This paper introduces a simplified method for low-temperature pressureless sintering of Al2O3-Ni-SiC nanocermets in air environment. In this method, a thin and continuous Ni shell was coated on the surface of Al2O3 particles using electroless deposition method. The composite powders were compressed to prepare bulk specimens. By preventing the ceramic particles from direct contact during the densification of green specimens, sintering temperature of cermet materials was reduced from that of Al2O3 (>1400 ºC) to the range of Ni solid-phase sintering temperature. Furthermore, dissolution of a low amount of phosphorus in the composition of Ni coatings led to the further decrease of the sintering temperature to 800 ºC. At such low temperature, pressureless sintering of the cermet in air environment was successfully performed instead of the common hot pressing process in a reducing atmosphere. Optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and X-ray diffraction (XRD) characterizations indicated that the microstructure of such sintered samples consists of a continuous Ni network surrounding Al2O3 grains, without any structural defects or Ni oxidation. Furthermore, the idea of reinforcement of the continuous Ni network by different amounts of SiC nanoparticles to enhance the mechanical properties of the cermet materials was investigated in this study. The results showed that Al2O3-Ni-5 wt.% SiC nanocermets sintered at 800 °C obtains the highest compressive strength of 242.5 MPa, hardness of 56.8 RA, and the lowest wear weight loss of 0.04 mg/m.

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