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Effect of ZrO, addition on mechanical and tribological properties of TiB,-Zr0,-composites TiB,-Zr0,-composites were produced by hot-pressing in argon. The mechanical and tribological properties of the composites were investigated in relation to the amount and the type of the ZrO, added. Addition of ZrO, reduced the sintering temperature of the TiB,-Zr0,-composites and led to growth inhibition of the TiB2 phase. ZrO, also increased the bending strength and fracture toughness of the composites. Tribological tests were carried out using laboratory tribometers under unlubricated oscillating sliding contact against A$O,-, Si,N,-and Sic-counterbodies. Abrasive wear of the ceramics against 80 mesh S i c grits was studied by using an abrasive wheel test. During sliding contact the composites showed high wear resistance but caused extensive wear of the counterbodies and high friction coefficients compaired to self-mated monolithic A1,0,-and Zr0,-ceramics. Volumetric wear loss of the TiB,-Zr0,-composites due to abrasive S i c grits was by a factor up to 30 lower than that of a commercial monolithic A1,0,. Wear resistance of the composites increased with decreasing amount of ZrO, and was higher for the composites with addition of partially stabilized tetragonal ZrO, than for those with addition of monoclinic ZrO,.

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