TY - CONF A1 - Scholz, Christian A1 - Wäsche, Rolf ED - Bartz, Wilfried J. T1 - Effect of sliding speed and relative humidity on the tribological behaviour of ceramic and polymer materials N2 - In many technical applications not only the actual friction coefficient is of importance, but rather the constancy is relevant for the functionality. Due to inconstant friction values, positioning processes can be substantially influenced. Aim of the present work is to characterize the effect of sliding speed and relative humidity on the tribological behavior of selected combinations. The tribological tests were carried out at room temperature in a ball-on-disk configuration at a normal load of 1 N and respectively 10 N under dry sliding conditions. The friction and wear behavior is significantly depending on the sliding speed and humidity conditions. Using a chamber enclosing the tribometer the relative humidity inside could be adjusted to dry (< 5% rH), normal (50% rH) and moist (100% rH) conditions during the testing time. Three different frequencies, 0.2 Hz, 2 Hz and 5 Hz, were used for tribological evaluations. Measuring the friction force hysteresis loop distinct differences in the frictional behavior of different material combinations could be observed. Materials selected were ceramics sliding against PP-based polymer and various polymers sliding against Ti6AlV4. T2 - 19th International colloquium Tribology - Industrial and automotive lubrication CY - Stuttgart/Ostfildern, Germany DA - 21.01.2014 KW - Stick slip KW - Polymer KW - Ceramic KW - Sliding speed KW - Relative humidity PY - 2014 SN - 978-3-943563-10-8 SP - Paper 8.11, 1 EP - 6 CY - Stuttgart/Ostfildern AN - OPUS4-30176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scholz, Christian A1 - Wäsche, Rolf T1 - Stick-slip and wear behavior of ceramic and polymer materials under reciprocating sliding conditions N2 - In many technical applications not only the actual friction coefficient is of importance, but rather the constancy relevant for the functionality. Due to inconstant ffiction values, positioning processes can be substantially influenced as well as vibrations can be induced. The appearance of this tribological effect, named stick-slip, depends on different factors such as sliding speed, relative humidity and ambient temperature occurring primarily after long operating periods. Beside ambient conditions the choice of materials in contact is the main influencing factor of an inconstant coefficient of friction during operating. Certain polymers are well known for their stick-slip tendencies in technical applications. These are on the one hand different modifications of PTFE (polytetrafluoroethylene) reinforced with glass fibers, bronze or graphite and on the other hand thermoplastics such as PE (polyester) or Pf (polyimide). The difference between static and dynamic values of the ffiction force is decisive for stick-slip phenomena. Furthermore, the stick-slip tendency of polymers strongly depends on the elastic material properties. Main softening material areas, which can be found in the contact, represent particularly vulnerable areas. The high friction value in the contact area decreases in most cases by increasing sliding speeds. However, beside polymers ceramic materials can also offer tendencies to stick-slip motion. Klaffke et al. already investigated the influence of ceramic materials on the stick-slip behavior in. T2 - WTC 2013 - 5th World tribology congress CY - Torino, Italy DA - 08.09.2013 KW - Stick-slip KW - Sliding speed KW - Polymers KW - Ceramics KW - Humidity PY - 2013 SP - 1 EP - 4 AN - OPUS4-29091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -