| 摘要 |
PURPOSE: To provide a method for producing uniform agglomerate free submicron/nanosize ceramic powder by incorporating a precursor soln. of a metallic cation salt in a polymeric foam. CONSTITUTION: La(NO3 )3 .6H2 O, Sr(NO3 )2 and Cr(NO3 )3 .9H2 O are dissolved in distilled water and are blended with a mixture composed of a polyol, an organic surfactant and a catalyst. Then, an isocyanate is added and blended with the soln. and the obtained mixture is transferred into two porcelain dishes without delay to be foamed and cured. Cured foam is heated at heating ratio of 5 deg.C/minute and is calcined at 750 deg.C for 5 hours in air to obtain La0.78 Sr0.22 Cr3-γpowder consisting of single phase, substantially agglomerate free, having uniform size, typical grain size of about 20 nanometer and high dergree of sintering in air. When pellets formed from the powder by compression molding are sintered in air at 1400 deg.C for about 2 hours, sintered ceramic having 96% density to theoretical value can be obtained.
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