M. Hadad et al. /Wear 260(2006)634-641 63 inate 20 三 三8 0.4 0134578911121415 0134578911121415 0134578911121415 Time [min] Time [min] HaLMMMWuhA+ 三985 884 2.a8 0.2 0134578911121415 0134578911121415 0134578911121415 Time [min] Time [min] 0.8 06 后06 e04 0134578911121415 0134578911121415 01345 911121415 Time [min Time [min Time [min] Fig. 6. Friction coefficients of laminates with different sliding orientations at the ambient temperature agreement with the literature [20, 23]. On the other hand, we at 300C. Contrary to the literature data [20], the friction can,however, not exclude that a simple oxidation process coefficient did not decrease compared to room tempera- within the contact area took place and that the increased ture experiments, see Fig. 7. However, the roughness of the due to a degradation of the mechanical material properties compare Figs. 3 and Compared to room temperature data, wear rate is related to increased thermomechanical wear worn surface increased Si3N4 under 300oC SiaNa-10%TiN composite under 2 memers~ww灬mNmy 八 0.8 0.2 345789 0134578911121415 Time [min] Time [min] Fig. 7. Friction coefficients Si3 N4 bulk and Si3 N4-30% TIN composite at 300C.M. Hadad et al. / Wear 260 (2006) 634–641 639 Fig. 6. Friction coefficients of laminates with different sliding orientations at the ambient temperature. agreement with the literature [20,23]. On the other hand, we can, however, not exclude that a simple oxidation process within the contact area took place and that the increased wear rate is related to increased thermomechanical wear due to a degradation of the mechanical material properties at 300 ◦C. Contrary to the literature data [20], the friction coefficient did not decrease compared to room tempera￾ture experiments, see Fig. 7. However, the roughness of the worn surface increased compared to room temperature data, compare Figs. 3 and 8. Fig. 7. Friction coefficients Si3N4 bulk and Si3N4–30% TiN composite at 300 ◦C