| Summary: | The paper describes an investigation of Al<sub>2</sub>O<sub>3</sub> samples and NiAl–Al<sub>2</sub>O<sub>3</sub> composites consolidated by pulse plasma sintering (PPS). In the experiment, several methods were used to determine the properties and microstructure of the raw Al<sub>2</sub>O<sub>3</sub> powder, NiAl–Al<sub>2</sub>O<sub>3</sub> powder after mechanical alloying, and samples obtained via the PPS. The microstructural investigation of the alumina and composite properties involves scanning electron microscopy (SEM) analysis and X-ray diffraction (XRD). The relative densities were investigated with helium pycnometer and Archimedes method measurements. Microhardness analysis with fracture toughness (K<sub>IC</sub>) measures was applied to estimate the mechanical properties of the investigated materials. Using the PPS technique allows the production of bulk Al<sub>2</sub>O<sub>3</sub> samples and intermetallic ceramic composites from the NiAl–Al<sub>2</sub>O<sub>3</sub> system. To produce by PPS method the NiAl–Al<sub>2</sub>O<sub>3</sub> bulk materials initially, the composite powder NiAl–Al<sub>2</sub>O<sub>3</sub> was obtained by mechanical alloying. As initial powders, Ni, Al, and Al<sub>2</sub>O<sub>3</sub> were used. After the PPS process, the final composite materials consist of two phases: Al<sub>2</sub>O<sub>3</sub> located within the NiAl matrix. The intermetallic ceramic composites have relative densities: for composites with 10 wt.% Al<sub>2</sub>O<sub>3</sub> 97.9% and samples containing 20 wt.% Al<sub>2</sub>O<sub>3</sub> close to 100%. The hardness of both composites is equal to 5.8 GPa. Moreover, after PPS consolidation, NiAl–Al<sub>2</sub>O<sub>3</sub> composites were characterized by high plasticity. The presented results are promising for the subsequent study of consolidation composite NiAl–Al<sub>2</sub>O<sub>3</sub> powder with various initial contributions of ceramics (Al<sub>2</sub>O<sub>3</sub>) and a mixture of intermetallic–ceramic composite powders with the addition of ceramics to fabricate composites with complex microstructures and properties. In composites with complex microstructures that belong to the new class of composites, in particular, the synergistic effect of various mechanisms of improving the fracture toughness will be operated.
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