significantly from the systems with the single phase SiC: The wear is reduced and the friction is increased. The wear reduction up to a factor of 10 is mainly due to the formation of an oxide film containing titanium oxides which is soft, stable in water and well adhering to the bulk material. This oxide film is transferred to the alumina ball but not to the silicon carbide ball.