Abstract
There are many compounds for pigments. in which blue pigment known as Cobalt-Blue is mainly cobalt aluminate produced by the reaction between alumina and cobalt onide at high temperature. We considered this reaction and the resnits obtained as follows.
(I) The compound production at about 1000° is indigo-blue cobalt aluminate (CoO.Al2O3), the reaction proceeded by the diffusion. It is clear that this reaction. Janders diffusion formula can be applied.
(2) The elistence of this compound is ascertained through the X-ray analysis, the lattice constant of the spinell type cubic lattice is 8.03A.
(3) In this reaction activation energy of diffusion is 30000 col.
