Oxide-dispersion-strengthened Ni-NiO composites were prepared by the powder metallurgy technique. The nickel oxides were added at the 1~15 wt. level. Control materials were also prepared without NiO added. The distribution of the NiO phase andgrain size of nickel matrix were observed metallographically in materials sintered at 1 473~1 673 K for 10.8 ks. The Vickers micro hardness of as-sintered materials was measured in order to investigate the correlation between the microstructure and theroom-temperature mechanical properties. The Vickers micro hardness of the samples sintered over 1 573 K increased almost linearly with NiO content. That of samples sintered below 1 573 K was smaller than that of samples sintered over 1 573 K. From theviewpoint of hardness, it was desirable to sinter samples at a temperature over 1 573 K. NiO particle growth was found to be governed by the Ostwald ripening law. The Vickers micro hardness was proportional to the root of the reciprocal grain size.
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