The present contribution reports some interesting and new results obtained while developing yttria‐stabilized tetragonal zirconia (Y‐TZP) using spark plasma sintering (SPS). The experimental results clearly showed that ZrO2‐nanoceramics with high hardness(∼14.5 GPa) can be processed at a lower sintering temperature of 1200°C in a short time (5 min). Another important result is that the newly developed Y‐TZP nanoceramics, compared with the conventional sintered TZP, exhibit better fretting wear resistance against bearing steel. The intergranular fracture and the grain pullout were observed as the major wear mechanisms of the zirconia nanoceramics.

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In the present work, we report the processing of ultrahard tungsten carbide (WC) nanocomposites with 6 wt% zirconia additions. The densification is conducted by the spark plasma sintering (SPS) technique in a vacuum. Fully dense materials are obtained after SPS at 1300°C for 5 min. The sinterability and mechanical properties of the WC-6 wt% ZrO 2 materials are compared with the conventional WC-6 wt% Co materials. Because of the high heating rate, lower sintering temperature, and short holding time involved in SPS, extremely fine zirconia particles (ϳ100 nm) and submicrometer WC grains are retained in the WC-ZrO 2 nanostructured composites. Independent of the processing route (SPS or pressureless sintering in a vacuum), superior hardness (21-24 GPa) is obtained with the newly developed WC-ZrO 2 materials compared with that of the WC-Co materials (15-17 GPa). This extremely high hardness of the novel WC-ZrO 2 composites is expected to lead to significantly higher abrasive-wear resistance.

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