The influence of grain boundary impurities on mechanical and tribological properties of zirconia
Two commercial zirconium oxides, one of high purity and one containing grain boundary impurities were compared in Vicker's indentation, scratch and wear tests. Impurities were found to cause a weakening of the grain boundaries with the following consequences on behavior: They decrease hardness and increase macroscopic toughness by intergranular microfissuration; scratches occur by plastic deformation in the pure (harder) sample and by intergranular fracture in the (tougher) sample with impurities. The effect of impurities on wear is complex. Little difference at low load in air is observed in sliding wear because the latter occurs by microfracture at very fine scale, much smaller than the grain size; sliding in water increases wear by intergranular fracture due to adsorption embrittlement, and this increase is larger in the impure samples. At high loads, subsurface fracture occurs by large cracks in the pure sample and by grain boundary fissuration in the other one.
- Research Organization:
- Stevens Inst. of Tech., Hoboken, NJ (United States)
- OSTI ID:
- 5120560
- Country of Publication:
- United States
- Language:
- English
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