Wear map of ceramics. (2nd Report, Construction of mild-severe wear mode map)

The overall objective of this study is to introduce a wear map of ceramics which shows the regions of dominant wear modes obtained in a wide range of materials and operating conditions. In the 1st report, it was clarified that the sliding wear mode of ceramics observed under various contact pressures, sliding velocities and temperatures can be classified into two types called `mild wear' and `severe wear' based on the ratio of worn surface roughness, R_y to mean grain size, D_g, and specific wear amount, w_s. In this paper, the critical condition of the mild and severe wear is analyzed using an intergranular fracture model from both the view points of mechanical and thermal aspects, and a wear map of ceramics, which can define the regimes of mild and severe wear, is introduced; it uses two dimensionless parameters named as the mechanical severity of contact S_c,m and the thermal severity of contact S_c,t, as the vertical and horizontal axes, respectively. The availability of the wear map constructed in this way can be proved by the experimental results observed over a wide range of materials and operating conditions.