MODELING AND MICROSTRUCTURAL MODIFICATION OF ALUMINA CERAMIC FOR IMPROVED TRIBOLOGICAL PROPERTIES

Very simplified models were deduced for identifying important factors influencing friction and wear of ceramics in unlubricated sliding cont act. Based on the theoretical predictions, laser surface alloying was used for modifying alumina ceramic by adding hafnia. Tribological test s were run on the modified ceramic, monolithic alumina and two differe nt cutting ceramics on the base of alumina under conditions of unlubri cated reciprocating sliding motion against Al2O3 balls. The friction c oefficient and Linear wear of the sliding pairs were substantially red uced and the transition from mild to severe wear shifted to higher app lied surface pressure for the microstructurally modified ceramic compa red with the monolithic alumina or the cutting ceramics, respectively.