Substrate gels for preparing synthetic food dye aluminum lakes were precipitated from 1 M-solution of aluminum chloride at 25°C by dropping therein 4. 5 M-solution of sodium hydroxide at a constant adding rate until the pH of the suspending solution attained at 5 to 7, in around 5. 5 hrs. The result-ing gels had the composition of aluminum chloride hydroxide Al(OH)_3-xCl_x, where the value of x was 0. 34, 0.30 and 0.24 for the pH value of 5. 0, 6. 0 and 7. 0, respectively.
Aluminum lakes prepared by dyeing the substrate gels by Tartrazine or Sunset Yellow FCF, had the composition Al(OH)_3-xCl_x-yD'′ Where D′ is the dye anion expressed as univalent ion. The value of x was estimated as the same or close to that for the substrate gels, which put forward the lake formation mechanism that the Cl ion in the substrate is substituted with the dye anion.
The dye-combining capacity was the largest and the dye elution the smallest for the lake from the substrate gel prepared at the pH of 5.0. The addition of aluminum chloride or hydrogen chloride solution into the slurry of the substrate gels that were prepared at the higher pH values, 6. 0 and 7. 0, improved largely the dye-eluting strength of the resulting lakes.
Lake specimens obtained in this experiment had the anti-eluting strength 3 to 5 times as high as commercial lakes, compared by the distribution coefficient of dye anions, K, determined by the method previously proposed by the authors.

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Zinc phosphatability was investigated about the metal added and their chemical compositions for the continuous annealing steel sheets. As the evaluation of zinc phosphatability, the methods by SEM, optical microscope and EPMA analysis were applied mainly.
So that, in case of the super ultra low carbon steel sheet using the metal added, if the Ti/C atom ratio for the Ti added steel sheet is about 4, that is fairly large, the area where is not covered by the zinc phosphate crystal was appeared. Further, in case of (Nb+Ti) /C atom ratio for the Nb-Ti added steel sheet is about 2, good zinc phosphatability was confirmed.
Besides, the influence of Cementite Fe₃C which is formed at the stage of Box Annealing Process was studied. The steel sheet in which the fine grain Fe₃C is dispersed uniformly, showed good zinc phosphatability. On the contrary, the steel sheet in which Fe₃C grew largely, showed poor zinc phosphatability.
The reason is considered that the fine grain Fe₃C becomes the nuclei of zinc phosphate crystal, so that it stimulates the zinc phosphating reaction. But, the largely grown Fe₃C will inhibit the reaction on that area because Fe₃C itself is inactive component. And also, it is considered that this phenomenon forming the large Fe₃C crystal is caused by the high temperature annealing condition over the A₁ transformation point and the high diffusion speed of carbon atom metallurgically.

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