Al_2O_3/TiC, Al_2O_3/Ti(C,N), Al_2O_3/(W,Ti)C, and Al_2O_3/SiC_w alumina-based composites, which provided a reasonably wide range of mechanical properties and microstructure, were produced by hot pressing. The unlubricated friction and wear behaviors of these composites against cemented carbide were studied in air atmosphere using the ring-block method. The friction coefficient and wear rates were measured, and the wear mechanisms were discussed in relation to mechanical properties and microstructure. Results showed that additions of TiC, Ti(C,N), (W,Ti)C, or SiC_w to the Al_2O_3 matrix increased the flexural strength, fracture toughness, and hardness compared to the monolithic Al_2O_3 matrix. The friction coefficient showed a downward trend with the increasing of the sliding speed, and decreased dramatically with increasing applied load for all the alumina-based composites. The Al_2O_3/TiC composite showed the highest wear rate, and the Al_2O_3/SiC_w the lowest one under identical test conditions. The higher wear resistance of Al_2O_3/SiC_w composite corresponded to its higher fracture toughness and hardness.
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