Elastohydrodynamic lubrication between rolling and sliding ceramic cylinders: An experimental investigation

The present work focuses on the investigation of the influence of bulk cera mic materials on the behavior of elastohydrodynamically (EHD) lubricated li ne contacts. The materials (Al2O3), zirconium oxide (ZrO2) and aluminum nit ride (AIN) are used. Comparative measurements were taken with steel disks m ade of 42CrMo4. Of primary important are the material parameters Young's mo dulus and thermal conductivity. The experimental variables pressure, temper ature and oil film thickness in the EHD contact of a two disk test rig were measured with the aid of evaporated thin film sensors, As the results show an increase in the Young's modulus causes a clear increase of the pressure level. The oil film thickness distributions show a decline of the flatteni ng width and of the constriction occurring at the contact outlet. The influ ence of the material with respect to its thermal conductivity dominates, ab ove ail, in the region of the load transmitting contact zone. The transitio n from a good to a bad conductor of heat causes a rise in temperature, more prominent for materials with lower thermal conductivities. This leads to v iscosity decrease causing clearly reduced oil film thicknesses in the conta ct. [S0742-4787(00)01404-1].