| 摘要 |
PURPOSE:To easily obtain an extremely slender acicular Al particle by thermally decomposing a needle crystal of ammonium aluminium carbonate hydroxide generated by applying an aluminium hydroxide or its hydrate with the ripening treatment. CONSTITUTION:The needle crystal of ammonium aluminium carbonate hydroxide expressed with the formula of Al(NH4)CO3(OH)2 is allowed to generate by the above-mentioned process and furthermore with the ripening treatment at >=60 deg.C. And the concentration of the aq. soln. of NH4HCO3 used for the ageing treatment is usually in the range of 0.1-1.5mol NH4HCO3/l. Further, the aq. soln. added with the varieties of the water-soluble acid or base is usable as the above-mentioned aq. soln., at request. Then, the aimed extremely slender alumina particle, for example, the particle having more or less 0.01mum width and a few mum length, is easily obtained by calcining the above-mentioned AAC crystal usually in the temp. range of 400-1,100 deg.C.
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